Dissipative Solitons, a Novel Paradigm for Mode-locked Lasers

The concept of a "dissipative soliton" provides an excellent framework for understanding complex mode-locked laser pulse dynamics from a unified picture. It has stimulated innovative laser cavity designs in the past few years. This tutorial lecture provides conceptual pictures illustrated with universal dynamics, highlights recent achievements and prospects for mode-locked laser development.

Dissipative rogue wave generation from a mode-locked fiber laser experiment

Rare events of extremely high optical intensity are experimentally recorded at the output of a mode-locked fiber laser operating in a chaotic multiple-pulse regime. These fluctuations result from ceaseless nonlinear interactions between pulses.

Dark-and-bright rogue waves in long wave-short wave resonance

Nonlinear Photonics, Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, in Proceedings Advanced Photonics, Part of Advanced Photonics, Barcelona, Spain, 28-31 July 2014

Universal soliton pattern formations in passively mode-locked fiber lasers

International audience; We investigate multiple-soliton pattern formations in a figure-of-eight passively mode-locked fiber laser. Operation in the anomalous dispersion regime with a double-clad fiber amplifier allows generation of up to several hundreds of solitons per round trip. We report the observation of remarkable soliton distributions: soliton gas, soliton liquid, soliton polycrystal, and soliton crystal, thus indicating the universality of such complexes.

Dissipative Rogue Waves Generated by Chaotic Pulse Bunching in a Mode-Locked Laser

Rare events of extremely high optical intensity are experimentally recorded at the output of a mode-locked fiber laser that operates in a strongly dissipative regime of chaotic multiple-pulse generation. The probability distribution of these intensity fluctuations, which highly depend on the cavity parameters, features a long-tailed distribution. Recorded intensity fluctuations result from the ceaseless relative motion and nonlinear interaction of pulses within a temporally localized multisoliton phase. © 2012 American Physical Society.

Optical bullets and "rockets" in nonlinear dissipative systems and their transformations and interactions

We demonstrate the existence of stable optical light bullets in nonlinear dissipative media for both cases of normal and anomalous chromatic dispersion. The prediction is based on direct numerical simulations of the (3+1)-dimensional complex cubic-quintic GinzburgLandau equation. We do not impose conditions of spherical or cylindrical symmetry. Regions of existence of stable bullets are determined in the parameter space. Beyond the domain of parameters where stable bullets are found, unstable bullets can be transformed into >rockets> i.e. bullets elongated in the temporal domain. A few examples of the interaction between two optical bullets are considered using spatial and temporal interact…

Numerical Maps for Fiber Lasers Mode Locked with Nonlinear Polarization Evolution: Comparison with Semi-Analytical Models

We have used a fully vectorial model based on two coupled nonlinear Schrodinger equations to study mode locking and pulse generation initiated and stabilized by nonlinear polarization evolution in a stretched pulse, double-clad, Yb-doped, fiber laser. The model takes explicitly into account gain saturation, finite amplification bandwidth, Kerr-induced self- and cross-phase modulations, group velocity dispersion, polarization control, and linear birefringence. Complete maps versus the orientation of intra-cavity wave-plates have been established. They comprise a large variety of pulse regimes that can be simply obtained by turning the intracavity wave-plate: stable single pulse per round tri…

Interactions and transformations of dissipative optical bullets

Nonlinear dissipation provides distinctive dynamical properties to optical bullets. According to the system parameters, the dynamical properties of single bullets range from fully stable to pulsating and instable bullets. We are here interested in the following stage, namely the interaction between several optical bullets.

Vibrations and oscillations of tri-soliton molecules in a mode-locked fiber laser

We present numerical simulations highlighting internal oscillations and vibrations within tri-soliton molecules generated by a mode-locked fiber laser. We highlight major qualitative differences as compared to two-soliton molecules.

Reef-knot microfiber resonators

International audience

Third-harmonic generation in optical microfibers: From silica experiments to highly nonlinear glass prospects

International audience; Using optical microfibers, phase matching between different propagation modes allows for third-harmonic generation (THG). After detailing the relevant phase matching conditions and overlap integrals, we provide a comparison between THG effective efficiencies in silica and tellurite glasses. We also explain the relatively easy, wideband, conversion that we observe experimentally in silica glass microfibers, from 155 mu m to the green, by the geometry of the tapering region.

