Thomson-csf

Thales

Centre National De La Recherche Scientifique

Universite Nice Sophia Antipolis

Thomson-brandt

Thomas-csf

Ecole Sup&#xc9;rieure De Physique Et De Chimie Industrielles

De La Ville De Paris

Jean-Pierre Huignard

Brigitte Loiseaux

Claude Puech

Daniel Dolfi

Christophe Nicolas

Cecile Joubert

Jean-Pierre Herriau

Michel Papuchon

Stéphanie Molin

Jean-Claude Lehureau

Jean-Paul Pocholle

Pierre Leclerc

Jean-Luc Ayral

Anne Delboulbe

Francois Micheron

Luigi d'Auria

Herve J Arditty

Pierre Tournois

Arnaud Brignon

Philippe Refregier

Martine Doisy

Umberto Bortolozzo

C&eacute;cile Joubert

Stefania Residori

Pascal Joffre

Michel Hareng

Serge Le Berre

Erich Spitz

Marcel Malard

Henri Rajbenbach

Francedillaois Le Carvennec

Abdellatif Marrakchi El Fellah

Jean-Marc Verdiell

Arnaud Peigne

Bruno Mourey

Jean-Noel Perbet

Joseph Colineau

Paul-Louis Meunier

Philippe Graindorge

Philippe Robin

Jean Chazelas

Jean-Pierre Le Pesant

Francois Le Carvennec

Philippe Defranould

Jerome Primot

Patrice Jano

Eric Lallier

Guy De Corlieu

Jean-Claude Carballes

Philippe Souchay

Christian Maillot

Christian Mayeux

Michael Atlan

Michele Labeyrie

Jean Philippe Reboul

Philippe Aubourg

Isabelle Ledoux

Laurent Mugnier

Laurence Pichon

Renaud Bouffaron

Jean-Louis Bruneel

Armand Nappo

Daniel Rak

Gauthier H De Monchenault

Loïc Morvan

Gerard Illiaquer

Henri Raobenbach

Sebastien Demoustier

Amaud Brignon

Andreas Oppenlander

Frederic Dizier

Jean-Luc Ayrai

Pascal Tournois

Frederic Naudan

Jean-Christophe Chanteloup

Cindy Bellanger

A distributed optical fiber sensor of dynamic stress state comprises: an optical assembly configured to generate a series of optical pulses; an optical fiber of optical length L; an optical system configured to: inject through the first end at least the series of optical pulses; receive at the level of the end at least one series of output optical pulses, arising from the input pulses after propagation and retro-propagation in the fiber; generate at least one continuous reference beam or reference optical pulses on the basis of the optical assembly or of output optical pulses; produce a series of interference zones corresponding to the interference between the reference beam or a reference pulse and a signal optical pulse arising from an output optical pulse; a holographic detector comprising: a liquid-crystal light valve, the valve disposed so that it at least partially covers the interference zones, and producing holograms on the basis of the interference zones; at least one optical detector configured to detect output optical signals diffracted by the holograms.

Distributed optical fibre sensor for sensing stress state

According to one aspect, the invention concerns an optical imaging device () for an object (OBJ) by off-axis holography comprising a light source () adapted for emitting an illumination wave (E) on the object, in transmission or reflection, and an assembly formed by one or more thick Bragg gratings () for receiving a wave (E) coming from the object thus illuminated and for deflecting a first component (E) of the wave coming from the object, called the reference wave, and to allow a second component (E) of the wave coming from the object, called the signal wave, to pass without deflection in such a way that the deflected reference wave presents predetermined deflection angles with respect to the non-deflected signal wave defined in two perpendicular planes. The imaging device according to the first aspect further comprises a two-dimensional detection device () for acquiring an interferogram resulting from the interference between said deflected reference wave and said signal wave and a computing unit for determining, from said interferogram, an amplitude and phase distribution of the signal wave in the plane of the object (hologram).

Devices and methods for optical imaging by means of off-axis digital holography

A fiber optic sensor for detecting an excitation in proximity to a fiber optic assembly, the excitation inducing a modulation of the phase of an optical signal propagating in the fiber optic assembly, the sensor comprises: a laser assembly emitting at least one laser beam; a fiber optic assembly; an optical system configured to: inject at least one portion of the laser beam; generate at least one laser signal beam issued from the laser beam injected into and propagated in the fiber assembly; generate at least one reference beam from the laser beam or the signal beam; produce at least one interference zone corresponding to the interference between a portion of the reference beam and a portion of the interference signal beam corresponding to the interference between a portion of the reference beam and a portion of the signal beam; a digital holography assembly comprising: a liquid-crystal spatial light modulator; a video camera configured to receive the interference zone and to transcribe it electrically to the liquid-crystal spatial light modulator in order to create thereon a phase hologram corresponding thereto; at least one optical detector configured to detect an output optical signal beam.

