40-GHz photonic waveform generator by linear shaping of four spectral sidebands

International audience; We show that the amplitude and phase shaping of only four sidebands of the optical spectrum is sufficient to synthesize parabolic, triangular, or flat-top pulse trains at high repetition rates. Selection of the symmetric carrier-suppressed waveform is easily achieved by changing the phase difference between the inner and outer spectral lines. Experiments carried out at a repetition rate of 40 GHz confirm the high quality of the intensity profiles that are obtained.

Emergence of extreme events in fiber-based parametric processes driven by a partially incoherent pump wave

Modulation instability (MI) generated by a picosecond coherent pulse has been recently identified as the key element of the generation of optical rogue-waves in supercontinuum-based systems [1]. Similar rare but highly energetic pulse structures can also appear in non-solitonic configurations such as Raman amplifiers driven by a partially incoherent pump wave propagating in fibres with low group velocity dispersion [2]. Therefore, one may wonder whether optical rogue-like event can also occur in MI-based amplifier because both Raman and parametric amplifiers benefit from a quasi-instantaneous gain. We provide here experimental evidence of rare optical events in a parametric amplifier in pre…

Simple guidelines to predict self-phase modulation patterns

International audience; We present a simple approach to predict the main features of optical spectra affected by self-phase modulation (SPM), which is based on regarding the spectrum modification as an interference effect. A two-wave interference model is found sufficient to describe the SPM-broadened spectra of initially transform-limited or up-chirped pulses, whereas a third wave should be included in the model for initially down-chirped pulses. Simple analytical formulae are derived, which accurately predict the positions of the outermost peaks of the spectra.

Numerical study of an optical regenerator exploiting self-phase modulation and spectral offset filtering at 40 Gbit/s

Topic: Nonlinear optics; International audience; In this work, we numerically investigate the performances of optical regenerators based on self-phase modulation and spectral offset filtering at 40 Gbit/s. We outline the different effects affecting the device performances and explain the choice of the optimal working power. The impact of the regenerator on the output signal is also analysed through a statistical approach. Both single- and double-stage configurations are investigated.

Characterisation and Mitigation of Self-Phase Modulation in Optical Fibres

International audience

Real Time Measurements of Spectral Instabilities in Ultrafast Fibre Laser Systems

International audience;

Higher-order modulation instability in fiber optics

We report on analytical, numerical and experimental studies of higher-order modulation instability in fiber optics. This new form of instability arises from the nonlinear superposition of elementary instabilities and manifests as complex, yet deterministic temporal pulse break-up dynamics. We use the Darboux transformation to analytically describe the process and compare with experiments. In particular, we show how suitably low frequency modulation on a continuous wave field allows for the excitation of higher-order modulation instability through cascaded four-wave mixing.

Parabolic pulse generation and applications

Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such pulses as well as the results obtained in a wide-range of experimental configurations.

A fiber based limiter at 170 Gbit/s for all-optical regeneration

International audience

Spectral compression of optical parabolic similariton

International audience

Spectral compression of optical parabolic similaritons

We numerically investigate the spectral recompression experienced by a self-similar parabolic pulse with an anormal initial chirp. Spectral compression factors above 10 and high-quality output pulses can be predicted.

Observation of Kuznetsov-Ma soliton dynamics in optical fibre

International audience; The nonlinear Schro¨dinger equation (NLSE) is a central model of nonlinear science, applying to hydrodynamics, plasma physics, molecular biology and optics. The NLSE admits only few elementary analytic solutions, but one in particular describing a localized soliton on a finite background is of intense current interest in the context of understanding the physics of extreme waves. However, although the first solution of this type was the Kuznetzov-Ma (KM) soliton derived in 1977, there have in fact been no quantitative experiments confirming its validity. We report here novel experiments in optical fibre that confirm the KM soliton theory, completing an important serie…

Experimental generation of optical flaticon pulses

International audience; We experimentally investigate the nonlinear reshaping of a continuous wave which leads to chirp-free and flat-top intense pulses or flaticons exhibiting strong temporal oscillations at their edges and a stable self-similar expansion upon propagation of their central region. This study was performed in the normal dispersion regime of a non-zero dispersion-shifted fiber and involved a sinusoidal phase modulation of the continuous wave. Our fiber optics experiment is analogous to considering the collision between oppositely directed currents near the beach, and it may open the way to new investigations in the field of hydrodynamics.

Monstruosité des vagues maritimes et leur explication par la lumière

Akhmediev breathers as ultra-wideband pulses

We analytically calculate and discuss the radio-frequency spectrum of the so called Akhmediev breathers (ABs), a class of nonlinear solutions of the nonlinear Schrodinger equation that governs the propagation in a single mode optical fiber. We propose a practical application of ABs to the field of ultra-wideband pulse generation. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:664–667, 2014

Experimental observation of dispersive photon focusing dam break flows

International audience

Tailored waveform generation in mode-locked fiber lasers by in-cavity pulse shaper

International audience; We numerically show the possibility of pulse shaping in a mode-locked fiber laser by inclusion of an amplitude-phase spectral filter into the laser cavity. Various advanced temporal waveforms are generated, including parabolic, flat-top and triangular pulses.

Supercontinuum generation in titanium dioxide waveguides

International audience; Optical supercontinua are a fundamental topic that has stimulated a tremendous practical interest since the early works of Alfano et al. in the 70’s in bulk components. Photonic crystal fibers have then brought some remarkable potentialities in tailoring the dispersive properties of a waveguide while maintaining a high level of confinement over significant propagation distances. The next breakthrough is to further reduce the footprint of the nonlinear component and to achieve the generation of optical supercontinuum on a photonic chip. To reach this aim, several platforms have been successfully investigated such as silicon, silicon germanium, silicon nitride, chalcog…

Génération photonique de trains paraboliques, triangulaires, rectangulaires à 40 GHz et 80 GHz

National audience

Generation of localized pulses from incoherent wave in optical fiber lines made of concatenated Mamyshev regenerators

International audience; We investigate the novel properties of optical fiber lines made of Mamyshev regenerators (MRs) based on self-phase modulation and subsequent spectral filtering. In particular, we show that such a regenerator line can be used to generate random sequences of optical pulses from an incoherent wave. This behavior is related to the existence of stable eigenpulses that can propagate unchanged through the regenerator line and act as attractors for incoming pulses. By changing the regenerator parameters, we also report the existence of multiple eigenpulses and limit cycles. Finally, we demonstrate that MRs could be used as efficient nonlinear gates in fiber laser cavities.

Various materials for 2-µm telecom applications

National audience

Manipulation expérimentale de la cohérence temporelle d'ondes partiellement cohérentes

National audience; Nous décrivons deux expériences nous permettant de manipuler les propriétés de cohérence d'ondes partiellement cohérentes. Les montages expérimentaux développés reposent sur la manipulation de la phase spectrale du champ initial, assistée éventuellement d'une modulation sinusoïdale préalable de sa phase temporelle. Les signaux d'autocorrélation en intensité mesurés soulignent le changement significatif des caractéristiques temporelles des signaux incohérents obtenus.

Flaticon pulses in optical fibers

International audience; We experimentally investigate the nonlinear reshaping of a continuous wave which leads to chirp-free and flat-top intense pulses or flaticons exhibiting strong temporal oscillations at their edges and a stable self-similar expansion upon propagation of their central region.

Kuznetsov-Ma Soliton Dynamics in Nonlinear Fiber Optics

The Kuznetzov-Ma (KM) soliton is a solution of the nonlinear Schrodinger equation derived in 1977 but never observed experimentally. Here we report experiments showing KM soliton dynamics in nonlinear breather evolution in optical fiber.

Kerr frequency comb generation in the normal dispersion regime of dispersion oscillating telecom fiber

The generation of optical frequency combs has a variety of applications from optical metrology to spectroscopy and wavelength division multiplexing. Nonlinear methods to generate frequency combs are based on multiple four-wave mixing (FWM) in highly nonlinear waveguides [1]. The mechanism for the generation of a wideband comb from a CW pump is Kerr-induced phase-matching of the FWM interaction or modulation instability (MI), which requires operating in the anomalous dispersion regime. Such restriction can be circumvented with a cavity geometry, where MI [2] and comb generation [3] may also be observed in the normal dispersion region. Alternatively, one may obtain MI and unequally spaced Ker…

Two-wave interferences space-time duality: Young slits, Fresnel biprism and Billet bilens

International audience; Taking advantage of the analogy that can be drawn between the spatial and temporal propagations, we explore two-wave temporal interference in textbook cases such as Young's double slits, Fresnel's biprism and Billet's bilens. We illustrate our approach by numerical simulations for short pulses propagating in dispersive optical fibers with parameters typical of those found in modern optical telecommunications.

High repetition rates and high quality optical pulse train generator based on solitons over finite background

This work proposes to fully exploit the nonlinear evolution undergone by a sinusoidal modulation with a finite background propagating along an optical fiber. For the original method to overcome this major drawback is to exploit the π phase shift that exists between the pulsed part and the background. By using a simple delay-line interferometer, it is possible to simultaneously double the repetition rate of the pulse train and to annihilate the deleterious background by imprinting a controlled π phase shift.

Generation of parabolic pulses and applications for optical telecommunications

International audience; Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such self-similar pulses as well as the results obtained in a wide-range of passive or active experimental configurations.

La photonique, une discipline pleine de promesses, l'exemple des télécommunications optiques

Fiber-based measurement of temporal intensity and phase profiles of an optical telecommunication pulse through self-phase modulation

International audience; We propose and experimentally validate an all-fiber based approach to characterize the phase and intensity profiles of optical pulses. Based on three optical spectra affected by different levels of self-phase modulation, we were able to reconstruct the temporal details of pulses typical of optical telecommunications.

Optical Nyquist pulse generation in mode-locked fibre laser

International audience

Des photons pour capturer la lumière, les couleurs et le mouvement

National audience

Demonstration of high speed optical transmission at 2 µm in various material based waveguides

International audience

Offsetting Self-Phase Modulation in Optical Fibre by Sinusoidally Time-Varying Phase

We report on our recent experimental and theoretical results on the use of a sinusoidally time-varying phase to suppress undesirable self-phase modulation of optical pulses propagating in fibre-optic systems.

Les bandes de gain paramétrique dans la fibre à dispersion oscillante

International audience

Generation of localized pulses from incoherent wave in optical fiber lines made of concatened Mamyshev regenerators

International audience

Data-driven Discovery of the Ideal Four Wave Mixing Modelin Nonlinear Fiber Optics

We use the machine learning technique of spars eregression to “reverseengineer” dynamical data to discover the underlying physical model of four wave mixing in nonlinear fibre optics.

Recent machine-learning applications in ultrafast nonlinear fibre photonics

Compression spectrale dans les fibres optiques en présence de dispersion normale

National audience; Nous étudions numériquement le phénomène de compression spectrale se déroulant dans une fibre optique à dispersion normale. Les conditions conduisant à une impulsion en quasi-limite de Fourier sont déterminées et nous montrons que loin de dégrader les performances, la présence de dispersion normale permet une amélioration significative des résultats.

The nonlinear Schrodinger equation and the propagation of weakly nonlinear waves in optical fibres and on the water surface

International audience; The dynamics of waves in weakly nonlinear dispersive media can be described by the nonlinear Schrödinger equation (NLSE). An important feature of the equation is that it can be derived in a number of different physical contexts; therefore, analogies between different fields, such as for example fiber optics, water waves, plasma waves and Bose–Einstein condensates, can be established. Here, we investigate the similarities between wave propagation in optical Kerr media and water waves. In particular, we discuss the modulation instability (MI) in both media. In analogy to the water wave problem, we derive for Kerr-media the Benjamin–Feir index, i.e. a nondimensional par…

Reconstruction of idealized phase-space topology of four-wave mixing observed in nonlinear fiber

We validate a new testbed revealing the phase-space topology of ideal four-wave mixing processes. An approach based on iterated initial conditions in a short fiber is compared with experimental datasets processed by a neural network.

Higher-order modulation instability in optical fibers

International audience; We report on theoretical, numerical and experimental study of a new form of instability in a nonlinear fiber. This process of higher-order modulation instability arises from the nonlinear superposition of elementary instability dynamics.

Linear and nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations

International audience; Using ultrafast photonic first-order differentiator applied on a partially coherent field, we report the generation of two correlated temporal waveforms and study their correlation properties upon linear and nonlinear propagation along the two orthogonal polarization axis of a dispersive optical fiber. Temporal correlations are maintained in linear propagation whereas Kerr nonlinearity generates anti-correlated temporal intensity patterns for both partially and uncorrelated fields. Experiments are in close agreement with the theoretical analysis.

Dissipative Optical Breather Molecular Complexes

We demonstrate different types of breathing soliton complexes in a mode-locked fibre laser: multi-breather molecules, and molecular complexes arising from the binding of two breather-pair molecules or a breather-pair molecule and a single breather.

Sampling and amplification technique based on XPM-induced focusing in normally dispersive optical fibers

International audience; We theoretically and experimentally investigate an all-optical amplification and sampling technique based on a XPM process between an arbitrary signal and an intense orthogonally polarized high repetition rate sinusoidal pump wave within a normally dispersive optical fiber.

Extreme statistics in Raman fiber amplifiers : from experiments to analytical description

International audience; We describe the concept of an all-fibered device that enables the optical magnification of the amplitude jitter of low-fluctuation pulse trains, facilitating the measurement of the statistical properties by usual photodiodes and electronic equipments. Taking advantage of a highly nonlinear fiber with anomalous dispersion followed by central optical bandpass filtering, we experimentally demonstrate an amplification of small-scale fluctuations by a factor 10.

Frequency locking of a breather fibre laser, fairy tree and devil's staircase

Breathing solitons exhibiting periodic oscillatory behaviour form an important part of many different classes of nonlinear wave systems. Recently, thanks to the development of real-time detection techniques, they have also emerged as a ubiquitous mode-locked regime of ultrafast fibre lasers [1,2]. The excitation of breather oscillations in a laser naturally triggers a second characteristic frequency in the system, which therefore shows competition between the cavity repetition frequency and the breathing frequency. The theoretical model describing nonlinear systems with two competing frequencies predicts frequency locking, in which the system locks into a resonant periodic response featurin…

All-fiber transform-limited spectral compression by self-phase modulation of amplitude shaped pulses

International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. Thanks to parabolic pulse shaping, a spectral compression by a factor 12 is achieved with an enhanced Strehl ratio.

Emergence of extreme events in fiber based nonlinear devices

International audience

Second zero dispersion wavelength measurement through soliton self-frequency shift compensation in suspended core fibre

International audience; A simple experimental technique to evaluate the second zero dispersion wavelength of very small core microstrutured fibres is described. Based on the effect of soliton self-frequency shift and its subsequent compensation in the vicinity of the second zero dispersion. the proposed method is applied to both standard and suspended core microstructured fibres by simply measuring the frequency stabilised soliton spectrum, avoiding any calculation and knowledge of any experimental parameters.

Real-time measurement of soliton-similariton explosions and intermittence instabilities in a mode-locked fibre laser

International audience; Ultrafast mode-locked lasers are well-known to display a rich variety of unstable dissipative soliton dynamics resulting from the interplay of nonlinearity, dispersion and dissipation. Although laser instabilities have been known and studied in depth for many years, their properties have recently received greatly renewed attention because of the development of time and frequency domain techniques that allow laser dynamics and instabilities to be measured in real-time. This has allowed the variations in circulating pulse characteristics to be examined on a roundtrip to roundtrip basis, providing a new window into understanding these instabilities and how they develop …

Extreme Statistics in Raman Fiber Amplifiers: From Analytical Description to Experiments

International audience; In this work, we investigate the emergence of rare and intense events during the Raman fiber amplification of a continuous wave. We highlight how dispersive properties and pump depletion can strongly influence the statistical properties of the amplified signal and its optical spectrum. Under certain conditions, the probability density functions of the amplified signal are calculated analytically and compared with the results of the numerical simulations. The conclusions are qualitatively validated by experiments carried out at telecommunication wavelengths.