Temporal Soliton “Molecules” in Mode-Locked Lasers: Collisions, Pulsations, and Vibrations

A few years after the discovery of the stable dissipative soliton pairs in passively mode-locked lasers, a large variety of multi-soliton complexes were studied in both experiments and numerical simulations, revealing interesting new behaviors. This chapter focuses on the following three subjects: collisions between dissipative solitons, pulsations of dissipative solitons, and vibrations of soliton pairs. Different outcomes of collisions between a soliton pair and a soliton singlet are discussed, showing possible experimental control in the formation or dissociation of ‘soliton molecules’. Long-period pulsations of single and multiple dissipative solitons are presented as limit cycles and o…

Baseband modulation instability as the origin of rogue waves

International audience; We study the existence and properties of rogue-wave solutions in different nonlinear wave evolution models that are commonly used in optics and hydrodynamics. In particular, we consider the Fokas-Lenells equation, the defocusing vector nonlinear Schrödinger equation, and the long-wave-shortwave resonance equation. We show that rogue-wave solutions in all of these models exist in the subset of parameters where modulation instability is present if and only if the unstable sideband spectrum also contains cw or zero-frequency perturbations as a limiting case (baseband instability). We numerically confirm that rogue waves may only be excited from a weakly perturbed cw whe…

Relative phase locking of pulses in a passively mode-locked fiber laser

In a passively mode-locked fiber ring laser, we report the experimental observation of relative phase locking of pulses in a wide variety of cases. Relative phase locking is observed in bunches of N pulses separated by more than 20 pulse widths as well as in close pulse pairs. In the latter case, the phase relationship between the two pulses is measured to be ±π/2, which is related to theoretical predictions formerly obtained from a Ginzburg-Landau distributed model. We have developed a simplified numerical model adapted to our laser, which keeps its essential features while significantly reducing the number of free parameters. The agreement with the experiment is excellent. © 2003 Optical …

Highly-chirped similaritons generation from a mode-locked fiber laser

In this communication, we report experimental and numerical results on dynamics and propagation of self-similar pulses in a passively mode-locked ytterbium doped DC fiber laser.

Passively mode-locked erbium-doped double-clad fiber laser operating at the 322nd harmonic

International audience; We report passive mode locking of a soliton erbium-doped double-clad fiber laser operating at the 322nd harmonic of the fundamental cavity frequency. Repetition rates up to 3 GHz have been obtained with pulses of 1 ps duration and 18 pJ of energy. The supermode suppression at the 322nd harmonic is better than 25 dB. In addition, the transition dynamics from a bunched state of pulses to stable harmonic mode locking is presented, revealing a very long time scale.

Roadmap to ultra-short record high-energy pulses out of laser systems

International audience

Bifurcations and multiple-period soliton pulsations in a passively mode-locked fiber laser

The multiple-period pulsations of the soliton parameters in a passively mode-locked fiber laser were discussed numerically and experimentally. It was found that the pulse acquired a periodic evolution that was not related to the round-trip time and consisted of many round trips. The macroperiodicity existed independently or in combination with other periodicity such as period doubling, tripling etc. Analysis shows that the new periods in the soliton modulation appear at bifurcation point related to certain points related to certain values of the cavity parameters.

Coexisting rogue waves within the (2+1)-component long-wave-short-wave resonance

5 pags.; 4 figs.; PACS number(s): 05.45.Yv, 47.20.Ky, 47.35.−i, 47.54.−r

Soliton complexes in dissipative systems: Vibrating, shaking and mixed soliton pairs

We show, numerically, that coupled soliton pairs in nonlinear dissipative systems modeled by the cubic-quintic complex Ginzburg-Landau equation can exist in various forms. They can be stationary, or they can pulsate periodically, quasiperiodically, or chaotically, as is the case for single solitons. In particular, we have found various types of vibrating and shaking soliton pairs. Each type is stable in the sense that a given bound state exists in the same form indefinitely. New solutions appear at special values of the equation parameters, thus bifurcating from stationary pairs. We also report the finding of mixed soliton pairs, formed by two different types of single solitons. We present …

Models for supercontinuum generation beyond the slowly-varying-envelope approximation

International audience; We show numerically that both the modified Korteweg–de Vries and the sine-Gordon models are conducive to the generation of supercontinua with spectral bandwidths of several octaves, when an intense short pulse is launched as the initial condition. These models beyond the slowly-varying-envelope approximation could play an important role in modeling supercontinuum generation in gas-filled hollow waveguides.

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.

Fiber laser mode locked through an evolutionary algorithm

Mode locking of fiber lasers generally involves adjusting several control parameters, in connection with a wide range of accessible short-pulse dynamics. In this Letter, we experimentally demonstrate the ability of an evolutionary algorithm to prescribe a set of cavity parameters entailing specific self-starting mode locking. The prescribed parameters are applied to electrically driven polarization controllers, thus shaping the effective nonlinear transfer function at play within the fiber cavity. According to the specifications of the objective function used for the optimization procedure, various short-pulse regimes are obtained. Our versatile method represents an effective novel avenue f…

Dissipative soliton interactions inside a fiber laser cavity

We report our recent numerical and experimental observations of dissipative soliton interactions inside a fiber laser cavity. A bound state, formed from two pulses, may have a group velocity which differs from that of a single soliton. As a result, they can collide inside the cavity. This results in a variety of outcomes. Numerical simulations are based either on a continuous model or on a parameter-managed model of the cubic-quintic Ginzburg-Landau equation. Each of the models provides explanations for our experimental observations. © 2005 Elsevier Inc. All rights reserved.

