Experimental characterization of quasiperiodic route to chaos in a VECSEL with SESAM.

We analyze the temporal dynamics of an optically-pumped quantum well vertical external-cavity surface-emitting laser (VECSEL) with a Semiconductor Saturable Absorber Mirror (SESAM) using the time series obtained when varying the pump power. We unveil the quasiperiodic route to chaos in the system by characterizing the Fourier spectra, the attractors in phase space, and the Lyapunov exponents for each temporal behavior observed: periodicity, quasiperiodicity, and chaos. Thus, we provide a complete description of this experimental observation of the route to chaos in a VECSEL-SESAM system.

Passively mode-locked high-frequency dual-VCSEL system.

Two VCSELs placed facing each other with one biased chip while the second chip is unbiased is shown as a promising alternative to the popularly used conventional SESAM mode-locked VECSEL to generate mode-locked pulses. We propose a theoretical model using time-delay differential rate equations and numerically show that the proposed dual-laser configuration functions as a typical gain-absorber system. Parameter space defined by laser facet reflectivities and current are used to show general trends in the exhibited nonlinear dynamics and pulsed solutions.

Polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror.

We investigate experimentally the polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror in the cavity. We demonstrate that the normalized Stokes parameters and degree of polarization are functions of time reaching extreme values around the pulse peaks. Our experiments show that light is elliptically polarized, being able to have a circular right-handed or left-handed component, depending on the orientation of the saturable absorber mirror.

Tailoring frequency combs through VCSEL polarization dynamics.

We investigate experimentally the nonlinear polarization dynamics of a VCSEL subject to optical injection of a frequency comb. By tuning the polarization of the injected comb to be orthogonal to that of the VCSEL, we demonstrate the generation of either a single polarization or a dual polarization frequency comb. The injection parameters (injected power and detuning frequency) are then used either to generate harmonics of the initial comb spacing or to increase the number of total output frequency lines up to 15 times the number of injected comb lines.

Nonlinear dynamics of a laser diode with an injection of an optical frequency comb.

We experimentally and theoretically demonstrate the variety of the nonlinear dynamics exhibited by a single frequency semiconductor laser subjected to optical injection from a frequency comb. The injection parameters (the detuning and the injection strength) and the comb properties (comb spacing and the amplitude of the injected comb lines) are varied to unveil several dynamics such as injection locking, wave-mixing, chaotic dynamics, and unlocked time-periodic dynamics corresponding to new comb solutions. The asymmetry of the injected comb is shown to modify the size of the injection locking region in the parameter space, as well as the common properties between the new comb solutions observed and the injected comb.

Control of dissipative rogue waves in nonlinear cavity optics: Optical injection and time-delayed feedback.

We investigate and review the formation of two-dimensional dissipative rogue waves in cavity nonlinear optics with transverse effects. Two spatially extended systems are considered for this purpose: the driven Kerr optical cavities subjected to optical injection and the broad-area surface-emitting lasers with a saturable absorber. We also consider a quasi-two-dimensional system (the two dimensions being space and time) of a fiber laser describing the complex cubic-quintic Ginzburg-Landau equation.

Delay-Differential-Equation Modeling of Mode-Locked Vertical-External-Cavity Surface-Emitting Lasers in Different Cavity Configurations.

A simple, versatile model for the dynamics of electrically and optically pumped vertical-external-cavity surface-emitting lasers, which are mode locked by a semiconductor saturable-absorber mirror, is presented. The difference between the laser operation in the linear and folded cavity, as well as the potential for a colliding pulse operation, are studied.

Localized chaos of elliptically polarized cavity solitons in broad-area VCSEL with a saturable absorber.

We introduce a spin-flip model for a broad-area vertical-cavity surface-emitting laser (VCSEL) with a saturable absorber. We demonstrate simultaneous existence of orthogonally linearly polarized and elliptically polarized cavity solitons. We show that polarization degree of freedom leads to a period-doubling route to spatially localized chaos of the elliptically polarized cavity solitons.

