Thales

Centre National De La Recherche Scientifique

Ecole Normale Superieure De Cachan

Arnaud Brignon

Jean-Pierre Huignard

Brigitte Loiseaux

Jérôme Bourderionnet

Gilles Feugnet

Sylvain Schwartz

Jérome Bourderionnet

Michel Sotom

Joseph Colineau

Daniel Dolfi

Matthieu Dupont-Nivet

Arnaud Le Kernec

Fabien Bretenaker

Anaëlle Maho

Marie Antier-Murgey

Cindy Bellanger

The invention relates to an optical reception device for receiving a signal from an antenna array comprising:

Device for optically receiving a signal coming from a phased antenna array and associated antenna system

An elementary device for coherently recombining a first elementary beam and a second elementary beam, includes a first input and a second input, into which are respectively injected the first elementary beam and the second elementary beam to be recombined, an output that delivers an output beam corresponding to the coherent recombination of the first and second elementary beams, a delay line placed on one of the paths of said elementary beams and configured to induce a variable delay on said path, a variable coupler comprising a first 2&#xd7;2 combiner, a phase modulator and a second 2&#xd7;2 combiner, a control detector configured to generate, from the complementary beam, an error signal (&#x3b5;), a feedback loop configured to determine, from the error signal, the delay and the phase difference to be applied.

Device and system for coherently recombining multi-wavelength optical beams

A laser-source assembly that is configured to illuminate a vacuum chamber containing atoms in the gaseous state so as to implement a cold-atom inertial sensor, the atoms having at least two fundamental levels that are separated by a fundamental frequency difference comprised between 1 and a few gigahertz, the assembly comprises: a master laser that emits a beam having a master frequency; a first control loop that is configured to stabilize the master frequency of the master laser on a frequency corresponding to half a set frequency of an atomic transition between a fundamental level and an excited level of the atoms; a slave laser that has a slave frequency; and a second control loop that is configured to stabilize the slave frequency of the slave laser with respect to the master frequency, the slave frequency being offset with respect to the master frequency successively, over time, by a first preset offset value, a second preset offset value, and a third preset offset value, the offset values being comprised in an interval equal to half the fundamental frequency difference plus or minus a few hundred MHz.

Laser source for a cold-atom inertial sensor

A passive resonant optical gyroscope comprising a cavity and operating with three frequencies comprises: a first injecting laser to inject a first optical beam into the cavity in a first direction; a second injecting laser to inject a second optical beam into the cavity in an opposite direction; a third injecting laser to inject a third optical beam into the cavity in one of the aforementioned directions, one laser amongst the injecting lasers having a master frequency, the two other injecting lasers, called the first and second slave lasers, respectively having a first slave frequency and a second slave frequency; a master servocontrol device; a first servocontrol stage comprising first and second slave devices; and a second servocontrol stage comprising first and second optical phase-locking devices respectively comprising a first and second slave oscillator to generate a first radiofrequency offset signal and a second radiofrequency offset signal.

Compact three-frequency resonant optical gyroscope

A method for measuring the delay between N pulses having a duration less than 100 picoseconds comprises the steps: collimated emission of the pulses having the same repetition frequency, emission of a reference pulse having the same repetition frequency capable of producing interference fringes with each of the pulses, for each of the pulses, detection, by a detector, of the coherent sum of this pulse with the reference pulse, this sum producing the interference fringes, the fringes originating from each of the pulses being distinguishable from one another. The reference pulse is emitted with an adjustable delay, and the method further comprises: for each delay, simultaneous measurement for the pulses of N contrasts of the interference fringes, for each of the pulses, a delay value between this pulse and the reference pulse is determined by the delay corresponding to the maximum contrast.

Method for measuring relative delays between optical propagation channels in pulsed operation

A system based on recombination by superposition using a diffractive optical element DOE to combine the beams is provided. An optical diffractive assembly is placed upstream of a diffractive optical element to make it possible, via an appropriate imaging system, to optimize the combining efficiency in the ultra-short pulse regime.

System for spatial recombination of ultrashort laser pulses by means of a diffractive element

A system for phasing periodically configured laser sources, which comprises: means for collimating and directing the beams arising from the sources onto a combining diffractive optical element with a periodic phase grating, with an angle of incidence that differs from one beam to the next, these angles of incidence being determined according to the period of the grating; means for controlling the phases of the sources based on a negative feedback signal arising from the combined beams; means for drawing off a fraction of the combined beams; on the path of this fraction of the beams, a Fourier lens, with the combining diffractive optical element in its object plane; a matrix of detectors in the image plane of the Fourier lens, capable of detecting intensity distributions; means for calculating the negative feedback signal based on these intensity distributions.

System for phasing a large number of laser sources

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

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 ( ).

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Palaiseau, France

Arnaud Brignon