All-optical nonlinear simultaneous polarization and intensity regeneration of a 40-Gb/s telecommunication signal

We experimentally report the simultaneous all-optical regeneration of the polarization state and the intensity profile of a 40 Gb/s Return-to-Zero telecommunication signal by means of Kerr effect occurring in a single segment of fiber.

Nonlinear spectral compression in optical fiber: A new tool for processing degraded signals

International audience; We propose two new applications of the spectral focusing by self-phase modulation that occurs in a nonlinear optical fiber. We numerically show the possibility of using nonlinear spectral compression to improve the optical signal to noise ratio and mitigate the amplitude jitter of the signal pulses. We also demonstrate experimentally that use of spectral focusing in a combination with an external sinusoidal phase modulation achieves efficient suppression of coherent spectral background.

Longitudinal phase evolution of Peregrine-like breathers

International audience; We report the first experimental study of the longitudinal evolution of breather pulses during nonlinear fiber propagation. Gerchberg-Saxton phase retrieval reveals a large phase shift across the point of maximum compression.

Temporal and Spectral Nonlinear Pulse Shaping Methods in Optical Fibers

The combination of the third-order optical nonlinearity with chromatic dispersion in optical fibers offers an extremely rich variety of possibilities for tailoring the temporal and spectral content of a light signal, depending on the regime of dispersion that is used. Here, we review recent progress on the use of third-order nonlinear processes in optical fibers for pulse shaping in the temporal and spectral domains. Various examples of practical significance will be discussed, spanning fields from the generation of specialized temporal waveforms to the generation of ultrashort pulses, and to stable continuum generation.

Dispositif fibré pour la détection de faibles fluctuations d'intensité d'impulsions ultracourtes

National audience; Nous présentons ici un dispositif fibré permettant d'exacerber les fluctuations d'intensité d'un train d'impulsions ultracourtes afin de faciliter leur détection. En exploitant l'effet Raman qui induit le décalage fréquentiel de ces impulsions suivi d'un filtrage passe-haut, nous montrons ainsi qu'il est possible de multiplier d'un facteur 13 les fluctuations du train initial.

Nonlinear sculpturing of optical pulses with normally dispersive fiber-based devices

International audience; We present a general method to determine the parameters of nonlinear pulse shaping systems based on pulse propagation in a normally dispersive fiber that are required to achieve the generation of pulses with various specified temporal properties. The nonlinear shaping process is reduced to a numerical optimization problem over a three-dimensional space, where the intersections of different surfaces provide the means to quickly identify the sets of parameters of interest. We also show that the implementation of a machine-learning strategy can efficiently address the multi-parameter optimization problem being studied.

Shallow water rogue wavetrains in nonlinear optical fibers

International audience; In addition to deep-water rogue waves which develop from the modulation instability of an optical CW, wave propagation in optical fibers may also produce shallow water rogue waves. These extreme wave events are generated in the modulationally stable normal dispersion regime. A suitable phase or frequency modulation of a CW laser leads to chirp-free and flat-top pulses or flaticons which exhibit a stable self-similar evolution. Upon collision, flaticons at different carrier frequencies, which may also occur in wavelength division multiplexed transmission systems, merge into a single, high-intensity, temporally and spatially localized rogue pulse.

Shallow water rogue waves in nonlinear optical fibers

The dynamics of extreme waves, often known as freak or rogue waves (RW), is presently a subject of intensive research. In oceanography, RW are mostly known as a sudden deep-water event which is responsible for ship wreakages and can be modeled by the 1D Nonlinear Schrodinger Equation (NLSE). In this framework, an ideal testbed is provided by optical pulse propagation in nonlinear optical fibers: extreme solitary wave emissions during supercontinuum generation or the first experimental observation of the Peregrine solitons have indeed been carried out exploiting the modulation instability occuring in fibers with anomalous dispersion.

Parabolic pulse generation through passive reshaping of gaussian pulses in a normally dispersive fiber

We numerically and experimentally demonstrate that a Gaussian pulse can be reshaped into a pulse with a stable parabolic intensity profile during propagation in normally dispersive nonlinear fibers.

Une application de la photonique : les télécommunications à très haut débit

The Gouy Phase Shift

L'optique une discipline pleine de promesses : l'exemple des télécommunications optiques

INFLUENCE OF THE INITIAL PHASE PROFILE ON THE ASYMPTOTIC SELF-SIMILAR PARABOLIC DYNAMICS

International audience; We describe the influence of the initial phase profile on the convergence towards asymptotic self-similar parabolic shape. More precisely, based on numerical simulations, we discuss the impact of an initial linear chirp and a p phase shift. If the parabolic shape has been found to describe accurately the pulse envelope, dark structures can appear and evolve also self-similarly on the parabolic background.

Parabolic Pulse Amplifiers

International audience; Recent studies in nonlinear optics have led to the discovery of a new class of ultrashort pulse generated in fiber amplifiers by the self-similar propagation of an arbitrary input pulse. These pulses with a parabolic shape and linear chirp, called `optical similaritons,' represent asymptotic solutions of the nonlinear Schrödinger equation with gain, towards which any initial pulse of given energy converges, independently of its intensity profile. Parabolic pulse amplifiers can be easily developed with standard optical fibers and commercial devices. Our goal here is to emphasize the main properties of similaritons and to discuss a few of their numerous new application…

Nonlinear spectrum broadening cancellation by sinusoidal phase modulation

International audience; We propose and experimentally demonstrate a new approach to dramatically reduce the spectral broadening induced by self-phase modulation occurring in a Kerr medium. By using a temporal sinusoidal phase modulation, we efficiently cancel to a large extend the chirp induced by the nonlinear effect. Experimental validation carried out in a passive or amplifying fiber confirm the interest of the technic for the mitigation of spectral expansion of long pulses.

Langevin’s model for soliton molecules in ultrafast fi ber ring laser cavity: investigating the interplay between noise and inertia

We describe the vibration pattern of a soliton-molecule using the Langevin’s model, i.e. noise source combined with a deterministic model. This simpler model allows investigating the interplay between fl uctuation and dissipation mechanisms at play.

Turbulent Dynamics of an Incoherently Pumped Passive Optical Fibre Cavity: quasi-solitons and dispersive waves

International audience; We study numerically and experimentally the dynamics of an incoherently pumped passive optical fibre ring cavity. We show that the cavity exhibits a quasi-soliton turbulence dynamics, whose properties are controlled by the degree of coherence of the injected pump wave: as the coherence of the pump is degraded, the cavity exhibits a transition from the quasi-soliton turbulent regime toward the weakly nonlinear turbulent regime characterized by short-lived rogue wave events. This behavior is reminiscent of the corresponding dynamics obtained in the purely conservative (Hamiltonian) problem. Experimental results are reported by using a standard telecommunication optical…

Asymptotic characteristics of parabolic similariton pulses in optical fiber amplifiers

The fundamental asymptotic nature of parabolic similariton pulses in normal-dispersion fiber amplifiers is experimentally demonstrated. With frequency-resolved optical gating characterization measurements with a fixed input pulse energy, the output parabolic pulse characteristics are shown to be invariant with the input pulse profile and duration and to be completely determined only by the amplifier parameters.

Accurate fiber-optic emulator of fundamental four-wave mixing theory

Experimental signatures of extreme optical fluctuations in lumped Raman fiber amplifiers

International audience; In this work, we experimentally investigate several temporal and spectral methods to highlight extreme fluctuations which can develop during the Raman amplification of an ultrashort pulse train. Forward and backward pumping schemes are compared to dual pass configurations.

La recherche en Physique : 2015, un concentré de lumière

National audience

Generation and detection of optical rogue-wave-like fluctuations in fiber Raman amplifiers

Rogue wave-like statistics is reported in a fiber Raman amplifier. The pump-signal noise transfer leads to the development of large peak-power fluctuations following a powerlaw probability distribution. Discrimination of the rarest events is demonstrated.

Self-phase modulation-based 2R regenerator including pulse compression and offset filtering for 42.6 Gbit/s RZ-33% transmission systems

International audience; We report on the experimental and theoretical study of a self-phase-modulation-based regenerator at 42.6 Gbit/s with a return-to-zero 33% format. We point out some detrimental effects such as intrachannel interactions and Brillouin scattering. An efficient solution, relying on a self-phase-modulation-based pulse compressor in combination with the regenerator, is proposed to overcome these detrimental phenomena. The experimental demonstration shows the effectiveness of a wavelength-transparent regenerator at 42.6 Gbit/s with a sensitivity-improvement of more than 5 dB and an eye-opening improvement of 2.3 dB in a back-to-back configuration, as well as a 10 times maxim…

Universal spectral dynamics of modulation instability : theory, simulation, experiment

A central process of nonlinear fibre optics is modulation instability (MI), where weak perturbations on a continuous wave are amplified to generate a parametric cascade of spectral sidebands. Although studied for many years, it has only been recently appreciated that MI dynamics can be described analytically by Akhmediev breather (AB) solutions to the nonlinear Schrodinger equation (NLSE) [1]. This has led to important results, including the first observation of the Peregrine Soliton [2]. AB theory has also shown that the spectral amplitudes at the peak of the MI gain curve yield a characteristic log-triangular spectrum, providing new insight into the initial phase of supercontinuum generat…

A fiber-based limiter at 170 Gbit/s for all-optical regeneration

We report the numerical and experimental studies of a spectrally filtered fiber-based optical limiter at 170 Gbit/s. The device, including less than 1 km-long of highly nonlinear optical fiber and a 3 nm-width filter, exhibits good performance at an average input power of 14.5 dBm. No power penalty has been observed and a strong robustness against optical noise has been demonstrated.

Supercontinuum to solitons: New nonlinear structures in fiber propagation

We review our recent work in the field of optical rogue wave physics and applications. Beginning from a brief survey of the well-known noise and incoherence processes in optical fiber supercontinuum generation, we trace the links to recent developments in studying the emergence of high contrast localised breather structures in both spontaneous and induced nonlinear instabilities. In the latter case, we discuss our recent measurements that have reported the experimental observation of the Peregrine soliton, a unique class of rational soliton predicted to exist over 25 years ago and never previously observed.

Réseau temporel dispersif dans une fibre optique

National audience; Nous exploitons l’analogie entre les domaines temporels et spectraux pour démontrer la génération de l’équivalent temporel d’un réseau de diffraction. En combinant une modulation de phase périodique et une propagation dispersive, nous observons en effet l’émergence de répliques temporelles de l’impulsion initiale correspondant aux ordres +1 et -1 d’un réseau de diffraction traditionnel.

Nonlinear pulse shaping : a versatile tool for ultrafast photonics and a building block of nonlinear fiber dynamics

International audience

Parabolic similaritons in optical fibers

International audience

Laser impulsionnel Raman à verrouillage de modes passif fonctionnant à 1 GHz

National audience

projet FOURIER - Fibre et optique ultra rapide pour l’investigation d’événements rares

Fiber-based optical functions for high-bit-rate transmissions

oral

Pulse doubling and wavelength conversion through triangular nonlinear pulse reshaping

International audience; We present a proof of principle experiment demonstrating the benefits of using a triangular temporal profile in the context of copying and wavelength conversion of telecommunication signals. Generated by passive nonlinear reshaping in a set of two carefully chosen fibres, the triangular shape enables efficient temporal and spectral doubling of the signals through self-phase modulation.

Parabolic pulse generation with dispersion decreasing optical fiber

We experimentally demonstrate the possibility to generate parabolic pulses via a single dispersion decreasing optical fiber with normal dispersion. We numerically and experimentally outline the influence of the dispersion profile.

Light-by-light polarization control and stabilization in optical fibers for telecommunication applications

With the advent of future transparent ultra high-bit rate capacity transmission networks, encoding the data would necessary involve all the physical parameters of a light beam, including multi-level in intensity, phase, polarization and even propagation modes. These complex optical fields will then naturally suffer from strong impairments imposed by linear and nonlinear propagation effects. Hence, developing new all-optical tools able to control or regenerate any properties of light has become of a crucial interest. In this work, we experimentally report that it is possible, using a unique segment of optical fiber, to all-optically manipulate and regenerate both the state of polarization (S…

Obtention d'impulsions en limite de Fourier par compression spectrale réalisée dans une fibre optique

National audience; Nous démontrons la compression spectrale d'impulsions picosecondes dans un montage totalement fibré aux longueurs d'onde des télécommunications optiques. Grâce à un façonnage préalable du profil d'intensité en une parabole, un facteur de compression dépassant 10 est démontré avec un facteur de Strehl significativement augmenté par rapport à une impulsion de forme sécante hyperbolique.

A neural network to explore the Fresnel diffraction of a sharp opaque semi-infinite screen

We describe the use of a neural network to investigate a very well-known problem of wave optics, i.e. the diffraction of an opaque semi-infinite screen. The inverse problem is also discussed.

New fiber laser architecture with transform-limited nonlinear spectral compression

International audience; We numerically demonstrate a new fiber laser architecture supporting spectral compression of negatively chirped pulses in passive normally dispersive fiber. Such a process is beneficial for improving the energy efficiency of the cavity as it prevents narrow spectral filtering from being highly dissipative. The proposed laser design provides an elegant way of generating transform-limited picosecond pulses.

Parabolic pulse generation in dispersion decreasing fiber amplifier

We obtain an exact dispersion profile that permits for the analytical description of self-similar pulse amplification and supercontinuum generation in tapered nonlinear fiber amplifiers.

Sources d'impulsions paraboliques pico- et femto- secondes à fibres optiques

National audience

Multiple four-wave mixing in optical fibers: 1.5–3.4-THz femtosecond pulse sources and real-time monitoring of a 20-GHz picosecond source

International audience; In this work, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. The sources are based on the non-linear compression of an initial beat-signal through a multiple four-wave mixing process taking place into an optical fiber. We experimentally demonstrate real-time monitoring of a 20 GHz pulse source having an integrated phase noise 0.01 radian by phase locking the initial beat note against a reference RF oscillator. Based on this technique, we also experimentally demonstrate a well-separated high-quality 110 fs pulse source having a repetition rate of 2 THz. Finally, we show…

Experimental observation of temporal dispersion gratings in fiber optics

We experimentally demonstrate a temporal analog to the diffraction optical grating in the Fraunhofer formalism. Using amplitude and phase temporal periodic modulations, we show that the accumulation of dispersion in fiber optics induces the development of temporally well-separated sidebands similar to the spatial orders of diffraction that are commonly observed in an optical grating operating in the far field.

Shaping Light in Nonlinear Optical Fibers

International audience; This book is a contemporary overview of selected topics in fiber optics. It focuses on the latest research results on light wave manipulation using nonlinear optical fibers, with the aim of capturing some of the most innovative developments on this topic. The book’s scope covers both fundamentals and applications from both theoretical and experimental perspectives, with topics including linear and nonlinear effects, pulse propagation phenomena and pulse shaping, solitons and rogue waves, novel optical fibers, supercontinuum generation, polarization management, optical signal processing, fiber lasers, optical wave turbulence, light propagation in disordered fiber medi…

Farey-Fraction Frequency Locking of a Breather Ultrafast Fibre Laser

Two-stage linear-nonlinear shaping of an optical frequency comb as rogue nonlinear-Schrödinger-equation-solution generator

International audience; We report a wave generator of complex solutions of the nonlinear Schrödinger equation (NLSE) combining both intensity and phase spectral shaping of an initial optical frequency comb with subsequent nonlinear propagation in an optical fiber. We apply the explicit analytical form of the two-breather solutions of the NLSE as a linear spectral filter to shape ideal modulation of a continuous wave. The additional nonlinear propagation of the tailored wave provides experimental evidence of both the growth and decay of the fundamental second-order periodic breather solution. The temporal and spectral profiles of the higher-order breather are in excellent agreement with the …

Exploring titanium dioxide as a new photonic platform

International audience; We report the development of titanium dioxide-based waveguides for applications in the near-and mid-infrared. Thanks to embedded metal grating couplers, we demonstrate error free 10 Gbit/s optical transmissions at 1.55 and 2 µm. We also demonstrate octave-spanning supercontinuum in cm-long waveguides. We explore the way to improve such waveguides through optimized fabrication process.