Optical fiber sensor

An optical fiber sensor for locating an excitation in proximity to an optical fiber assembly comprises: a laser assembly configured to emit N laser beams indexed i with N&#x3e;1, of respective emission wavelength &#x3bb;i, an optical fiber assembly comprising N successive sections indexed i, an optical system configured to: inject the laser beams, receive N signal beams indexed i respectively of wavelengths &#x3bb;i, generate N reference beams indexed i respectively of wavelengths &#x3bb;i, produce N interference areas indexed i, a holographic detector comprising: a liquid crystal light valve that at least partially covers the interference areas, and is configured to produce N holograms indexed i from, respectively, N interference areas, at least one optical detector configured to detect N output optical signals indexed I, a processing unit adapted to identify the section of the fiber assembly situated in proximity to the excitation to be located.

Sensor with high-sensitivity optical fiber having a holographic detector comprising a liquid crystal light valve

The invention relates to a laser device comprising a number of fiber amplifiers () delivering a number of optical waves, which is supplied by an oscillator () that delivers a signal wave, characterized in that said device comprises:

Laser device comprising means for controlling the phase of a large number of coherent sources

The subject of the present invention is a dynamic sensor of physical quantities with optical waveguide with optically-pumped amplifier medium, which requires no interferometer or reference sensor and which makes it possible to obtain at least the same level of performance, in terms of sensitivity, as known sensors of this type, and this waveguide is linked at one end to a selective mirror, and comprises at its other end an interrogation laser, the reflection of which on the selective mirror produces a wave which, by interference with the incident wave, provokes the periodic saturation of the gain of the waveguide.

Dynamic sensor of physical quantities with optical waveguide with optically pumped amplifier medium

The general field of the invention is that of fiber-optic sensors comprising at least one measurement optical fiber having an optically pumped doped amplifying medium, the optical characteristics of which are sensitive to a physical quantity, the fiber having at least one Bragg grating. The fiber is designed so as to generate, in the amplifying medium, two optical waves having different optical frequencies that propagate in the same direction after reflection on the Bragg grating and are emitted by the amplifying medium, the two optical frequencies depending on the physical quantity. The two waves may be generated using either a birefringent polarization-maintaining fiber or a DBR (Distributed Bragg Reflector) laser cavity. Notably, this sensor may be used as a hydrophone.

Self-referenced optical fiber sensor and related sensor network

A laser source is disclosed with coherent recombination of N spatial monomode laser beams having N phase shifters controlled by a phase-lock device (). The phase-lock device has an optical device () capable of taking at least a portion of each of the N beams. The optical device has an optical element () capable of applying a phase deformation, and at least one matrix (M) of detectors capable of detecting a first image (im) of a wave surface corresponding to the N beams. The matrix (M) of detectors also detects a second image (im) deformed by the optical element (). Processing means () are provided for processing the first and second images. The processing means are configured so as to measure the phase pistons between on the sub-pupils (sp) corresponding to the N beams and to apply phase corrections c(&#x3c6;) to each of the N beams, by means of said N phase shifters so as to minimize the phase pistons.

Laser source with coherent beam recombination

An fiber-optic interferometric rotation sensor device has a laser source combined with an optical fiber. These are configured to cause interference between a beam from the laser source and a beam coming from the optical fiber. The laser source includes an optical cavity having a gain lasing medium. The sensor device includes, along the path of the beam output by the laser cavity, a beam splitter device associated with a mirror, wherein the beam split off from the beam output by the laser cavity is sent into one of the ends of the optical fiber and directed from the other end toward the gain lasing medium to form a nonlinear mirror. The splitter device is followed by a detector.

Fiber-optic interferometric rotation speed sensor including a non-linear mirror

A pumped-fiber laser comprising a multimode doped fiber ( ) and a holographic spatial mode conversion device ( ).

Power fiber laser with mode conversion

Color display system, which includes an electrooptic modulation screen (LCD) and in which a chromatic modulator (RC) is provided between the multiple-wavelength light source (S, C) and the screen (LCD). This chromatic modulator modulates a wavelength or a restricted range of wavelengths of the source in order to adjust the saturation of the various primaries transmitted to the screen as well as to effect colorimetric balance. Applications include liquid-crystal color displays.

Illumination system for an electrooptic color display screen

A holographic projection screen for large screen projection and back projection with a liquid crystal projector. The screen includes at least one layer made of a photosensitive material in which at least one index grating may be recorded by an interference of an optical recording wave with an optical object wave. The thickness of the layer is equal to or greater than n,&Lgr;,/2&pgr;, where n,is the average index of the photosensitive material, &Lgr; is the average spacing of the index grating and &lgr; is the recording wavelength.

Holographic projection screen and method of production

A compact illumination device intended especially for illuminating an active matrix in a monochromatic or trichromatic display device. This device includes a source and collimating device in order to deliver a lighting direction from the source along a direction (Dy) and two optical components (M,) and (M,) which anamorphose the lighting in a direction parallel to the direction (Dy) and in a direction (Dz) perpendicular to the direction (Dy), respectively. These components may typically be of the holographic grating type operating in transmission or in reflection.

Compact lighting device

Optical recording medium having a plurality of recording layers

Display device and flat television screen using this device

Growing community of inventors

Paris, France

Jean-Pierre Huignard