arXiv subjects

Julien Javaloyes

Publications and source records attributed to Julien Javaloyes.

31 records · Page 2Linked to original sources

arXiv2020

Bound States of Light Bullets in Passively-Mode-Locked Semiconductor Lasers

In this paper, we analyze the dynamics and formation mechanisms of bound states (BSs) of light bullets in the output of a laser coupled to a distant saturable absorber. First we approximate the full three-dimensional set of Haus master equations by a reduced equation governing the dynamics of the transverse profile. This effective theory allows us to perform a detailed multiparameter bifurcation study and to identify the different mechanisms of instability of BSs. In addition, our analysis reveals a non-intuitive dependence of the stability region as a function of the linewidth enhancement factors and the field diffusion. Our results are confirmed by direct numerical simulations of the full system.

nlin.PS↗

arXiv2020

Discrete Light Bullets in Passively Mode-Locked Semiconductor Lasers

In this paper, we analyze the formation and dynamical properties of discrete light bullets (dLBs) in an array of passively mode-locked lasers coupled via evanescent fields in a ring geometry. Using a generic model based upon a system of nearest-neighbor coupled Haus master equations we show numerically the existence of dLBs for different coupling strengths. In order to reduce the complexity of the analysis, we approximate the full problem by a reduced set of discrete equations governing the dynamics of the transverse profile of the dLBs. This effective theory allows us to perform a detailed bifurcation analysis via path-continuation methods. In particular, we show the existence of multistable branches of discrete localized states (dLSs), corresponding to different number of active elements in the array. These branches are either independent of each other or are organized into a snaking bifurcation diagram where the width of the dLS grows via a process of successive increase and decrease of the gain. Mechanisms are revealed by which the snaking branches can be created and destroyed as a second parameter, e.g., the linewidth enhancement factor or the coupling strength are varied. For increasing couplings, the existence of moving bright and dark dLSs is also demonstrated.

nlin.PS↗

arXiv2020

Topological Localized states in the time delayed Adler model: Bifurcation analysis and interaction law

The time-delayed Adler equation is arguably the simplest model for an injected semiconductor laser with coherent injection and optical feedback. It is able to reproduce the existence of topological localized structures (LSs) and their rich interactions. In this paper we perform the first extended bifurcation analysis of this model and we explore the mechanisms by which LSs emerge. We also derive the effective equations governing the motion of distant LSs and we stress how the lack of parity in time-delayed systems leads to exotic, non-reciprocal, interactions between topological localized states.

nlin.PS↗

arXiv2020

Dispersive instabilities in Passively Mode-Locked Integrated External-Cavity Surface-Emitting Lasers

We analyze the dynamics of passively mode-locked integrated external-cavity surface-emitting Lasers (MIXSELs) using a first-principle dynamical model based upon delay algebraic equations. We show that the third order dispersion stemming from the lasing micro-cavity induces a train of decaying satellites on the leading edge of the pulse. Due to the nonlinear interaction with carriers, these satellites may get amplified thereby destabilizing the mode-locked states. In the long cavity regime, the localized structures that exist below the lasing threshold are found to be deeply affected by this instability. As it originates from a global bifurcation of the saddle-node infinite period type, we explain why the pulses exhibit behaviors characteristic of excitable systems. Using the multiple time-scale and the functional mapping methods, we derive rigorously a master equation for MIXSELs in which third order dispersion is an essential ingredient. We compare the bifurcation diagram of both models and assess their good agreement.

physics.optics↗

arXiv2019

Mesoscopic limit cycles in coupled nanolasers

Two coupled semiconductor nanolasers exhibit a mode switching transition, theoretically characterized by limit cycle $-$or mode-beating$-$ oscillations. Their decay rate is vanishingly small in the thermodynamic limit, i.e. when the spontaneous emission noise $β$-factor tends to zero. We provide experimental evidence of mesoscopic limit cycles $-$with $\sim 10^3$ intracavity photons$-$ through photon statistics measurements. We first show that the order parameter quantifying the limit cycle amplitude can be reconstructed from the mode intensity statistics. As a main result we observe a maximum of the averaged amplitude at the mode switching, accounting for limit cycle oscillations. We finally relate this maximum to a dip of mode cross-correlations, reaching a minimum of $g_{ij}^{(2)}=2/3$, which we show to be a mesoscopic limit. Coupled nanolasers are thus an appealing testbed for the investigation of spontaneous breaking of time-translation symmetry in presence of strong quantum fluctuations.

quant-ph↗

arXiv2019

Impact of high-order effects on soliton explosions in the complex cubic-quintic Ginzburg-Landau equation

We investigate the impact of higher-order nonlinear and dispersive effects on the onset of soliton explosions in the complex cubic-quintic Ginzburg-Landau equation. We show how the interplay of the high order effects (HOEs) results in the splitting of symmetric explosion modes and to the formation of right- or left-side periodic explosions. In addition, we demonstrate that HOEs induce a series of pulsating instabilities, leading to a significant reduction of the stability region of the single soliton solution.

nlin.PS↗

arXiv2018

Spontaneous symmetry breaking and trapping of temporal Kerr cavity solitons by pulsed or amplitude modulated driving fields