Emergence of rogue waves from optical turbulence

International audience; We provide some general physical insights into the emergence of rogue wave events from optical turbulence by analyzing the long term evolution of the field. Depending on the amount of incoherence in the system (i.e., Hamiltonian), we identify three turbulent regimes that lead to the emergence of specific rogue wave events: (i) persistent and coherent rogue quasi-solitons, (ii) intermittent-like rogue quasi-solitons that appear and disappear erratically, and (iii) sporadic rogue waves events that emerge from turbulent fluctuations as bursts of light or intense flashes.

The temporal analogue of diffractive couplers

International audience; Based on the space-time duality of light, we numerically demonstrate that temporal dispersion grating couplers can generate from a single pulse an array of replicas of equal amplitude. The phase-only profile of the temporal grating is optimized by a genetic algorithm that takes into account the optoelectronic bandwidth limitations of the setup.

Generation and detection of optical rogue-wave like fluctuations in fiber Raman amplifiers

International audience; Rogue wave-like statistics is reported in a fiber Raman amplifier. The pump-signal noise transfer leads to the development of large peak-power fluctuations following a power-law probability distribution. Discrimination of the rarest events is demonstrated.

Comparaison expérimentale de techniques de caractérisation en intensité et phase d'impulsions optiques ultracourtes

Nous comparons experimentalement les resultats de la caracterisation en intensite et en phase d'impulsions optiques ultracourtes obtenus par differentes techniques employant un montage auto/inter-correlateur en intensite et un analyseur de spectre. Nous employons pour ces tests une impulsion en limite de Fourier, une impulsion affectee par l'auto-modulation de phase et une impulsion similariton.

High speed optical transmission at 2 μm in subwavelength waveguides made of various materials

We report the transmission of a 10 Gbps telecommunication signal at 2 μm in waveguides made of three different materials: Si, SiGe and TiO2. Bit error rates below 10−9 can be achieved after transmission in the devices with subwavelength dimensions.

Génération de doublets d’impulsions picosecondes à très haut débit

National audience

Optical OCDMA enhanced by nonlinear optics

International audience; Intended for the next generation of optical access networks, OCDMA is of great interest to meet the demand of increasing the number of users per access fiber, especially as spectral phase coding increases its performance in the optical domain. This, however, requires handling broad spectra and short pulses, which are best dealt with using opto-electronic or all-optical devices instead of slower electronics. Among others, we demonstrate spectral-phase-coded OCDMA using a fiber-based saturable absorber as thresholding in the receiver.

Four-wave mixing instabilities in telecom fibers

Instabilities in fiber four-wave mixing are investigated, revealing the formation of colliding dispersive shock waves in the normal GVD regime and collective modulation instabilities in the anomalous GVD regime.

Tailored soliton statistics in supercontinuum generation

Supercontinuum (SC) generation in highly nonlinear photonic crystal fibers (PCF) has stimulated tremendous interest in recent years [1]. Particular results that have received recent widespread attention concern the observation of “optical rogue waves,” statistically rare extreme red-shifted Raman solitons appearing on the long wavelength edge of the SC spectrum [2]. Further numerical analysis of these fluctuations have showed explicitly that the rogue soliton statistics exhibit strongly non-Gaussian extreme-value characteristics [3]. The previous studies of optical rogue wave statistics in SC generation have been carried out considering PCF with only one zero dispersion wavelength (ZDW). It…

Simultaneous 2R regeneration of WDM signals in a single optical fibre

Two experimental implementations of amplitude regeneration of WDM signals based on self-phase modulation (SPM) in optical fibres are discussed. The two examples differ in their approach of mitigation of inter-channel nonlinearities.

40 GHz pulse source based on cross-phase modulation-induced focusing in normally dispersive optical fibers.

We theoretically and experimentally investigate the design of a high-repetition rate source delivering well-separated optical pulses due to the nonlinear compression of a dual-frequency beat signal within a cavity-less normally dispersive fiber-based setup. This system is well described by a set of two coupled nonlinear Schrodinger equations for which the traditional normally dispersive defocusing regime is turned in a focusing temporal lens through a degenerated cross-phase modulation process (XPM). More precisely, the temporal compression of the initial beating is performed by the combined effects of normal dispersion and XPM-induced nonlinear phase shift provided by an intense beat signa…

Real time measurement of long parabolic optical similaritons

International audience; Long optical similaritons using a Raman fibre amplifier are generated. These pulses, with a highly parabolic profile, are monitored in real time on a high speed oscilloscope. Tunability of both the temporal and spectral widths of the pulses is then investigated.

Farey Tree and Devil's Staircase of a Breather Mode-Locked Fibre Laser

Data Transmissions at 1.98 µm in cm-long SiGe Waveguides

International audience; We demonstrate an error-free transmission of 10-Gbit/s optical signals along a SiGe waveguide at a wavelength of 1.98 μm. Bit error rate measurements confirm the absence of penalty during the transmission through a 2.5-cm long waveguide having a width of 2.2 μm.

Elargissement spectral d’impulsions par ondes de choc dispersives dans les fibres optiques

National audience; Nous étudions l’élargissement spectral induit par ondes de choc dispersives d’impulsions générées par modulation électro-optique dans une fibre optique en dispersion normale.

Effets de polarisation non-linéaires et événements extrêmes dans les fibres optiques

All-fibered high-quality 28-GHz to 112 GHz pulse sources based on nonlinear compression of optical temporal besselons

The generation of high quality pulse trains at repetition rates of several tens of GHz remains a crucial step for optical telecommunications, optical sampling or component testing applications. Unfortunately, the current bandwidth limitations of optoelectronic devices do not allow the direct generation of well-defined optical pulse trains with low duty cycles. An attractive solution is based on a direct temporal phase modulation that is then converted into an intensity modulation thanks to a dispersive element that imprints a spectral quadratic phase. Picosecond pulses at repetition rates of several tens of GHz have been successfully demonstrated [1] . However, this approach suffers from a …

40-GHz Pulse Source Based on XPM-Induced Focusing in Normally Dispersive Optical Fiber

International audience

Parabolic pulse evolution in normally dispersive fiber amplifiers preceding the similariton formation regime

We show analytically and numerically that parabolic pulses and similaritons are not always synonyms and that a self-phase modulation amplification regime can precede the self-similar evolution. The properties of the recompressed pulses after SPM amplification are investigated. We also demonstrate that negatively chirped parabolic pulses can exhibit a spectral recompression during amplification leading to high-power chirp-free parabolic pulses at the amplifier output.

320GHz, 640GHz and 1THz femtosecond pulse sources based on multiple four wave mixing in highly non linear optical fibers

Ultra-high repetition rate, transform-limited femtosecond pulse trains have been generated around 1555 nm at 320 GHz, 640 GHz and 1 THz through the compression of a dual frequency beat-signal in a highly nonlinear optical fiber.

Pulsating Solitons in Mode-Locked Fibre Lasers

International audience; We report on our direct experimental observation of a new regime of operation of passively mode-locked fibre lasers where the laser oscillator generates pulsating solitons with extreme ratios of maximal to minimal intensities in each period of pulsations. The soliton spectra also experience large periodic broadening and compression. Spatio-temporal intensity and dispersive Fourier-transformation measurements enable us to capture such transient dynamics in real time.

Synthesis of optical pulses by use of similaritons.

We propose and demonstrate experimentally a novel method for synthesizing chirp-free pulses of any desired temporal shape by means of chirp compensation and spectral filtering of optical Raman similaritons. The synthesized pulse shape is independent of the waveform, wavelength and energy of the initial pulses that are used for the similariton generation. Pulses are fully characterized by means of different techniques including cross-correlation and spectrum measurements, and the PICASO technique.

Shallow water optical rogue waves: Optical tsunamis

Performance optimisation of dual-pump NALM fibre laser using machine learning inference

We apply predictive regression to find optimum operating regimes in a recently proposed layout of a flexible Figure-8 laser having two independently pumped segments of active fibre in its bidirectional ring.

Self-Optimising Breather Ultrafast Fibre Laser

We demonstrate the self-optimisation of the breather regime in an ultrafast fibre laser through an evolutionary algorithm. Depending on the specified merit function, single breathers with controllable breathing ratio and period, and breather molecular complexes with a controllable number of constituents can be obtained.

Les couleurs et la lumière

Les couleurs nous entourent et sont indispensables à notre existence. Elles peuvent tirer leur origine et leurs propriétés de mécanismes très différents : le pigment de peinture a physiquement peu de points communs avec les processus à l’œuvre dans la formation d’un arc en ciel. Pour mieux comprendre ces différents aspects, nous reviendrons sur ce qu’est la lumière ainsi que les différentes sources de lumières désormais disponibles. Nous évoquerons également les couleurs « invisibles » pour l’œil mais qui sont néanmoins exploitées dans de nombreuses applications modernes.

Nonlinear pulse shaping : a versatile tool for ultrafast photonics

National audience

Simple model of self-phase modulation spectral patterns in optical fibres

Self-phase modulation (SPM) has been extensively studied for several decades in optical fibers. This phenomenon manifests itself by a change of the frequency spectrum of a pulse, owing to the nonlinear index variation that follows the temporal evolution of the pulse. In the general case, the spectrum of the transmitted pulse cannot be calculated analytically and only approximate or rms expressions giving the bandwidth of the transmitted spectrum are used. In this paper, we present a novel theoretical treatment of SPM based on a spectral interference model. We show that a two-wave interference process is sufficient to describe the main features of the SPM-broadened spectra of initially Fouri…

Control of complex nonlinear wave dynamics in dissipative systems by machine learning

Ultrafast mode-locked fibre lasers exploiting nonlinearity in the pulse formation process are well-known to display a rich landscape of "dissipative soliton'' dynamics, which results from the interplay of the nonlinearity with dispersion and dissipation. Reaching a desired operating regime in a fibre laser generally depends on precisely adjusting multiple parameters in a high-dimensional space, in connection with the wide range of accessible pulse dynamics, which is usually performed through a trial-and-error experimental procedure, due to the lack of analytic relationship between the cavity parameters and the pulse features. The practical difficulties associated with such a procedure can b…

Nonlinear spectral shaping and optical rogue events in fiber-based systems

International audience; We provide an overview of our recent work on the shaping and stability of optical continua in the long pulse regime. Fibers with normal group-velocity dispersion at all-wavelengths are shown to allow for highly coherent continua that can be nonlinearly shaped using appropriate initial conditions. In contrast, supercontinua generated in the anomalous dispersion regime are shown to exhibit large fluctuations in the temporal and spectral domains that can be controlled using a carefully chosen seed. A particular example of this is the first experimental observation of the Peregrine soliton which constitutes a prototype of optical rogue-waves.

Enhanced nonlinear spectral compression in fibre by external sinusoidal phase modulation

International audience; We propose a new, simple approach to enhance the spectral compression process arising from nonlinear pulse propagation in an optical fibre. We numerically show that an additional sinusoidal temporal phase modulation of the pulse enables efficient reduction of the intensity level of the side lobes in the spectrum that are produced by the mismatch between the initial linear negative chirp of the pulse and the self-phase modulation-induced nonlinear positive chirp. Remarkable increase of both the extent of spectrum narrowing and the quality of the compressed spectrum is afforded by the proposed approach across a wide range of experimentally accessible parameters.

Façonnage optique non-linéaire dans les fibres optiques

National audience

Broadband multiplex CARS micro-spectroscopy in the picosecond regime

International audience

Un réseau neuronal pour explorer la diffraction par un bord d'écran

National audience; Nous décrivons ici un projet visant à explorer avec un groupe d'étudiants en physique de niveau licence l'utilisation d'un réseau neuronal pour simuler un problème traditionnel de l'optique ondulatoire, i.e. la diffraction d'un bord d'écran dont la solution analytique est connue. Par cette première approche de l'intelligence artificielle, nous avons pu mettre l'accent sur les étapes essentielles nécessaires pour mettre en oeuvre ces nouvelles technologies numériques. Mots clés : diffraction de Fresnel ; apprentissage par réseau neuronal.

Machine learning approach for nonlinear pulse shaping in optical fibres

We use a supervised machine-learning approach to solve both the direct and inverse problems relating to the nonlinear shaping of optical pulses in optical fibres.

Photonic waveform generator by linear shaping of four spectral sidebands

International audience; Changing the optical phase difference between four spectral sidebands is sufficient to synthesize various pulse shapes. Experiments at 40 GHz confirm that high quality parabolic, triangular or flat-top temporal intensity profiles can be achieved.

All-fibered high-quality low duty-cycle 20-GHz and 40-GHz picosecond pulse sources

International audience; In this work, we demonstrate all-fibered 20-GHz and 40-GHz picosecond pulse sources with duty cycles as low as 1/14. The pulse train is achieved via the high-quality compression of an initial sinusoidal beating through four segments of optical fibers. General design rules are proposed and experimental results are in agreement with numerical predictions.

Une nouvelle famille d'ondes scélérates dans les fibres optiques

National audience; Nous démontrons une nouvelle famile d'ondes scélérates qui peut émerger dans les fibres optiques à dispersion normale.

Temporal and spectral nonlinear pulse shaping in normally dispersive optical fibers

The combination of the third-order optical nonlinearity with chromatic dispersion in optical fibers offers an extremely rich variety of possibilities for tailoring the temporal and spectral content of a light signal, depending on the regime of dispersion that is used. Because the nonlinear dynamics of pulses propagating in fibers with normal group-velocity dispersion is generally sensitive to the initial pulse condition, it is possible to nonlinearly shape the propagating pulses through control of the initial pulse temporal intensity and/or phase profile. Here, we review recent progress on the use of third-order nonlinear processes in normally dispersive fibers for pulse shaping in the temp…

Extreme statistics in Raman fiber amplifiers : influence of pump depletion and dispersion

OSA 2010 NonLinear Photonics Best Student Poster Award; International audience; We experimentally and theoretically investigate the influence of pump depletion effects on extreme statistics observed in fiber Raman amplifiers. We also report on the impact of the dispersion of the fiber.

Optical peregrine soliton generation in standard telecommunication fibers

By combining real time characterization with cut-back measurements, we provide the first direct observation of Peregrine-like soliton longitudinal evolution dynamics and report a new effect associated with the breakup of a Peregrine soliton into two subpulses, each providing similar characteristics of localization upon finite background. Experimental results are in good agreement with simulations.

