Thomson-csf

Ixblue

Photonetics S.a.

Photonetics

Phononetics, S.a.

Photonectics

Photonetic S.a.

Herve Lefevre

Philippe Martin

Frederic Guattari

Herve J Arditty

Philippe Graindorge

Cedric Molucon

Serge Botti

Marc Turpin

Bernard Laloux

Eric Ducloux

Jean P Bettini

Joachin Honthaas

Jean-Jacques Bonnefois

Thierry Gaiffe

Pascal Simonpietri

Laurent Disdier

Michel Papuchon

Michel Lacombat

Bertrand Merigot

Didier Rolly

Sylvie Vatoux

Stephane Chouvin

Dominique Rojas

Alain Enard

Denis Mangeot

Sebastien Ferrand

Gilles Le Boudec

Edouard Taufflieb

Van-Dong Pham

Nathalie Cerre

Joachim Honthaas

Jean-Pierre Bettini

Sambath Bann

Karl Aubry

Cedric Alain Jacky Molucon

Francois X Desforge

Phillipe Graindorge

Joel Morisse

Interferometric measurement device includes a light source emitting a source signal and optical coupling elements receiving the source signal, directing part of the latter towards a measurement pathway including a Sagnac ring interferometer, of frequency f, producing a power output signal Ppolarized according to a first polarization direction, tapping off another part of the source signal towards a compensation pathway producing a return power compensation signal P, and directing the output and compensation signals towards detection elements. The compensation pathway includes polarization rotation elements producing the compensation signal according to a second cross-direction of polarization, and optical looping elements redirecting part of the compensation signal towards the measurement pathway; the detection elements include a single detector connected to the coupling elements for receiving the output signal and the compensation signal; the device further includes power equilibration elements equalizing the output power and/or return power are routed towards the detector.

Interferometric measurement device

An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving a light signal with input light power and delivering a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter to be measured and being proportional to the input light power; an optical radiation detector, receiving the modulated light signal exiting from the measurement interferometer and delivering a modulated electrical signal representative of the output light power; a filtering interferometer, insensitive to the physical parameter to be measured, having a free spectral range ISL and a finesse F selected such that an interval of frequencies, centerd around an optimal frequency fequal to (2k+1)ISL/2, k being a natural number, and of width &#x394;f equal to [0.9&#x2212;(3/2F)]ISL, includes the modulation frequency of the modulated light.

Interferometric measurement device comprising a filtering interferometer

A fiber-optic measurement device () includes a SAGNAC ring interferometer () having a proper frequency f, a detector () and a modulation chain () generating a phase-shift modulation &#x3c6;(t) between the two counter-propagating waves () propagating in the ring interferometer. The device aims to reduce measurement faults due to the linearity defects in the modulation chain of such a measurement device with optical fiber. For this reason, the fiber-optic measurement device reduces the amplitude of the phase-shift modulation &#x3c6;(t) which is the sum of a first biasing phase-shift modulation component &#x3c6;(t) and a first counter-reaction phase-shift modulation component &#x3c6;(t), the phase-shift modulation &#x3c6;(t) falling or rising by twice the amplitude of the first biasing phase-shift modulation component &#x3c6;(t). A rate gyro including such a measurement device and an inertial stabilization or navigation unit including at least one such rate gyro are also described.

Fibre-optic measurement device, rate gyro, and inertial stabilisation and navigation unit

A fiber-optic interferometric measurement device () intended to measure a physical parameter (QR), includes: a wide-spectrum light source (); a SAGNAC fiber-optic interferometer (), in which there propagate two counter-propagating light waves () including measurement elements () sensitive to the physical parameter that results in a non-reciprocal phase difference &#x394;&#x3c6;&#x3c1; between the two light waves; and a detector () delivering an electric signal representative of the physical parameter. The measurement elements include a ring resonator () in transmission mode including a first coupler () and a second coupler () respectively, which couple a first arm () and a second arm () respectively of the SAGNAC interferometer to the ring resonator, in such a way that the two light waves travel in opposing directions of travel (H,AH).

Fibre-optic interferometric measurement device comprising a ring resonator, gyrometer and inertial attitude or navigation unit comprising such a device

A fiber-optic measurement device () includes a SAGNAC ring interferometer () having a proper frequency f. The aim is to improve response time while maintaining high precision across the measurement range. Biasing elements () are used to produce: a first biasing phase-differential modulation component &#x394;&#x3c6;(t) () which is periodic in time-slots, having levels +&#x3c0; and &#x2212;&#x3c0;, at a first biasing modulation frequency fsuch that f=(2k+1) f, kbeing a natural number; and a second periodic biasing phase-differential modulation component &#x394;&#x3c6;(t) (), having extreme amplitudes +&#x3c0;/a and &#x2212;&#x3c0;/a, a being a non-zero real number such that |a|&#x3e;1, at a second biasing modulation frequency fsuch that f=(2k+1) f, kbeing a non-zero natural number such that k&#x3e;k. A gyrometer including such a measurement device and a navigation or inertial-stabilization system including at least one such gyrometer are also described.

Fiber-optic measurement device, gyrometer, and navigation and inertial-stabilization system

An integrated optical circuit includes an optically transparent substrate including: an input face, an output face, an upper face and a lower face, the upper and lower faces extending between the input and output faces; at least one optical waveguide which includes at least one first end situated on the input face and a second end situated on the output face; and at least one optical attenuation zone able to attenuate an optical signal transmitted via the substrate to the outside of the waveguide. The waveguide has a non-rectilinear optical path between the first and second end, the attenuation zone extends from the upper face to the lower face, and is positioned on a straight line segment joining the first and second end of the optical waveguide, the waveguide and the attenuation zone having respective dimensions such that the attenuation zone does not cut the waveguide.