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

National audience

Rains of solitons in a figure-of-eight passively mode-locked fiber laser

International audience; We report experimental observation of rains of solitons in figure-of-eight fiber laser passively mode-locked through nonlinear optical loop mirror. Soliton pulses are created from an extended noisy background and drift until they reach a condensed phase comprising several tens of aggregated solitons. The observation of this dynamics tends to strengthen the idea of the universality of the collective behavior of solitons.

Dissipative soliton resonance as a guideline for high-energy pulse laser oscillators

Dissipative soliton resonance (DSR) occurs in the close vicinity of a hypersurface in the space of parameters of the equation governing propagation in a dissipative nonlinear medium. Pulsed solutions can acquire virtually unlimited energies as soon as the equation parameters converge toward that specific hypersurface. Here we extend previous studies that have recently unveiled DSRs from the complex cubic-quintic Ginzburg-Landau equation. We clearly confirm the existence of DSR for a wide range of parameters in both regimes of chromatic dispersion, and we establish general features of the ultra-high-energy pulses that can be found close to a DSR. Application to high-energy mode-locked fiber …

Potentialities of glass air-clad micro- and nanofibers for nonlinear optics

Micro- and nanofibers constitute an attractive platform for testing nonlinear devices with millimeter size in a simple and flexible fashion, with potential applications in ultra-fast all-optical communications. In this article, we present challenges that must be addressed and targets that can be reached using such a platform. We describe a tunable laser source capable of delivering pulses with a kilowatt peak power and a sub-0.1-nm linewidth that is specially designed for the study of resonant devices such as the nonlinear loop resonator. Experimental and simulation results are presented for silica microfiber based nonlinear devices. The prospect of developing hybrid devices combining highl…

Performance of microfiber ring resonators

International audience

Theoretical study of microfiber resonator devices exploiting a phase shift

Phase shifts within microfiber resonators can be exploited to demonstrate compact and fast-responding devices. Two examples, a sensor and a bistable device, where the origins of the phase shift are fundamentally different, are investigated. In the sensor the phase change originates from the change of refractive index of the medium surrounding the microfiber ring. This is a linear mechanism which translates into a change of resonance wavelength. Calculations of a silica microfiber ring immersed in an aqueous solution and operating at a wavelength of 1550 nm show that with a fiber 550 nm in diameter the sensitivity approaches a maximal value of about 1137 nm/RIU. In contrast to the sensitivit…

Impact of slow gain dynamics on soliton molecules in mode-locked fiber lasers

International audience; We theoretically demonstrate and experimentally confirm the major influence of gain dynamics on soliton molecules that self-assemble in mode-locked lasers. Both slow gain recovery and depletion play a pivotal role in the formation of chirped soliton molecules characterized by an increasing separation from leading to trailing pulses. These chirped molecules actually consist of many pulses and may be termed macromolecules. They are experimentally observed in a fiber laser and numerically modeled by an approach that properly includes the slow gain dynamics. Furthermore, it is shown that these processes stabilize soliton trains in fiber lasers by inhibiting internal osci…

Dynamics of the transition from polarization disorder to antiphase polarization domains in vector fiber lasers

We demonstrate that nonlinear polarization coupling in a fiber ring laser without polarization-selective elements, subject to the effects of average anomalous dispersion, Kerr effect, and nonlinear gain saturation, can lead to the antisynchronization of spatiotemporal chaos into a wide variety of ordered laminar states of orthogonal polarization temporal domains. These antiphase polarization domains include stable lattices of soliton trains with high duty cycle at repetition rates of hundreds of MHz, as well as sparse trains of coupled dark and bright solitary waves.

Dissipative rogue waves out of fiber lasers

We study rogue waves in dissipative systems such as unidirectional fiber laser. We have found that the probability of producing extreme pulses in this setup is higher than in any other system considered so far.

Dissipative soliton in a laser cavity: A novel concept in action

International audience; The recent concept of a dissipative optical soliton sheds new light for understanding the stability of optical pulses that are generated in passively mode-locked lasers. Considering in these lasers the multiple pulsing regime of operation, the dissipative soliton concept is able to explain the great diversity of interaction behaviours that have been observed experimentally. Among the most spectacular behaviours are the formation of "soliton molecules" and "elastic-type" collisions. The dissipative soliton also explains the existence of complex limit cycles of pulsations within single pulse operation.