Design and control of NxN microphotonics switch array based on non-adiabatic theory

The development of linear programmable nanophotonics processors requires large number of couplers to route light through the photonic chip. This number scales nonlinearly with the number of inputs and outputs [1] , making the device increasingly complex to control, and bulky. Regarding the latter aspects, densely packed array of waveguides would be an elegant solution. In order to couple selectively the different –at first isolated- waveguides, we rely on the analogy between the equations governing the unidirectional propagation in optics and the time evolution in quantum physics [2] . Namely, as seen in fig. 1-a , if each waveguide can be considered as a photonic energy level, then a trans…

Nonlinear Sculpturing of Optical Pulses in Fibre Systems

The interplay among the effects of dispersion, nonlinearity and gain/loss in optical fibre systems can be efficiently used to shape the pulses and manipulate and control the light dynamics and, hence, lead to different pulse-shaping regimes [1,2]. However, achieving a precise waveform with various prescribed characteristics is a complex issue that requires careful choice of the initial pulse conditions and system parameters. The general problem of optimisation towards a target operational regime in a complex multi-parameter space can be intelligently addressed by implementing machine-learning strategies. In this paper, we discuss a novel approach to the characterisation and optimisation of …

A comment on “Research on the nonlinear pulse propagation by numerical analysis” by Li and Yin [Optik 12 (13) (2011) 1195–1200]

In the article entitled "Research on the nonlinear pulse propagation by numerical analysis" , Li Li and Aihan Yin summarize the key elements affecting the nonlinear propagation of an optical pulse in an optical fiber. We comment these results.

Nonlinear femtosecond pulse propagation in all-solid photonic bandgap fiber

Nonlinear femtosecond pulse propagation in all-solid photonic bandgap fiber is investigated experimentally and numerically for both the photonic bandgap guiding in the central silica core and the total internal reflection in germanium doped inclusions.

High-harmonic km-long self-pulsed Raman fiber laser

Raman all-fiber lasers have attracted considerable interest during the past two decades due to their convenient use and extended wavelength coverage when compared to rare-earth-doped fiber lasers. Still, little is known about their potential as pulsed laser sources. Mode locked Raman fiber lasers have been demonstrated quite recently [1,2], as well as harmonic mode-locking with a record of 500,000 intra-cavity pulses in a dissipative four-wave mixing configuration using a fiber Bragg grating [3].

Évènements extrêmes et turbulence optique

National audience; Nous montrons l'impact de l'incohérence dans un système hamiltonien sur l'émergence d'événements extrêmes de types ondes scélérates, en analysant l'évolution à long terme du champ optique. Trois régimes sont identifiés: le premier (i) est caractérisé par des ondes persistantes, le second (ii) est marqué par des ondes intermittentes et le dernier (iii) par de rares ondes sporadiques.

Emergence of extreme events in fiber-based nonlinear devices

We review our experimental and theoretical results showing the emergence of rogue events during light propagation in fiber-based nonlinear systems. Distinct statistical properties are underlined through parametric and Raman amplifications, supercontinuum generation and optical turbulence.

Breather Molecular Complexes in a Passively Mode‐Locked Fiber Laser

International audience; Breathing solitons are nonlinear waves in which the energy concentrates in a localized and oscillatory fashion. Similarly to stationary solitons, breathers in dissipative systems can form stable bound states displaying molecule-like dynamics, which are frequently called breather molecules. So far, the experimental observation of optical breather molecules and the real-time detection of their dynamics are limited to diatomic molecules, that is, bound states of only two breathers. In this work, the observation of different types of breather complexes in a mode-locked fiber laser: multibreather molecules, and molecular complexes originating from the binding of two breat…

Spectral analog of the Gouy phase shift

We demonstrate the existence of the spectral phase shift a pulse experiences when it is subjected to spectral focusing. This $\frac{\ensuremath{\pi}}{2}$ phase shift is the spectral analog of the Gouy phase shift a 2D beam experiences when it crosses its focal plane. This spectral Gouy phase shift is measured using spectral interference between a reference pulse and a negatively chirped parabolic pulse experiencing spectral focusing in a nonlinear photonic crystal fiber. To avoid inherent phase instability in the measurement, both reference and parabolic pulses are generated with a $4\mathrm{\text{\ensuremath{-}}}f$ pulse shaper and copropagate in the same fiber. We measure a spectral phase…

Dualité temps-espace dans la propagation de la lumière

National audience; L’optique ondulatoire est souvent enseignée à travers ses manifestations dans le domaine spatial : motifs d’interférence, figures de diffraction, propagation en espace libre... En exploitant le domaine de Fourier, il est possible de dresser une analogie formelle entre la diffraction 1D de la lumière et la dispersion subie par impulsion ultrabrève. Cela a permis la transposition de solutions connues de l’optique spatiale à l’optique temporelle. Ainsi, régie par une phase quadratique, la lentille temporelle copie la lentille traditionnelle et a permis ainsi d’imaginer expérimentalement de nouvelles approches de caractérisation d’impulsions ultrabrèves.Dans cette contributio…

Phase evolution of Peregrine-like solitons in nonlinear fiber optics

Optical fiber systems are well-known to provide convenient platforms in which one may investigate a large variety of fascinating fundamental nonlinear coherent structures such as solitons or self-similar patterns. Interestingly, one of the major conclusions of the studies dealing with extreme-value fluctuations is that the temporal and spectral characteristics of localization processes can be well described in terms of solitons over finite background and in particular in terms of Peregrine soliton (PS) [1]. Whereas the longitudinal evolution of the temporal and spectral intensity of the PS have been characterized in detail [2], much less attention has been experimentally devoted to the evol…

Higher-Order Modulation Instability in Nonlinear Fiber Optics

International audience; We report theoretical, numerical, and experimental studies of higher-order modulation instability in the focusing nonlinear Schrödinger equation. This higher-order instability arises from the nonlinear superposition of elementary instabilities, associated with initial single breather evolution followed by a regime of complex, yet deterministic, pulse splitting. We analytically describe the process using the Darboux transformation and compare with experiments in optical fiber. We show how a suitably low frequency modulation on a continuous wave field induces higher-order modulation instability splitting with the pulse characteristics at different phases of evolution r…

Pulse Generation and Shaping Using Fiber Nonlinearities

Experimental observation of the spectral Gouy phase shift

We experimentally observe and measure the spectral phase shift of a pulse subjected to spectral focusing. We find a phase shift of π/2, reaffirming the Gouy phase shift as a general consequence of wave confinement whether in space/momentum or frequency/time coordinates.

Dispersion managed self-similar parabolic pulses

International audience; We describe the propagation of a parabolic self-similar pulse in an anomalous dispersive nonlinear fibre. Given the capacity of a linearly chirped parabolic pulse to retain its typical shape over a short propagation distance, we introduce the concept of dispersion managed self-similar pulses and outline potential benefits in terms of spectral broadening enhancement.

Octave Spanning Supercontinuum in Titanium Dioxide Waveguides

International audience; We report on the experimental generation of an octave-spanning supercontinuum in a 2.2 cm-long titanium dioxide optical waveguide with two zero dispersion wavelengths. The resulting on-chip supercontinuum reaches the visible wavelength range as well as the mid-infrared region by using a femtosecond fiber laser pump at 1.64 µm.

Nonlinear pulse shaping in normally dispersive fibers : experimental examples

International audience; While the combination of Kerr nonlinearity with dispersion in optical fibers can seriously impair high speed optical transmissions, it also provides an attractive solution to generate new temporal and spectral waveforms. We explain in this talk how to take advantage of the progressive temporal and spectral reshapings that occur upon propagation in a normally dispersive fiber. We base our discussion on several experimental results obtained at telecommunication wavelengths.

Optical rogue waves and localized structures in nonlinear fiber optics

We review our recent work in the field of optical rogue wave physics. Beginning from a brief survey of the well-known instabilities in optical fiber, we trace the links to recent developments in studying the emergence of high contrast localized breather structures in both spontaneous and induced nonlinear instabilities.

Modélisation mathématique et étude expérimentale des instabilités non-linéaires, des vagues scélérates et des phénomènes extrêmes

Le soliton Peregrine, une onde fondamentale des dynamiques non-linéaires

National audience; Des ondes très variées sont régies par l’équation de Schrödinger non-linéaire : la lumière dans les fibres optiques, les vagues océaniques, les ondes dans les plasmas, les condensats de Bose-Einstein… Quand la non-linéarité compense la dispersion, un soliton peut se propager tout en maintenant ses caractéristiques temporelles et spectrales inchangées. En présence d’une onde continue, une autre onde non-linéaire existe : le soliton Peregrine (PS), prédit dès 1983 [1] mais démontré expérimentalement seulement en 2010 [2]. Au contraire du soliton usuel, le PS apparait de nulle part, concentre temporellement et spatialement son énergie, puis disparait sans laisser de trace.Le…

Non-adiabatic control in NxN integrated photonic switch

National audience

Spectral sideband splitting inn strongly dispersion oscillating fibers

Vidéo de la présentation donnée : https://youtu.be/SBA2WLKw5jw; International audience

2R regeneration architectures based on multi-segmented fibres

The benefits of using a multi-segmented arrangement of optical fibres for Self-Phase Modulation-based 2R optical regeneration are described both theoretically and experimentally. Significant improvements in terms of the performance and practicality are achieved.

Modelling Nonlinear Propagation of Periodic Waveforms in Optical Fibre with a Neural Network

We deploy a neural network to predict the spectro-temporal evolution of a periodic waveform upon nonlinear fibre propagation and demonstrate efficient probing of the input-parameter space for on-demand comb generation or significant spectral/temporal focusing occurrence.

Mieux comprendre la dualité temps/fréquence et la modulation de phase optique

National audience; L'analyse de Fourier tient une place majeure dans l'analyse et la compréhension de nombreux phénomènes de la physique et de l'ingénierie contemporaines. Pourtant les étudiants, qui ont souvent découvert cette notion à travers des travaux numériques, ne cernent pas forcément toute la richesse qui peut être tirée de l'analyse conjointe dans les do-maines temporels et spectraux, notamment dans le domaine de l'optique. Nous avons mis en place dans le cadre de la seconde année du master Physique Lasers et Matériaux de l'Université de Bourgogne une expérience permettant d'insister sur ces notions et de montrer sur un exemple non trivial de modulation de phase périodique, les pr…

Fiber-based device for the detection of low-intensity fluctuations of ultrashort pulses

International audience; We describe a fiber-based device that can significantly enhance the low intensity fluctuations of an ultrashort pulse train to detect them more easily than with usual direct detection systems. Taking advantage of the Raman intrapulse effect that progressively shifts the central frequency of a femtosecond pulse propagating in an anomalous dispersion fiber, a subsequent spectral filtering can efficiently increase the level of fluctuations by more than one order of magnitude. We show that attention has to be paid to maintain the shape of the statistical distribution unaffected by the nonlinear process.

Réseaux métalliques pour le couplage dans des guides en dioxyde de titane

National audience; Nous montrons la fabrication de réseaux métalliques enterrés entre deux couches de dioxyde de titane. En utilisant un supercontinuum, nous démontrons expérimentalement une efficacité de couplage supérieure à -8 dB pour une bande passante à 3 dB supérieure à 80 nm.

Le light painting pour éclairer une classe de primaire

National audience

50 years of fiber solitons

The study of temporal solitons has revolutionized fiber optics, yielded new classes of ultrafast laser and opened multiple interdisciplinary applications.

Ligth by light polarization control for telecommunication applications

International audience; In this work, we report for the first time the experimental achievement of an all-fibered polarization attraction, which can occur in optical fibers at telecommunication wavelengths. More precisely, we have experimentally shown that is possible to all-optically control and stabilize the state of polarization of a 10 Gbit/s telecommunication signal through the injection of a counter-propagating control pump wave. Eye diagrams recordings and bit error rate measurements have shown that this new type of all-optical function, almost lossless and instantaneous has a promising potential for telecommunication applications.

Extreme events in fiber based amplifiers

International audience; We present experimental and theoretical results showing the emergence of rogue wave-like extreme intensity spikes during fiber-based amplification processes such as Raman effect or induced-modulational instability that rely on quasi-instantaneous gain. We outline that under certain circumstances, a partially incoherent pumping can induce large fluctuations of the amplified signal, and we propose various means to spectrally select the most extreme structures.

Titanium Dioxide Waveguides for Data Transmissions at 1.55 µm and 1.98 µm

International audience; We demonstrate error free transmissions of 10 Gbps signals in titanium dioxide waveguides at wavelengths of 1.55 or 2 µm. An efficient coupling of light is achieved thanks to metal grating couplers and we have checked that the component could be used with standard CWDM SFP+ devices.

Complete measurement of the phase-space topology of fiber four-wave mixing using iterated initial conditions

We experimentally demonstrate an optical fiber testbed enabling the quantitative study of ideal four-wave mixing. We directly measure the complex phase-space topology including features such as the separatrix, Fermi Pasta Ulam recurrence, and stationary waves.

Caractérisation théorique du régénérateur 2R exploitant l'automodulation de phase dans une fibre optique

National audience; Nous étudions théoriquement un régénérateur 2R exploitant l'automodulation de phase dans une fibre optique, suivie d'un filtrage spectral décalé en fréquence. Nous utilisons deux approches différentes mais complémentaires : l'approche « fonction de transfert » et l'approche « amélioration du facteur Q ». Nous mettons notamment en évidence l'impact de la gigue temporelle pour expliquer un désaccord entre les deux approches.

High-quality 10 and 20 GHz repetition rate optical sources based on the spectral phase tailoring of a temporal sinusoidal phase modulation

International audience; We theoretically introduce and experimentally demonstrate a new approach to generate high-quality, high repetition-rate pulse trains. This method is based on a temporal sinusoidal phase modulation combined with a triangular spectral phase shaping. Experimental results validate the concept at repetition rates of 10 and 20 GHz.

Pulse transition to similaritons in normally dispersive fibre amplifiers

selected by the editors of Journal of Optics as a Highlight of 2013a video linked to the experiments can be seen at : http://youtu.be/thbXaW91D5g; International audience; A detailed experimental characterization of the transition process of an initially Gaussian pulse to the asymptotic self-similar parabolic solution in optical fibre amplifiers operating in the normal dispersion regime is performed.

Impact of amplitude jitter and signal-to-noise ratio on the nonlinear spectral compression in optical fibres

International audience; We numerically study the effects of amplitude fluctuations and signal-to-noise ratio degradation of the seed pulses on the spectral compression process arising from nonlinear propagation in an optical fibre. The unveiled quite good stability of the process against these pulse degradation factors is assessed in the context of optical regeneration of intensity-modulated signals, by combining nonlinear spectral compression with centered bandpass optical filtering. The results show that the proposed nonlinear processing scheme indeed achieves mitigation of the signal's amplitude noise. However, in the presence of a jitter of the temporal duration of the pulses, the perfo…

Experimental properties of parabolic pulses generated via Raman amplification in standard optical fibers

Parabolic pulses at 1550 nm have been generated in a standard telecommunications fiber using Raman amplification. The parabolic output pulse characteristics are studied as a function of input pulse energy and duration.

Optical waveform tailoring in passive and laser cavity fibre systems

International audience; The interplay among the effects of dispersion, nonlinearity and gain/loss in optical fibres is a powerful tool to generate a broad range of pulse shapes with tuneable properties. Here we propose a method to optimise the systems parameters for a given pulse target. By reducing the system complexity and applying machine-learning strategies, we show that it is possible to efficiently identify the sets of parameters of interest. Two configurations are numerically investigated: pulse shaping in a passive normally dispersive fibre and pulse generation in a dual-pump nonlinear-amplifying-loop-mirror mode-locked fibre laser.

Nanosecond thermo-optical dynamics of polymer loaded plasmonic waveguides

The thermo-optical dynamics of polymer loaded surface plasmon waveguide (PLSPPW) based devices photo-thermally excited in the nanosecond regime is investigated. We demonstrate thermo-absorption of PLSPPW modes mediated by the temperature-dependent ohmic losses of the metal and the thermally controlled field distribution of the plasmon mode within the metal. For a PLSPPW excited by sub-nanosecond long pulses, we find that the thermo-absorption process leads to modulation depths up to 50% and features an activation time around 2ns whereas the relaxation time is around 800ns, four-fold smaller than the cooling time of the metal film itself. Next, we observe the photo-thermal activation of PLSP…

Impact of a temporal sinusoidal phase modulation on the optical spectrum

International audience; We discuss the effects of imparting a temporal sinusoidal phase modulation to a continuous wave on the frequency spectrum. While a practical analytical solution to this problem already exists, we present here a physical interpretation based on interference processes. This simple model will help the students better understand the origin of the oscillatory structure that can be observed in the resulting spectrum and that is characteristic of Bessel functions of the first kind. We illustrate our approach with an example from the field of optics.

