On-demand generation of soliton molecules through evolutionary algorithm optimization.

Combining evolutionary algorithm optimization with ultrafast fiber laser technology, we report on the self-generation of stable two-soliton molecules with controllable temporal separation. A fiber laser setup including an adjustable virtual saturable absorber achieved through nonlinear polarization evolution and an intracavity pulse shaper is used to generate two-soliton molecules with a user-defined 3-8 ps internal delay.

Optical soliton molecular complexes in a passively mode-locked fibre laser.

Ultrashort optical pulses propagating in a dissipative nonlinear system can interact and bind stably, forming optical soliton molecules. Soliton molecules in ultrafast lasers are under intense research focus and present striking analogies with their matter molecules counterparts. The recent development of real-time spectral measurements allows probing the internal dynamics of an optical soliton molecule, mapping the dynamics of the pulses' relative separations and phases that constitute the relevant internal degrees of freedom of the molecule.

Dissipative shock waves in all-normal-dispersion mode-locked fiber lasers.

We propose an interpretation of the pronounced "M" spectral shape that is a recurrent feature in all-normal-dispersion mode-locked fiber laser dynamics. Our interpretation involves shock wave formation regularized by dissipation, modeled by a modified Burgers equation. The large fringes appearing at the edges of the spectrum result from discontinuities in the spectral phase.

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.

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.

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

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.

Stationary and pulsating dissipative light bullets from a collective variable approach.

A collective variable approach is used to map domains of existence for (3+1)-dimensional spatiotemporal soliton solutions of a complex cubic-quintic Ginzburg-Landau equation. A rich variety of evolution behaviors, which include stationary and pulsating dissipative soliton dynamics, is revealed. Comparisons between the results obtained by the semianalytical approach of collective variables, and those obtained by a purely numerical approach show good agreement for a wide range of equation parameters.

Phase-locked soliton pairs in a stretched-pulse fiber laser.

We report the experimental observation of stable pulse pairs with a +/-pi/2 phase difference in a passively mode-locked stretched-pulse fiber ring laser. In our setup the stabilization of interacting subpicosecond pulses is obtained with a large range of pulse separations, namely, from 2.7 to 10 ps, without the need for external control.

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.

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.

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.

Quantized separations of phase-locked soliton pairs in fiber lasers.

We report the discovery of a quantization of the separation between phase-locked soliton pairs that is related to the radiation waves known as Kelly sidebands, in a passively mode-locked fiber ring laser. Our numerical simulations that predict this phenomenon have been confirmed by our experimental results.

Soliton pairs in a fiber laser: from anomalous to normal average dispersion regime.

We report the observation of self phase-locked pulse pairs in a stretched-pulse fiber laser operating in the normal path-averaged dispersion regime. Numerical simulations agree with our experimental results. More insight is provided with a numerical comparison between intracavity profiles of pulse pairs in anomalous and in normal dispersion regimes.