Thomson-csf

Bernard Desormiere

Georges Hepner

Luigi d'Auria

Charles Maerfeld

Erich Spitz

Jean-Paul Castera

Gregoire Eumurian

Gerard Auvray

Gerard Volluet

Olivier Menager

Albert Courty

Marc Berte

Francois Duthoit

Edouard Bridoux

In a device for shifting the frequency of an optical wave, two optical waveguides coupled by an optical wave which propagates in the symmetric mode are excited and subjected to the action of an electromagnetic traveling wave having the effect of shifting the frequency of the optical wave which undergoes a transition from the symmetric mode to the antisymmetric mode. A transfer device supplied with a direct-current voltage V.sub.O serves to re-convert the antisymmetric mode to the symmetric mode in order to add the two light signals and to obtain a single output signal translated by the frequency F. This permits the construction of BLU optical modulators.

Device for optical frequency translation and a modulator in which said

A device for measuring the gradient of a magnetic field comprises on the same support two magnetooptical layers separated by a half-wave plate. A linearly polarized light beam successively passes through these three optical components and its polarization plane rotates by a value proportional to the gradient of the field in its propagation direction.

Device for measuring the gradient of a magnetic field by the

An optical magnetometer for measuring the component h of a magnetic field in a direction x by the Faraday effect. A semiconductor laser produces two laser beams which are directed from opposite faces of the laser in opposite directions along two fiber optic cables. The opposite beams of light enter a magneto-optical medium and then continue via the opposite fiber optic cable to return to the laser where the two light beams are recoupled. An alternating magnetic field at frequency f and a compensation field are applied to the magneto-optical medium in a direction parallel to the direction x to produce the Faraday effect. The laser intensity of the recoupled light beams is proportional to the magnetic field to be measured. A photodetector samples portions of the recoupled light beam and provides a current i.sub.d which is proportional to the recoupled beam intensity. The current i.sub.d is filtered at frequencies f, for compensating the field h to be measured, and 2f. The magneto-optical medium used is preferably formed by a substituted YIG ferrimagnetic layer, grown by epitaxy on a non-magnetic garnet.

Optical magnetometer using a laser coupled to a magneto-optical medium

A system for connection by means of optical fibers for the bidirectional exchange of data between a fixed central unit and peripheral units integral with a frame driven with a rotary movement, this system comprising radiating energy emitting and receiving means situated in the fixed part, coupled by optical fibers forming unidirectional data exchange paths to a single mixing fiber, itself coupled to optical fibers forming bidirectional data exchange paths coupled to radiating energy emitting and detecting means associated with the peripheral units integral with the mobile frame. Furthermore, the mixing fiber is split into two parts coupled together by a rotary optical joint.

Optical connection system for the bidirectional exchange of data between

The invention concerns the magneto-optical deflectors which enable an incident beam of radiant energy to be deflected in a variable manner under the control of a magnetic field. It consists in using a thin film of a magnetic material forming a diffraction grating, means for travelling the incident beam along the plane of this thin film, and means for magnetically controlling the step-width of the grating, thus controlling the angle of deflection given by this grating.

Magneto optical deflector

The invention relates to elastic surface-wave structures. The elastic surface wave structure in accordance with the invention comprises a non magnetic substrate and a surface wave transducer containing at least one emissive zone situated in a deposited layer of magnetostrictive material subjected to an alternating magnetic field and to a magnetic polarization field.

Magnetostrictive elastic surface wave structure

The present invention relates to devices intended to measure magnetic fields, and also known as magnetometers. It consists in using a zeroing method to measure the influence of the Faraday effect of the field being measured, upon a radiated energy beam propagating in guided fashion through a thin film of magnetic material.

Magnetomer using a thin magnetic film optical waveguide with a.c.

The invention relates to switches which enable connections to be optically established between at least one incoming electrical circuit and one of several outgoing electrical circuits. It comprises associating at least one electrical light source, a thin magnetic layer forming a diffraction network and photoelectric receivers, the thin layer enabling the light beam issuing from the source to be directed onto the receivers selected.

Electrically controlled optical switch

The present invention relates to the monitoring of the machining of a wafer of piezoelectric material by a beam of charged particles. The monitoring method is performed by measuring and displaying the complex voltage-current relationship produced by the electrical excitation of the wafer using a variable-frequency measuring signal applied to electrodes carried by the wafer.

Method of monitoring the machining by ion bombardment of a piezoelectric

The correlator comprises a piezo-electric substrate on the ends of which there are arranged two transducers supplied with two electrical signals and emitting two contra-propagating surface waves. The correlator furthermore comprises m processing channels supplied with electrical signals induced by the surface waves at m 'points' on the substrate which are distributed in the direction of propagation of the waves. Each channel comprises a non-linear device and an integrator furnishing a sample of the correlation function of the two signals.

Surface elastic wave analogue correlator

The invention relates to a device which forms the product of convolution of two signals available in electrical form. This device consists of a substrate of lead molybdate in which there are created, at the two ends, volume elastic waves, which are longitudinal and transverse respectively for each of the two applied signals. The non-linear interaction of these waves produces an elastic wave of transverse mode, representing the product of convolution of the two signals.

Elastic volume wave convolution device

A device for converting the propagation mode of radiated energy, ulitizing the Cotton-Mouton effect. It is constituted by a substrate upon which there is deposited an epitaxially produced film of yttrium-iron garnet, magnetized in a direction having at least one component normal to the direction of energy propagation, and with a thickness such that the propagation velocities of the two modes, initial and final, are identical to one another.

Magneto-optical propagation mode converter

A multiple channel non-reciprocal junction device for the transmission of microwaves. It is constituted by a wafer of ferrimagnetic material, to which there is applied in a longitudinal direction a uniform magnetic field; the wafer is covered, alternately on each of its faces, with transverse metal layers which are not opposite one another; each of the channels corresponds to a section of wafer metallized on both its faces and provided at its ends with means for the emission and reception of the microwave which is to be transmitted.

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Paris, France

Bernard Desormiere