Nonlinear dynamics of modulated signals in optical fibers

International audience; The nonlinear Schrodinger equation (NLSE) describes the nonlinear waves localization dynamics in weakly dispersive media, and it has been extensively studied in various contexts in nonlinear science. A particular class of solutions of the NLSE that has recently attracted considerable attention is that of the solitons on finite background as their localization dynamics have been proposed as an important mechanism underlying the formation of extreme amplitude waves on the surface of the ocean. Much of this work has also been motivated by an extensive parallel research effort research in optics that has shown how nonlinear optical fiber systems can be used to implement …

Découvrir la polarisation à partir de l’application en ligne Emanim

National audience

Transform-limited spectral compression by self-phase modulation of amplitude-shaped pulses with negative chirp

International audience; Spectral compression by self-phase modulation of amplitude- and phase-shaped pulses is demonstrated as superior compared to pulses that have only been phase shaped. We synthesize linearly negatively chirped parabolic pulses, which we send through a nonlinear photonic crystal fiber, in which self-phase modulation compresses the spectrum of the pulses to within 20% of the Fourier transform limit.

Generalisation and experimental validation of design rules for self-phase modulation-based 2R regenerators

We report the design of 2R-regenerators based on self-phase modulation in lossy fibers. We experimentally demonstrate the applicability of the proposed scaling rules and present detailed characterization of the pulse characteristics at the regenerator output.

Quasi-phase-matched third harmonic generation in optical fibers using refractive-index gratings

International audience; The purpose of this work is to demonstrate the quasi-phase-matching of third harmonic generation process in optical fibers using refractive-index gratings. We compare conversion efficiency calculated with analytical coupled modes theory and numerical approach employing system of coupled generalized nonlinear Schrödinger equation. Moreover, we show that introducing the phase matching condition that takes into account the nonlinear contribution to propagation constants significantly increases the conversion efficiency by several orders of magnitude. Finally we optimize the grating constant to maximize conversion efficiency.

Generation of aperiodic picosecond pulses sequences from incoherent optical waves

We present an original method to generate optical pulses trains with random time-interval values from incoherent broadband sources. Our technique relies on the remarkable properties of a line made of cascaded SPM-based optical regenerators.

Ondes scélérates en optique

National audience

Nonlinear parametric resonances in quasiperiodic dispersion oscillating fibers

We numerically study the evolution of the spectrum of parametric resonance or modulation instability sidebands in quasiperiodic dispersion oscillating fibers. We separately consider a linear variation along the fiber of either the spatial period, the average dispersion, or the amplitude of the dispersion oscillation. We found that this linear variation of the dispersion oscillating fiber parameters may provide different novel mechanisms for the splitting of the resonance sideband spectrum, owing to coherent interference between quasi-resonant waves that are generated at different points along the fiber. (C) 2015 Elsevier B.V. All rights reserved.

Self-phase modulation in optical fibres

International audience

Octave-spanning supercontinuum generation in titanium dioxide waveguides

International audience

Seeded and spontaneous higher-order modulation instability

International audience; We report on the dynamics of the higher-order modulation instability in optical fibers and show that it is the very same phenomenon that underpins the emergence of rogue waves in the early stage of supercontinuum generation.

Nonlinear spectral compression in fibre as a power-limiting device

Spectral compression (SC) by self-phase modulation in optical fibre has been known for a long time and has since been reported for various parameters [1]. In this paper, we analyse the impact of amplitude fluctuations and a degraded optical signal-to-noise ratio (OSNR) of the seed pulses on the SC process by means of extensive nonlinear Schrodinger equation numerical simulation. Remarkably, our results show that the SC is rather stable against these pulse degradation factors, thereby revealing its potential for use in the context of optical regeneration of intensity-modulated signals. We therefore propose an optical scheme combining SC with an optical bandpass filter (OBPF) centred at the c…

Machine learning for ultrafast nonlinear photonics

Recent years have seen the rapid growth of the field of smart photonics where the deployment of machine-learning strategies is the key to enhance the performance and expand the functionality of optical systems. Here, we review our recent results obtained in collaboration with the University of Aston (S. Boscolo) and the University of Franche-Comté (J.M. Dudley) by providing several examples of advances enabled by machine-learning tools such as neural networks (NNs).We describe the use of a supervised feedforward NN paradigm to solve the direct and inverse problems relating to nonlinear pulse shaping in optical fibres, bypassing the need for direct numerical solution of the governing propaga…

Supercontinuum généré par fibre optique à cristal photonique pour l'accès multiple à répartition par code

National audience

High-repetition-rate source delivering optical pulse trains with a controllable level of amplitude and temporal jitters

International audience; We theoretically propose and numerically validate an all-optical scheme to generate optical pulse trains with varying peak-powers and durations. A shaping of the spectral phase thanks to discrete /2 phase shifts enables an efficient phase-to-intensity conversion of a temporal phase modulation based on a two-tone sinusoidal beating. Experiments carried out at telecommunication wavelengths and at a repetition rate of 10 GHz confirm the ability of our approach to efficiently generate a train made of pulses with properties that vary from pulse-to-pulse. The levels of jitters can be accurately controlled.

Nonlinear Pulse Shaping Using photonic Crystal fibers

Theory of parabolic pulse propagation in nonlinear dispersion decreasing optical fiber amplifiers

Optical fibers ; Nonlinear optics ; Optical fiber amplifiers ; Optical amplifier ; Optical solitons ; Electromagnetic wave propagation ; Pulse propagation ;; International audience; We show that pulse spectral broadening in normally dispersive nonlinear fiber amplifiers may be enhanced by introducing a suitable dispersion tapering. We obtain an analytical dispersion profile that permits one to reduce pulse propagation in a varying dispersion fiber to the case of an equivalent fiber with constant parameters.

La tache d’Arago temporelle en optique fibrée non-linéaire

National audience

Exploring 10 Gb/s transmissions in Titanium dioxide based waveguides at 1.55 µm and 2.0 µm

International audience

Scaling guidelines of a soliton-based power limiter for 2R-optical regeneration applications

International audience; In this work, we report scaling rules for the design of an all-fibered soliton-based power limiter for reamplification and reshaping (2R) regeneration process. In particular, we propose general guidelines to fix the optimum fiber length and initial power of the regenerator. We quantitatively point out the optical power limiting effect of the device enabling a significant reduction of the amplitude jitter of a degraded signal. Influence of the initial level of amplitude jitter is discussed and the results are compared with a self-phase modulation-based configuration working in the normal dispersion regime. Realistic numerical simulations in the context of 160 Gbit/s s…

All-fiber spectral compression of picosecond pulses at telecommunication wavelength enhanced by amplitude shaping

International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. A spectral compression by a factor 12 is achieved. Performing temporal shaping with a parabolic pulse significantly improves the spectral compression with much lower substructures and an enhanced Strehl ratio.

Rogue wave description: Rational solitons and wave turbulence theory

We show that rogue waves can emerge from optical turbulence and that their coherent deterministic description provided by the rational solutions is compatible with the statistical description provided by the wave turbulence theory.

Les breathers d'Akhmediev comme source à très haut-débit ou à ultra large bande

Experimental demonstration of an ultrafast all-optical bit-error indicating scheme

International audience; We experimentally demonstrate an all-optical bit error monitoring scheme based on the self-phase modulation occurring during the propagation in a highly nonlinear fiber followed by an optical bandpass filter. Numerical simulations are confirmed by experimental observations performed at a repetition rate of 40 Gb/s.

All-optical regeneration of polarization of a 40 Gbit/s return-to-zero telecommunication signal

International audience; We report all-optical regeneration of the state of polarization of a 40 Gbit/s return-to-zero telecommunication signal. The device discussed here consists of a 6.2-km-long nonzero dispersion-shifted fiber, with low polarization mode dispersion, pumped from the output end by a backward propagating wave coming from either an external continuous source or a reflection of the signal. An initially scrambled signal acquires a degree of polarization close to 100% toward the polarization generator output. All-optical regeneration is confirmed by means of polarization and bit-error-rate measurements as well as real-time observation of the eye diagrams. We show that the physic…

De l’optique à la photonique, ou comment concentrer la lumière dans l’espace et le temps, évolution d’une discipline en Bourgogne du XVII au XXI siècle.

National audience

All-optical simultaneous polarization attraction and intensity regeneration of a 40-Gbit/s RZ signal

We experimentally report the dual all-optical instantaneous regeneration of both the state of polarization and the intensity profile of a 40 Gbit/s Return-to-Zero telecommunication signal by means of a unique segment fiber.

Gain sideband splitting in dispersion oscillating fibers

International audience; We analyze the modulation instability spectrum in a varying dispersion optical fiber as a function of the dispersion oscillation amplitude, and predict a novel sideband splitting into different sub-sidebands for relatively large dispersion oscillations

Langevin's Model for Soliton Molecules in Ultrafast Fiber Ring Laser Cavity

Interactions et collisions de similaritons optiques

National audience; We investigate theoretically and experimentally the dynamics of the self-similar amplification of two optical parabolic pulses in a normally dispersive Raman amplifier. The interaction between pulses of same wavelengths creates an oscillation which further evolves into a train of dark solitons through the combined effects of non-linearity, normal dispersion and adiabatic Raman gain. In the case of pulses of different wavelengths, collisions can occur. We demonstrate that similaritons are stable against collisions: they interact during their overlap but regain their parabolic shape after collision. The collision induces a sinusoidal modulation inside the overlap region, wh…

Le dioxyde de titane pour la photonique

National audience

Optical Peregrine soliton generation in standard telecommunications fiber

International audience; We present detailled experimental and numerical results showing the generation and breakup of the optical Peregrine soliton in standard telecommunications fiber. The impact of non-ideal initial conditions is studied through direct cut back measurements of the longitudinal evolution of the emerging soliton dynamics, and is shown to be associated with the splitting of the Peregrine soliton into two subpulses.

All-optical measurement of residual chromatic dispersion and OSNR using self-phase modulation in optical fiber

International audience; We describe a new all-fibered device providing high accuracy all-optical measurements of both optical signal to noise ratio and residual chromatic dispersion. Taking advantage of the self-phase modulation driven spectral evolution of pulses propagating in a highly non-linear medium, we have numerically and experimentally validated the benefits of using an anomalous dispersive fiber combined with a central spectral filtering.

Exploring 10 Gb/s transmissions in Titanium dioxide based waveguides at 1.55 pm and 2.0 pm

Exploring new spectral bands for optical transmission is one of the solutions to support the increasingly demand of data traffic. The recent development of dedicated hollow-core photonic bandgap fibers [1], associated to the emergence of thulium doped fiber amplifiers [2] has recently focused the attention further in the infrared, and more specifically around 2 μm. Regarding integrated photonics, it becomes therefore interesting to find a suitable platform to operate at 2 μm as well as in the other more conventional spectral bands (going from 800 nm to 1550 nm). Here, we propose titanium dioxide (TiO 2 ) as a good candidate for integrated waveguide photonics and demonstrate, for the first t…

The Peregrine soliton in nonlinear fibre optics

International audience; The Peregrine soliton is a localized nonlinear structure predicted to exist over 25 years ago, but not so far experimentally observed in any physical system. It is of fundamental significance because it is localized in both time and space, and because it defines the limit of a wide class of solutions to the nonlinear Schrödinger equation (NLSE). Here, we use an analytic description of NLSE breather propagation to implement experiments in optical fibre generating femtosecond pulses with strong temporal and spatial localization, and near-ideal temporal Peregrine soliton characteristics. In showing that Peregrine soliton characteristics appear with initial conditions th…

Source optique fibrée pour la microscopie CARS

De la diffraction de Fresnel aux outils temporels : comment voir et manipuler la lumière à l’échelle de la pico- ou femto-seconde

International audience

Temporal analogue of the Fresnel diffraction by a phase plate in linear and nonlinear optical fibers

The analogy existing between spatial and temporal optics has motivated many studies to interpret spatial phenomena in the domain of ultrafast optics [1] . Indeed, dispersion and one-dimensional diffraction may share the same mathematical formalism. Temporal analogues of common optical systems have been proposed such as lenses, imaging systems, diffraction gratings, which opens up a whole range of new possibilities for ultrafast photonics.

Les bandes de gain paramétrique dans une fibre à dispersion oscillante

National audience; Nous discuterons différents régimes de propagation où la forme et la complexité des bandes d’IM varient significativement. Nous présenterons notamment des résultats d’expériences menées aux longueurs d’ondes des télécommunications optiques. Enfin, nous exploiterons ce processus dans le cadre d’une d’une conversion de fréquence combinée à une compression temporelle d’un train d’impulsion à haut débit.

Gain sideband splitting in dispersion oscillating fibers

International audience; We analyze the modulation instability spectrum in a varying dispersion optical fiber as a function of the dispersion oscillation amplitude. For large dispersion oscillations, we predict a novel sideband splitting into different sub-sidebands. The emergence of the new sidebands is observed whenever the classical perturbation analysis for parametric resonances predicts vanishing sideband amplitudes. The numerical results are in good quantitative agreement with Floquet or Bloch stability analysis of four-wave mixing in the periodic dispersion fiber. We have also shown that linear gain or loss may have a dramatic influence in reshaping the new sidebands.

Propagation non-linéaire dans les fibres optiques par réseaux de neurones artificiels

National audience; Nous mettons en œuvre différents réseaux de neurones artificiels pour prédire l’évolution des profils temporels et spectraux d’intensité après propagation dans une fibre optique en présence de non-linéarité forte. Le problème inverse est également considéré.

Regenerative 40 Gbit/s wavelength converter based on similariton generation.

International audience; We present an all-optical regeneration technique based on spectral filtering of self-similar parabolic pulses (similaritons). In particular, we demonstrate numerically and experimentally that ghost pulses, which occur in the zero bit slots of telecommunication pulse trains, can be effectively suppressed. These results are obtained with a 40 Gbit/s pulse train.

Beneficial impact of wave-breaking for coherent continuum formation in normally dispersive nonlinear fibers

International audience; We study the evolution of a pulse propagating in a normally dispersive fiber in the presence of Kerr nonlinearity. We review the temporal and spectral impact of optical wave-breaking in the development of a continuum. The impact of linear losses or gain is also investigated.

Effects of fourth-order fiber dispersion on ultrashort parabolic optical pulses in the normal dispersion regime

International audience; We propose a new method for the generation of both triangular-shaped optical pulses and flat-top, coherent supercontinuum spectra using the effect of fourth-order dispersion on parabolic pulses in a passive, normally dispersive highly nonlinear fiber. The pulse re-shaping process is described qualitatively and is compared to numerical simulations.

