Dissipative Spatial Solitons Research Articles

Dynamics of dissipative spatial solitons over a sharp potential

We analyze various scenarios of the dynamics of a spatial soliton interacting with a sharp potential barrier (SPB) in the complex Ginzburg–Landau model with the cubic-quintic nonlinearity. In optical realizations of the model, the SPB corresponds to a local notch in the refractive-index field. Possible outcomes of the interaction include splitting of the soliton, its lateral drift, formation of tree-like multi-jet patterns, and destruction of the soliton. The results suggest applications to the design of two- and multi-route splitters of light beams.

Complex spatial structures due to atomic coherence

The coupling of diffraction and optical coherence of a three-level medium in an optical cavity is considered. Self-organisation and pattern formation due to a combination of electromagnetically induced transparency, close-to-resonance Kerr effects and diffraction is demonstrated. Self-focusing in the peaks of the resulting Turing pattern leads to localised amplification of the input pump. Spatial dissipative solitons with controllable position, dispersion and coherence are also described.

Regimes of a wide-aperture laser with nonlinear scattering medium

Regimes of a wide-aperture laser with a layer of a heterogeneous medium with a nonlinear refractive index placed inside the cavity are considered. The conditions of bistability of the regimes with transversely uniform intensity are analyzed. The conditions of formation of spatial dissipative solitons in this laser are discussed.

Dissipative optical solitons

This paper presents a review of the general properties of dissipative spatial and temporal optical solitons and setups for shaping them. Information is presented concerning the first publications on dissipative optical solitons, and the current status of this research is analyzed.

Quantum fluctuations of spatial dissipative solitons in a nonlinear interferometer

A quantum Langevin equation is derived that makes it possible to study the radiation field in a large-aperture nonlinear interferometer excited by external classical radiation. This equation is linearized in the vicinity of the solution for a stationary soliton. A mathematical formalism for obtaining a spectral representation of the solution to the linearized problem is constructed. It is shown that, in general, the excitation spectrum of a soliton consists of three branches, two of which belong to a continuous spectrum, while the third branch is discrete. The spectral representation obtained makes it possible to rigorously define the operator of soliton coordinate fluctuations, since, as is shown in the study, the traditional definition of this operator leads to a divergence in the vicinity of the solution. A new type of dissipative soliton is found, which is a natural generalization of a stationary soliton and takes into account its motion. A relation is found between this soliton and the contribution to the solution for field fluctuations from the discrete spectrum expansion. The mean squares of fluctuations of the soliton coordinate and momentum are calculated. A range of parameters is determined where the momentum of the soliton can always be measured with a spread smaller than the standard quantum limit. This possibility is related to the occurrence of states squeezed with respect to the soliton momentum. A scheme is proposed for the experimental observation of these states.

Dissipative solitons in quantum dot lasers

The spatiotemporal dynamics of radiation in wide-aperture semiconductor quantum-dot lasers is studied analytically and numerically. It was found that the choice of relatively rapid amplifying layers with quantum dots of a small size and slow absorbing layers with a maximal rate of exciton capture from wetting layers is optimal for the stability of spatial dissipative solitons in a single-longitudinal-mode laser. A large relaxation time of the slow absorber was found to result in a substantial decrease in the sensitivity of solitons to the tilt of the mirrors, which increases their stability and gives real chances of the experimental revealing of laser solitons.

Field structures in nonlinear large-aperture cavity schemes with lens elements

An equation for the slowly varying envelope of a field in a large-aperture interferometer or a laser with intracavity lens elements is obtained using the quasi-optical approach and mean-field approximation. The case of a negative diffraction length of the cavity is analyzed. Ways for determining the transverse dimensions of dissipative spatial optical solitons in nonlinear interferometers and lasers are discussed.

Dissipative discrete spatial optical solitons in a system of coupled optical fibers with the Kerr and resonance nonlinearities

The propagation of monochromatic radiation in a system of weakly coupled single-mode optical fibers with saturable amplification and absorption and Kerr nonlinearity of the refractive index is analyzed. Conditions of stability and bistability of plane-wave regimes are determined. Discrete dissipative optical solitons are found and their stability is studied. The hysteresis dependences of the peak intensity of the discrete solitons on the value of the Kerr nonlinearity and the input beam intensity are demonstrated. The numerical estimates of the parameters of the spatial dissipative discrete solitons are presented.

