Regimes of Passive Mode-Locking of Fiber Lasers

We present results of a numerical simulation and analysis of various regimes of passive mode-locking of fiber lasers including a single pulse  and multipulse operation, bound states of solitons, and harmonic passive mode-locking. Our results on the multipulse regimes consist of the multihysteresis dependences of a number of pulses in the laser cavity, of pulse peak intensities and an intracavity radiation energy on a pump power. The analysis of mechanisms of an intersoliton interaction in the laser cavity has been performed. The opportunity of the coding of information with the use of bound soliton sequences has been demonstrated. Various mechanisms for control of intersoliton interactionr are proposed

Quantization of binding energy of structural solitons in passive mode-locked fiber lasers

On basis of numerical simulation of fiber laser passive mode locking, we have determined the quantum binding-energy levels for a pair of interacting structural solitons. These solitons have powerful wings and correspondingly large binding energies. It has been found that the field amplitude functions for steady states corresponding to neighboring energy levels have opposite parity. We have pointed out the analogy between the energy quantization for laser bound solitons and for a particle moving in potential well. The possibility of a coexistence of in-, opposite-, and π/2-phase soliton pairs has been found. In the case of multiple soliton trains, we have demonstrated the realization of highly stable soliton sequences with any required distribution along the soliton train of various types of bonds between neighboring pulses

Peculiarities of soliton formation in passive mode-locked lasers with anisotropic fibers

Date du colloque : 06/2010International audienc

Dissipative Soliton Resonance in Passive Mode-Locked Lasers

By numerical simulation it is found that the dissipative soliton resonance prevents to an appearance in generation of new pulses with increasing pump power. It can be used for generation of high-energy pulses

Polarization dynamics in nonlinear anisotropic fibers

We give an extensive study of polarization dynamics in anisotropic fibers exhibiting a third-order index nonlinearity. The study is performed in the framework of the Stokes parameters with the help of the Poincaré sphere. Stationary states are determined, and their stability is investigated. The number of fixed points and their stability depend on the respective magnitude of the linear and nonlinear birefringence. A conservation relation analogous to the energy conservation in mechanics allows evidencing a close analogy between the movement of the polarization in the Poincaré sphere and the motion of a particle in a potential well. Two distinct potentials are found, leading to the existence of two families of solutions, according to the sign of the total energy of the equivalent mechanical system. The mechanical analogy allows us to fully characterize the solutions and also to determine analytically the associated beat lengths. General analytical solutions are given for the two families in terms of Jacobi’s functions. The intensity-dependent transmission of a fiber placed between two crossed polarizers is calculated. Optimal conditions for efficient nonlinear switching compatible with mode-locking applications are determined. The general case of a nonlinear fiber ring with an intracavity polarizer placed between two polarization controllers is also considered

Mechanism of dispersive-wave soliton interaction in fiber lasers

Date du colloque : 06/2012International audienc

Dispersive Wave Interaction between Solitons in Fiber Lasers with Saturable Absorbers

On basis of numerical simulation it is found that the long-distance soliton wings can be formed by dispersive waves emitted by ultrashort pulses due to of various lumped elements in passive mode-locked fiber lasers. Peculiarities of the interaction of two solitons through such wings in lasers with lumped saturable absorbers (SA) are analyzed. Different sets of bound steady-states of two-soliton molecule are obtained. Among them there are sets with and without an alternation of parity of neighboring quantum steady-states. It is shown that the investigated interaction can result in mechanisms of both attraction and repulsion of loosely bound solitons. It is demonstrated a coding of an information by highly-stable bound soliton sequences

Spectral-selective management of dissipative solitons in passive mode-locked fibre lasers

We study properties of dissipative solitons in passive mode-locked fibre lasers due to additional intracavity narrow spectral selection. Such selection allows us to control the soliton velocity, the nature of the interaction between solitons (attraction or repulsion), to create a bistable state in which the velocity of a single soliton can have two different values, to realize an elastic particle-like collision between single solitons. In the investigated laser system, the soliton interaction distance can be considerably larger than the soliton duration, which allows the realization of passive harmonic mode-locking

Passive mode-locked fiber lasers: multiple pulse regimes and operation of high-energy pulses

On basis of numerical simulation we have investigated the multihysteresis phenomena in fiber mode-locked lasers, the regimes of multipulse operation, and the generation of high-energy pulses due to the dissipative soliton resonance. The obtained results ar

Structural dissipative solitons in passive mode-locked fiber lasers

On the basis of numerical simulation of fiber laser passive mode locking with anomalous dispersion we have found the dissipative solitons with powerful pedestals having oscillating structure. The pedestal structure causes a complex structural spectrum. These solitons can be multistable: with the same laser parameters the pedestals can have different structures. For some nonlinear-dispersion parameters there exist solitons with asymmetric structural pedestals moving relatively solitons with symmetric ones