Search results for "MODULATION"
showing 10 items of 948 documents
2R regeneration architectures based on multi-segmented fibres
2008
The benefits of using a multi-segmented arrangement of optical fibres for Self-Phase Modulation-based 2R optical regeneration are described both theoretically and experimentally. Significant improvements in terms of the performance and practicality are achieved.
Generalisation and experimental validation of design rules for self-phase modulation-based 2R regenerators
2007
We report the design of 2R-regenerators based on self-phase modulation in lossy fibers. We experimentally demonstrate the applicability of the proposed scaling rules and present detailed characterization of the pulse characteristics at the regenerator output.
Étude et manipulation de modes résonants en champ proche optique
2010
Within the quick nano-fabrication techniques evolution and the increasing needs in low space and energy opto-electronic functions on-chip integration, studies and control of electromagnetic resonances of sub-micrometric objects are crucial issues. One aim of this work was then to improve our knowledge of the light-matter interaction. To this end, optical near-field experiments and complementary numerical development of models have been performed to study electromagnetic resonances due to light-matter interaction in sub-micrometric resonators. As an introduction, the first part of the manuscript presents the main phenomena involved in near-field optical microscopy and the used SNOM operation…
Temporal coherence in mirrorless optical parametric oscillators
2012
International audience; One of the unique features of mirrorless optical parametric oscillators based on counterpropagating three-wave interactions is the narrow spectral width of the wave generated in the backward direction. In this work, we in- vestigate experimentally and numerically the influence that a strong phase modulation in the pump has on the spectral bandwidths of the parametric waves and on the efficiency of the nonlinear interaction. The effects of group-velocity mismatch and group-velocity dispersion are elucidated. In particular, it is shown that the substan- tial increase in temporal coherence of the backward-generated wave can be obtained even for pumping with a temporally…
Complex rogue wave in the fiber optics
2016
This manuscript presents the generation of complex rogue waves related to nonlinear instabilities occurring through the propagation of light in standard optical fibers. Linear and nonlinear physical phenomena involved are first listed, in particular some of them by analogy with the field of hydrodynamics. The different forms of rogue waves induced by the modulation instability process are then presented. They are also known as "breathers", and they are obtained by solving the nonlinear Schrödinger equation. From these exact solutions, various experimental systems were designed by means of numerical simulations based on two rogue-wave excitation methods. The first one is an exact generation …
Design rules for nonlinear spectral compression in optical fibers
2016
International audience; We present comprehensive design rules to optimize the process of spectral compression arising from nonlinear pulse propagation in an optical fiber. Extensive numerical simulations are used to predict the performance characteristics of the process as well as to identify the optimal operational conditions within the space of system parameters. It is shown that the group-velocity dispersion of the fiber is not detrimental and, in fact, helps achieve optimum compression. We also demonstrate that near-transform-limited rectangular and parabolic pulses can be generated in the region of optimum compression.
Photo-thermal modulation of surface plasmon polariton propagation at telecommunication wavelengths
2013
International audience; We report on photo-thermal modulation of thin film surface plasmon polaritons (SPP) excited at telecom wavelengths and traveling at a gold/air interface. By operating a modulated continuous-wave or a Q-switched nanosecond pump laser, we investigate the photo-thermally induced modulation of SPP propagation mediated by the temperature-dependent ohmic losses in the gold film. We use a fiber-to-fiber characterization set-up to measure accurately the modulation depth of the SPP signal under photo-thermal excitation. On the basis of these measurements, we extract the thermo-plasmonic coefficient of the SPP mode defined as the temperature derivative of the SPP damping const…
Pulse doubling and wavelength conversion through triangular nonlinear pulse reshaping
2011
International audience; We present a proof of principle experiment demonstrating the benefits of using a triangular temporal profile in the context of copying and wavelength conversion of telecommunication signals. Generated by passive nonlinear reshaping in a set of two carefully chosen fibres, the triangular shape enables efficient temporal and spectral doubling of the signals through self-phase modulation.
Pulvérisation ciblée sur les tâches d’adventices détectées par drône en colza
2019
L’idée de cartographier les zones infestées par les adventices pour restreindre la surface traitée, et donc les quantités d’herbicides utilisées, méritait d’être testée. Depuis l’acquisition des données par drone, en passant par le traitement des images, jusqu’à l’exploitation de la carte par le pulvérisateur au champ. C’est pourquoi, Terres Inovia a décidé de collaborer avec AIRINOV pour conduire un essai sur colza en vue de la pulvérisation ciblée sur les tâches d’adventices détectées préalablement par drone. Cette étude exploratoire avait pour objectif de vérifier l’intérêt, la faisabilité, la pertinence et l’efficacité d’une telle technique. Elle s’inscrit dans le projet européen H2020 …
Plasticity in the olfactory system: modulation by the odorant environment and diet
2015
As the primary neuronal element in the olfactory system, olfactory sensory neurons (OSNs) are responsible for detecting odor molecules, transforming chemical information to electrical signals and sending these signals to the brain. Being exposed to the environment, their lifetime is limited. The olfactory epithelium has the remarkable ability to regenerate sensory neurons throughout life. There is little data showing the effects of the environment, such as odorant exposure, on the properties of OSNs. Similarly, knowledge on the modulation by the physiological state of the animal (i.e. nutritional status) is limited. The long-term goal of our group is to investigate how the OSNs function dur…