Truncated thermalization of incoherent optical waves through supercontinuum generation in photonic crystal fibers

We revisit the process of optical wave thermalization through supercontinuum generation in photonic crystal fibers. We report theoretically and numerically a phenomenon of `truncated thermalization': The incoherent optical wave exhibits an irreversible evolution toward a Rayleigh-Jeans thermodynamic equilibrium state characterized by a compactly supported spectral shape. The theory then reveals the existence of a frequency cut-off which regularizes the ultraviolet catastrophe inherent to ensembles of classical nonlinear waves. This phenomenon sheds new light on the mechanisms underlying the formation of bounded supercontinuum spectra in photonic crystal fibers.

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.

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…

The dynamics of a developing CW supercontinuum: Analytical predictions and experiments

International audience; We show that the development of the supercontinuum spectrum in the quasi-CW regime can be interpreted analytically in terms of Akhmediev Breathers. Theory and experiment are in excellent agreement.

Experimental observation of dispersive photon focusing dam break flows

International audience

Emergence of spectral incoherent solitons through supercontinuum generation in photonic crystal fibers

International audience; We report an experimental and numerical study of the spontaneous emergence of spectral incoherent solitons through supercontinuum generation in a two zero-dispersionwavelengths photonic crystal fiber. By using a simple experimental setup, we show that the highly nonlinear regime of supercontinuum generation is characterized by the emergence of a spectral incoherent soliton in the low-frequency edge of the supercontinuum spectrum. We show that a transition occurs from the discrete spectral incoherent soliton to its continuous counterpart as the power of the laser is increased. Contrary to conventional solitons, spectral incoherent solitons do not exhibit a confinement…

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…

Rogue Breather Structures in Nonlinear Systems with an Emphasis on Optical Fibers as Testbeds

Demonstration of Experimental Infrared Spectral Broadening in Chalcogenide As2S3 Suspended Core Microstructured Optical Fibers

International audience

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.

Modulation instability, Akhmediev Breathers and continuous wave supercontinuum generation

Numerical simulations of the onset phase of continuous wave supercontinuum generation from modulation instability show that the structure of the field as it develops can be interpreted in terms of the properties of Akhmediev Breathers. Numerical and analytical results are compared with experimental measurements of spectral broadening in photonic crystal fiber using nanosecond pulses

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.

Spectral incoherent solitons

Solitons have been usually considered as inherently coherent localized structures and the discovery of incoherent optical solitons has represented a significant progress [1]. As occurs for standard coherent solitons, incoherent solitons are characterized by a confinement of the field in the spatial or in the temporal domain. We introduce here a novel type of incoherent solitons that are neither spatial nor temporal, i.e., the incoherent field does not exhibit any confinement in the spatiotemporal domain; however, the uncorrelated frequency components that constitute the incoherent field exhibit a localized soliton behavior in the frequency domain [2].

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.

Microstructured Optical Fibers from As2S3 Glass for Fiber Optics Sources in the MIR range

International audience

Recent developments in chalcogenide photonic crystal fibres

Elaboration of low-losses highly non linear chalcogenide optical fibers for the generation of efficient non linear effects in the infrared remains a challenge. In recent years, much work has been devoted to the study of microstructured optical fibers (MOFs) with different designs and various elaboration processes. Their background losses were typically of several dB/m.

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.

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.

Manakov Polarization Modulation Instability in Normal Dispersion Optical Fiber

We observed polarization modulation instability in the normal dispersion regime of randomly birefringent multi-km telecom optical fiber. The instability is pumped by two wavelength multiplexed and orthogonally polarized intense continuous lasers.

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.

Impact of optical and structural aging in As_2S_3 microstructured optical fibers on mid-infrared supercontinuum generation

We analyze optical and structural aging in As2S3 microstructured optical fibers (MOFs) that may have an impact on mid-infrared supercontinuum generation. A strong alteration of optical transparency at the fundamental OH absorption peak is measured for high-purity As2S3 MOF stored in atmospheric conditions. The surface evolution and inherent deviation of corresponding chemical composition confirm that the optical and chemical properties of MOFs degrade upon exposure to ambient conditions because of counteractive surface process. This phenomenon substantially reduces the optical quality of the MOFs and therefore restrains the spectral expansion of generated supercontinuum. This aging process …

Hydrodynamics of periodic breathers

We report the first experimental observation of periodic breathers in water waves. One of them is Kuznetsov–Ma soliton and another one is Akhmediev breather. Each of them is a localized solution of the nonlinear Schrödinger equation (NLS) on a constant background. The difference is in localization which is either in time or in space. The experiments conducted in a water wave flume show results that are in good agreement with the NLS theory. Basic features of the breathers that include the maximal amplitudes and spectra are consistent with the theoretical predictions.