Design of a continuously tunable delay line using vectorial modulational instability and chromatic dispersion in optical fibers

International audience; We design an all-optical tunable delay line based on both dispersive and wavelength conversion stages involving modulational instability of a two-frequency pump field propagating in a highly birefringent fiber. More precisely, we numerically show that, by varying the frequency separation between the two orthogonally polarized pump waves, we achieve a controllable and continuous delay of hundreds of picoseconds for signal pulse durations from picoseconds to nanoseconds, without pulse distortion and with only small peak power fluctuations. The proposed method does not require any tunable bandpass filter and can be applied to delay digital data streams at tens of Gbit/s…

Auto-setting breather mode-locked fibre laser

International audience

High-quality optical pulse train generator based on solitons on finite background

International audience; We report a simple method to exploit the typical properties of solitons on finite background in order to generate high repetition rate and high quality optical pulse trains. We take advantage of the nonlinear evolution of a modulated continuous wave towards localized structures upon a nonzero background wave in anomalous dispersive fiber. After a stage of nonlinear compression, a delay-line interferometer enables the annihilation of the finite background and simultaneously allows the repetition rate doubling of the pulse train.

All-optical fiber-based devices for ultrafast amplitude jitter magnification

International audience; We propose two fiber-based architectures that enable the all-optical magnification of ultrafast amplitude fluctuations of picosecond or femtosecond pulse trains. An increase of the fluctuations by more than one order of magnitude is experimentally achieved.

Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using parabolic pulses formed in a fiber Bragg grating

International audience; We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPMbroadened pulses centred at 1542nm with 92% of the pulse energy remaining within the 29nm 3dB spectral bandwidth. Appli…

Amplifier similariton fiber laser with nonlinear spectral compression

International audience; We propose a new concept of a fiber laser architecture supporting self-similar pulse evolution in the amplifier and nonlinear spectral pulse compression in the passive fiber. The latter process allows for transform-limited picosecond pulse generation, and improves the laser's power efficiency by preventing strong spectral filtering from being highly dissipative. Aside from laser technology, the proposed scheme opens new possibilities for studying nonlinear dynamical processes. As an example, we demonstrate a clear period-doubling route to chaos in such nonlinear laser system.

Artificial neural networks for nonlinear pulse shaping in optical fibers

International audience; We use a supervised machine-learning model based on a neural network to predict the temporal and spectral intensity profiles of the pulses that form upon nonlinear propagation in optical fibers with both normal and anomalous second-order dispersion. We also show that the model is able to retrieve the parameters of the nonlinear propagation from the pulses observed at the output of the fiber. Various initial pulse shapes as well as initially chirped pulses are investigated.

Etude numérique des performances d'un régénérateur 2R à fibre

National audience; Nous étudions l'impact de la gigue initiale d'amplitude sur les performances d'un régénérateur 2R basé sur l'auto-modulation de phase dans une fibre optique. Les paramètres optimaux de fonctionnement du dispositif dépendent significativement de cette gigue initiale. Nous nous intéressons également au rendement énergétique du dispositif et montrons de quelle manière l'utilisation de l'amplification Raman permet de l'accroître.

Amplification parabolique : aspects fondamentaux

National audience

L’énergie du XXIème siècle : différentes formes et nombreux enjeux

National audience; L’énergie est cœur de nos sociétés modernes. Sa production, sa transformation, son acheminement sont autant d’enjeux cruciaux qu’il est nécessaire de maîtriser, tout en prenant en compte les contraintes environnementales. Après avoir donné quelques perspectives historiques, je dresserai un panorama des solutions actuelles en essayant de dégager les atouts et limites de chaque type d’énergie.

Dispositif et procede de traitement d'un signal optique

Transition dynamics in optical fiber amplifiers operating in the normal dispersion regime

Over the past decade there has been large interest in ultrafast optical fiber amplifiers operating in the normal dispersion regime because of the discovery that, high-energy pulses with a parabolic intensity profile and linear frequency chirp are the asymptotic solution to the system for arbitrary initial conditions [1]. These so-called “similariton” solutions propagate in a self-similar manner, holding certain relations (scaling) between pulse power, duration, and chirp parameter. While the asymptotic similariton features seem now well understood [1], the physics of the transition to this solution from arbitrary initial pulses has not been fully explored yet (most of the previous attempts …

Collision de mascarets optiques dans les fibres optiques

Une vidéo de la conférence est disponible à l'adresse suivante : https://youtu.be/c_R9D-VNMZo; National audience; Les instabilités optiques générées par mélange à quatre ondes sont étudiées expérimentalement dans les fibres optiques. En régime de dispersion normale, elles se traduisent par la génération d’ondes de choc et par des collisions successives de ces trains d’ondes.

All-Fibered High-Quality 20-GHz and 40-GHz Picosecond Pulse Generator

International audience; In this work, we investigate the generation of 20 and 40 GHz pulse trains by nonlinear compression of an initial beating in a cavity-less optical-fiber-based configuration. High temporal stability is obtained by generating the sinusoidal beating by means of an intensity modulator driven by an external clock. The residual timing jitter induced by the RF phase modulation is then reduced by managing the cumulated dispersion of the compression line whereas complete polarization stabilization is obtained thanks to a modified setup including a Faraday rotator mirror. Finally a high-quality 160 Gbit/s signal is generated from our low duty-cycle 40 GHz pulse source thanks to…

Self-phase modulation based 2R optical regenerator for the simultaneous processing of two WDM channels

International audience

Enhanced nonlinear spectral compression in fibre by sinusoidal phase modulation

International audience

Fiber-based measurement of temporal intensity and phase profiles through self-phase modulation

International audience

Nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations

Using photonic first-order differentiator applied on a partially coherent field, we generate two correlated temporal waveforms and experimentally study their correlation properties upon nonlinear propagation along the two orthogonal polarization axis of an optical fiber.

Thermo-plasmonic components at telecom wavelength

International audience

Instabilités optiques dans les fibres a dispersion oscillante

Génération d'impulsions ultrabrèves de haute puissance et a haut taux de répétition par amplification fibrée en régime auto-similaire ou d'auto-modulation de phase

National audience; Nous démontrons l'amplification d'impulsions pico- et femto-secondes par un dispositif fibré à un taux de répétition de 1 GHz obtenu par utilisation d'un VECSEL passivement mode-locké. Deux régimes non-linéaires d'amplification sont alors clairement mis en évidence, l'un dominé par l'auto-modulation de phase et l'autre par une évolution autosimilaire. Ce dernier régime conduit après recompression temporelle à des impulsions en limite de Fourier avec une durée temporelle inférieure à 150 fs.

Impact d'une modulation de phase anti-Brillouin sur la génération d'un train d'impulsions picosecondes dans une fibre optique

National audience; Dans ce travail, nous mettons en évidence l'influence d'une modulation de phase anti-Brillouin sur la gigue temporelle d'un train d'impulsions picosecondes généré par compression non-linéaire d'un battement sinusoïdal au sein d'une fibre optique.

Self-similarity in ultrafast nonlinear optics

International audience; Recent developments in nonlinear optics have led to the discovery of a new class of ultrashort pulse, the `optical similariton'. Optical similaritons arise when the interaction of nonlinearity, dispersion and gain in a high-power fibre amplifier causes the shape of an arbitrary input pulse to converge asymptotically to a pulse whose shape is self-similar. In comparison with optical solitons, which rely on a delicate balance of nonlinearity and anomalous dispersion and which can become unstable with increasing intensity, similaritons are more robust at high pulse powers. The simplicity and widespread availability of the components needed to build a self-similar amplif…

Double-seed stabilization of a continuum generated from fourth-order modulation instability

Summary form only given. Modulation instability (MI) is a ubiquitous process in which a weak field is exponentially amplified through a balance between dispersive and nonlinear effects. In single-mode scalar optical fibers, the positive Kerr nonlinearity phase-mismatch can be compensated by anomalous second-order dispersion, a process known as MI2. But phase-matched solutions can also exist in normal second-order dispersion region, thanks to negative even higher-order terms [1]. This process, that we label MI4, gives rise to a pair of narrow sidebands widely detuned far from the pump. MI may grow spontaneously from broadband noise and is usually the main process involved in the early stages…

Interaction between optical parabolic pulses in a Raman fiber amplifier

We investigate the interaction between optical parabolic pulses in a Raman fiber amplifier. Self-similar amplification of two identical time-delayed pulses creates an oscillation which further evolves into a train of dark solitons through the combined effects of non-linearity, normal dispersion and adiabatic Raman gain. Theoretical predictions are in good agreement with experimental results.

Photo-thermal modulation of surface plasmon polariton propagation at telecommunication wavelengths

International audience; We report on photo-thermal modulation of thin film surface plasmon polaritons (SPP) excited at telecom wavelengths and traveling at a gold/air interface. By operating a modulated continuous-wave or a Q-switched nanosecond pump laser, we investigate the photo-thermally induced modulation of SPP propagation mediated by the temperature-dependent ohmic losses in the gold film. We use a fiber-to-fiber characterization set-up to measure accurately the modulation depth of the SPP signal under photo-thermal excitation. On the basis of these measurements, we extract the thermo-plasmonic coefficient of the SPP mode defined as the temperature derivative of the SPP damping const…

All-fibered high-quality low duty-cycle 160-GHz femtosecond pulse source

International audience; In this paper, we report the experimental demonstration of an all-optical fiber-based 160-GHz femtosecond pulse source exhibiting a duty cycle as low as 1/17. The 380-fs wellseparated Gaussian pulses are generated thanks to the strong temporal compression of an initial beat-signal propagating into three distinct segments of optical fiber. Experimental results are supported by numerical simulations based on the generalized nonlinear Schrödinger equation. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

All-fibered high-quality low duty-cycle picosecond high-repetition rate pulse sources

International audience

Pulse shaping in mode-locked fiber lasers by in-cavity spectral filter

International audience; We numerically show the possibility of pulse shaping in a passively mode-locked fiber laser by inclusion of a spectral filter into the laser cavity. Depending on the amplitude transfer function of the filter, we are able to achieve various regimes of advanced temporal waveform generation, including ones featuring bright and dark parabolic-, flat-top-, triangular- and saw-tooth-profiled pulses. The results demonstrate the strong potential of an in-cavity spectral pulse shaper for controlling the dynamics of mode-locked fiber lasers.

Solitons sur fond continu en optique non-linéaire fibrée

National audience

Observation of Peregrine-like events in focusing dispersive dam break flows

International audience

Temporal and spectral nonlinear shaping techniques in optical fibers

International audience

New developments in the study of optical parabolic pulses in normally dispersive fibers

International audience; We report two recent studies dealing with the evolution of parabolic pulses in normally dispersive fibers. On the one hand, the nonlinear reshaping from a Gaussian intensity profile towards the asymptotic parabolic shape is experimentally investigated in a Raman amplifier. On the other hand, the significant impact of the fourth order dispersion on a passive propagation is theoretically discussed: we numerically demonstrate flat-top, coherent supercontinuum generation in an all-normal dispersion-flattened photonic crystal fiber. This shape is associated to a strong reshaping of the temporal profile what becomes triangular.

Breather Dynamics in Ultrafast Fibre Lasers and Their Intelligent Control

We review our recent work on the dynamics of breathing solitons in fibre lasers, including single breathers, breather molecular complexes, breather explosions and breather frequency locking at Farey fractions, and their control by genetic algorithms.

Impact of structural irregularities on high-bite-rate pulse compression techniques in photonics crystal fibre

International audience; The impact of structural irregularities on high bit rate pulse compression techniques is evaluated in photonic crystal fibre. Specifically, more robust pulse compression to longitudinal fluctuations in the normal dispersion regime is reported. The physical limits of these pulse compression techniques in the presence of dispersion fluctuations are identified and the fact that state-of-the-art fabrication tolerances are sufficient for future experimental applications is confirmed.

Wavelength conversion and temporal compression of a pulse train using a dispersion oscillating fiber

International audience; We demonstrate the generation of a picosecond pulse train taking advantage of the cross gain occurring in a dispersion oscillating fibre. The resulting frequency-converted signal is detuned by more than 20 nm from the pump and can be temporally compressed by a factor 2 compared to the input sinusoidal pump wave.

Performance analysis of dual-pump nonlinear amplifying loop mirror mode-locked all-fibre laser

We numerically characterise, in the three-dimensional space of adjustable cavity parameters, the performance of a recently reported layout of a flexible figure-8 laser having two independently pumped segments of active fibre in its bidirectional ring (Smirnov et al 2017 Opt. Lett. 42 1732–5). We show that this optimisation problem can be efficiently addressed by applying a regression model based on a neural-network algorithm.

Rogue waves, rational solitons and wave turbulence theory

International audience; Considering a simple one dimensional nonlinear Schrödinger optical model, we study the existence of rogue wave events in the highly incoherent state of the system and compare them with the recently identified hierarchy of rational soliton solutions. We show that rogue waves can emerge in the genuine turbulent regime and that their coherent deterministic description provided by the rational soliton solutions is compatible with an accurate statistical description of the random wave provided by the wave turbulence theory. Furthermore, the simulations reveal that even in the weakly nonlinear regime, the nonlinearity can play a key role in the emergence of an individual r…

Source optique à très haut débit basée sur la compression non-linéaire de besselons optiques

National audience; Nous démontrons la génération expérimentale de trains d’impulsions ultrabrèves à des taux de répétition allant de 28 à 112 GHz. Notre approche se base sur la compression non-linéaire de besselons dans une fibre optique hautement non-linéaire à dispersion normale. Les impulsions obtenues atteignent des durées subpicosecondes.

Nonlinear pulse shaping in optical fibers

International audience

Les vagues monstrueuses de l’océan expliquées par la lumière

National audience

Self-phase modulation patterns in optical fibres

International audience; Self-phase modulation (SPM), one of those very fascinating effects discovered in the early days of nonlinear optics, refers to the phenomenon by which an intense optical beam propagating in a Kerr medium (e.g., an optical fibre) induces through the nonlinearity of the medium a modulation of its phase that is proportional to its own intensity profile [1]. For an input pulsed beam, the induced time-dependent phase change is associated with a modification of the optical spectrum, which depends on the initial frequency modulation (chirp) of the pulse electric field. If the pulse is initially Fourier-transform-limited or up-chirped, SPM leads to spectral broadening, where…

Étude expérimentale d'un système hybride WDM/DS-OCDMA pour un réseau d'accès optique haut-débit

National audience; Nous présentons une solution hybride WDM/DS-OCDMA pour l'application réseau d'accès optique haut-débit.

Group birefringence cancellation in highly birefringent photonic crystal fibre at telecommunication wavelengths

International audience; The spectral dependence of the group modal birefringence in a highly birefringent nonlinear photonic crystal fibre is studied both numerically and experimentally. The sign inversion and the cancellation of the group modal birefringence in the telecommunication window is demonstrated. Two simple experimental techniques are used to evaluate the wavelength of zero polarisation mode dispersion. The experimental results are in excellent agreement with numerical calculations based on vectorial beam propagation method simulations.

Peregrine soliton generation and breakup in standard telecommunications fiber

International audience; We present experimental and numerical results showing the generation and breakup of the Peregrine soliton in standard telecommunications fiber. The impact of non-ideal initial conditions is studied through direct cut back measurements of the longitudinal evolution of the emerging soliton dynamics, and is shown to be associated with the splitting of the Peregrine soliton into two subpulses, with each subpulse itself exhibiting Peregrine soliton characteristics. Experimental results are in good agreement with simulations.

Experiments on breathers in nonlinear fibre

International audience

Sources optiques à 10 et 20 GHz basées sur la compensation spectrale d'une phase temporelle sinusoïdale

National audience; Nous introduisons théoriquement et démontrons expérimentalement une nouvelle approche à même de générer des trains impulsionnels de grande qualité et à haut-débit. Cette méthode repose sur une modulation temporelle par une phase sinusoïdale suivie de l’application d’une phase spectrale triangulaire.

Dynamique des solitons de Kuznetsov-Ma observée en optique fibrée non-linéaire

International audience; Le soliton de Kuznetzov-Ma est une solution de l'équation de Schrödinger non-linéaire qui a été identifiée dès 1977 mais qui à ce jour n'avait encore jamais été observée expérimentalement. Nous décrivons ici une expérience mettant en évidence la dynamique du soliton KM à travers la propagation non-linéaire de breathers dans une fibre optique.