We report on a systematic study of temporal Kerr cavity soliton dynamics in the presence of pulsed or amplitude modulated driving fields. In stark contrast to the more extensively studied case of phase modulations, we find that Kerr cavity solitons are not always attracted to maxima or minima of driving field amplitude inhomogeneities. Instead, we find that the solitons are attracted to temporal positions associated with specific driving field values that depend only on the cavity detuning. We describe our findings in light of a spontaneous symmetry breaking instability that physically ensues from a competition between coherent driving and nonlinear propagation effects. In addition to identifying a new type of Kerr cavity soliton behaviour, our results provide valuable insights to practical cavity configurations employing pulsed or amplitude modulated driving fields.

physics.optics↗

arXiv2018

A Functional Mapping for Passively Mode-Locked Semiconductor Lasers

We present a novel approach for the analysis of passively mode-locked semiconductor lasers that allows for efficient parameter sweeps and time jitter analysis. It permits accessing the ultra-low repetition rate regime where pulses become localized states. The analysis including slow (e.g. thermal) processes or transverse dynamics becomes feasible. Our method bridges the divide between the phenomenological, yet highly efficient, pulse iterative model that is the Haus master equation, and the more involved first principle descriptions relying on time delayed equations. Our iterative functional mapping exploits the fundamental division of the mode-locking regime between fast and slow stages and allows computing the dynamics only in the pulse vicinity. Reductions of the simulation times and of the memory footprint up to two orders of magnitudes are demonstrated. Finally, the mapping also provides a general framework for deducing the Haus master equation from first principle models based upon delayed differential equations.

physics.optics↗

arXiv2017

Dynamics of Temporal Localized States in Passively Mode-Locked Semiconductor Lasers

We study the emergence and the stability of temporal localized structures in the output of a semiconductor laser passively mode-locked by a saturable absorber in the long cavity regime. For large yet realistic values of the linewidth enhancement factor, we disclose the existence of secondary dynamical instabilities where the pulses develop regular and subsequent irregular temporal oscil- lations. By a detailed bifurcation analysis we show that additional solution branches that consist in multi-pulse (molecules) solutions exist. We demonstrate that the various solution curves for the single and multi-peak pulses can splice and intersect each other via transcritical bifurcations, lead- ing to a complex web of solution. Our analysis is based upon a generic model of mode-locking that consists in a time-delayed dynamical system, but also upon a much more numerically efficient, yet approximate, partial differential equation. We compare the results of the bifurcation analysis of both models in order to assess up to which point the two approaches are equivalent. We conclude our analysis by the study of the influence of group velocity dispersion, that is only possible in the framework of the partial differential equation model, and we show that it may have a profound impact on the dynamics of the localized states.

physics.optics↗

arXiv2017

Quench dynamics in strongly coupled laser cavities

Strongly coupled dissipative optical cavities with nonlinear interactions give new opportunities to explore symmetry breaking phenomena and phase transitions, Josephson dynamics and quantum criticality. Among the different experimental realizations, photonic crystal coupled nanocavities operating in the laser regime are outstanding systems since nonlinearity, gain/dissipation and intercavity coupling can be judiciously tailored. Yet, although most common scenarios emerge from quasi-dynamical equilibrium where the gain nearly compensates for losses, little is known about far out-of-equilibrium dynamics resulting, for instance, from short pulsed pumping inducing a classical "quench". Here we show that bimodal nanolasers generically display transient dynamics after quench which, when projected onto the nonlasing mode, exhibit superthermal light. Such a mechanism is akin to the fast cooling of a suspension of Brownian particles under gravity, with the intracavity intensity playing the role of the inverse temperature. We implement a simple experimental technique to access the probability density functions, that enabled quantifying the distance from thermal equilibrium --and hence the degree of residual order-- via the Gibbs entropy. This allowed us to further detect mixing of thermal states with coherent broken parity phases, thus paving the road for investigating far nonequilibrium thermodynamics with multimode optical oscillators.

physics.optics↗

arXiv2016

Stimulated scattering in strongly coupled nanolasers induced by Rabi oscillations

Two coupled-cavity systems, or "photonic dimers", are efficient test-beds for both fundamental optics -the realization of quantum correlated states, Josephson physics, and so forth-, and applications such as optical flip-flop memories. In this work we report on the first observation of nonlinear mode interaction in a photonic dimer formed by two semiconductor photonic crystal coupled nanolasers. For this, we investigate energy transfer between hybrid modes, which manifests as a switching from the blue-detuned (bonding) to the red-detuned (anti-bonding) modes. An mean-field model allows us to explain this phenomenon as stimulated scattering due to carrier population oscillations in the cavities at the Rabi frequency. Such asymmetrical mode interaction is universal in semiconductor laser photonic molecules, and unveils the origin of cross-correlation dips in the statistics of mode fluctuations.

physics.optics↗

arXiv2016

Refractory period of an excitable semiconductor laser with optical injection

Injection-locked semiconductor lasers can be brought to a neuron-like excitable regime when parameters are set close to the unlocking transition. Here we study experimentally the response of this system to repeated optical perturbations and observe the existence of a refractory period during which perturbations are not able to elicit an excitable response. The results are analyzed via simulations of a set of dynamical equations which reproduced adequately the experimental results.

physics.optics↗

arXiv2015

Controllable spiking patterns in long-wavelength VCSELs for neuromorphic photonics systems

Multiple controllable spiking patterns are obtained in a 1310 nm Vertical Cavity Surface Emitting Laser (VCSEL) in response to induced perturbations and for two different cases of polarized optical injection, namely parallel and orthogonal. Achievement of reproducible spiking responses in VCSELs operating at the telecom wavelengths offers great promise for future uses of these devices in ultrafast neuromorphic photonic systems for non-traditional computing applications.

physics.optics↗