Octave-spanning coherent supercontinuum generation in a step-index tellurite fiber and towards few-cycle pulse compression at 2 μ m

Abstract We experimentally demonstrate 140-THz bandwidth (at −20 dB) supercontinuum generation in a 10 cm-long all-normal dispersion step-index tellurite fiber pumped by a turn-key femtosecond fiber laser emitting at 2 . 11 μ m at a repetition rate of 19 MHz. The soliton self-frequency shifted thulium-doped fiber mode-locked laser emits initial transform-limited pulses, with 85-fs pulse duration, that are subsequently quasi-linearly chirped (over more than 50 THz) during the above nJ-level nonlinear propagation. Moreover, we numerically demonstrate the possible pulse compression down to 12 fs by means of additional linear propagation in a standard step-index fluoride fiber with anomalous di…

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.

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…

Suppression of the frequency drifts in polarization modulational instability spectra by means of a photon reservoir

By appropriately combining the effects of second- and fourth-order dispersion, and by carefully choosing the pump power, we create a photon reservoir which suppresses the drifts of sidebands in the spectra of polarization modulational instability

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

Effects of structural irregularities on modulational instability phase matching in photonic crystal fibers

International audience; The effect of structural irregularities in photonic crystal fibers on scalar and vector modulational instability (MI) processes is studied by numerical simulations and experiments. For an anomalous-dispersion regime pump, variations in core ellipticity as small as 0.5% over length scales of the order of several meters are shown to have a negligible effect on scalar MI, yet they completely suppress vector MI. In contrast, for a normal-dispersion regime pump, vector MI is shown to be robust against such fluctuations.

Cross-phase modulational instability induced by Raman scattering in highly birefringent fiber

We report experimental and theoretical studies of Raman-induced cross-phase modulational instabilities (XPMI) in a high-birefringence, normally dispersive optical fiber. Experimental results reveal that the Raman-Stokes wave, generated by a quasi-CW pump beam, interacts with the latter to create a novel type of XPMI sidebands. These sidebands are characterized by a narrow gain bandwidth. The sideband frequencies are well reproduced by a linear stability analysis as well as by full numerical solutions of the coupled generalized nonlinear Schrödinger equations.

Collision of Akhmediev Breathers in Nonlinear Fiber Optics

We report here a novel fiber-based test bed using tailored spectral shaping of an optical-frequency comb to excite the formation of two Akhmediev breathers that collide during propagation. We have found specific initial conditions by controlling the phase and velocity differences between breathers that lead, with certainty, to their efficient collision and the appearance of a giant-amplitude wave. Temporal and spectral characteristics of the collision dynamics are in agreement with the corresponding analytical solution. We anticipate that experimental evidence of breather-collision dynamics is of fundamental importance in the understanding of extreme ocean waves and in other disciplines dri…

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…

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.

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

Thermodynamic approach of supercontinuum generation in photonic crystal fiber

We show that the spectral broadening process inherent to supercontinuum generation may be described as a thermalization process, which results from the natural irreversible evolution of the optical field towards a thermodynamic equilibrium state.

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.

Recent developments in chalcogenide PCF

International 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…

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 …

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.

