Search results for "fibres"
showing 10 items of 122 documents
AMPLIFICATION ET CONTROLE TOUT-OPTIQUE DE LA POLARISATION D'UN SIGNAL TELECOM CADENCE A 10 GB/S AU SEIN D'UNE FIBRE OPTIQUE
2012
National audience; Nous démontrons la possibilité de combiner l'amplification Raman et l'attraction de polarisation d'un signal retour-à-zéro cadencé à 10 Gb/s au moyen d'une onde pompe laser contra-propagative dans un unique segment de fibre
Chalcogenide microstructured optical fibers : from linear to nonlinear properties
2010
International audience; In this talk, we review the linear properties of chalcogenide microstructured optical fibers (MOFs) of several types. We mainly focus our talk on mid-infrared applications of such fibers. We start with the general properties of solid core MOFs made of these high index glasses and compare them with the ones of silica. Then, we give some details concerning a solid core MOF made of TAS glass. Next, we describe the first guiding suspended chalcogenide MOF and explain how it was designed for supercontinuum generation in the mid-infrared. Both linear and nonlinear properties of As2S3 suspended core MOFs are also numerically studied. In the next part, We describe the design…
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 …
First archaeobotanical mentions of hemp leaved nettle ( Urtica cannabina ), in association with hemp ( Cannabis sativa ), on two sites in Champagne
2021
La culture du chanvre (Cannabis sativa) semble maintenant bien renseignée à partir du Xe siècle de notre ère en France septentrionale (Boulen et Zech-Matterne 2012), et l’utilisation des orties pour leurs fibres, généralement l’ortie dioïque (Urtica dioica), est également avérée. Toutefois, l’ortie à feuille de chanvre (Urtica cannabina) n’avait encore jamais été mentionnée parmi les études bioarchéologiques (pollen et macrorestes). Cette espèce a cependant été découverte pour la première fois à l’occasion d’une étude palynologique dans un contexte daté du XIVe siècle du site de Bezannes « le Village » (51), fouillé en 2013 (Gucker et al., en cours). Une fouille très récente à Troyes « Plan…
Formulation, caractérisation et validation d'un pain "satiétogène"
2011
This PhD project was aimed at the formulation, the characterization and the validation of one bread, processed from flour selected to increase the satiety effects on humans. For the last several decades, the prevalence of overweight and obesity around the world has been increasing. The risks of obesity are responsible for a stagnation of life expectancy in some industrialized countries. In order to stop this pandemic phenomenon, dietary fibre appears to have beneficial effects on the decrease in feeling hunger, caloric intake and body weight of obese participants. The first goal of this work was to process two fibre-enriched breads: one of them was a “whole grain” bread (PF1), and the secon…
Intérêt d'une supplémentation en acides gras polyinsaturés dans un modèle expérimental de glaucome chez le rat
2009
Diplôme : Dr. d'Université
Microfibres for nonlinear optics
2011
In this thesis, I present my works on the fabrication, the characterization and the use of optical microfibres. Microfibres are optical fibres drawn down to sub-wavelength diameters by a temperature controlled process. Due to their small dimensions, microfibers have very special properties such as a high confinement of the electromagnetic field, a enhanced non-linear coefficient and a large evanescent tail. These properties are studied in the first chapter, after which a description of the techniques used for the drawing and manipulation of the microfibres is given. Next, we present our experiments on non-linear effects in silica microfibres. In particular, we show that it is possible to ge…
Study of fatigue behavior of plant fiber reinforced composites : taking into account the variability of properties
2012
The present study focuses on the characterization and comparison of the quasi-static and fatigue properties of flax and glass fibre reinforced composites with an epoxy matrix. An extensive experimental campaign of fatigue tests have been performed using the measured quasi-static tension and in plane-shear properties. It appears that the static and fatigue characteristics of the glass/epoxy composites are higher than that of flax/epoxy ones with similar fibre volume fraction and lay-ups. However, due to the low density of flax reinforcements, the differences between the specific properties of the two materials are low. The measurement of the evolution of the fatigue properties has highlighte…
IDENTIFICATION OF THE VISCOELASTIC CONSTITUTIVE EQUATIONS OF FLAX FIBREREINFORCED LAMINATESBY VIBRATION ANALYSIS
2015
International audience; Experimental and numericalapproaches to identify the viscoelastic properties of flax fibrereinforced epoxy composite laminatesare proposed in this study. The method used consisted theidentification of the evolutions of both loss factor and stiffness through the use of the frequency responses. Several free-free symmetrically guided beams were excited on the dynamic range of 10 to 4000 Hz with a swept sine excitation focused around their first’s modes. A fractional derivative Zener model was used to predict the behaviourof on-axis ply complex moduli. The modified ply constitutive law was then implemented in Classical Lamination Theory (CLT) calculation routine. The pro…