Paul-Henri Pioger

Ultra wide band supercontinuum generation in air-silica holey fibers by SHG-induced modulation instabilities.

Second harmonic generation in an air-silica microstructured optical fiber pumped by subnanosecond pulses is used in order to initiate modulation instability processes in normal and anomalous dispersion regimes. This allows us to generate an ultra wide and flat supercontinuum (350-1750 nm), covering the entire transparency window of silica and exhibiting a singlemode transverse profile in visible range.

Reflection of quadratic solitons at the boundary of nonlinear media

We report experimental evidence of soliton reflection at the boundary of quadratic nonlinear media. The evolution of beams incident upon the interface of periodically poled LiNbO3 and uniform LiNbO3 is considered; in the whole device the linear refractive index is homogeneous. Linear beam transmission and soliton reflection at the nonlinear phase-mismatched boundary were observed. Numerical simulations that correspond to the experiments are also presented.

Spatial trapping of short pulses in Ti-indiffused LiNbO(3) waveguides.

We show numerically and experimentally that spatial trapping can be induced in quadratic media even if the pump pulses duration is shorter than the group-delay mismatch between fundamental wave and second-harmonic components. The influence of phase mismatch and pulse power on the trapping effect is discussed. Spatial, temporal, and spectral behaviors that accompany self-trapped propagation are highlighted.

Soliton emission at a phase-mismatch boundary in a quadratic nonlinear film waveguide

We report the experimental demonstration of spatial nonlinear beam displacement caused by an interface between periodically modulated and uniform quadratic nonlinearity. We observe intensity- and phase-mismatch-dependent spatial beam displacement at 1548 nm in lithium niobate waveguides. The device has the potential to provide a soliton-emission-based, ultrafast all-optical switch.

Generation of quadratic spatially trapped beams with short pulsed light

We report a numerical and experimental investigation on the generation of spatial self-narrowed beams with short temporal pulsed excitation in quadratic film waveguides. The impact of temporal group-velocity mismatch between the quadratic multiple interacting signals is shown. We accurately studied the spatial, temporal and spectral signals dynamics versus pulse power and phase mismatch. We show that spatial self-trapping can be induced even if the pump pulse duration is significantly shorter than the group delay mismatch between interacting waves for large enough positive phase mismatches.

Spatial addressing of picosecond signals at 1549 nm in engineered nonlinear waveguides

We observed spatial addressing of light by bidirectional spatial emission of beams at a quadratically nonlinear interface in periodically poled lithium niobate waveguides. The interface consisted of the boundary between two quasi-phase-matched regions with different poling period. We show the intensity and phase-mismatch (temperature or wavelength) dependence of the phenomena.

Spatial routing at 125 Gbit/s based on noncollinear generation of self-trapped beams in Ti:PPLN film waveguides

We investigated numerically and experimentally spatial switching and spatial steering of optical beams based on the noncollinear excitation of self-trapped waves in a quadratic nonlinear medium. The two input fields at the fundamental frequency give birth either to a single spatial soliton or to two separate solitons. Their propagation directions and their location on the output face of the crystal are conditioned by the phase difference between the input beams. An all-optical ultra fast switch based on that scheme was then implemented in a periodically poled lithium niobate film waveguide. Pulse dropping in a 125 Gbits/s pulse train at 1548 nm has been demonstrated.

Multi-Watt Supercontinuum Generation in a Nonlinear Fiber Amplifier

A nonlinear fiber amplifier is used to simultaneously achieve large spectral broadening and amplification of nanosecond pulses. The output supercontinuum extends from 1.05 to 1.75 µm, with a spectral power density higher than 3 mW/nm.

Temporal reshaping of picosecond pulses at 1548 nm based on soliton emission and spatial filtering in non-uniform Ti:PPLN waveguides

We studied an ultra-fast nonlinear temporal reshaping mechanism based on spatial soliton emission in Ti:PPLN waveguides combined with spatial filtering. We demonstrated efficient temporal reshaping of 4-picosecond pulses at 1548 nm.

DYNAMICS OF SPATIAL SOLITONS AT PHASE-MISMATCH INTERFACES

We studied the dynamics of spatial solitons at a phase-mismatch interface in quadratic nonlinear waveguides. We present here a simple formalism to analyze intensity-dependent reflection, refraction and emission of beams. Experimental demonstrations at a phase-mismatch PPLN/LiNbO3 interface are reported.