Silicon-microring into a fiber laser cavity for high-repetition-rate pulse train generation

International audience; In 1997, Yoshida et al. inserted a Fabry-Perot filter in a modulation instability fiber laser cavity [1], the free spectral range (FSR) of the Fabry-Perot fixed the RF to 115 GHz; however the pulsed laser was poorly stable. Since then, lasers of increasing performance have been demonstrated using variants of this method. In 2012, Peccianti et al., demonstrated the first fiber laser harmonically mode-locked by integrated high-finesse microresonator [2]. The doped silica, on-chip microresonator provided both high spectral selectivity and nonlinearity, thus promoting the dynamics pulsed at 200 GHz. By using a silicon microring resonator (SMRR), this approach lead to the…

Slow and fast nonlinearities in microfiber resonators

Nonlinear optical properties of microfiber resonators are investigated. First, a miniature optical resonator standing in air is realized out of a silica microfiber, and measurements of the intensity transfer function show a wide variety of hysteresis cycles obtained at low scanning frequency of the input power. The results are satisfactorily interpreted through the action of thermally-induced nonlinear phase shifts. Secondly, we discuss the conditions under which the fast Kerr nonlinearity can be used efficiently in microfiber resonators under pulsed optical operation.

Dissipative rogue wave generation in multiple-pulsing mode-locked fiber laser

Following the first experimental observation of a new mechanism leading to optical rogue wave (RW) formation briefly reported in Lecaplain et al (2012 Phys. Rev. Lett. 108 233901), we provide an extensive study of the experimental conditions under which these RWs can be detected. RWs originate from the nonlinear interactions of bunched chaotic pulses that propagate in a fiber laser cavity, and manifest as rare events of high optical intensity. The crucial influence of the electrical detection bandwidth is illustrated. We also clarify the observation of RWs with respect to other pulsating regimes, such as Q-switching instability, that also lead to L-shaped probability distribution functions.…

Collective Dynamics of Dissipative Solitons in Mode-locked Lasers

International audience

Potentialities of glass air-clad micro- and nano-fibers for nonlinear optics

International audience

Roadmap on optical rogue waves and extreme events

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

Rogue wave statistics from a noise-like-pulse laser

We report on experimental conditions in a fiber ring laser where noise-like pulse emission fulfills the rogue wave criteria. We highlight the role of dispersion, and use the dispersive Fourier-transform method to study spectral fluctuations.

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].

Observation of a nonlinear microfiber resonator

Measurements of the intensity transfer function of a silica microfiber resonator are shown to follow a wide variety of hysteresis cycles, depending on the cavity detuning and the scanning frequency of the range of input powers. We attribute these observations to a nonlinear phase shift of thermal origin and provide a simple model that reproduces well our measurements. The response time is found to be around 0.6 ms.

Multipole solitary wave solutions of the higher-order nonlinear Schrödinger equation with quintic non-Kerr terms

We consider a high-order nonlinear Schrodinger (HNLS) equation with third- and fourth-order dispersions, quintic non-Kerr terms, self steepening, and self-frequency-shift effects. The model applies to the description of ultrashort optical pulse propagation in highly nonlinear media. We propose a complex envelope function ansatz composed of single bright, single dark and the product of bright and dark solitary waves that allows us to obtain analytically different shapes of solitary wave solutions. Parametric conditions for the existence and uniqueness of such solitary waves are presented. The solutions comprise fundamental solitons, kink and anti-kink solitons, W-shaped, dipole, tripole, and…

High Order Harmonic Passive Mode-Locking In Double-Clad Fiber Laser

We report passive mode-locking of a soliton erbium-doped double-clad fiber laser operating at the 322nd harmonic of the fundamental cavity frequency. Repetition rates scalable up to 3 GHz have been obtained with a pulse duration of about 1 ps and a pulse energy of about 18 pJ. The supermode suppression at the 322nd harmonic is better than 25 dB. The dynamics of emergence of this operating regime is also presented revealing a very long timescale.

Stationary and Pulsating Dissipative Optical Bullets in Dissipative systems

International audience

Soliton rains in a fiber laser: experimental study

International audience

Dissipative soliton pulsations with periods beyond the laser cavity round trip time

We review recent results on periodic pulsations of the soliton parameters in a passively mode-locked fiber laser. Solitons change their shape, amplitude, width and velocity periodically in time. These pulsations are limit cycles of a dissipative nonlinear system in an infinite-dimensional phase space. Pulsation periods can vary from a few to hundreds of round trips. We present a continuous model of a laser as well as a model with parameter management. The results of the modeling are supported with experimental results obtained using a fiber laser. © World Scientific Publishing Company.