Thermodynamic approach of supercontinuum generation

International audience; This paper is aimed at providing an overview on recent theoretical and experimental works in which a thermodynamic description of the incoherent regime of supercontinuum generation has been formulated. On the basis of the wave turbulence theory, we show that this highly nonlinear and quasi-continuous-wave regime of supercontinuum generation is characterized by two different phenomena. (i) A process of optical wave thermalization ruled by the four-wave mixing effects: The spectral broadening inherent to supercontinuum generation is shown to result from the natural tendency of the optical field to reach its thermodynamic equilibrium state, i. e., the state of maximum n…

Observation of Manakov polarization modulation instability in the normal dispersion regime of randomly birefringent telecom optical fiber

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…

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…

A Brillouin fiber laser at 2 µm based on a step-index tellurite (TeO2) optical fiber

International audience; We demonstrate Brillouin lasing at 2-µm using a step-index Tellurite-glass optical fiber in a passive fiber ring cavity. A low lasing threshold of 70 mW was achieved with a Brillouin gain of 1.05 × 10-10 m/W for a Brillouin frequency shift of 6.165 GHz. Stimulated Brillouin scattering (SBS) in optical fibers is a nonlinear process with important applications such as distributed optical fiber sensing, microwave photonics, optical storage, and fiber lasers. The latter application has attracted significant interest as highly coherent laser sources with sub-Hz linewidth can be achieved using SBS in optical cavities. To date, most of Brillouin fibers lasers (BFLs) have be…

Temporal dynamics of incoherent waves in noninstantaneous response nonlinear Kerr media

International audience; We consider the temporal evolution of an incoherent optical wave that propagates in a noninstantaneous response nonlinear medium, such as single mode optical fibers. In contrast with the expected Raman-like spectral redshift due to a delayed nonlinear response, we show that a highly noninstantaneous response leads to a genuine modulational instability of the incoherent optical wave. We derive a Vlasov-like kinetic equation that provides a detailed description of this process of incoherent modulational instability in the temporal domain.

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

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

International audience

Towards a Thermodynamic Description of Supercontinuum Generation

Based on the kinetic wave theory, we describe continuous-wave supercontinuum generation as a thermalization process, i.e., an irreversible evolution of the optical field towards a state of maximum nonequilibrium entropy.

Thermodynamic approach of statistical nonlinear optics

The coherence properties of random nonlinear optical fields can be described in detail by thermodynamic arguments based on the wave turbulence theory. We shall review recent progress on this kinetic approach of statistical nonlinear optics.

Temporal incoherent solitons supported by a defocusing nonlinearity with anomalous dispersion

http://pra.aps.org/; International audience; We study temporal incoherent solitons in noninstantaneous response nonlinear media. Contrarily to the usual temporal soliton, which is known to require a focusing nonlinearity with anomalous dispersion, we show that a highly noninstantaneous nonlinear response leads to incoherent soliton structures which require the inverted situation: In the focusing regime (and anomalous dispersion) the incoherent wave packet experiences an unlimited spreading, whereas in the defocusing regime (still with anomalous dispersion) the incoherent wave packet exhibits a self-trapping. These counterintuitive results are explained in detail by a long-range Vlasov formu…

Mid-infrared supercontinuum generation from 2 to 14 μm in various chalcogenide glasses optical fibers

Chalcogenide glasses optical fibers with step index or microstructured profiles are drawn from low toxicity compositions. Supercontinuum generation lead to an infrared spectrum spanning from 2 to 14µm with a 10µm core fiber of 40mm length.

Discrete spectral incoherent solitons in nonlinear media with noninstantaneous response

International audience; We show theoretically that nonlinear optical media characterized by a finite response time may support the existence of discrete spectral incoherent solitons. The structure of the soliton consists of three incoherent spectral bands that propagate in frequency space toward the low-frequency components in a discrete fashion and with a constant velocity. Discrete spectral incoherent solitons do not exhibit a confinement in the space-time domain, but exclusively in the frequency domain. The kinetic theory describes in detail all the essential properties of discrete spectral incoherent solitons: A quantitative agreement has been obtained between simulations of the kinetic…

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.

Roadmap on optical rogue waves and extreme events

Nail Akhmediev et al. ; 38 págs.; 28 figs.

Façonnage optique non-linéaire dans les fibres optiques

National audience

3.5-μm bandwidth mid-infrared supercontinuum generation in a 2-cm long suspended-core chalcogenide fiber

A supercontinuum source extending from 0.6 to 4.1 µm has been successfully generated in a 2-cm long As2S3 chalcogenide suspended-core fiber by means of a nJ-level 200-fs pumping at 2.5 µm.

