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. Each type is stable in the sense that a given bound state exists in the same form indefinitely. New solutions appear at special values of the equation parameters, thus bifurcating from stationary pairs. We also report the finding of mixed soliton pairs, formed by two different types of single solitons. We present regions of existence of the pair solutions and corresponding bifurcation diagrams

Dissipative vortex solitons in 2D-lattices

We report the existence of stable symmetric vortex-type solutions for two-dimensional nonlinear discrete dissipative systems governed by a cubic-quintic complex Ginzburg-Landau equation. We construct a whole family of vortex solitons with a topological charge S = 1. Surprisingly, the dynamical evolution of unstable solutions of this family does not alter significantly their profile, instead their phase distribution completely changes. They transform into two-charges swirl-vortex solitons. We dynamically excite this novel structure showing its experimental feasibility.Comment: 4 pages, 20 figure

Solitary-wave vortices in quadratic nonlinear media

We find families of vortex solitary waves in bulk quadratic nonlinear media under conditions for second-harmonic generation. We show that the vortex solitary waves are azimuthally unstable and that they decay into sets of stable spatial solitons. We calculate the growth rates of the azimuthal perturbations and show how those affect the pattern of output light. © 1998 Optical Society of AmericaPeer ReviewedPostprint (published version

Electromagnetic scattering from very rough random surfaces and deep reflection gratings

A theoretical study of electromagnetic wave scattering from deep perfectly conducting one-dimensional random rough surfaces and reflection gratings is performed by means of the extinction theorem. The scattering equations are solved numerically (instead of being solved by the usual analytical procedures, which are valid only for slight corrugations). This permits us to obtain an exhaustive collection of results for the mean scattered intensity as a function of polarization and surface parameters. In particular, Lambertian scattering and enhanced backscattering are predicted for random surfaces. Also, the range of validity of the Kirchhoff approximation is established for random surfaces whose correlation length is comparable with or smaller than the wavelength. Concerning gratings, random surfaces whose correlation length is comparable with or smaller than the wavelength. Concerning gratings, is shown that the blaze of the antispecular order for gratings is at the root of the enhanced backscattering for random surfaces. © 1989 Optical Society of AmericaThis research was supported by the Comisión Interministerial de Ciencia y Tecnología under grant PB0278.Peer Reviewe

Generation of pulse trains in the normal dispersion regime of a dielectric medium using a relaxing nonlinearity

We show that modulation-type instability can occur in the normal dispersion regime of a dielectric medium for the case of a relaxing self-focusing nonlinearity. This instability leads to the generation of pulse trains with almost no pedestal when periodic boundary conditions are applied. © 1991 American Institute of PhysicsThis work was supported by the Joint Services Optical Program of the Air Force Office of Scientific Research and the Army Research Office, the Army Research Office (DAAL03-88-KOO66), and J. M. Soto-Crespo acknowl- edges a grant from the Ministerio de Education y Ciencia, Spain.Peer Reviewe

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. Among the bistable cases, we show how both clockwise and anticlockwise rotating double bullet complexes can be formed out of the phase-controlled interaction of two single bullets. The internal dynamics of pulsating double bullet complexes, with oscillations in both the spatial separation between the two bullets and the bullet shape in time domain is also detailed

Extreme wave dynamics in ultrashort fiber lasers

Conferencia invitada; IS-PALD 2015, Metz, France, November 4- 6, 2015; http://ispald.web2.ncku.edu.tw/We review recent experiments that demonstrate the existence of optical wave transients of unusually high amplitude in fiber lasers operated in the vicinity of mode locking. These transients are analyzed in the context of optical rogue wave formation, with an important role played by the constraints of ultrafast measurements. From these investigations, a universal rogue wave mechanism is highlighted, which results from the evolution of a chaotic bunch of pulses or sub-pulses, subjected to numerous inelastic collisions, while traveling round the laser cavity.Peer Reviewe

Experimental evidence for soliton explosions

We show, experimentally and numerically, that Ti:sapphire mode-locked lasers can operate in a regime in which they intermittently produce exploding solitons. This happens when the laser operates near a critical point. Explosions happen spontaneously, but external perturbations can trigger them. In stable operation, all explosions have similar features, but are not identical. The characteristics of the explosions depend on the intracavity dispersion