Polarization-domain-wall complexes in fiber lasers

To study the possible build-up of polarization-domain-walls (PDWs) in fiber laser cavities, an erbium-doped fiber ring laser was used and a wide range of vector polarization dynamics that can be selected at a given pump power, by using the degrees of freedom of two intracavity polarization controllers (PC) was investigated. A simple theoretical model that explains polarization switching in fiber ring lasers featuring a normally dispersive cavity with a typical, moderate, level of birefringence is presented. Such polarization dynamics, based on a special class of polarization-domain-wall structures, agrees qualitatively well with experimental observations. The paper stresses on the complex a…

Vector Modulational Instabilities and Soliton Experiments

In optical fibers, the interaction between nonlinear and dispersive effects leads to phenomena such as modulational instability (MI)[1, 2, 3, 4, 5, 6], in which a continuous or quasi-continuous wave undergoes a modulation of its amplitude or phase in the presence of noise or any other small perturbation. The perturbation can originate from quantum noise (spontaneous-MI) or from a frequency shifted signal wave (induced-MI). MI has been observed for the first time for a single pump wave propagating in a standard non birefringe.nt fiber (scalar MI)[7]. It has been shown that scalar MI only occurs when the group velocity dispersion (GVD) is negative (anomalous dispersion regime).

Glass microfibers: use in nonlinear optics and near-field characterization

International audience

Vibrating soliton pairs in a mode-locked laser cavity

International audience; We show numerically the existence of vibrating soliton pairs that are consistent with observations performed with a passively mode-locked fiber laser. These vibrating pairs are new types of multisoliton complexes that exist in the vicinity of the phase-locked soliton pairs discovered a few years ago [Opt. Lett. 27, 966 (2002)]. The pairs are found numerically with a laser propagation model that includes nonlinear dissipation and cavity periodicity, and they can appear following a Hopf-type bifurcation when a cavity parameter is tuned.

Dissipative soliton resonance in a passively mode-locked fiber laser

The phenomenon of dissipative soliton resonance (DSR) predicts that an increase of pulse energy by orders of magnitude can be obtained in laser oscillators. Here, we prove that DSR is achievable in a realistic ring laser cavity using nonlinear polarization evolution as the mode-locking mechanism, whose nonlinear transmission function is adjusted through a set of waveplates and a passive polarizer. The governing model accounts explicitly for the arbitrary orientations of the waveplates and the polarizer, as well as the gain saturation in the amplifying medium. It is shown that DSR is achievable with realistic laser settings. Our findings provide an excellent design tool for optimizing the mo…

Nonlinear dynamics of temporal optical soliton molecules in lasers

Recent experiments demonstrate that fiber laser cavities are able to support various multisoliton complexes, analogous to soliton molecules. These advances, which could have impact on optical information transmission or storage, are guided by the concept of dissipative soliton and supported by numerical simulations. DOI: 10.2529/PIERS060828120520 As passively mode-locked lasers rely strongly on nonlinear dissipation, there is a growing interest in understanding various pulse dynamics in terms of the dynamics of dissipative solitons [1]. In particular, the interaction between dissipative temporal solitons can lead to the formation of stable multi-soliton complexes. The stability of multi-sol…

Light bullets and dynamic pattern formation in nonlinear dissipative systems

In the search for suitable new media for the propagation of (3+1) D optical light bullets, we show that nonlinear dissipation provides interesting possibilities. Using the complex cubic-quintic Ginzburg-Landau equation model with localized initial conditions, we are able to observe stable light bullet propagation or higher-order transverse pattern formation. The type of evolution depends on the model parameters. ©2005 Optical Society of America.

Soliton rains in a fiber laser: An experimental study

Rains of solitons constitute a class of nonlinear dynamics of dissipative soliton ensembles that we briefly reported in Opt. Express 17, 11776 (2009) from a fiber laser experiment. The existence of a relatively intense noisy background together with several tens of soliton pulses aggregated in a condensed soliton phase constitutes a necessary condition for their appearance. New soliton pulses form spontaneously from the background fluctuations and drift until they reach the condensed soliton phase. We here relate in detail the experimental conditions under which soliton rains manifest and their key features, describe related dynamics observed in their vicinity, and propose an explanation fo…

Dissipative Solitons: present understanding, applications and new developments

Dissipative solitons form a new paradigm for the investigation of phenomena involving stable structures in nonlinear systems far from equilibrium. Basic principles can be applied to a wide range of phenomena in science. Recent results involving solitons and soliton complexes of the complex cubic-quintic Ginzburg–Landau equation are presented.

Quantized separations of phase-locked soliton pairs in fiber lasers

Quantized separations of phase-locked soliton pairs in fiber lasers were presented. The relation between the Kelly sidebands and the quantized separations between solitons was confirmed. Simulation results showed that the solitons can see each other at relatively larger distances than they would in the absence of radiation.

