Thomson-csf

Photonetics

Photonetics S.a.

Electricite De France

Philippe Graindorge

Herve J Arditty

Herve Lefevre

Philippe Martin

Bernard Laloux

Herv&eacute; Lefevre

Laurent Disdier

Jean-Pierre Huignard

Michel Papuchon

Jacques Dubos

Yannic Bourbin

Serge Botti

Jean P Bettini

Jean-Pierre Gerardin

Denis Mangeot

Francois X Desforges

Denis Trouchet

Francis Gautnier

Sophie Bourzeix

Gilles Le Boudec

Jean-Louis Lesne

Daniel Gatti

Dominique Meyet

Laser source comprising a first active arm extending from a first end reflector up to a dispersing system grid and containing an amplifier medium that produces a first luminous beam. A second passive arm extends from the grid to a second end reflector, the grid generating a second beam by diffraction of the first beam, wherein the second end reflector closes the second passive arm and is partially reflecting to enable extraction of a luminous flux. An optical component produces, from the second beam, a third beam translated and antiparallel, to return to the grid which, by diffraction, forms a fourth beam translated and antiparallel to the first beam.

Laser source with integral filtering of the amplified spontaneous emission

A partially reflecting optical component ( ) generating, from an incident beam ( ), two secondary beams, one of them being reflected ( ), the other one being transmitted ( ). According to the invention, it comprises a first wholly reflecting planar face ( ) and a second partially reflecting planar face ( ), the second face being perpendicular to the first one, a third wholly reflecting planar face ( ), the first and third faces being in the same plane, this component providing the unidimensional auto-alignment of the reflected beam ( ) with the incident beam ( ), the respectively transmitted and reflected beams being each formed with two half-beams having matching wave fronts. The invention also relates to an external cavity laser source comprising such a component as a unidimensional auto-aligned reflector.

Partly reflecting optical component and laser source incorporating such a component

Multiwavelength laser source transmitting a luminous flux including as many amplifier wave-guides as potential transmission wavelengths, a collimation optic system for collimating the beams transmitted by the wave-guides, a network and a retroreflector making up the network, a dispersive retroreflecting device that defines with each wave-guide, an external resonating cavity, whereas each wave-guide has an inner face and an outer face with respect to its associated cavity. A Fabry-Perot interferometer with reduced fine adjustment is placed in the cavity between the collimation optic system and the network, whereby the interferometer is tilted with respect to the axis of the cavity and forms a little selective filter, whose variation law of the wavelength transmitted in relation to the angle of incidence is identical with that of the dispersive retroreflecting device.

Multiwavelength source

Continuously wavelength-tunable monomode laser source

This invention relates to a singlemode laser source tunable in wavelength with a self-aligned external cavity, comprising: a resonant cavity having an output face that is partially reflecting (331) and a retroreflecting dispersive device (31, 39), defining a main collimating axis (351) and a secondary collimating axis (381), an amplifier wave guide (33) placed in position inside the resonant cavity. The retroreflecting dispersive device comprises a plane diffraction grating (31) having dispersion planes and an orthogonal reflecting dihedral (39) whose line of intersection (391) is parallel to the dispersion plane of the diffraction grating containing the collimating axes (351, 352).

Singlemode laser source tunable in wavelength with a self-aligned

This invention relates to a singlemode laser source tunable in wavelength with a self-aligned external cavity, comprising: a resonant cavity having an output face that is partially reflecting (331) and a retroreflecting dispersive device (31, 39), defining a main collimating axis (351) and a secondary collimating axis (381), an amplifier wave guide (33) placed in position inside the resonant cavity. The retroreflecting dispersive device comprises a plane diffraction grating (31) having dispersion planes and an orthogonal reflecting dihedral (39) whose line of intersection (391)is parallel to the dispersion plane of the diffraction grating containing the collimating axes (351, 352).

A measuring device comprises a light source with a wide spectrum feeding an optical sensor through an optical fiber. The sensor comprises an interferometer adjusted to a dull tint and an optical component sensitive to a measured parameter, which may be either a pressure, a measured displacement or an index of refraction of a fluid, a readout device includes the photodetector, a processing unit and an optical wedge for producing fringes, whose lateral positions, in contrast, are representative of the spectrum of the flux leaving the interferometer and analyzed by the photodetector. The processing unit measures the lateral position of the fringe and converts it into a value of the parameter P.