Attractor hopping between polarization dynamical states in a vertical-cavity surface-emitting laser subject to parallel optical injection.

We present experimental and theoretical results of noise-induced attractor hopping between dynamical states found in a single transverse mode vertical-cavity surface-emitting laser (VCSEL) subject to parallel optical injection. These transitions involve dynamical states with different polarizations of the light emitted by the VCSEL. We report an experimental map identifying, in the injected power-frequency detuning plane, regions where attractor hopping between two, or even three, different states occur.

Drifting cavity solitons and dissipative rogue waves induced by time-delayed feedback in Kerr optical frequency comb and in all fiber cavities.

Time-delayed feedback plays an important role in the dynamics of spatially extended systems. In this contribution, we consider the generic Lugiato-Lefever model with delay feedback that describes Kerr optical frequency comb in all fiber cavities. We show that the delay feedback strongly impacts the spatiotemporal dynamical behavior resulting from modulational instability by (i) reducing the threshold associated with modulational instability and by (ii) decreasing the critical frequency at the onset of this instability.

Semiconductor surface emitting lasers for photon pairs generation.

We study the feasibility of generating photon pairs in a resonant Vertical-Cavity Surface-Emitting Laser (VCSEL) as a result of a third-order non-linear, four wave mixing interaction. We focus on degenerate four wave mixing in the spontaneous regime where two pump photons are annihilated to create a pair of signal and idler photons. Using the methods of quantum optics, we calculate the two-photon production rate, the spectrum of the generated photons, and the signal-idler cross-correlations.

Coexistence of cavity solitons with different polarization states and different power peaks in all-fiber resonators.

We theoretically investigate a weakly birefringent all-fiber cavity subject to linearly polarized optical injection. We describe the propagation of light inside the cavity using, for each linear polarization component of the electric field, the Lugiato-Lefever model. These two components are coupled by cross-phase modulation.

Polarization dynamics induced by parallel optical injection in a single-mode VCSEL.

We report an experimental study of the polarization nonlinear dynamics in a 1550 nm single-mode vertical-cavity surface-emitting laser (VCSEL) subject to parallel optical injection. Experimentally measured stability maps identifying regions of different nonlinear dynamics for various values of bias current are reported. We show that VCSELs with more than a 35 dB polarization mode suppression ratio can have rich nonlinear dynamics in both linear polarizations, including periodic and chaotic behaviors appearing simultaneously in both polarization modes.

Two-dimensional dissipative rogue waves due to time-delayed feedback in cavity nonlinear optics.

We demonstrate a way to generate two-dimensional rogue waves in two types of broad area nonlinear optical systems subject to time-delayed feedback: in the generic Lugiato-Lefever model and in the model of a broad-area surface-emitting laser with saturable absorber. The delayed feedback is found to induce a spontaneous formation of rogue waves. In the absence of delayed feedback, spatial pulses are stationary.

Subwavelength grating as both emission mirror and electrical contact for VCSELs in any material system.

Semiconductor-metal subwavelength grating (SMSG) can serve a dual purpose in vertical-cavity surface-emitting lasers (VCSELs), as both optical coupler and current injector. SMSGs provide optical as well as lateral current confinement, eliminating the need for ring contacts and lateral build-in optical and current confinement, allowing their implementation on arbitrarily large surfaces. Using an SMSG as the top mirror enables fabrication of monolithic VCSELs from any type of semiconductor crystal.

Synchronization of polarization chaos from a free-running VCSEL.

We theoretically demonstrate the possibility to synchronize polarization chaos generated by a free-running vertical-cavity surface-emitting laser (VCSEL). We highlight two distinct synchronization regimes: 1) a high-quality synchronization regime where all polarization modes and total intensity are synchronized, which shows good robustness against parameter mismatch, and 2) a "slow time-scale" synchronization where the slower part of the dynamics-that is, the random-like hopping between the two scrolls of the chaotic attractor-synchronizes while the faster oscillations remain unsynchronized.

Energy exchange between modes in a multimode two-color quantum dot laser with optical feedback.