Multi-gigahertz repetition-rate-selectable passive harmonic mode locking of a fiber laser

We demonstrate a passive harmonically mode-locked erbium-doped fiber laser that operates at selectable harmonics spanning from the 6th to the 928th, which corresponds to repetition rates ranging from 153 MHz to 22.2 GHz. The noteworthy laser output stability is attested by supermode suppression levels as large as 41 dB. The influence of a continuous wave background on harmonics stability is tested.

Dark three-sister rogue waves in normally dispersive optical fibers with random birefringence

11 pags.; 4 figs.; OCIS codes: (190.3100) Instabilities and chaos; (190.4370) Nonlinear optics, fibers; (060.5530) Pulse propagation and temporal solitons.

Caractérisation des impulsions optiques courtes et ultracourtes

International audience

Demonstration of a reef knot microfiber resonator.

We propose a new way to realize a microfiber optical resonator by implementing the topology of a reef knot using two microfibers. We describe how this structure, which includes 4 ports and can serve as an add-drop filter, can be fabricated. Resonances in an all-silica reef knot are measured and good fits are obtained from a simple resonator model. We also show the feasibility of assembling a hybrid silica-chalcogenide reef knot structure.

Rains of Solitons in a Fiber Laser

We report a novel and intriguing nonlinear dynamics observed in a fiber laser cavity, in which soliton pulses are created from an extended noisy background and drift until they reach a condensed phase comprising several tens of aggregated solitons. This soliton flow can be adjusted with manual cavity tuning, and can even be triggered by the injection of an external low-power cw laser.

Dissipative solitons and their interactions

Coupled soliton pairs in nonlinear dissipative systems can exist in various forms. They can be stationary, or they can pulsate periodically, quasi-periodically or chaotically, as is the case for single solitons. Each type is stable in the sense that a given bound state exists in the same form inde.nitely. Single solitons can be perfectly stable for a given set of parameters. However, this does not mean that a bound state formed from them is either stationary or stable. Moreover, their relations can be highly complicated. Such is the life of dissipative solitons. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Transition from polarization disorder to antiphase polarization domains in a fiber laser

Adjusting polarization coupling in a fiber ring laser may lead to anti-synchronization of spatio-temporal disorder into ordered laminar states of orthogonal polarization temporal domains, as well as stable lattices of soliton trains.

Effect of slow gain dynamics in mode-locked fiber lasers: Chirped soliton molecules

We theoretically and experimentally demonstrate the pivotal role of the gain dynamics in the formation of chirped soliton molecules in mode-locked lasers. Such molecules are characterized by an increasing separation from leading to trailing pulses.

Vibrating and shaking soliton pairs in dissipative systems

We show that two-soliton solutions in nonlinear dissipative systems can exist in various forms. As with single solitons, they can be stationary, periodic or chaotic. In particular, we find new types of vibrating and shaking soliton pairs. Each type of pair is stable in the sense that the bound state exists in the same form indefinitely. © 2006 Elsevier B.V. All rights reserved.

Generating ultra-short high-energy pulses using dissipative soliton resonance: Pulse compression schemes

Dissipative soliton resonance (DSR) refers to a phenomenon where the energy of the stable soliton solution increases to extremely large values in a nonlinear dissipative system modeled by the complex cubic-quintic Ginzburg-Landau equation (CGLE) [1]. It occurs in the vicinity of a specific hyper-surface in the multi-dimensional space of the CGLE parameters. The phenomenon has applications in designing laser oscillators generating ultra-high energy pulses, since the dynamics of such lasers can be well-modeled by the CGLE. The DSR was first found in normally-dispersive media, in concordance with the current design trend for high-energy mode-locked laser oscillators [2–4]. However, we have sho…

Generation of Bound States of Three Ultrashort Pulses With a Passively Mode-Locked High-Power Yb-Doped Double-Clad Fiber Laser

We report the generation of high-power ultrashort bound states of three pulses in an ytterbium-doped double-clad fiber laser. The laser is mode-locked through nonlinear polarization rotation technique in a unidirectional cavity configuration. A pair of diffraction grating is incorporated in the cavity to compensate for the normal dispersion of the fiber. The laser generates chirped bound states of three pulses with either equal or different time separations, with more than 500-pJ energy per pulse. These pulses are subsequently compressed to 100 fs with a compression factor of more than 40.