Polarization modulation instability in a Manakov fiber system

International audience; The Manakov model is the simplest multicomponent model of nonlinear wave theory: It describes elementary stable soliton propagation and multisoliton solutions, and it applies to nonlinear optics, hydrodynamics, and Bose-Einstein condensates. It is also of fundamental interest as an asymptotic model in the context of the widely used wavelength-division-multiplexed optical fiber transmission systems. However, although its physical relevance was confirmed by the experimental observation of Manakov (vector) solitons in a planar waveguide in 1996, there have in fact been no quantitative experiments confirming its validity for nonlinear dynamics other than soliton formatio…

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.

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.

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.

CONVERSIONS DE FREQUENCE ULTRA LARGE BANDE PAR MELANGE A QUATRE ONDES INTERMODAL EN CASCADE DANS LES FIBRES MULTIMODES

International audience; Nous mettons en évidence des effets de conversion spectrale paramétrique avec des décalages spectraux très importants (~200THz) dans une fibre à gradient d'indice qui, pompée avec une source laser picoseconde à 1064nm, supporte quatre modes de propagation. À travers des études expérimentales, analytiques et numériques détaillées, nous montrons que les multiples raies paramétriques sont générées par un processus en cascade complexe faisant intervenir des mélanges à quatre ondes intermodaux. Les longueurs d'onde paramétriques résultantes s'étendent dans le visible jusqu'à 410nm et dans le proche infrarouge jusqu'à 1355nm. MOTS-CLEFS : dynamique spatio-temporelle ; conv…

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…

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.

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…

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.

Wave turbulence and thermalization of random nonlinear waves

International audience

Enhanced supercontinuum generation in tapered tellurite suspended core fiber

Abstract We demonstrate 400-THz (0.6–3.3 µm) bandwidth infrared supercontinuum generation in a 10 cm-long tapered tellurite suspended core fiber pumped by nJ-level 200-fs pulses from an optical parametric oscillator. The increased nonlinearity and dispersion engineering extended by the moderate reduction of the fiber core size are exploited for supercontinuum optimization on both frequency edges (i.e., 155-THz overall gain), while keeping efficient power coupling into the untapered fiber input. The remaining limitation of supercontinuum bandwidth is related to the presence of the high absorption beyond 3 µm whereas spectral broadening is expected to fully cover the glass transmission window…

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.

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.

Long-Range interaction of temporal incoherent solitons

Contrary to conventional solitons, temporal incoherent solitons are sustained by a defocusing nonlinearity with anomalous dispersion and exhibit a non-mutual attractive-repulsive interaction. We explain these results by a long-range Vlasov formalism.

Superregular Breathers in Optics and Hydrodynamics: Omnipresent Modulation Instability beyond Simple Periodicity

Since the 1960s, the Benjamin-Feir (or modulation) instability (MI) has been considered as the self-modulation of the continuous “envelope waves” with respect to small periodic perturbations that precedes the emergence of highly localized wave structures. Nowadays, the universal nature of MI is established through numerous observations in physics. However, even now, 50 years later, more practical but complex forms of this old physical phenomenon at the frontier of nonlinear wave theory have still not been revealed (i.e., when perturbations beyond simple harmonic are involved). Here, we report the evidence of the broadest class of creation and annihilation dynamics of MI, also called superre…

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.

Impact of the material absorption on the modulational instability spectra of wave propagation in high index glass fibers.

International audience

Filament-induced visible-to-mid-IR supercontinuum in a ZnSe crystal: Towards multi-octave supercontinuum absorption spectroscopy

Abstract We report on the generation of multiple-octave supercontinuum laser source spanning from 0.5 μm to 11 μm induced by multi-filamentation in a ZnSe crystal. The generated supercontinuum is both spatially and spectrally characterized. It is then exploited in a proof-of-principle experiment for methane spectroscopy measurements by means of the supercontinuum absorption spectroscopy technique. The entire absorption spectrum is successfully recorded within the whole spectral bandwidth of the supercontinuum. Experimental results are in fairly good agreement with the HITRAN database, confirming the reliability and stability over several hours of the generated supercontinuum.

Cascaded intermodal four-wave mixing in a few-mode fiber

During the last few years, intensive works on multimode fibers allowed for the observation of a series of complex and novel nonlinear spatiotemporal phenomena such as: multimode solitons, geometric parametric instability, supercontinuum generation, and self-induced beam cleaning [1-4]. Among these phenomena, intermodal four-wave mixing (IMFWM) demonstrated larger frequency shifts in comparison with single-mode fibers. In this work, we studied IMFWM in a few-mode graded-index fiber (GRIN-FMF) pumped in the normal dispersion regime at 1064 nm. We report parametric sidebands detuned by hundreds of THz from the pump.