Integrated optical circuit with traversing attentuation zone

An integrated optical circuit includes a substrate having an input face, an output face, a lower face and an upper face, at least one optical waveguide having a first waveguide end located on the input face of the substrate and a second waveguide end located on the output face of the substrate. The lower face of the substrate includes a first part that is planar and parallel to the upper face and an optical block, the optical block being positioned in the median plane and in the incidence plane, the optical block forming a protrusion at least at the primary reflection point of the integrated optical circuit with respect to the first planar part of the lower face and the optical block being capable of receiving and attenuating at least one non-guided optical beam propagating on the optical path of a primary reflection.

Attenuated primary reflection integrated optical circuit

An interferometric system includes a polarization separation element (), a first polarization conversion element (), a Mach-Zehnder interferometer () including a first () and second () arms connected to one another by a first () and second () ends in order for a first and second beams () having the same polarization to pass through the interferometer in a reciprocal manner in opposite directions of propagation, respectively, so as to form a first and second interferometric beam (), a second polarization conversion element () for obtaining an interferometric beam (), the polarization of which is converted, a polarization-combining element (), and a detection element () suitable for detecting an output beam ().

Apolarized interferometric system, and apolarized interferometric measurement method

An integrated optical circuit includes a substrate having an input face, an output face, a lower face and an upper face, an optical waveguide extending between a first end located on the input face of the substrate and a second waveguide end located on the output face of the substrate. The integrated optical circuit further includes at least one off-center groove, the off-center groove extending from the lower face to the inside of the substrate, the at least one off-center groove being located at a non-zero distance d from the median plane, the off-center groove replacing a central groove and the at least one off-center groove being capable of attenuating the non-guided optical beam transmitted by the substrate between the first end and the second end.

Integrated optical circuit with an off-center groove

Disclosed is a fiber optic interferometer including: a wideband optical source having a decoherence time &#x3c4;; a coil including N turns of a fiber optic with length L; an optical element separating the incident beam into first and second beams coupled to first and second ends of the fiber respectively, so the first beam travels through the fiber optic in a first direction and the second beam travels through the fiber optic in a counter propagating direction; and a detector detecting the intensity of the output beam. The fiber optic is a high polarization mode dispersion type, and the length L of the fiber optic coil is more than twice the fiber correlation length, so the fiber operates in a coupled PMD mode, and the propagation differential group delay between two orthogonal polarization states, accumulated over the length of the fiber, is greater than the decoherence time of the source.

Interferometer with a fiber optic having a high PMD in coupled mode, fiber optic gyroscope (FOG), and inertial navigation system including such a gyroscope

Light source with stabilized broadband and associated optical fiber

The invention relates to an optical spectrum analyzer of an incident light beam (101) and a process for analyzing the corresponding spectrum. The spectrum analyzer comprises addressing means (1), a diffraction grating (2), a reflecting dihedron (3), a device (4) for adjusting the rotation of the reflecting dihedron and reception means (5). A polarization separator (11) divides the incident beam (101) into a first and second parallel secondary beam (102, 104), of linearly polarized light along the directions parallel to and perpendicular to the grooves in the grating respectively, and a .lambda./2 plate (12) placed on the path of the first secondary beam (102) applies a perpendicular polarization direction to this beam. The grating diffracts the secondary beams (103, 104) a first time, the reflecting dihedron exchanges their directions, the grating diffracts them a second time, the .lambda./2 plate applies a 90.degree. rotation to the polarization state of the second secondary beam (110) and the separator recombines the secondary beams (109, 111) into a single main beam (112) returned to reception means.

Optical spectrum analyzer and process for analyzing the corresponding

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

A process and an optical gyroscope are provided for measuring rotation speeds (S) about N axes. The light source and the photodetector are common. Controlled modulation phase differences .delta..PHI..sub.c,i COMPRISE biasing components .delta..PHI..sub.m,i (42, 45, 46) with a common modulation period T.sub.m and common amplitude. Since each half-period T.sub.m /2 is divided into N time intervals .delta.t.sub.i, a change in the sign of the biasing component .delta..PHI..sub.m,i associated with each interferometer I.sub.i is produced at the beginning of one and only one .delta.t.sub.i time interval. Sagnac phase shifts .delta..PHI..sub.s,i are obtained by sampling a signal on the N time intervals.

Process for measuring rotation speeds about several axes, and a

An appliance for measuring polarization mode dispersion (PMD) of a waveguide (2) comprises a source (1, 6) of wide-band polarized light, an interferometer (5) capable of receiving a light beam (21) sent by the source (1, 6), a detector (3) capable of detecting the light beam (25) from the interferometer (5), and an electronic processing unit (4) connected to the detector (3), capable of extracting a value .tau. representative of the polarization mode dispersion of the waveguide (2). The interferometer (5) divides a measuring light beam (22) sent by the source (1) into two interference light beams (23, 24). The measuring appliance comprises at least one birefringent element (17) positioned on the interferometer (5), capable of producing an algebraic difference of relative phase shifts in each of the two interference light beams (23, 24) equal to .pi..

Appliance for measuring polarization mode dispersion and corresponding

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Paris, France

Herve Lefevre