0000000000993402
AUTHOR
Frédéric Audo
Experimental observation of dispersive photon focusing dam break flows
International audience
Manipulation expérimentale de la cohérence temporelle d'ondes partiellement cohérentes
National audience; Nous décrivons deux expériences nous permettant de manipuler les propriétés de cohérence d'ondes partiellement cohérentes. Les montages expérimentaux développés reposent sur la manipulation de la phase spectrale du champ initial, assistée éventuellement d'une modulation sinusoïdale préalable de sa phase temporelle. Les signaux d'autocorrélation en intensité mesurés soulignent le changement significatif des caractéristiques temporelles des signaux incohérents obtenus.
Fiber-based measurement of temporal intensity and phase profiles of an optical telecommunication pulse through self-phase modulation
International audience; We propose and experimentally validate an all-fiber based approach to characterize the phase and intensity profiles of optical pulses. Based on three optical spectra affected by different levels of self-phase modulation, we were able to reconstruct the temporal details of pulses typical of optical telecommunications.
Offsetting Self-Phase Modulation in Optical Fibre by Sinusoidally Time-Varying Phase
We report on our recent experimental and theoretical results on the use of a sinusoidally time-varying phase to suppress undesirable self-phase modulation of optical pulses propagating in fibre-optic systems.
Linear and nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations
International audience; Using ultrafast photonic first-order differentiator applied on a partially coherent field, we report the generation of two correlated temporal waveforms and study their correlation properties upon linear and nonlinear propagation along the two orthogonal polarization axis of a dispersive optical fiber. Temporal correlations are maintained in linear propagation whereas Kerr nonlinearity generates anti-correlated temporal intensity patterns for both partially and uncorrelated fields. Experiments are in close agreement with the theoretical analysis.
Nonlinear spectral compression in optical fiber: A new tool for processing degraded signals
International audience; We propose two new applications of the spectral focusing by self-phase modulation that occurs in a nonlinear optical fiber. We numerically show the possibility of using nonlinear spectral compression to improve the optical signal to noise ratio and mitigate the amplitude jitter of the signal pulses. We also demonstrate experimentally that use of spectral focusing in a combination with an external sinusoidal phase modulation achieves efficient suppression of coherent spectral background.
Nonlinear spectrum broadening cancellation by sinusoidal phase modulation
International audience; We propose and experimentally demonstrate a new approach to dramatically reduce the spectral broadening induced by self-phase modulation occurring in a Kerr medium. By using a temporal sinusoidal phase modulation, we efficiently cancel to a large extend the chirp induced by the nonlinear effect. Experimental validation carried out in a passive or amplifying fiber confirm the interest of the technic for the mitigation of spectral expansion of long pulses.
Le soliton Peregrine, une onde fondamentale des dynamiques non-linéaires
National audience; Des ondes très variées sont régies par l’équation de Schrödinger non-linéaire : la lumière dans les fibres optiques, les vagues océaniques, les ondes dans les plasmas, les condensats de Bose-Einstein… Quand la non-linéarité compense la dispersion, un soliton peut se propager tout en maintenant ses caractéristiques temporelles et spectrales inchangées. En présence d’une onde continue, une autre onde non-linéaire existe : le soliton Peregrine (PS), prédit dès 1983 [1] mais démontré expérimentalement seulement en 2010 [2]. Au contraire du soliton usuel, le PS apparait de nulle part, concentre temporellement et spatialement son énergie, puis disparait sans laisser de trace.Le…
Self-phase modulation in optical fibres
International audience
Fiber-based measurement of temporal intensity and phase profiles through self-phase modulation
International audience
Nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations
Using photonic first-order differentiator applied on a partially coherent field, we generate two correlated temporal waveforms and experimentally study their correlation properties upon nonlinear propagation along the two orthogonal polarization axis of an optical fiber.
Self-phase modulation patterns in optical fibres
International audience; Self-phase modulation (SPM), one of those very fascinating effects discovered in the early days of nonlinear optics, refers to the phenomenon by which an intense optical beam propagating in a Kerr medium (e.g., an optical fibre) induces through the nonlinearity of the medium a modulation of its phase that is proportional to its own intensity profile [1]. For an input pulsed beam, the induced time-dependent phase change is associated with a modification of the optical spectrum, which depends on the initial frequency modulation (chirp) of the pulse electric field. If the pulse is initially Fourier-transform-limited or up-chirped, SPM leads to spectral broadening, where…
Mitigation of self-phase modulation by sinusoidally time varying phase
The propagation of intense ultra-short optical pulses in a Kerr medium such as an optical fibre remains a critical issue for many optical systems. This is because the self-phase modulation (SPM) of the propagating pulse usually causes a severe broadening of the pulse spectrum that is typically accompanied by an oscillatory structure. Several strategies have been proposed and successfully deployed to counteract the deleterious effects of SPM in fiber-optic systems, including spatial or temporal scaling to reduce the impact of nonlinearity. Other approaches rely on the exploitation of the peculiar properties of parabolic shaped pulses and self-similar evolution. However, none of these last te…
Elimination de l’auto-modulation de phase dans un amplificateur à fibre
National audience; Nous introduisons et démontrons expérimentalement une nouvelle approche pour améliorer le taux d’extinction d’une impulsion affectée par un fond continu cohérent. Cette méthode repose sur une modulation temporelle par une phase sinusoïdale suivie d’une étape de recompression spectrale non-linéaire.
Propagation non-linéaire de champs partiellement incohérents mais avec une cohérence mutuelle contrôlée
National audience