Strong infrared spectral broadening in low-loss As-S chalcogenide suspended core microstructured optical fibers

Made available in DSpace on 2013-08-28T14:10:10Z (GMT). No. of bitstreams: 1 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) Made available in DSpace on 2013-09-30T19:22:36Z (GMT). No. of bitstreams: 2 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) WOS000275454100017.pdf.txt: 34647 bytes, checksum: b4efba760b21442eba43e7096f213b3e (MD5) Previous issue date: 2010-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:33:52Z No. of bitstreams: 2 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) WOS000275454100017.pdf.txt: 34647 bytes, ch…

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 …

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.

Ondes scélérates en optique

National audience

Octave-spanning supercontinuum generation in titanium dioxide waveguides

International audience

Control of Space-Time Trajectories of Noise-Driven Optical Extreme Events in Metamaterial Waveguides

Metamaterials offer the potential to precisely manipulate electromagnetic wave propagation in ways that cannot be achieved with materials found in nature. The formation and propagation of optical spatial solitons in metamaterials has been already investigated [1]. Here we report the theoretical and numerical investigations on temporal-spectral dynamics of nonlinear extreme events arising from the initial noise-perturbed plane wave in metamaterial waveguides. A typical waveguide structure used here is a planar structure with a metamaterial core and a part of the structure, in the form of the substrate, is replaced with a magnetooptic material. We assume that the core material is isotropic an…

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.

Experimental signature of optical wave thermalization through supercontinuum generation in photonic crystal fiber

International audience; We report an experimental, numerical and theoretical study of the incoherent regime of supercontinuum generation in a two zero dispersion wavelengths fiber. By using a simple experimental setup, we show that the phenomenon of spectral broadening inherent to supercontinuum generation can be described as a thermalization process, which is characterized by an irreversible evolution of the optical field towards a thermal equilibrium state. In particular, the thermodynamic equilibrium spectrum predicted by the kinetic wave theory is characterized by a double peak structure, which has been found in quantitative agreement with the numerical simulations without adjustable pa…

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

National audience

Optical Dark Rogue Wave

AbstractPhotonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena and lead to novel space-time analogies, for example with multi-parti…

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.

Mid-infrared supercontinuum generation in suspended-core Chalcogenide and Tellurite optical fibers

We report the experimental generation of mid-infrared supercontinuum in tellurite and chalcogenide suspended-core fibers pumped close to their zero-dispersion in femtosecond regime. The resulting supercontinua extend until 2.8µm in tellurite and 3.2µm in chalcogenide fibers.

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

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.

Thermodynamic description of supercontinuum generation

International audience

CARACTÉRISATION ET MODÉLISATION DE PEIGNES DE FRÉQUENCES KERR DANS DES CAVITÉS LASER BRILLOUIN À FIBRE

Nous étudions une cavité en anneau non réciproque simple et reconfigurable pour générer des peignes de fréquences optiques accordables. Nous démontrons que des peignes cohérents peuvent être obtenus en exploitant finement la rétrodiffusion Brillouin stimulée et le mélange à quatre ondes en cascade dans la cavité à fibre non-linéaire.

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…

General approach to spatiotemporal modulational instability processes

International audience; In this article, we derive the general exact solution of the modulation instability gain. The solution described here is valid for 1-D, 2-D, and 3-D cases considering any temporal response function of the medium and with possible higher order Kerr nonlinearities. In particular, we show that the gain induced by modulation instability is initial condition dependent, while the usual calculations do not lead to such a dependence. Applications for current and high-interest nonlinear propagation problems, such as 1-D optical fiber propagation with delayed Raman response and 2-D filamentation in gases, are investigated in detail. More specifically, we demonstrate that the 2-D …

Source optique fibrée pour la microscopie CARS

Grating-assisted third-harmonic generation in photonic crystal fibers using a pulse pump

We demonstrate that quasi-phase-matching of the third-harmonic generation process can be obtained for a pulse pump in the photonic crystal fiber with a refractive-index grating. Conversion efficiency is calculated numerically using a system of coupled generalized nonlinear Schrodinger equations. We propose a special design of the microstructured fiber for the third-harmonic generation and analyze different phenomena limiting the maximum efficiency for short (femtosecond) and long (picosecond) pump pulses. Moreover, we show that a certain level of a group-velocity mismatch between the pump and the third harmonic can increase the maximum efficiency in the long pulse regime.