We investigate experimentally and theoretically the multimode dynamics of a two-color quantum dot laser subject to time-delayed optical feedback. We unveil energy exchanges between the longitudinal modes of the excited state triggered by variations of the feedback phase, and observe that the modal competition between longitudinal modes appears independently within the ground state and excited state emission. These features are accurately reproduced with a quantum dot laser model extended to take into account multiple modes for both ground and excited states.

Polarization switching and injection locking in vertical-cavity surface-emitting lasers subject to parallel optical injection.

Polarization switching in a long-wavelength vertical-cavity surface-emitting laser (VCSEL) under parallel optical injection is analyzed in a theoretical and experimental way. For the first time, to our knowledge, we report experimentally a state in which injection locking of the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL are simultaneously obtained. We obtain very simple analytical expressions that describe both linear polarizations.

Vector cavity solitons in broad area Vertical-Cavity Surface-Emitting Lasers.

We report the experimental observation of two-dimensional vector cavity solitons in a Vertical-Cavity Surface-Emitting Laser (VCSEL) under linearly polarized optical injection when varying optical injection linear polarization direction. The polarization of the cavity soliton is not the one of the optical injection as it acquires a distinct ellipticity. These experimental results are qualitatively reproduced by the spin-flip VCSEL model.

Optimization of electrically tunable VCSEL with intracavity nematic liquid crystal.

We optimize the wavelength tuning range of a Vertical-Cavity Surface-Emitting Laser with an intracavity layer of nematic Liquid Crystal (LC-VCSEL) lasing around 1.3 μm. The tunability is obtained by applying voltage to the liquid crystal layer, which esentially is to vary the refractive index from the extraordinary to the ordinary.

Asymmetric dwell-time statistics of polarization chaos from free-running VCSEL.

We experimentally report on asymmetric dwell-time statistics of polarization chaos dynamics generated from free-running vertical-cavity surface-emitting lasers (VCSELs). Theoretically, we explain this behavior by introducing a misalignment between the phase and amplitude anisotropy within the spin-flip model for VCSELs. It induces an asymmetry in the VCSEL polarization behavior which is then responsible for significant changes in the statistics of the chaotic mode-hopping with an increase in the average residence time and an inversion of the dominant mode.

Vertical-cavity surface-emitting laser with a liquid crystal external cavity.

A tuneable external cavity consisting of a thin layer of nematic liquid crystal (LC) and a dielectric reflector is placed on the top of a vertical-cavity surface-emitting laser (VCSEL). By changing the voltage across the LC layer, the optical path length of the external cavity can be tuned. As a result, the emitting properties of the LC-VCSEL, including polarization state and emission wavelength, can be controlled by the voltage applied over the LC layer.

Chaotic behavior of cavity solitons induced by time delay feedback.

We investigate spatiotemporal dynamics of cavity solitons in a broad area vertical-cavity surface-emitting laser with saturable absorption subject to time-delayed optical feedback. We show that the inclusion of feedback leads to a period doubling route to chaos of spatially localized light structures.

Experimental observation of localized structures in medium size VCSELs.

We report experimental evidence of spontaneous formation of localized structures in a 80 μm diameter Vertical-Cavity Surface-Emitting Laser (VCSEL) biased above the lasing threshold and under optical injection. Such localized structures are bistable with the injected beam power and the VCSEL current. We experimentally investigate the formation of localized structures for different detunings between the injected beam and the VCSEL, and different injection beam waists.

Impact of optical feedback on current-induced polarization behavior of 1550 nm vertical-cavity surface-emitting lasers.

Polarization switching (PS) between two orthogonal linearly polarized fundamental modes is experimentally observed in commercial free-running 1550 nm vertical-cavity surface-emitting lasers (VCSELs) (Raycan). The characteristics of this PS are strongly modified after introducing a polarization-preserved (PP) or polarization-orthogonal (PO) optical feedback. Under the case that the external cavity is approximately 30 cm, the PP optical feedback results in the PS point shifting toward a lower injection current, and the region within which the two polarization modes coexist is enlarged with the increase of the PP feedback strength.