398 research outputs found
Optimal frequency conversion in the nonlinear stage of modulation instability
We investigate multi-wave mixing associated with the strongly pump depleted
regime of induced modulation instability (MI) in optical fibers. For a complete
transfer of pump power into the sideband modes, we theoretically and
experimentally demonstrate that it is necessary to use a much lower seeding
modulation frequency than the peak MI gain value. Our analysis shows that a
record 95 % of the input pump power is frequency converted into the comb of
sidebands, in good quantitative agreement with analytical predictions based on
the simplest exact breather solution of the nonlinear Schr\"odinger equation
HÂą-PERTURBATIONS OF SMOOTH SOLUTIONS FOR A WEAKLY DISSIPATIVE HYPERELASTIC-ROD WAVE EQUATION
We consider a weakly dissipative hyperelastic-rod wave equation (or weakly dissipative Camassa-Holm equation) describing nonlinear dispersive dissipative waves in compressible hyperelastic rods. By fixed a smooth solution, we establish the existence of a strongly continuous semigroup of global weak solutions for any initial perturbation from . In particular, the supersonic solitary shock waves [8] are included in the analysis
Observation of the stepwise blue shift of a dispersive wave preceding its trapping by a soliton
International audienceThe trapping of a weak dispersive wave by an intense soliton is a complex process occurring at the early stage of supercontinuum generation. It is theoretically predicted to arise from multiple soliton-dispersive wave interactions, producing a stepwise frequency blue shift of the dispersive wave. We report here the first experimental evidence of this frequency blue shift using a tapered fiber which acts as a prism, allowing to disperse the blue spectral components in order to identify unambiguously each soliton-dispersive wave collision
Emission of multiple dispersive waves from a single Raman-shifting soliton in an axially-varying optical fiber
International audienceWe provide the experimental demonstration of the generation of multiple dispersive waves from a single soliton propagating in the vicinity of the first zero-dispersion wavelength of an axially-varying optical fiber. The fiber is designed such that the Raman-shifting soliton successively hits three times the longitudinally evolving zero-dispersion wavelength, which results in the emission of three distinct dispersive waves at different fiber lengths. These results illustrate how suitably controlled axially-varying fibers allow to tailor the soliton dynamics in a very accurate way
Spatiotemporal Characterization of Supercontinuum Extending from the Visible to the Mid-Infrared in Multimode Graded-Index Optical Fiber
We experimentally demonstrate that pumping a graded-index multimode fiber
with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat
supercontinuum generation with a uniform bell-shaped spatial beam profile
extending from the visible to the mid-infrared at 2500\,nm. We study the
development of the supercontinuum along the multimode fiber by the cut-back
method, which permits us to analyze the competition between the Kerr-induced
geometric parametric instability and stimulated Raman scattering. We also
performed a spectrally resolved temporal analysis of the supercontinuum
emission.Comment: 5 pages 7 figure
Efficient modelling of nonlinear propagation in multimode graded-index fibers
International audienceWe develop an effective 1+1D model describing nonlinear propagation in multimode graded-index fibers. The model is able to quantitatively reproduce recently observed phenomena like geometric parametric instability and broadband dispersive wave emission
Dynamics of cascaded resonant radiations in a dispersion-varying optical fiber
International audienceWe use a dispersion-varying optical fiber to experimentally explore the dynamics of resonant radiations emitted from Raman-shifting solitons in the vicinity of the second zero-dispersion. The evolving zero-dispersion wavelength with fiber length allows to observe unprecedented processes such as a cascade of resonant radiations, the emission of multiple resonant radiations from a single soli-ton and the generation of a 500 nm continuum exclusively composed of resonant radiations. All experiments are interpreted using numerical simulations of the generalized nonlinear Schrödinger equation which are in excellent agreement
Optical event horizons from the collision of a soliton and its own dispersive wave
International audienceWe observe experimentally the spectral signature of the collision between a soliton and the dispersive wave initially emitted from the soliton itself. This collision, interpreted in terms of an optical event horizon, is controlled by the use of an axially varying fiber which allows us to shape both the soliton and dispersive wave trajectories so that they both collide at a precise location within the fiber. The interaction of the dispersive wave with the soliton generates a reflected wave with a conversion efficiency which can be controlled by the input pump power. These experimental results are confirmed by numerical solution of the generalized nonlinear Schrödinger equation and by the analytical calculation of the conversion efficiency
Impact of higher-order dispersion on geometric parametric instability in GRIN multimode fibers
International audience
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