Abstract: A modulator enables the modulation of a wave in the medium infrared range by means of a signal modulating the amplitude of another electromagnetic wave in the near infrared range. The modulator comprises: a central layer such that the electrons of the conduction band have at least two permitted discrete levels of energy, the energy difference of which corresponds to a frequency close to the frequency of the wave to be modulated, and such that the holes of the valence band have permitted levels of energy such that the difference in energy between the permitted fundamental level for the holes in the valence band and the permitted fundamental level for the electrons in the conduction band has a value close to that corresponding to the frequency of the control wave.

Abstract: A frequency shifter to shift the frequency of a guided wave in the medium infrared range comprises:an optical guide, formed by semiconducting materials, on the surface of which a diffraction grating is created by carriers photo-induced by a periodic illumination.standard optic means projecting, on the surface of the guide, two wave beams having different frequencies in the near infrared or visible range, to produce, by interference, a periodic illumination of the surface of the guide. This illumination induces photocarriers constituting a diffraction grating which is in translational motion at constant speed. This motion shifts the frequency of the diffracted wave by Doppler effect.

Abstract: An optic fiber correlator having a first laser and a second laser emitting with the same frequency and with an amplitude modulated respectively by a first and second signal which are correlated. The correlator also has an optic fiber with its two ends respectively coupled to the two lasers and a length which is at least equal to the length corresponding to the maximum duration of the signals which are to be correlated and the optic fiber has a flattened surface throughout its length. A thin layer of non-centrosymmetrical structure material is applied to the flattened surface throughout the length of the fiber and light emitted by the layer is collected at a frequency which is twice the frequency of the two lasers in order to provide an electric signal which is the function of the intensity of the light and this electric signal expresses the correlation integral of the two correlated signals.

Abstract: An embodiment of the disclosed device includes: two coupled laser diodes, emitting a light wave which is modulated in frequency and amplitude by electrical signals which control the selection of one among several interconnections and represent a sequence of binary data also included is an optical guide embedded in the surface of a semiconductor substrate and a diffraction grating etched on the surface of the guide and substrate, coupled to the guide to diffract the light in several directions depending on the wavelength as well as photodiodes respectively located in one of the directions where the light can be diffracted, to give an electrical signal representing the binary data transmitted in the direction corresponding to the photodiode. In other embodiments, the photodiodes are coupled to laser diodes by means of a holographic grating.

Abstract: The source and the device comprise a generator of a pump wave, optical means for coupling with a monomode optical fiber for guiding and highly confining the pump wave so that a four photon non linear interaction is created. At least one section of this optical fiber is disposed in a thermostat controlled enclosure associated with a temperature control device so as to obtain continuous tuning in a range of frequencies belonging to the near infra red spectrum.

Abstract: The invention concerns an optical guiding structure comprising, between two optical confinement layers, an optical guiding layer and an optical guiding element separated from each other by a layer for stopping chemical attack, to obtain by epitaxy methods and by chemical attack, a guiding element of which it is possible to precisely calibrate the thickness obtain surfaces of excellent quality and perform cutting out with sharpness, the invention being applicable to producing lasers and optical phase modulators.

Abstract: Disclosed is an integrated optical waveguide. This integrated optical waveguide is obtained by doping a lithium niobate monocrystal simultaneously or in two stages, by a titanium strip, in a manner known per se, to obtain a guiding zone for the optical wave, and by a titanium film of smaller thickness which covers the guiding zone and the lateral zones to preserve a waveguide in the guiding zone and improve the electro-optical behavior of the guide to which an electrical field is applied.

Abstract: An integrated optics polarizing device having a flat substrate made for example from lithium niobate, in which an integrated wave guide has been created by doping with titanium ions and one or more so called interaction regions interacting on the wave, formed within the material of the substrate, and having refraction indices such that a wave with a first polarization direction propagates in a guided mode in said wave guide and a wave with an orthogonal polarization is extinguished. Said interaction regions are obtained by modifying the material of said substrate in a controlled way by doping or ion substitution.

Abstract: A differential absorption polarizer is constructed to be used in accordance with integrated optics.This polarizer includes, on a waveguide layer formed on a substrate, a layer of dielectric material whose surface has hollows and bosses and therefore several inclined zones. The hollows and bosses define minimum (em) and maximum (eM) thicknesses of the layer, which bracket the resonance thickness of the dielectric for the polarization there to be absorbed.The dielectric material layer is coated with a metal layer.