Stability of Dissipative Solitons as Solutions of Asymmetrical Complex Cubic-quintic Ginzburg-Landau Equation

The existence and nonlinear dynamics of optical dissipative spatial solitons asym- metrical with respect to transverse coordinates are studied. Steady state solutions of asym- metrical complex cubic-quintic Ginzburg-Landau equation are computed using the variational approach extended in order to treat asymmetrical input. Using established stability criterion a domain of dissipative parameters for stable solitonic solutions is flxed. Analytical predictions are conflrmed by numerically simulated evolution of an asymmetrical input pulse towards a stable and robust dissipative soliton. DOI: 10.2529/PIERS060905192230

Absorption-induced optical bistability and dissipative solitons in a BEC interferometer

A model of the absorption-induced nonlinear response of an atomic Bose-Einstein condensate driven by a weak resonant laser beam is presented. The model takes into account the slow BEC decay due to spontaneous emission and magnetic-trap loss by binary collisions, as well as compensation of the decay by injection of ground-state atoms into the trap. It is shown that the nonlinear response is much stronger than in other nonlinear optical media. For a BEC interferometer driven by a monochromatic beam, the threshold intensity for hysteretic switching is found, and dissipative spatial solitons are demonstrated.

Realization of a Cavity-soliton Laser Based on Broad-area Vertical-cavity Devices with Frequency-selective Feedback

The spontaneous formation of small-area bistable lasing spots is observed at dif- ferent positions within the aperture of a broad-area VCSEL with frequency-selective feedback. These spots can be switched on and ofi with an incoherent injected fleld. They are interpreted as spatial dissipative solitons. Approaches to model these devices are presented and flrst results on the occurrence of localization are reported.

Observation of a Discrete Family of Dissipative Solitons in a Nonlinear Optical System

We report on the observation of a discrete family of spatial dissipative solitons in a simple optical pattern forming system, which is based on a modified single-mirror feedback arrangement. After a pitchfork bifurcation the system possesses two (nearly) equivalent coexisting states of different polarizations. The spatial solitons correspond to excursions from one of the two states serving as a background state towards the other one. The members of the soliton family differ in the number of high-amplitude radial oscillations. The observations are in good agreement with numerical simulations and general expectations for dissipative solitons.

Stability properties of multiwavelength, incoherent, dissipative spatial solitons

We have investigated the interaction between two dissipative spatial solitons of different frequencies in periodically patterned semiconductor optical amplifiers. The experimental results are in good agreement with the theory. Simulations suggest that multiwavelength interactions do not produce stable bound solitons unless the system's modeling equations are completely symmetric.

Excitation of localized spatial structures of different symmetry in a system of two thin films

We consider spatial dissipative solitons arising in the system of two nonlinear thin films which interact resonantly with light. Symmetric and nonsymmetric solitons and methods of their exciting and switching are studied.

Coherent interactions of dissipative spatial solitons.

We report observation of the interaction between two coherent dissipative spatial solitons in a periodically patterned semiconductor optical amplifier with power levels of tens of milliwatts. The interactions are nonlocal and phase dependent and exhibit surprising features, such as soliton birth. The experimental results are in good agreement with the numerical simulations.

Midband dissipative spatial solitons.

We show dissipative spatial solitons in nonlinear optical microresonators in which the refractive index is laterally modulated. In addition to "normal" and "staggered" dissipative solitons, similar to those in spatially modulated conservative systems, a narrow "midband" soliton is shown, having no counterparts in conservative systems.

Spatial solitons and Anderson localization

Stochastic (Anderson) localization is the spatial localization of the wave function of a quantum particle due to a random spatial potential. We show that a corresponding phenomenon can stabilize dissipative spatial solitons in nonlinear optical resonators: spatial solitons in resonators with randomly distorted mirrors are more stable than those in perfect mirror resonators. We demonstrate the phenomenon numerically, by investigating solitons in lasers with a saturable absorber, and analytically, by deriving and analyzing the coupled equations of spatially coherent and incoherent field components.

Stable spatial solitons in semiconductor optical amplifiers.

The existence of stable dissipative spatial solitons at low intensities in patterned electrode semiconductor optical amplifiers (SOAs) is predicted theoretically. In contrast to conventional SOAs, this system may support stable solitons because the inherent saturating losses provide subcritical bifurcations for both the plane-wave and the soliton solution.

Dissipative optical solitons

This paper presents a review of the general properties of dissipative spatial and temporal optical solitons and setups for shaping them. Information is presented concerning the first publications on dissipative optical solitons, and the current status of this research is analyzed.