Search results for "linear"

Emergence of rogue waves from optical turbulence

2011

International audience; We provide some general physical insights into the emergence of rogue wave events from optical turbulence by analyzing the long term evolution of the field. Depending on the amount of incoherence in the system (i.e., Hamiltonian), we identify three turbulent regimes that lead to the emergence of specific rogue wave events: (i) persistent and coherent rogue quasi-solitons, (ii) intermittent-like rogue quasi-solitons that appear and disappear erratically, and (iii) sporadic rogue waves events that emerge from turbulent fluctuations as bursts of light or intense flashes.

Classical wave thermalisation in chaotic multimode optical fibre

2023

Simultaneous 2R regeneration of WDM signals in a single optical fibre

2009

Two experimental implementations of amplitude regeneration of WDM signals based on self-phase modulation (SPM) in optical fibres are discussed. The two examples differ in their approach of mitigation of inter-channel nonlinearities.

New concepts based on nonlinear polarization effects and Raman amplification in optical fibers

2009

We report a theoretical analysis and experimental demonstration of a polarization attraction process at telecommunication wavelengths in isotropic optical fibers. The combined effects of polarization attraction and Raman amplification are also presented.

Quasi-phase-matched third harmonic generation in optical fibers using refractive-index gratings

2011

International audience; The purpose of this work is to demonstrate the quasi-phase-matching of third harmonic generation process in optical fibers using refractive-index gratings. We compare conversion efficiency calculated with analytical coupled modes theory and numerical approach employing system of coupled generalized nonlinear Schrödinger equation. Moreover, we show that introducing the phase matching condition that takes into account the nonlinear contribution to propagation constants significantly increases the conversion efficiency by several orders of magnitude. Finally we optimize the grating constant to maximize conversion efficiency.

Shallow water rogue waves in nonlinear optical fibers

2013

The dynamics of extreme waves, often known as freak or rogue waves (RW), is presently a subject of intensive research. In oceanography, RW are mostly known as a sudden deep-water event which is responsible for ship wreakages and can be modeled by the 1D Nonlinear Schrodinger Equation (NLSE). In this framework, an ideal testbed is provided by optical pulse propagation in nonlinear optical fibers: extreme solitary wave emissions during supercontinuum generation or the first experimental observation of the Peregrine solitons have indeed been carried out exploiting the modulation instability occuring in fibers with anomalous dispersion.

Nonlinear phase shift measurement by heterodyne detection in waveguides optics

2022

Nonlinear optics has been a productive field of research and investigation for a few decades now, but the rapid progression of photonic integration platforms in recent years has opened up a whole new range of applications. On-chip integration of effective saturable absorbers and secondary sources including Brillouin laser, supercontinua, or frequency combs are few examples of the very wide possibilities offered by nonlinear nanophotonics. In this context, materials with large third-order optical nonlinearities become highly sought after, as they enable the development of nonlinear functionalities at low input powers. Given a large number of potential candidates as material for nonlinear nan…

Le dioxyde de titane : un matériau nouveau pour la photonique à 1.55 µm et à 2 µm

2018

In the next decades, the limits of current optical communication systems will be reached unless new solutions are adopted. On of them is the use of a new spectral range around 2 µm enabled by the emergence of thulium-doped fiber amplifiers. In this thesis, we will focus on it in the context of very short distances transmissions on photonic chips. Various materials, mainly titanium dioxide (TiO2), will be explored.This thesis work has two main objectives. On the one hand, it aims to demonstrate that a material relatively unexplored, titanium dioxide, is promising for telecom applications by comparing it to more mature plateforms. On the other hand, it tends to introduce the spectral band aro…

Generation of aperiodic picosecond pulses sequences from incoherent optical waves

2007

We present an original method to generate optical pulses trains with random time-interval values from incoherent broadband sources. Our technique relies on the remarkable properties of a line made of cascaded SPM-based optical regenerators.

Orientation of Polar Molecules by Laser Induced Adiabatic Passage

2002

International audience; We show that two overlapping linearly polarized laser pulses of frequencies ω and its second harmonic 2ω can strongly orient linear polar molecules, by adiabatic passage along dressed states. The resulting robust orientation can be interpreted as a laser-induced localization in the effective double well potential created by the fields, which induces a preliminary molecular alignment. The direction of the orientation can be selected by the relative phase of the fields.