On the possibility of observing bound soliton pairs in a "wave-breaking-free" mode-locked fiber laser

To generate ultrashort pulses with higher energy in passively mode-locked fiber lasers, several groups have recently focused on the development of laser cavities operating in normal path-averaged dispersion, with a view to achieve wave-breaking-free operation. The mode-locking mechanism in fiber laser play a key role in providing scalability limitation: for instance, nonlinear polarization evolution can be overdriven. Furthermore, the differential gain of the doped fiber decreases along with the traveled distance. From all of these limitations, it follows that power scalability is always bounded for virtually any mode-locked laser cavity design. In general, the consequence is the emergence …

Microfiber Resonators in the Linear and the Nonlinear Regimes

International audience; The microfiber resonators presented here were made by forming an open knot with silica microfibers in air. Resonance spectra were observed in the near infrared and more recently in the visible. The knot structure was mechanically stable and was maintained upon immersion in a liquid. Upon immersion the change of refractive index of the medium surrounding the knot shifted the spectral region where resonances were observed. Moreover, using a liquid which could be polymerized, we have imbedded microfiber knot resonators in a solid matrix to form rugged devices. In the presence of nonlinearity a resonator can exhibit bistability. This behaviour was studied both numericall…

Statistical description of soliton clustering in fiber lasers with slow-gain dynamics

We demonstrate theoretically that the dynamic clustering of solitons observed in a variety of experiments are due to the initial phase and position of interacting solitons with the slow gain dynamics of the fiber laser.

Generation and characterization of 06-THz polarization domain-wall trains in an ultralow-birefringence spun fiber

Polarization domain-wall (PDW) trains have been generated at a repetition rate of 0.6 THz in an ultralow-birefringence spun optical fiber and measured by use of an adapted frequency-resolved optical gating technique. Characterization of the intensity and the phase of the PDW train shows complete switching between adjacent domains of counterrotating circular polarizations and directly confirms predictions based on numerical simulations of the incoherently coupled nonlinear Schrödinger equations.

On the possibility of observing bound soliton pairs in a wave-breaking-free mode-locked fiber laser

On the basis of numerical simulations, we explain the formation of the stable bound soliton pairs that were experimentally reported in a high-power mode-locked ytterbium fiber laser [Opt. Express 14, 6075 (2006)], in a regime where wave-breaking-free operation is expected. A fully vectorial model allows one to rigorously reproduce the nonmonotonic nature for the nonlinear polarization effect that generally limits the power scalability of a single-pulse self-similar regime. Simulations show that a self-similar regime is not fully obtained, although positive linear chirps and parabolic spectra are always reported. As a consequence, nonvanishing pulse tails allow distant stable binding of high…

Dissipative rogue waves: extreme pulses generated by passively mode-locked lasers.

We study numerically rogue waves in dissipative systems, taking as an example a unidirectional fiber laser in a nonstationary regime of operation. The choice of specific set of parameters allows the laser to generate a chaotic sequence of pulses with a random distribution of peak amplitudes. The probability density function for the intensity maxima has an elevated tail at higher intensities. We have found that the probability of producing extreme pulses in this setup is higher than in any other system considered so far. © 2011 American Physical Society.

Complete intensity and phase characterisation of optical pulse trains at terahertz repetition rates

Complete intensity and phase characterisation of optical pulse trains at terahertz repetition rates is carried out using an adapted frequency-resolved optical gating technique. The experimental characterisation of a 2.5 THz train of dark solitons in an optical fibre is in good agreement with numerical simulations.

Bistable Device based on the Kerr Effect in a Microfiber Resonator

We propose a bistable device based on the Kerr effect in a microfiber resonator. Our simulations show that low switching powers (in the order of a few tens of mW) are expected with tellurite microfibers.

Microfiber Resonators

International audience

Optical spectra beyond the amplifier bandwidth limitation in dispersion-managed mode-locked fiber lasers

We investigate the intracavity pulse dynamics inside dispersionmanaged mode-locked fiber lasers, and show numerically that for a relatively wide range of parameters, pulse compression dynamics in the passive anomalous fiber can be accompanied by a significant enhancement of the spectral width by a factor close to 3. Varying the average cavity dispersion also reveals chaotic dynamics for certain dispersion ranges. The impact of the implementation of an optical output port to tap optimal pulse features is discussed. © 2011 Optical Society of America.

Collective coordinate approach for the dynamics of light pulses in fiber ring lasers

We present an efficient variational approach for fiber lasers in which light pulses may execute complex dynamics, and we establish its validity by comparison with the numerical approach based on the generalized nonlinear Schroedinger equation.

Dynamics of distorted and undistorted soliton molecules in a mode-locked fiber laser

Recent developments in real-time ultrafast measurement techniques have enabled us to prove experimentally that soliton molecules execute internal motions with some aspects similar to those of a matter molecule. Such an analogy between the dynamics of soliton molecules and the dynamics of matter molecules is based on the assumption that the dissipative solitons constituting a molecule are rigid entities sharing a common profile. Whereas this assumption drastically reduces the number of degrees of freedom, it does not hold true in general and we demonstrate that it overlooks some of the essential dynamical features of the soliton molecule. We present a theoretical study based on the principle…

Potentialities of fiber lasers in the generation of coherent UV radiation

Generation of optical domain-wall structures from modulational instability in a bimodal fiber.