Breathing Solitons in a Passively Harmonic Mode-Locked Fibre Laser

We report on the first experimental observation of breathing solitons in a passively harmonic mode-locked fibre laser. Various features of a 4th-harmonic operation state showing breather oscillations with a period of 5 roundtrips are discussed.

Phase-space topology of fiber four-wave mixing

Fibre microstructurée à deux zéros de dispersion : étude des fluctuations de microstruture sur des applications à haut-débit et détermination expérimentale du second zéro de dispersion

Collisions between similaritons in optical fiber amplifiers

We consider the self-similar amplification of two optical pulses of different wavelengths in order to investigate the effects of a collision between two similaritons. We theoretically demonstrate that similaritons are stable against collisions in a Raman amplifier: similaritons evolve separately in the amplifier without modification of the scaling of their temporal width and chirp and by conserving their velocities, only interact during their overlap and regain their parabolic form after collision. We show both theoretically and experimentally that the collision of two similaritons induces a sinusoidal modulation inside the overlap region, whose frequency decreases during the interaction. T…

Génération de séquences d'impulsions picosecondes apériodiques à partir d'ondes optiques incohérentes

National audience

Experimental control over soliton interaction in optical fiber by pre-shaped input field

Interactions between femtosecond solitons in a nonlinear photonic-crystal fiber are of fundamental interest. But many practical applications would abound if solitons could be arbitrarily superposed into multiples in the fiber. Here, we numerically and experimentally demonstrate a first step towards this aim, the creation of a soliton pair with arbitrary relative phase, delay, and frequency throughout almost the entire output parameter space with the aid of a pre-shaped fiber input field.

Spectral dynamics of modulation instability described using Akhmediev breather theory

International audience; The Akhmediev breather formalism of modulation instability is extended to describe the spectral dynamics of induced multiple sideband generation from a modulated continuous wave field. Exact theoretical results describing the frequency domain evolution are compared with experiments performed using single mode fiber around 1550 nm. The spectral theory is shown to reproduce the depletion dynamics of an injected modulated continuous wave pump and to describe the Fermi-Pasta Ulam recurrence and recovery towards the initial state. Realistic simulations including higher-order dispersion, loss and Raman scattering are used to identify that the primary physical factors that …

Polarized multiplex coherent anti-Stokes Raman scattering using a picosecond laser and a fiber supercontinuum

International audience; We perform multiplex coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy with a picosecond pulsed laser and a broadband supercontinuum (SC) generated in photonic crystal fiber. CARS signal stability is achieved using an active fiber coupler that avoids thermal and mechanical drifts. We obtain multiplex CARS spectra for test liquids in the 600–2000 cm−1 spectral range. In addition we investigate the polarization dependence of the CARS spectra when rotating the pump beam linear polarization state relative to the linearly polarized broad stokes SC. From these polarization measurements we deduce the Raman depolarization ratio, the resonant versus nonresonant …

High speed optical transmission at 2 µm in subwavelength waveguides made of various materials

International audience

In-Cavity Transformations for New Nonlinear Regimes of Pulse Generation in Mode-Locked Fibre Lasers

International audience; We review recent progress in the research on nonlinear mechanisms of pulse generation in passively mode-locked fibre lasers. These include parabolic self-similar pulse mode-locking, a mode-locking regime featuring pulses with a triangular distribution of the intensity, and spectral compression arising from nonlinear pulse propagation. We also report on the possibility of achieving various regimes of advanced temporal waveform generation in a mode-locked fibre laser by inclusion of a spectral filter into the laser cavity.

High quality low duty cycle 20-GHz and 40-GHz picosecond pulse sources

International audience

Breather laser dynamics and their intelligent control

Breathers are localized structures showing periodic variations in parameters. They are found in various fields of science, and are currently attracting significant research interest in virtue of their relationship with a rich set of important nonlinear phenomena. They have recently emerged as a universal ultrashort pulse regime in passively mode-locked fibre lasers. Here, we reviewed our recent works in this fast-growing field, including the first observation of breathing dissipative solitons and their complexes in mode-locked fibre lasers[1-3], breather explosions[4], and intelligent control of breathers over breathing periods, breathing ratios, and the number of breathers[5]. Finally, fra…

All-optical nonlinear processing of both polarization state and intensity profile for 40 Gbit/s regeneration applications

International audience; In this paper, we report all-optical regeneration of the state of polarization of a 40-Gbit/s return-to-zero telecommunication signal as well as its temporal intensity profile and average power thanks to an easy-to-implement, all-fibered device. In particular, we experimentally demonstrate that it is possible to obtain simultaneously polarization stabilization and intensity profile regeneration of a degraded light beam thanks to the combined effects of counterpropagating four-wave mixing, self-phase modulation and normal chromatic dispersion taking place in a single segment of optical fiber. All-optical regeneration is confirmed by means of polarization and bit-error…

Multi-parameter optimisation of dual-pump NALM fibre laser using machine-learning approaches

Recently, a new design of a model-locked all-fibre Figure-8 laser employing a nonlinear amplifying loop mirror (NALM) with two active fibre segments and two independently controlled pump-power modules has been proposed and experimentally demonstrated. This laser layout combines the reliability and robustness of conventional Figure-8 lasers with the flexibility of nonlinear-polarisation-evolution (NPE) lasers, providing access to a variety of generation regimes with a relatively wide adjustment range of the pulse parameters. Moreover, it enables reliable and reproducible live electronic adjustment of the lasing regimes, which is practically impossible to do by adjusting fibre-based polarisat…

Impact of initial pulse shape on the nonlinear spectral compression in optical fibre

International audience; We theoretically study the effects of the temporal intensity profile of the initial pulse on the nonlinear spectral compression process arising from nonlinear propagation in an optical fibre. Various linearly chirped input pulse profiles are considered, and their dynamics is explained with the aid of time-frequency representations. While initially parabolic-shaped pulses show enhanced spectral compression compared to Gaussian pulses, no significant spectral narrowing occurs when initially super-Gaussian pulses are used. Triangular pulses lead to a spectral interference phenomenon similar to the Fresnel bi-prism experiment.

Mitigation of self-phase modulation by sinusoidally time varying phase

The propagation of intense ultra-short optical pulses in a Kerr medium such as an optical fibre remains a critical issue for many optical systems. This is because the self-phase modulation (SPM) of the propagating pulse usually causes a severe broadening of the pulse spectrum that is typically accompanied by an oscillatory structure. Several strategies have been proposed and successfully deployed to counteract the deleterious effects of SPM in fiber-optic systems, including spatial or temporal scaling to reduce the impact of nonlinearity. Other approaches rely on the exploitation of the peculiar properties of parabolic shaped pulses and self-similar evolution. However, none of these last te…

Création d'un peigne de fréquences de longueur d'onde centrale accordable à partir d'ondes continues

National audience; Nous démontrons expérimentalement la possibilité d'exploiter l'auto-glissement fréquentiel Raman combiné soit à la compression d'un battement sinusoïdal, soit à l'instabilité de modulation induite. Les deux approches ont permis de générer un peigne de fréquences de largeur spectrale supérieure à 100 nm dont la fréquence centrale s'est décalée vers les hautes longueurs d'ondes.

All-fibered high-quality low duty-cycle picosecond high repetition rate pulse sources

In this work, we demonstrate all-fibered 20-GHz and 40-GHz picosecond pulse sources with duty cycles as low as 1/14. The pulse train is achieved via the high-quality compression of an initial sinusoidal beating through four segments of optical fibers. We investigate the limits of the scalability to higher repetition rates.

Spectral Slicing of a Supercontinuum Source for WDM/DS-OCDMA Application

WDM and optical CDMA are leading contenders to easily upgrade access network performances in terms of multiple access technique. Both methods can be used at once, using a single multiwavelength optical source. We show, numerically and experimentally, that spectral slicing of a 10-GHz pulse train broadened to a supercontinuum yields pulses suitable for use in a direct sequence optical CDMA system. Simulations with optical CDMA encoders and decoders based on superstructured fiber Bragg gratings indicate good performance can be expected.

Elimination de l’auto-modulation de phase dans un amplificateur à fibre

National audience; Nous introduisons et démontrons expérimentalement une nouvelle approche pour améliorer le taux d’extinction d’une impulsion affectée par un fond continu cohérent. Cette méthode repose sur une modulation temporelle par une phase sinusoïdale suivie d’une étape de recompression spectrale non-linéaire.

Reconstruction of phase-space topology in fiber four-wave mixing

We propose an experimental technique aimed to reveal a fundamental four-wave mixing process resulting in a complete reconstruction of the phase-space topology. The analysis is accompanied by training of a neural network on the experimental data.

Active reduction of fluctuations in fourth-order modulation instability

International audience; We experimentally study the fluctuation properties of a scalar fourth-order modulation instability process obtained by pumping a photonic crystal fiber in the normal dispersion region. We observe large wavelength-dependant pulse-to-pulse fluctuations which cannot be significantly reduced by stimulating the process with a single seed. Their reduction requires two seeds slightly detuned from the maximum gain frequency in order to also stimulate the second-order modulation instability process cascaded from the fourth-order one. This concept is validated by experiments and numerical simulations.

Design rules for nonlinear spectral compression in optical fibers

International audience; We present comprehensive design rules to optimize the process of spectral compression arising from nonlinear pulse propagation in an optical fiber. Extensive numerical simulations are used to predict the performance characteristics of the process as well as to identify the optimal operational conditions within the space of system parameters. It is shown that the group-velocity dispersion of the fiber is not detrimental and, in fact, helps achieve optimum compression. We also demonstrate that near-transform-limited rectangular and parabolic pulses can be generated in the region of optimum compression.

Exploiter une plateforme de recherche en télécommunications optiques pour souligner la dualité temps/fréquence

National audience; L’analyse de Fourier [1] tient une place majeure dans l’analyse et la compréhension de nombreux phénomènes de la physique et de l’ingénierie contemporaines. Pourtant les étudiants, qui ont souvent découvert cette notion à travers des travaux numériques ou en cours de mathématiques, ne cernent pas forcément toute la richesse qui peut être tirée de l’analyse conjointe dans les domaines temporels et spectraux, notamment dans le domaine de l’optique [2, 3]. De plus, si une grande attention est souvent accordée aux profils temporels ou spectraux en intensité, la notion de phase est souvent balayée beaucoup rapidement.Nous avons mis en place dans le cadre de la seconde année du…

Diverses manifestations de l'effet Raman lors de la propagation d'impulsions femtosecondes dans une fibre microstructurée

National audience; Dans le cadre de la génération de supercontinuum, nous mettons en évidence les dynamiques spectrales majeures de solitons liées à l'effet Raman dans une fibre microstructurée, à l'aide d'un montage expérimental simple. L'étude menée ici concerne l'évolution d'impulsions femtosecondes en régime de dispersion anormale d'une fibre microstructurée présentant deux longueurs d'onde de dispersion nulle. A l'aide de simulations numériques, nous confirmons nos différentes observations expérimentales ayant relevé les manifestations suivantes liées à l'effet Raman : l'auto-décalage en fréquence des solitons, la compensation de cet auto-décalage, mais également la formation et l'auto…

Pulse generation with dispersion decreasing optical fiber

International audience

On recent progress in all-fibered pulsed optical sources from 20 GHz to 2 THz based on multiple four wave mixing approach

International audience; In this paper, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. Based on the nonlinear compression of an initial beat-signal in optical fibers through a multiple four-wave mixing process, we theoretically and experimentally demonstrate that this simple technique allows an efficient and accurate design of versatile pulse sources having repetition rates and pulse durations ranging from 20 GHz up to 2 THz and from 10 ps up to 110 fs, respectively.

Propagation non-linéaire d'impulsions femtosecondes dans une fibre optique à bande interdite à cœur solide

National audience; Nous décrivons une étude expérimentale et numérique de l'évolution non-linéaire d'impulsions ultrabrèves se propageant dans une fibre optique à bande interdite à coeur solide. Suivant le mécanisme de guidage employé, des dynamiques significativement différentes sont mises en évidence.

Parabolic pulse formation and applications

Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such pulses as well as the results obtained in a wide-range of experimental configurations.

Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using a fiber Bragg grating based parabolic pulse shaper

We demonstrate the generation of ultra-flat broadened spectra by seeding a nonlinear fiber with parabolic pulses shaped using a fiber grating. Applications in pulse compression and spectral slicing are shown.

Parabolic similaritons in optical fibres

International audience; Recent developments in nonlinear optics have brought to the fore of intensive research an interesting class of pulses with a parabolic intensity prole and a linear instantaneous frequency shift or chirp [1, 2]. Parabolic pulses propagate in optical bres with normal group-velocity dispersion in a self-similar manner, holding certain relations (scaling) between pulse power, duration and chirp parameter, and can tolerate strong nonlinearity without distortion or wave breaking. These solutions, which have been dubbed similaritons, were demonstrated theoretically and experimentally in ber ampliers in 2000. Similaritons in ber ampliers are, along with solitons in passive b…

Observation of Optical Undular Bores in Multiple Four-Wave Mixing

International audience; We demonstrate that wave-breaking dramatically affects the dynamics of nonlinear frequency conversion processes that operate in the regime of high efficiency (strong multiple four-wave mixing). In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores (dispersive shock waves) that mimic the typical behavior of dispersive hydrodynamics exhibited, e.g., by gravity waves and tidal bores. Thanks to the nonpulsed nature of the beat signal employed in our experiment, we are able to clearly observe how the periodic nature of …

Applications of sinusoidal phase modulation in temporal optics to highlight some properties of the Fourier transform

International audience; Fourier analysis plays a major role in the analysis and understanding of many phenomena in physics and contemporary engineering. However, students, who have often discovered this notion through numerical tools, do not necessarily understand all the richness that can be derived from joint analysis in the temporal and spectral domains, particularly in the field of optics. As part of the second year of the Master's degree in Physics Lasers and Materials at the University of Burgundy, we have set up a set of experiments to highlight these concepts and to show, on a non-trivial example of periodic phase modulation, the precautions to be taken in the interpretation of the …

Etude et contrôle des portraits de phase du processus idéal de mélange à quatre ondes dans les fibres optiques

L’équation de Schrödinger non linéaire régit l’évolution des ondes dans de nombreux domaines non linéaires tels que l’hydrodynamique, la physique des plasmas, les condensats de Bose-Einstein et l’optique fibrée. Dans ce dernier cas, l’onde subit des changements dans un milieu dispersif combiné à un déphasage non linéaire dépendant de l’intensité. Le processus clé sous-jacent est le mélange à quatre ondes, qui décrit l’échange d’énergie entre des composantes de fréquence discrètes. En raison de la croissance des bandes latérales additionnelles et des pertes optiques qui limitent la distance d’interaction potentielle, il est notoirement difficile d’observer expérimentalement la dynamique idéa…

Optimisation de la densité spectrale d'énergie obtenue par auto-décalage fréquentiel Raman dans une fibre microstructurée

National audience

Exploring titanium dioxide as a new photonic platform

International audience; We report the development of titanium dioxide-based waveguides for applications in the near-and mid-infrared. Thanks to embedded metal grating couplers, we demonstrate error free 10 Gbit/s optical transmissions at 1.55 and 2 µm. We also demonstrate octave-spanning supercontinuum in cm-long waveguides. We explore the way to improve such waveguides through optimized fabrication process.

Optical rogue waves: Physics and impact

International audience; We review our recent work in the field of optical rogue wave physics and applications. Beginning from a brief survey of the well-known instabilities in optical fiber supercontinuum generation, we trace the links to recent developments in studying the emergence of high contrast localized breather structures in both spontaneous and induced nonlinear instabilities. We also discuss the precise nature of optical rogue wave statistics and examine the dynamics leading to the formation of extreme events in the context of noise-driven supercontinuum generation.