Nonlinear frequency conversion in a birefringent microstructured fiber tuned by externally applied hydrostatic pressure.

We studied vector frequency conversion in externally tuned microstructured fibers for applications as a novel, nonlinear fiber-optic sensor. We investigated both experimentally and numerically a possibility of shifting vector and scalar modulation instability gain bands by pressure-induced changes in the linear properties of a microstructured fiber. Our results show that polarization-dependent vector nonlinear processes sensitive to variation of fiber group velocity difference (group birefringence) exhibit a clear advantage for pressure-sensing applications compared with scalar nonlinear processes only sensitive to group velocity dispersion changes. Analytical predictions and numerical simu…

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.

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.

Suppression of the frequency drift of modulational instability side bands by means of a fiber system associated with a photon reservoir.

International audience

Nonlinear mode coupling in a birefringent microstructured fiber tuned by externally applied hydrostatic pressure

We studied the effect of power coupling between two linearly polarized modes, which occurs during nonlinear propagation in an externally tuned birefringent microstructured fiber. We investigated both experimentally and numerically the possibility of measuring hydrostatic pressure by tracking the nonlinear power coupling between the fiber polarization modes. We analyzed the impact of the fiber length exposed to pressure and the input polarization state on the coupling efficiency. We also revealed that the observation of nonlinear power coupling between the polarization modes is limited by linear coupling occurring in the leadthroughs to the pressure chamber. Moreover, we demonstrated that th…

Optical Cavity-Less 40-GHz Picosecond Pulse Generator in the Visible Wavelength Range

International audience; High-repetition-rate optical frequency-comb sources emitting picosecond pulses play important roles in variousscientific researches and industrial applications. Such ultrafast pulse sources are mostly generated in opticalcavities or microresonators. By means of the wavelength-conversion techniques, it is possible to transfer thecavity-based near-IR robust and compact sources to the mid-IR or to the visible wavelength regions [1-2], forwhich there is an increasing demand, for biophotonics and other applications. Here we demonstrate the generationof high-repetition-rate picosecond pulses in the visible wavelength range by using a fully optical cavity-lessconfiguration.…

Characterizing and Modeling Kerr Frequency Combs in Fiber Cavity Brillouin Lasers

We study a re-configurable nonreciprocal ring cavity setup to generate tunable optical frequency combs. Coherent combs can be obtained by finely exploiting stimulated Brillouin scattering and cascaded four-wave mixing in the nonlinear fiber cavity.

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)

Solitons sur fond continu en optique non-linéaire fibrée

National audience

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

International audience

Multioctave midinfrared supercontinuum generation in suspended-core chalcogenide fibers

An As2S3 fiber-based supercontinuum source that covers 3500 nm, extending from near visible to the midinfrared, is successfully reported by using a 200-fs-pulsed pump with nJ-level energy at 2.5 μm. The main features of our fiber-based source are two-fold. On the one hand, a low-loss As2S3 microstructured optical fiber has been fabricated, with typical attenuation below 2 dB/m in the 1-4 μm wavelength range. On the other hand, a 20-mm-long microstructured fiber sample is sufficient to enable a spectral broadening, spreading from 0.6 to 4.1 μm in a 40 dB dynamic range.

Wave-turbulence approach of supercontinuum generation: Influence of self-steepening and higher-order dispersion

International audience; We analyze the influence of self-steepening and higher-order dispersion on the process of optical wave thermalization. This study is aimed at developing a thermodynamic formulation of supercontinuum generation in photonic crystal fibers. In the highly nonlinear regime of supercontinuum generation, the optical field exhibits a turbulent dynamics that may be described by the kinetic wave theory. In this respect, the phenomenon of spectral broadening inherent to supercontinuum generation may be interpreted as a natural process of thermalization, which is characterized by an irreversible evolution of the optical field toward a thermodynamic equilibrium state. The numeric…

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.