We study experimentally modulational instability in a normally dispersive bimodal fiber under modal group-velocity-matching conditions. In the strong pump depletion regime, higher order sideband harmonics detected in the output spectra as well as autocorrelation measurements reveal the formation of subpicosecond domain-wall structures. Across these temporal structures the electromagnetic field distribution switches abruptly between the two transverse modes of the fiber. These structures are reminiscent of the so-called domain-wall soliton. Our results constitute therefore an experimental indication of the existence of this fundamental soliton.

Spatiotemporal optical solitons in nonlinear dissipative media: From stationary light bullets to pulsating complexes

Nonlinear dissipative systems display the full (3+1) D spatiotemporal dynamics of stable optical solitons. We review recent results that were obtained within the complex cubic-quintic Ginzburg-Landau equation model. Numerical simulations reveal the existence of stationary bell-shaped (3+1) D solitons for both anomalous and normal chromatic dispersion regimes, as well as the formation of double soliton complexes. We provide additional insight concerning the possible dynamics of these soliton complexes, consider collision cases between two solitons, and discuss the ways nonstationary evolution can lead to optical pattern formation. © 2007 American Institute of Physics.

Optical bullets and double bullet complexes in dissipative systems

We show that optical light bullets can coexist with double bullet complexes in nonlinear dissipative systems. Coexistence occurs for a relatively large range of the system parameters, and is associated with either marginal stability or bistable existence of the two dissipative soliton species. In the case of marginal stability, spontaneous transformations of single bullets into double bullet complexes are observed. Among the bistable cases, we show how both clockwise and anticlockwise rotating double bullet complexes can be formed out of the phase-controlled interaction of two single bullets. The internal dynamics of pulsating double bullet complexes, with oscillations in both the spatial s…

Watch-hand-like optical rogue waves in three-wave interactions

11 págs.; 6 figs.; OCIS codes: (190.3100) Instabilities and chaos; (190.5530) Pulse propagation and temporal solitons; (190.4410) Nonlinear optics, parametric processes.

322nd harmonic in the passively mode-locked erbium-doped double-clad fiber laser

International audience

Group interactions of dissipative solitons in a laser cavity: the case of 2+1.

What can be the outcome of the interaction between a dissipative soliton pair and a soliton singlet? We report an experimental observation of ???elastic??? collisions as well as ???inelastic??? formation of triplet soliton states in a fiber laser setup. These observations are supported with the numerical simulations based on the dispersion (parameter) managed cubic-quintic Ginzburg-Landau equation model.

Potentialities of microfibers for non linear optics

Micro- and nanofibers present attractive optical properties and may be used in a variety of structures and devices. We report in this work the first global study on the non linear properties of these microfibers: an adequate source is built and its characteristics are described, our first results with a silica loop resonator are presented. Third harmonic generation is obtained in these conditions, however, the low intrinsic non linear index prevents the generation of large non linear effects. The use of highly non linear materials, such as soft glasses, is therefore discussed, with their potentialities and the challenges their integration with standard microfibers represent.

Vibrating temporal soliton pairs

The study of temporal multisoliton complexes in dissipative systems is of potential interest for the development of new schemes of optical data transport and processing. In the present work, we thus consider pulsations of a soliton pair that consist mainly in the oscillations of the temporal separation and phase relationship between the two pulses, so that the relative motion of the two bound solitons resembles a vibrational motion.

Dissipative solitons for mode-locked lasers

International audience; Dissipative solitons are localized formations of an electromagnetic field that are balanced through an energy exchange with the environment in presence of nonlinearity, dispersion and/or diffraction. Their growing use in the area of passively mode-locked lasers is remarkable: the concept of a dissipative soliton provides an excellent framework for understanding complex pulse dynamics and stimulates innovative cavity designs. Reciprocally, the field of mode-locked lasers serves as an ideal playground for testing the concept of dissipative solitons and revealing their unusual dynamics. This Review provides basic definitions of dissipative solitons, summarizes their imp…

Dark- and bright-rogue-wave solutions for media with long-wave–short-wave resonance

5 pags.; 5 figs.; PACS number(s): 46.40.−f, 47.20.Ky, 47.35.−i, 47.52.+j

Third-harmonic generation in optical microfibers

We explain the relatively easy, wideband, THG conversion that we observe experimentally in silica glass microfibers by the tapering geometry. As a challenging perspective, we compare THG effective efficiencies in silica and tellurite glasses.