Search results for "Dispersion"
showing 10 items of 1101 documents
Tailored soliton statistics in supercontinuum generation
2009
Supercontinuum (SC) generation in highly nonlinear photonic crystal fibers (PCF) has stimulated tremendous interest in recent years [1]. Particular results that have received recent widespread attention concern the observation of “optical rogue waves,” statistically rare extreme red-shifted Raman solitons appearing on the long wavelength edge of the SC spectrum [2]. Further numerical analysis of these fluctuations have showed explicitly that the rogue soliton statistics exhibit strongly non-Gaussian extreme-value characteristics [3]. The previous studies of optical rogue wave statistics in SC generation have been carried out considering PCF with only one zero dispersion wavelength (ZDW). It…
The nonlinear Schrodinger equation and the propagation of weakly nonlinear waves in optical fibres and on the water surface
2015
International audience; The dynamics of waves in weakly nonlinear dispersive media can be described by the nonlinear Schrödinger equation (NLSE). An important feature of the equation is that it can be derived in a number of different physical contexts; therefore, analogies between different fields, such as for example fiber optics, water waves, plasma waves and Bose–Einstein condensates, can be established. Here, we investigate the similarities between wave propagation in optical Kerr media and water waves. In particular, we discuss the modulation instability (MI) in both media. In analogy to the water wave problem, we derive for Kerr-media the Benjamin–Feir index, i.e. a nondimensional par…
Nonlinear parametric resonances in quasiperiodic dispersion oscillating fibers
2015
We numerically study the evolution of the spectrum of parametric resonance or modulation instability sidebands in quasiperiodic dispersion oscillating fibers. We separately consider a linear variation along the fiber of either the spatial period, the average dispersion, or the amplitude of the dispersion oscillation. We found that this linear variation of the dispersion oscillating fiber parameters may provide different novel mechanisms for the splitting of the resonance sideband spectrum, owing to coherent interference between quasi-resonant waves that are generated at different points along the fiber. (C) 2015 Elsevier B.V. All rights reserved.
Wave-turbulence approach of supercontinuum generation: Influence of self-steepening and higher-order dispersion
2009
International audience; We analyze the influence of self-steepening and higher-order dispersion on the process of optical wave thermalization. This study is aimed at developing a thermodynamic formulation of supercontinuum generation in photonic crystal fibers. In the highly nonlinear regime of supercontinuum generation, the optical field exhibits a turbulent dynamics that may be described by the kinetic wave theory. In this respect, the phenomenon of spectral broadening inherent to supercontinuum generation may be interpreted as a natural process of thermalization, which is characterized by an irreversible evolution of the optical field toward a thermodynamic equilibrium state. The numeric…
In-situ diagnostic of ultrashort probes based on Kerr-index transient Bragg grating
2019
Pump-probe experiments are essential tools to investigate ultrafast dynamics of laser-matter interaction. We are particularly interested in the dynamics of transparent dielectrics under high numerical aperture focusing. Two main challenges arise for the weak probe pulse. First, we need a precise knowledge of the probe delay with respect to the pump pulse. Second, dispersion compensation of the ultrashort probe pulse generally requires a prism compressor, which can generate angular dispersion, and therefore incorrect interpretation of the pumpprobe measurements.
Parabolic pulse evolution in normally dispersive fiber amplifiers preceding the similariton formation regime
2006
We show analytically and numerically that parabolic pulses and similaritons are not always synonyms and that a self-phase modulation amplification regime can precede the self-similar evolution. The properties of the recompressed pulses after SPM amplification are investigated. We also demonstrate that negatively chirped parabolic pulses can exhibit a spectral recompression during amplification leading to high-power chirp-free parabolic pulses at the amplifier output.
Gap solitons in nonlinear electrical transmission lines
2005
We study theoretically and numerically the properties of monochromatic waves in a nonlinear electrical transmission line,whose capacitance has a periodic spatial variation.ln the continuum limit and weak amplitude limit we reduce the characteristic equations of this system to NLS equation. We find analytical solutions for the voltage envelope, which propagate with frequency in the gap induced by the capacitance periodicity. Our numerical experiments show that, when the input voltage increases, the transmissivity in the gap increases and the voltage envelope approaches the stationnary shape predicted by theory.
Source linewidth effects in temporal imaging of Gaussian Schell-model pulses
2006
A transform-limited Gaussian pulse generated from an externally modulated stationary source is launched within a temporal imaging system composed of a second-order dispersion followed by a time lens and a subsequent quadratic dispersion. We consider the effect of the statistical properties of the emitted light for temporal imaging. In particular, it is shown that the design parameters that ensure a received signal with the minimum root-mean-square (rms) width achievable, which is called the temporal image of the incident pulse, are strongly dependent on the coherence properties of the input waveform. Finally, limitations on the temporal resolution of the setup are highlighted and a realisti…
Group interactions of dissipative solitons in a laser cavity: the case of 2+1.
2009
What can be the outcome of the interaction between a dissipative soliton pair and a soliton singlet? We report an experimental observation of ???elastic??? collisions as well as ???inelastic??? formation of triplet soliton states in a fiber laser setup. These observations are supported with the numerical simulations based on the dispersion (parameter) managed cubic-quintic Ginzburg-Landau equation model.
Temporal self-imaging effect for chirped laser pulse sequences: Repetition rate and duty cycle tunability
2005
We express parabolic-dispersion-induced transformations of a linearly chirped signal in terms of those suffered by the unchirped version of the same input signal. Specifically, we unveil that any amount of chirping and dispersion produces, aside from a scale factor, the same pulse-distortion effect as a certain parabolic dispersion in the unchirped input. This relevant result allows us to derive, as a particular case, the dispersion condition that leads to the temporal self-imaging phenomenon for laser pulse sequences globally affected by a quadratic-phase modulation. This combined action of chirping and dispersion is proposed as a technique for generating laser pulse sequences with customi…