Opto-electronic measuring device with optical air wedge spectral

A method of positioning an object relative to a plane, and apparatus therefor. According to the method, the plane is swept by the axis of a light-beam between a source assembly and a detection assembly, and the object is translated approximately perpendicularly to the plane, the detection assembly emitting a signal representative of the light received and therefore, the position of the object relative to the plane. The signal emitted by the detection assembly is measured as a function of time, the translation of the object being halted when the signal has a particular form. The particular form of the signal corresponds to the position of the object in which the shoulder masks a predetermined fixed part of the light-beam during part of its sweep. The apparatus comprises the source assembly for producing the light-beam, a deflecting member for angularly deflecting the light-beam, a first optical system for causing the deflected light-beam to sweep a plane parallel to the light-beam, the detection assembly, a second optical system for focusing the deflected light-beam onto the detection assembly. An electronic processor processes the signal emitted by the detection assembly as a function of time. The deflecting member is placed at the focus of the first optical system and the detection assembly is placed at the focus of the second optical system.

Method for positioning an object relative to a plane and measuring

A measuring method and device are provided based on the analysis of a channelled light spectrum, particularly for measuring a low amplitude movement of a mobile surface, possibly representative of the variation of a physical magnitude convertible into such a movement. Said device comprises a two beam interferometer (3) with two reflecting surfaces, one (5) fixed and the other (6) mobile, defining a difference of the rate of progress (e) of the light rays in the interferometer, a light source (1) and an analyzer (8) for analyzing the channelled spectrum generated by said light source in said interferometer, the analyzer is formed by means (9) for spactially spreading the channelled spectrum, by means of a filter (12) whose transmission and/or reflection coefficient is periodic, at least in one direction, of fixed period equal or substantially equal, except possibly for a factor, to the period of the spatial distribution of the spatially spread spectrum; and at least one photodetector (14,14') receiving the light transmitted and/or reflected by said network for determining said difference of rate of progress.

Channelled light spectrum analysis measurement method and device, more

The discriminating device comprises an optical coupler (4) having at least three ends (5 to 8) to which are connected a semiconductor source of light (1) whose intensity is modulated, a semiconductor photoconductor (2) and an optical probe constituted by a multi-mode optical fibre (3) whose end has a pointed shape. This discriminating device is in particular applicable in a device for measuring the voluminal fraction of at least one fluid of a current of non-mixible fluids.

Device for discriminating fluids having different refractive indices and

A method of coiling an optical fiber gyroscope and an optical fiber coil thus obtained, which method consists in coiling, on a cylindrical support comprising a central channel, a first layer for forming a helical optical fiber winding with constant pitch, passing the optical fiber through the central channel in the form of a single turn and coiling additional layers, in the same direction as the first layer, using the interturn spaces of the underlying layers.

Method of coiling an optical fiber gyroscope and an optical fiber coil

The device for measuring a nonreciprocal phase shift involves phase modulation of countercirculating waves in a closed-loop interferometer by means of a reciprocal-effect phase modulator. The modulating signal is a periodic signal having a period 2t.sub.o, where t.sub.o is the transit time of an electromagnetic wave in the closed loop. A digital phase ramp generated in the form of a stair-step signal is combined with the phase-modulating signals and applied as feedback. In an additional embodiment, control circuits are provided for correcting the modulation scale factor.

Device for measuring a nonreciprocal phase shift produced in a

The invention relates to the interferometric detection of reciprocal and non-reciprocal effects affecting the propagation of optical radiation in a two-armed interferometer. The invention relates to a two-armed interferometer terminating by a photorefractive medium used as an interactive reflector according to the four-wave interferometer principle. The invention particularly applies to the measurement of physical quantities such as displacement, linear velocity, angular velocity, magnetic field, pressure and temperature.

Michelson interferometer with a photorefractive mirror

The invention provides a process for forming a fiber keeping a circular polarization and a device for implementing this process. This process consists, during drawing and twisting of the fiber from a formable material source, in remelting on the surface a part of the volume of said fiber in a zone where it is subjected to twisting stresses.

Process and device for manufacturing a fiber keeping a circular

A heating device including a carbon dioxide laser beam directed towards a spherical mirror and then directed from an ellipsoidal mirror so as to concentrate the energy of said laser on a surface ring of a threadlike object.

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Chevigny Saint Sauveur, France

Philippe Graindorge