Génération de similaritons optiques à 1550 nm par amplification Raman dans une fibre NZ-DSF

Nous presentons la premiere observation experimentale de similaritons optiques generes par amplification Raman a 1550 nm dans une fibre a dispersion decalee. Une caracterisation FROG des impulsions indique un profil d'intensite parabolique et un chirp lineaire conformes aux predictions theoriques.

Asymptotic properties of incoherent waves propagating in an all-optical regenerators line

International audience; We present an original method to generate optical pulse trains with random time-interval values from incoherent broadband sources. More precisely, our technique relies on the remarkable properties of a line made of cascaded self-phase modulation-based optical regenerators. Depending on the regenerator parameters, various regimes with noticeably different physical behaviors can be reported.

Nonlinear pulse shaping and polarization dynamics in mode-locked fiber lasers

International audience; We review our recent progress on the study of new nonlinear mechanisms of pulse shaping in passively mode-locked fiber lasers. These include a mode-locking regime featuring pulses with a triangular distribution of the intensity, and spectral compression arising from nonlinear pulse propagation. We also report on our recent experimental studies unveiling new types of vector solitons with processing states of polarization for multi-pulse and tightly bound-state soliton (soliton molecule) operations in a carbon nanotube (CNT) mode-locked fiber laser with anomalous dispersion cavity.

Existence of nested oscillators in soliton molecules revealed by Mode Decomposition

Un réseau de verre ou comment la fibre optique permet de battre tous les records

80 GHz waveform generator by optical Fourier synthesis of four spectral sidebands

International audience

Peregrine soliton in optical fiber-based systems

International audience; We report the first observation in optics of the Peregrine soliton, a novel class of nonlinear localized structure. Two experimental configurations are explored and the impact of non-ideal initial conditions is discussed.

Nonlinear pulse shaping in optical fibers : a versatile tool for ultrafast photonics and fundamental wave propagation studies

International audience; The study of the combination of Kerr nonlinearity with dispersion in optical fibers has been stimulating much interest since the 80s. If such a combination can seriously impair the quality of high speed optical transmissions, it can on the contrary become an attractive solution to generate new temporal and spectral waveforms. We explain in this talk how to take advantage of the progressive temporal and spectral reshapings that occur upon propagation. We base our discussion on several experimental results obtained in the last decade at the Laboratoire Interdisciplinaire Carnot de Bourgogne. Examples exploiting both the normal and anomalous regimes of dispersion will be…

Lumière sur les vagues scélérates : le soliton de Peregrine enfin observé !

National audience

Experimental generation of parabolic pulses via Raman amplification in optical fiber

Parabolic pulse generation via Raman amplification is experimentally demonstrated in 5.3 km of non-zero dispersion shifted fiber presenting normal group velocity dispersion at the injected signal pulse wavelength of 1550 nm. The fiber is pumped by a commercially-available continuous wave source at 1455 nm, and the intensity and chirp of the amplifier output are characterized using frequency-resolved optical gating. For 2.4 pJ input pulses of 10 ps duration, the output pulse characteristics are studied as a function of amplifier gain over the range 11-24 dB, allowing the evolution of the input pulse to a parabolic pulse to be clearly seen for amplifier gains exceeding 15 dB. Numerical compre…

Amplifier similariton fibre laser with nonlinear spectral compression

We propose and numerically demonstrate a new concept of fibre laser architecture supporting self-similar pulse evolution in the amplifier and nonlinear pulse spectral compression in the passive fibre. The latter process is beneficial for improving the power efficiency as it prevents strong spectral filtering from being highly dissipative.

Reduced set of descriptors for experimental analysis of nonlinear optics phenomena

Rediscovered dynamics of nonlinear fiber optics: from breathers to extreme localisation

International audience

Recent advances in chalcogenide holey fibres

oral

Nonlinear Pulse Shaping in Optical Fibres with a Neural Network

We use a supervised machine-learning model based on a neural network to solve the direct and inverse problems relating to the shaping of optical pulses that occurs upon nonlinear propagation in optical fibres.

Optical rogue-wave-like extreme value fluctuations in fiber Raman amplifiers

International audience; We report experimental observation and characterization of rogue wave-like extreme value statistics arising from pump-signal noise transfer in a fiber Raman amplifier. Specifically, by exploiting Raman amplification with an incoherent pump, the amplified signal is shown to develop a series of temporal intensity spikes whose peak power follows a power-law probability distribution. The results are interpreted using a numerical model of the Raman gain process using coupled nonlinear Schrödinger equations, and the numerical model predicts results in good agreement with experiment.

All-optical fiber-based amplitude jitter magnifier

International audience; We describe the concept of an all-fibered device that enables the optical magnification of the amplitude jitter of low-fluctuation pulse trains, facilitating the measurement of the statistical properties by usual photodiodes and electronic equipments. Taking advantage of a highly nonlinear fiber with anomalous dispersion followed by central optical bandpass filtering, we experimentally demonstrate an amplification of small-scale fluctuations by a factor 10.

Model-free modelling of nonlinear pulse shaping in optical fibres

International audience; Machine learning is transforming the scientific landscape, with the use of advanced algorithmic tools in data analysis yielding new insights into many areas of fundamental and applied science. Photonics is no exception, and machine-learning methods have been applied in a variety of ways to optimise and analyse the output of optical fibre systems. In parallel with these developments, pulse shaping based on nonlinear propagation effects in optical fibres has developed into a remarkable tool to tailor the spectral and temporal content of light signals, leading to the generation of a large variety of optical waveforms. Yet, due to the typically large number of degrees of fre…

Propagation non-linéaire de champs partiellement incohérents mais avec une cohérence mutuelle contrôlée

National audience

Optical CDMA enhanced by nonlinear optics

Intended for the next generation of optical access networks, OCDMA is of great interest to meet the demand of increasing the number of users per access fiber, especially as spectral phase coding increases its performance in the optical domain. This, however, requires handling broad spectra and short pulses, which are best dealt with using opto-electronic or all-optical devices instead of slower electronics. Among others, we demonstrate spectral-phase-coded OCDMA using a fiber-based saturable absorber as thresholding in the receiver.

Impact du profil de phase initial sur l'évolution asymptotique d'impulsions dans un amplificateur à fibre

National audience; Nous étudions numériquement l'impact d'une dérive de fréquence initiale ou d'un saut de phase initial sur la dynamique asymptotique d'une impulsion se propageant dans un amplificateur à fibre à dispersion normale. Nous montrons notamment que si l'enveloppe de l'impulsion reste correctement décrite par l'expression analytique d'un similariton parabolique, des structures sombres peuvent néanmoins se superposer à cette enveloppe.

Propagation non linéaire dans des fibres optiques par réseaux de neurones artificiels

National audience; Les techniques d’apprentissage machine transforment le paysage de la recherche traditionnelle avec l’utilisation d’outils algorithmiques avancés pour l’analyse de données massives offrant de nouveaux angles de vue. Les domaines de la photonique et de l’optique ultra-rapide n’échappent pas à cette révolution. Nous nous intéressons dans cette contribution à la mise en œuvre de telles techniques appliquées à la mise en forme non-linéaire d’impulsions se propageant dans une fibre optique en présence de non-linéarités optiques. En effet, la combinaison de la dispersion et de la non-linéarité au cours de la propagation modifie profondément les profils temporels et spectraux de …

Evolution d'impulsions paraboliques dans un amplificateur a fibre optique hors regime asymptotique

National audience; Nous montrons que les impulsions paraboliques ne sont pas systématiquement synonymes de similaritons : un régime d'amplification dominé par l'auto-modulation de phase peut ainsi précéder le régime auto-similaire. Les caractéristiques des impulsions obtenues après recompression sont étudiées. Nous démontrons également qu'une impulsion parabolique de chirp initial négatif subit une recompression spectrale, conduisant à une impulsion parabolique de haute-énergie et en limite de Fourier.

Experimental parabolic pulse generation with an active dispersion decreasing fiber

We experimentally demonstrate the use of an hybrid configuration to generate parabolic pulses. We combine dispersion decrease with distributed gain. This leads to several benefits on the parabolic generated pulses compared with a passive configuration.

Spectral compression by self-phase modulation

International audience

Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber

Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber is experimentally and numerically investigated. Guiding light in such fiber occurs via two mechanisms: photonic bandgap in the central silica core or total internal reflection in the germanium doped inclusions. By properly combining spectral filtering, dispersion tailoring and pump coupling into the fiber modes, we experimentally demonstrate efficient supercontinuum generation with controllable spectral bandwidth.

Titanium dioxide waveguides for supercontinuum generation and optical transmissions in the near-and mid-infrared

International audience; We report the development of titanium dioxide-based waveguides for applications in the near-and mid-infrared. Thanks to embedded metal grating couplers, we demonstrate error free 10 Gbit/s optical transmissions at 1.55 and 2 µm. With additional management of the dispersion profile, we also demonstrate octave spanning supercontinuum in cm-long TiO2 waveguides.

Machine learning for ultrafast nonlinear photonics

Optical besselon waves

International audience; We theoretically describe a new type of an optical waveform, the ‘besselon’, which is synthesised by the line-by-line application of π/2-spectral phase shifts to sinusoidally phase-modulated continuous-wave light.

Mid-infrared supercontinuum generation in suspended-core chalcogenide and tellurite optical fibers

Summary form only given. The generation of optical supercontinua in the mid-infrared region and especially their expansion beyond the intrinsic limit dictated by fused silica is currently a subject of high interest. Tellurite and chalcogenide glasses have serious advantages because of their wide transmittance window which can reach more than 10 μm while the Kerr nonlinearity can be 500 times stronger than fused silica. These different features make them serious candidates for broad mid-infrared supercontinuum generation. For example, supercontinuum as broad as 4000-nm bandwidth has been generated in a sub-cm long Tellurite microstructured fiber by Domachuk et al. in ref. [1] by means of a f…

Générateur et procédé pour la génération d’impulsion optique optiques à haut taux de répétition

Autour de l’équation de Schrödinger non-linéaire dans les fibres optiques : similaritons, régénération, sources fibrées et évènements extrêmes

Direct temporal reconstruction of picosecond pulse by cross-correlation in semiconductor device

Cross-correlation measurements using the two-photon absorption process in a semiconductor is experimentally demonstrated for two pulses of different wavelengths (shifted by ~200 nm) and durations (20 times ratio). These measurements were found to be highly repeatable and fully suitable for the determination of the temporal intensity profile of picosecond (ps) pulses.

Design scaling laws for self-phase modulation-based 2R-regenerators

We report global scaling laws linking the design of SPM-based 2R-regenerators to their ability to reduce amplitude noise and improve the signal extinction ratio.

Émergence de flaticons dans les fibres optiques

Conférence pouvant être vue sur http://youtu.be/p9OnhcHQ3Mw; National audience; Nous étudions expérimentalement la propagation non-linéaire d'une onde continue menant à l'émergence d'impulsions au sommet plat et sans dérive de fréquence. Ces impulsions, appelées flaticons, subissent une évolution auto-similaire de leur partie centrale et présentent des oscillations temporelles marquées dans leurs flancs.

Third harmonic generation in optical fibers with long period grating

Parabolic pulse generation with active or passive dispersion decreasing optical fibers

International audience; We experimentally demonstrate the possibility to generate parabolic pulses via a single dispersion decreasing optical fiber with normal dispersion. We numerically and experimentally investigate the influence of the dispersion profile, and we show that a hybrid configuration combining dispersion decrease and gain has several benefits on the parabolic generated pulses.

Accrochage de fréquence dans un laser à fibre à respiration : observation de l’arbre de Farey et de l’escalier du diable

Contrairement au soliton brillant, les solitons à respiration présentent un comportement oscillatoire périodique. L’utilisation des fibres optiques a grandement facilité leur observation: l’interaction sur une grande distance entre la non-linéarité Kerr et la dispersion, en la quasi-absence de dissipation a ainsi permis la caractérisation fine des solitons à respiration d’Akhmediev, de Ma ou bien encore de leur cas limite, le soliton de Peregrine.Grâce au développement des techniques de détection en temps réel, les cavités laser à fibre offrent une autre plateforme extrêmement intéressante. Dans le contexte des lasers ultrarapides à modes bloqués, la génération d’impulsions à respiration co…

Soliton generation and rogue-wave like behavior through fourth order modulation instability

International audience; We numerically study the dynamics of ultra-broadband wavelength converters based on fourth-order scalar modulation instability. We report the spontaneous emergence of solitons and trapped radiation waves as well as L-shaped associated statistical signatures.

Compression spectrale améliorée par une modulation de phase corrective sinusoïdale

National audience; En exploitant une modulation de phase sinusoïdale temporelle additionnelle, nous montrons qu’il est possible d’améliorer significativement les performances d’une compression spectrale réalisée en régime de propagation hautement non-linéaire. Les simulations numériques indiquent ainsi une amélioration des facteurs de compression ainsi que du rapport de Strehl.

Light-by-light polarization control for telecommunication applications

In this work, we report for the first time the experimental achievement of an all-fibered polarization attraction, which can occur in optical fibers at telecommunication wavelengths. More precisely, we have experimentally shown that is possible to all-optically control and stabilize the state of polarization of a 10 Gbit/s telecommunication signal through the injection of a counter-propagating control pump wave. Eye diagrams recordings and bit error rate measurements have shown that this new type of all-optical function, almost lossless and instantaneous has a promising potential for telecommunication applications.

Nonlinear pulse shaping by coherent addition of multiple redshifted solitons

International audience; The injection of a phase- and amplitude-shaped pulse into a photonic-crystal fiber provides additional degrees of freedom that can significantly influence the nature of nonlinear propagation and nonlinear and dispersive interactions. This strong sensitivity of nonlinear effects-particularly the Raman soliton self-frequency shift-greatly extends the parameter space available to generate tailored output fields for applications such as microscopic imaging. By numerical simulations, we identify the relevant interpulse interactions, and we experimentally demonstrate the additional capabilities of this nonlinear pulse-shaping method.

Nonlinear pulse sculpturing in passive and laser cavity fibre systems

International audience; In recent years, there has been a growing interest from the photonics community in the generation of non-conventional optical waveforms because of their applications in all-optical signal processing and microwave signal manipulation. While sinusoidal, Gaussian and hyperbolic secant intensity profiles are now routinely produced by modulators or mode-locked lasers, other signal waveforms such as parabolic, triangular or flat-top pulse shapes remain rather hard to synthesize. Several approaches to the generation of specialized waveforms have been explored, including linear spectral shaping, the use of special Mach-Zehnder modulator architectures, and coherent Fourier sy…

Si and Si-rich silicon-nitride waveguides for optical transmissions and nonlinear applications around 2 µm

We show that cm-long silicon and silicon-rich silicon nitride waveguides with subwavelength transverse dimensions can efficiently sustain high-speed transmissions at 2 μm. We report the transmission of a 10 Gbit/s signal with negligible power penalty. Parametric conversion in both continuous and pulsed pump regimes is also demonstrated, as well as the spectral broadening of picosecond pulses.

Ondes scélérates et autres manifestations extrêmes dans les fibres optiques

National audience; Nous présentons divers exemples d'évènements rares optiques qui peuvent apparaître lors de la propagation d'impulsions dans des fibres optiques. Ainsi, différents types de structures optiques se démarquant très nettement du comportement statistique moyen ont été mis en évidence dans les processus de génération de supercontinua optiques ainsi que dans les phases d'amplification paramétrique ou Raman.

Façonnage optique intra-cavité dans un laser impulsionnel à fibre

National audience