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…

Nonlinear pulse shaping in optical fibers

International audience

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

Temporal Dynamics of Incoherent Nonlinear Waves

We review different formalisms describing incoherent waves: the wave turbulence kinetic equation, the Vlasov equation in analogy with Gravitation, the weak Langmuir turbulence equation describing spectral solitons and incoherent dispersive shocks.

Thermalization of random nonlinear waves: Application to optical waves

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.

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

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 …

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.

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…

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.

Supercontinuum Generation in Tellurite Optical Fibers

This chapter presents a state of the art of infrared supercontinuum generation in heavy oxide tellurite optical fibers from the experimental results published by the international community. As a first part, a bibliographic table gathers the literature on which this work is based. Then, the second part briefly returns on the tellurite glass compositions, the third part presents the different fiber structures (microstructured, suspended core or step-index fibers, tapered fibers), the fourth part discusses the pumping sources in relation with the fiber chromatic dispersion as well as coupling issues, the supercontinuum performances are presented in the fifth part, and the sixth part deals wit…

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

National audience

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.

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.

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

National audience

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

International audience

Recent advances in chalcogenide holey fibres

oral

Mid-infrared 2000-nm bandwidth supercontinuum generation in suspended-core microstructured Sulfide and Tellurite optical fibers

International audience; In this work, we report the experimental observation of supercontinua generation in two kinds of suspended-core microstructured soft-glass optical fibers. Low loss, highly nonlinear, tellurite and As2S3 chalcogenide fibers have been fabricated and pumped close to their zero-dispersion wavelength in the femtosecond regime by means of an optical parametric oscillator pumped by a Ti:Sapphire laser. When coupled into the fibers, the femtosecond pulses result in 2000-nm bandwidth supercontinua reaching the Mid-Infrared region and extending from 750 nm to 2.8 mu m in tellurite fibers and 1 mu m to 3.2 mu m in chalcogenide fibers, respectively.

Stimulated Brillouin scattering in Germanium-doped-core optical fibers up to 98% mol doping level

International audience; We experimentally investigate stimulated Brillouin scattering in several highly GeO2-doped optical fibers and report wide frequency tunability over more than 3 GHz and Brillouin gain 7 times larger than in standard silica fibers.

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.

Toward a thermodynamic description of supercontinuum generation

International audience; We consider the incoherent nonlinear regime of the supercontinuum generation process in optical fibers. We show that, under certain conditions, the phenomenon of spectral broadening inherent to the supercontinuum generation may be described by simple thermodynamic arguments based on the kinetic wave theory. Accordingly, the supercontinuum generation process may be regarded as a thermalization process, which is characterized by an irreversible evolution of the optical field toward a thermodynamic equilibrium state, i.e., the state of maximum nonequilibrium entropy.

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.

Seeding of modulation instability in a nonlinear fiber ring cavity

International audience

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

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.

Third harmonic generation in optical fibers with long period grating

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.

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.

Management of OH absorption in tellurite optical fibers and related supercontinuum generation

Abstract We report the fabrication and the characterization of low OH content and low loss tellurite optical fibers. The influence of different methods of glass fabrication on fiber losses has been investigated. The use of the purest commercial raw materials can reduce the losses below 0.1 dB/m at 1.55 μm. Incorporation of fluoride ions into the tellurite glass matrix makes the optical fibers transparent up to 4 μm. A suspended core microstructured fiber has been fabricated and pumped by nanojoule-level femtosecond pulses, thus resulting in more than 2000-nm bandwidth supercontinuum after a few centimeters of propagation.

Suspended core tellurite glass optical fibers for infrared supercontinuum generation

International audience; We report the fabrication and characterization of tellurite TeO(2)-ZnO-Na(2)O (TZN) microstructured suspended core optical fibers (MOFs). These fibers are designed for infrared supercontinuum generation with zero dispersion wavelength (ZDW) at 1.451 mu m. The measured losses at this wavelength are approximately 6 dB/m for a MOF with a 2.2 mu m diameter core. The effective area of a particular fiber is 3.5 mu m(2) and the nonlinear coefficient is calculated to be 437 W(-1)km(-1). By pumping a 20 cm long fiber at 1.56 mu m with a sub-nj femtosecond laser source, we generate a supercontinuum (SC) spanning over 800 nm in the 1-2 mu m wavelength range.