Abstract: The invention relates to a fibre optic measuring device of the type in which the change in a measured parameter generates a phase difference between two waves in a SAGNAC ring interferometer (2). Electronic means (7) comprise a processing system (9) delivering a signal depending on the measured parameter and electronic means (12) controlling the phase modulator (4). The electronic means (12) produce a control signal for the modulator determined in such a way that the phase difference .delta..PHI..sub.m which it produces between the counter-propagating waves periodically takes the following four successive values: ##EQU1## where .PHI..sub.o is a constant phase shift and it depends on a, and a is a positive constant satisfying the condition: cos .PHI..sub.o =cos a.PHI..sub.o.

Abstract: A coherent signal processing device is provided using a monomode optical fiber as delay line, comprising a source and a ring interferometer with a bidirectional coupler and a monomode optical fiber loop whose ends are coupled to two combined accesses of the coupler. The source is connected to one of the opposite accesses and a detector is connected to the last access. For processing, a series of electrooptical phase modulators, separated by identical fiber lengths corresponding to a given delay, are controlled simultaneously by an electric pulse signal. The processing is coherent for it results from the interferences between two optical waves following opposite paths.

Abstract: A spool for optic fibers and its winding method are disclosed. The cylinder of the spool has grooves in which rods are placed during the winding operation. Thus, the circumference of the spool is greater than that of the cylinder. After winding, the rods are removed so that the winding stresses are relaxed.

Abstract: The invention relates to an optical fiber measuring device of the type in which variation of a measured parameter causes a difference of progression of light waves in the optical fiber. Such a device permits measurement of speed of rotation, or of current and magnetic field. The device includes an electronic device for digitally processing a signal indicative of phase shift of one light wave relative to another, the light waves propagating through a preferably monomode optical fiber in a SAGNAC ring interferometer, modulated by a phase modulator.

Abstract: The disclosure pertains to a device for the measurement, in a wide range, of a non-reciprocal phase shift generated in a ring interferometer, to a measuring method and, chiefly , to an optic fiber gyrometer. It also concerns a method of measurement, notably a method for the measurement of rotation speed. The disclosure concerns an improvement in a measuring device comprising a phase modulation device enabling the phase to be automatically locked to an interference fringe of the device. The improvement lies mainly in the fact that the light source emits, in the ring, several light frequencies so as to make it possible to remove uncertainty on the order (0, .pi., 2.pi., etc.) of the interference fringe on which the automatic control is achieved. The disclosure can be applied notably to the making of devices for the measurement of angular speeds. The disclosure can be aplied chiefly to the making of optic fiber gyrometers.

Abstract: A multiple-point temperature sensor, with optic fibers, uses the effect of variation in the birefringence in a birefringent optic fiber as a function of temperature. This sensor has a plane polarized, wide spectrum source coupled to a monomode optic fiber for preservation of polarization, along one of the neutral axes, with weak coupling points distributed along this fiber. A polarizer at 45.degree. to the neutral axes of the fiber is placed at the output of this sensing fiber. The output radiation is analyzed by spectroscopy, for example in a Michelson interferometer, capable of being swept, associated with a detector. The interferometer shifts needed to detect the extreme values of the transmission function are measurements of temperature deviations.

Abstract: A method for the detection of localized polarization couplings in a birefringent guided optical system uses a polarizer, at 45.degree. with respect to the axes of the optical system placed at its output, and followed by a Michelson type interferometer in which one of the optical paths has a variable length. When the length of an optical path undergoes variation, interference fringes appear on half of the energy emitted. The difference in the length of the optical paths when fringes of this type appear characterizes the position of a localized polarization coupling, and the contrast between the fringes measured for this difference in length characterizes the amplitude ratio between the primary wave and the coupled wave. The invention can be applied in particular, to the assembly of the components of a birefringent optical system.

Abstract: An optic fiber hydrophone comprises a wide spectrum optical source, a super-luminescent diode for example, associated with an optic fiber assembly comprising chiefly a side-hole optic fiber, subjected to the field of pressure, forming a sensor, transmitting the optic radiation in the slow and fast modes respectively, and a second fiber, not subjected to the field of pressure, the neutral axes of which are oriented with respect to the neutral axis of the first fiber so that the wave transmitted in slow mode in one fiber is transmitted in fast mode in the other fiber, it being possible to connect these two fibers by a polarization maintaining fiber in the event that the sensor is offset with respect to the source, a polarizing fiber enabling the creation of the interferences, and a radiation detector at the output of the fiber assembly.

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: A method and corresponding device, are provided for detecting the propagation time variations in the ring of an interferometer and includes phase modulation of the contrarotating waves travelling through the ring by means of assymetric square waves at a period twice the initial propagation time, which create level zero phase shift stretches in the modulation of the difference between the two waves emerging from the ring. These level stretches result in pulses in the detected output signal whose width is variable with the propagation time. The invention applies particularly to the control of the wave length of the source of the interferometer, particularly with respect to temperature variations of the source.

Abstract: An optical signal rejection filter has a beam separator giving light waves with two different transmission devices and with different propagation times. Optoelectronic detectors receive these waves and give equivalent electrical signals to a differential amplifier which gives a signal representing the difference between the signals received. This filter can be used, preferably, in ring interferometers.

Abstract: A ring interferometer device is provided comprising monomode optical fiber, a radiation separator and a mode filter coupled optically to a coherent light source. In a first approach, this source is a semiconductor diode of the type operating alternately as light emitter and receiver depending on the biasing. In a second approach, the source is a light emitting semiconductor diode coupled by its front face to the mode filter and by its rear face to a detector, said diode acting as light amplifier.

Abstract: A connecting device is disclosed wherein an end of a fiber is joined to a connecting block which has one side polished and is bonded to a side, also polished, of an integrated optic circuit. The connecting block further has another side, inclined with respect to the its first side, making it possible to illuminate the side of the connecting block and to observe the image of the interference fringes sent back by the interface between the connecting block and the integrated optic circuit. According to the method of the invention, the connecting block is positioned by observing the previous image, and the bonding is then made.

Abstract: A three-axis fiber-optic interferometer as applicable in particular to a gyrometer comprises three optical fibers forming rings disposed along three different axes. The three optical fibers are fed by a light beam emitted by a single source. A single interference photodetector receives the light beam after transit through the different fibers. Coupling devices couple the second fiber to the first fiber and the third fiber to the second fiber.

Abstract: A device is provided forming a strictly ring interferometer having a ring formed by a monomode fiber, a source, separation and recombination means, and a monomode fiber segment forming mode filter. According to the invention, this monomode fiber segment is provided with a shutter generating directional losses intercepted by an optoelectronic detection member.

Abstract: 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.

Abstract: 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.

Abstract: A compact optical coupling device particularly adapted for coupling between a source and two optical fiber ends having a function of separation of the radiation from the source between these two ends. The device comprises a small-size separator cube, a plano-convex microlens whose flat face is bonded to the input face of the separator cube, and two square-section end-pieces bonded to the two output faces of the separator cube, each enclosing one fiber end.

Abstract: The present patent application discloses an optical fiber interferometric rate gyro using the SAGNAC effect particularly adapted to the measurement of low rotational speeds comprising, between the radiation splitting and recombining device which directs two waves simultaneously towards the two ends of a single mode wound optical fiber and recombines the two waves emerging from the fiber after travelling in opposite directions at each of the two ends of the fiber, a splitter associated with a detector picking up a fraction of the wave emerging from the corresponding end, the speed measurement being obtained from signals from these detectors and from the signal from a detector picking up the radiation resulting from the recombination of both waves.