Abstract: An integrated optics optical polarization conversion device comprising a guide structure formed by integrated optics in a flat substrate made from a uniaxial crystalline material having electro-optical properties in which two distinct modes may propagate. In accordance with the invention, the optical axis of the crystal of said substrate forms an angle with the plane of the substrate less than (.pi./2) radians. In one of the variants, said axis is parallel to the direction of propagation of the guided wave and the device comprises a single set of homogeneous electrodes.

Abstract: The invention relates to a coupler in which the coupling between the waveguides is carried out on the one hand, by means of evanescent waves propagating in the medium separating these guides, and on the other hand by means of a non-linear interaction in the substrate, where the waveguides are produced. A first guide is produced by ion exchange of H.sup.+ ions and a second guide by local titanium diffusion in the substrate.

Abstract: 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.

Abstract: The invention relates to a device for measuring a magnetic field, comprising a source of rectilinearly polarized light. A magnetooptical medium is situated in the path of the beam, this medium being followed by a mirror refecting this beam. This medium is a medium of which the intrinsic propagation modes are polarized in right-hand and left-hand directions, and which retains the circular polarization. An element acting as a separator by polarization is situated between the source and the medium, a detector device being coupled to the same.

Abstract: An interferometer having a tunable optical resonator using a monomode optical fiber as the light propagation medium. According to a preferred embodiment the fiber (1) is wound around a cylindrical mandrel (7) made from a piezoelectric ceramic material. Multiple reflections are ensured by reflecting deposits at the fiber ends. Rapid scanning of several orders of interference can be obtained by applying an alternating voltage V to the ceramic material.

Abstract: The invention relates to ring interferometers. It aims at making strictly reciprocal a ring interferometer of any known structure, by means of a mode filter which allow a particular mode to be selected among all the modes likely to be propagated in the loop and to arrive at the detection device; this filtering is carried out by a mode filter comprising for example a screen pierced with a hole or an integrated wave-guide or optical fiber portion which are advantageously monomode.

Abstract: An integrated optical device including at least one hybrid optical junction with two input paths and two output paths, for transmitting light energy from the input to the output paths as a function of phase difference between the inputs. The junction includes a Y-shaped node formed by three monomodal optical wave-guides situated in a refractive medium with a lower refractive index than that of the three wave-guides.

Abstract: An integrated optical structure creating directional coupling between two waveguides in which an index disturbance accompanying the guided photons is caused to act on two closely-spaced waveguides, this disturbance being produced by a progressive elastic wave with sloping wavefronts emitted by an electromechanical transducer.

Abstract: Non-linear optical devices incorporating an integrated waveguide on a substrate, also relating to a non-linear optical device utilizing a passive layer covering the integrated waveguide making it possible by increasing the effective index ranges of the fundamental and harmonic radiations to obtain a phase matching for two propagated modes having an increased overlap integral value. The invention is more particularly applicable to frequency doubling making it possible to obtain a visible radiation source from a primary source functioning in the very-near infrared region.

Abstract: An electro-optical switch for switching optical radiation between two wave guides having a coupling zone with two pairs of electrodes (E.sub.11, E.sub.12, E.sub.21, E.sub.22) respectively associated with two guides (1, 2) and positioned so as to cover a variable fraction of the width of the guides. As a result, the electro-optical effects produced and, therefore, the propagation velocities in the two guides are made variable as a function of the electrical connection mode of the electrodes. Two switching states are obtained with a considerable tolerance for the length of the guides (2L) and the control voltage.

Abstract: The current-measuring device in accordance with the invention comprises an optical fiber wound around the conductor in which flows the current to be measured, a laser source, means for separating the radiation emitted by the source towards the two ends of the wound fiber, and for recombining the radiation emerging from these two ends, a conductor circuit through which flows an adjustable reference current, a detection device supplying a signal characteristic of the interferences between the two waves emerging from the fiber, the reference current being adjusted so that the phase shift between the two contra-rotating waves in the fiber is zero, this current being then proportional to the current to be measured flowing in the principal conductor.