Andrey Komarov

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. In addition, the transition dynamics from a bunched state of pulses to stable harmonic mode locking is presented, revealing a very long time scale.

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.

`Cis' bound states of three localized pulses of the cubic-quintic CGL equation

We investigate triplet bound states with a new symmetry, called cis, using the cubic–quintic CGL equation. We show that the leading term of the functional J[ψ], which governs the evolution of the momentum of the solution to the CGL equation, vanishes for the cis-symmetry. Numerical investigations show that stable cis triplet bound states are solutions of the CGL equation. Quasi-stable cis-states are also found, and also a stable quasi-stationary asymmetrical triplet state. Then we show that it is possible to experimentally distinguish between the trans and cis triplet states, using either the optical spectrum or the collinear autocorrelation trace.

Multiple Pulsing and Hysteresis Phenomena in Fiber Lasers: Theory and Experiment

We investigate both theoretically and experimentally the multiple pulsing behaviour of an erbium-doped double-clad fiber laser passively mode-locked through nonlinear polarization rotation. Hysteresis phenomena are predicted theoretically and found experimentally in both the normal and anomalous dispersion regime

Spectral Control over the Interaction of Ultrashort Pulses in Fiber Lasers

The interaction of light pulses in passively mode-locked fiber lasers operating has been studied. The numerical simulation has been used to demonstrate that a narrow-band selector inserted in a laser cavity allows the character of the interaction to be changed: depending on the detuning of the selector passband from the center of the gain band, ultrashort pulses can both attract and repel one another. Peculiarities of the pulse interaction have been studied at different parameters of the laser system.

Passive mode-locking of a fiber laser operating in the regime of undumped regular spiking

Computer simulation is used to investigate a new regime of oscillation of fiber lasers in which passive mode-locking takes place simultaneously with the regime of regular undumped spiking induced by an intracavity saturable absorber. Such a superposition regime takes place when part of the output radiation of the laser operating in the regime of spiking is propagated through a fiber-optic delay line and is coupled back into the laser cavity in a time interval equal to the time interval between adjacent spikes. The advantages of the proposed regime of oscillation relative to other means of achieving passive mode-locking in fiber lasers are discussed. The proposed regime is of interest for obtaining reproducible high-energy light pulses.

Manipulation of large soliton ensembles in Er-doped double-clad fiber laser

We have studied the influence of an external continuous wave on a passively mode-locked fiber laser operating in the soliton regime. Starting from an irregular soliton distribution it is shown that harmonic mode-locking is obtained.

Analysis of soliton complexes in high power fiber lasers

We consider a fibre laser operating in a regime where thousands of solitons coexist in the cavity. Because of the soliton interaction, different soliton patterns or complexes are generated depending on the laser parameters. We point out an analogy between soliton complexes and the states of the matter: soliton gas, soliton supersonic flow, soliton liquid, soliton polycrystal and soliton crystal.

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.

Modelling of multiple soliton operation of fiber lasers with anomalous frequency dispersion

On basis of numerical simulation we study the peculiarities of the formation of ultrashort pulses, their interaction, the formation of stable multiple soliton structures in passive mode-locked fiber lasers with anomalous frequency dispersion. It is found the novel type of a dissipative soliton. The single soliton of this type has asymmetric spatial and spectral profiles and demonstrates bistability: two stable states with right and left spectral-spatial asymmetries for which the single soliton velocities are different.