Biomedical subjects

J M Soto-Crespo

Publications and source records attributed to J M Soto-Crespo.

9 recordsLinked to original sources

PubMed2006

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.

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PubMed2005

Soliton as strange attractor: nonlinear synchronization and chaos.

We show that dissipative solitons can have dynamics similar to that of a strange attractor in low-dimensional systems. Using a model of a passively mode-locked fiber laser as an example, we show that soliton pulsations with periods equal to several round-trips of the cavity can be chaotic, even though they are synchronized with the round-trip time. The chaotic part of this motion is quantified using a two-dimensional map and estimating the Lyapunov exponent. We found a specific route to chaotic motion that occurs through the creation, increase, and overlap of "islands" of chaos rather than through multiplication of frequencies.

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PubMed2004

Bifurcations and multiple-period soliton pulsations in a passively mode-locked fiber laser.

We observed, numerically and experimentally, multiple-period pulsations of the soliton parameters in a passively mode-locked fiber laser. Pulsation periods can vary from a few to hundreds of round trips. Short and long period pulsations can appear in combination. The new periods in the soliton modulation appear at bifurcation points related to certain values of the cavity parameters.

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PubMed2004

Strongly asymmetric soliton explosions.

We have observed, in numerical simulations, strongly asymmetric soliton explosions in dissipative systems modeled by the one-dimensional complex cubic-quintic Ginzburg-Landau equation. The explosions occur at one side of the soliton, in spite of the fact that the initial conditions and the equation itself are symmetric. From one explosion to the next, the side of the soliton where it occurs alternates, so that the left- and right-hand sides of the soliton explode successively. We give explanations for this effect based on a linear stability analysis of the unstable soliton. We also describe the transition from the stationary soliton into the exploding one as a three-stage process of soliton cooling.

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PubMed2003

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.

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PubMed2002

Composite solitons and two-pulse generation in passively mode-locked lasers modeled by the complex quintic Swift-Hohenberg equation.

The complex quintic Swift-Hohenberg equation (CSHE) is a model for describing pulse generation in mode-locked lasers with fast saturable absorbers and a complicated spectral response. Using numerical simulations, we study the single- and two-soliton solutions of the (1+1)-dimensional complex quintic Swift-Hohenberg equations. We have found that several types of stationary and moving composite solitons of this equation are generally stable and have a wider range of existence than for those of the complex quintic Ginzburg-Landau equation. We have also found that the CSHE has a wider variety of localized solutions. In particular, there are three types of stable soliton pairs with pi and pi/2 phase difference and three different fixed separations between the pulses. Different types of soliton pairs can be generated by changing the parameter corresponding to the nonlinear gain (epsilon).

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PubMed2002

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.

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PubMed2001

Pulsating solitons, chaotic solitons, period doubling, and pulse coexistence in mode-locked lasers: complex Ginzburg-Landau equation approach.

The complex Ginzburg-Landau equation (CGLE) is a standard model for pulse generation in mode-locked lasers with fast saturable absorbers. We have found complicated pulsating behavior of solitons of the CGLE and regions of their existence in the five-dimensional parameter space. We have found zero-velocity, moving and exploding pulsating localized structures, period doubling (PD) of pulsations and the sequence of PD bifurcations. We have also found chaotic pulsating solitons. We have plotted regions of parameters of the CGLE where pulsating solutions exist. We also demonstrate the coexistence (bi- and multistability) of different types of pulsating solutions in certain regions of the parameter space of the CGLE.

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PubMed2000

Pulsating, creeping, and erupting solitons in dissipative systems.

We present three novel pulsating solutions of the cubic-quintic complex Ginzburg-Landau equation. They describe some complicated pulsating behavior of solitons in dissipative systems. We study their main features and the regions of parameter space where they exist.

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