Abstract: Disclosed is a method for producing an optical fiber coil including the following steps: a. symmetrical winding of an optical fiber around a shaft, the winding forming a pattern including a same number N of layers of each half of the optical fiber, one layer including a set of turns of optical fiber and spaces between adjacent turns, the winding forming a sectored arrangement including a regular stacking area including at least one continuous sealing surface between two layers of adjacent turns, and an overlap area where portions of optical fiber linking different turns cross each other; b. infiltration of a glue through an external surface of the overlap area in such a way that the glue infiltrates into the spaces located between adjacent turns in the regular stacking area.

Abstract: Disclosed is an optical fiber interferometric system including a light source (1), a fiber optic coil (8), a coil splitter (3), a photodetector (2), and a polarization filtering unit. According to an embodiment, the polarization filtering unit includes a first waveguide polarizer (51), at least one second thin-plate polarizer (52) and an optical waveguide section (12), the at least one second polarizer (52) being disposed in the Rayleigh zone between a first waveguide end (21) of the first polarizer (51) and a second waveguide end (22) of the optical waveguide section (12).

Abstract: 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 fp, producing a power output signal POUT polarized according to a first polarization direction, tapping off another part of the source signal towards a compensation pathway producing a return power compensation signal PRET, and directing the output and compensation signals towards detection elements.

Abstract: System including a dead weight and equipment on a trolling line released from and retrieved to a receiving structure of a vessel, the dead weight including a controllable element for blocking and unblocking the line, so as to immobilize the line relative to the dead weight in the blocked configuration, and to allow the line to run relative to the dead weight in the unblocked configuration; a first detection element for detecting whether or not or not the equipment has moved to a predefined distance from the dead weight; a control element configured, in case of an order to release: —in a step 2L, to release the equipment from the structure, —in a step 3L, when the first detection element detects the equipment has moved to the predefined distance, to then release the dead weight and control the blocking and unblocking element to shift to the blocked configuration.

Abstract: An interferometric system with multi-axis optical fiber and a method for processing an interferometric signal in such a system, the multi-axis interferometric system includes a light source (1); a plurality of N optical-fiber coils (11, 12), a first optical separation element (3) capable of splitting the source beam (100) into a first split beam (140) and a second split beam (240); shared phase-modulation element (4); a photodetector (2) and a signal-processing system (800). The N optical-fiber coils (11, 12) are connected in parallel, the coils having respective transit times T1, T2, . . . TN that all differ from one another, and the signal-processing system (800) is capable of processing the interferometric signal (720) detected by the shared photodetector (2) as a function of the respective transit times in the various coils.

Abstract: Disclosed is a waveguide polarizing optical device, including a first waveguide polarizer (6), a section of a second optical waveguide (31) and a second thin-plate polarizer (52) having a physical thickness T and a refractive index n, the second thin-plate polarizer (52) being disposed on the optical path between a waveguide end (8) of the first polarizer (6) and one end (32) of the second optical waveguide (31), the physical distance d between the waveguide end (8) of the first polarizer (6) and the end (32) of the second optical waveguide (31) being less than or equal to twice the Rayleigh length and the physical thickness T of the second polarizer (52) being less than or equal to the physical distance d.

Abstract: 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 foptim equal to (2k+1)ISL/2, k being a natural number, and of width ?f equal to [0.9?(3/2F)]ISL, includes the modulation frequency of the modulated light.

Abstract: Disclosed is a master model (1) defining a useful surface having a complex shape, including a set of juxtaposed frames (2a, 2b, 2c), each frame including a panel having a useful edge (8), the frames being disposed parallel and held rigidly connected with predefined spacings such that the useful edges of same form the useful surface. The panel of each frame includes a blind slot (10) forming an opening passing through the thickness, and the frames are rigidly connected by a spar (3, 3a, 3b, etc.) suitable for being inserted (6) in the lengthwise direction (L) of same into the slots and including transverse notches (11) for receiving and holding the frames, each notch being arranged to receive, by a relative transverse translational movement (7) of the spar relative to the frames, the part in question of the panel of each frame.

Abstract: A fiber-optic measurement device (10) includes a SAGNAC ring interferometer (20) having a proper frequency fp, a detector (14) and a modulation chain (30) generating a phase-shift modulation ?m(t) between the two counter-propagating waves (24, 25) 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 ?m(t) which is the sum of a first biasing phase-shift modulation component ?b1(t) and a first counter-reaction phase-shift modulation component ?cr1(t), the phase-shift modulation ?m(t) falling or rising by twice the amplitude of the first biasing phase-shift modulation component ?b1(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.

Abstract: A fiber-optic interferometric measurement device (100) intended to measure a physical parameter (QR), includes: a wide-spectrum light source (103); a SAGNAC fiber-optic interferometer (110), in which there propagate two counter-propagating light waves (101, 102) including measurement elements (1140) sensitive to the physical parameter that results in a non-reciprocal phase difference ??? between the two light waves; and a detector (104) delivering an electric signal representative of the physical parameter. The measurement elements include a ring resonator (1143) in transmission mode including a first coupler (1141) and a second coupler (1142) respectively, which couple a first arm (111) and a second arm (112) respectively of the SAGNAC interferometer to the ring resonator, in such a way that the two light waves travel in opposing directions of travel (1143H, 1143AH).

Abstract: A system and a method for the navigation of a mobile vehicle, suitable for determining and displaying a safe navigation zone for the mobile vehicle. The navigation system includes a dead reckoning navigation system (10), a calculator (50), a storage memory (60), an embedded sensor (20), and an electronic mapping system (70). The calculator (50) is suitable for calculating an estimated position of the mobile vehicle from speed and/or acceleration measurements and a comparison of the measurement of an environmental parameter with a geographical database. The calculator (50) is suitable for calculating the probability density of the presence of the mobile vehicle around each point on the map in order to deduce a safety zone (12) corresponding to a presence probability higher than, or equal to, a pre-determined threshold p.

Abstract: System for stabilizing a positioner of an equipment item, the positioner being oriented via an orientation command, and installed on a vehicle undergoing motions, the positioner including angular coders producing angular measurements and a set of gyrometric sensors producing measurements of rates of instantaneous rotation, and exhibiting biases, the positioner including a calculation unit with elements of intra-positioner slaving-correction of the instantaneous rates of rotation of the item using measurements and the orientation command to stabilize the item following the line of sight. The vehicle includes an element for measuring the attitude of the vehicle giving vehicle attitude measurements. The system includes calculation elements for controlling the positioner according to a control law to correct the biases by virtue of the vehicle attitude information and by implementing a state observer combining an estimation of attitude of an item and the measurements of rates of rotation of an item of equipment.

Abstract: An active acoustic control method for attenuating disturbing narrow-band noise with at least one counter-noise loudspeaker and at least one error microphone in a space forming a material electroacoustic system, the method implementing, in a computing element, a control law with an internal model and disturbance observer with a model of the electroacoustic system, previously obtained by an identification method. The current configuration of the electroacoustic system can vary over time, a nominal configuration of the electroacoustic system is previously determined, a corresponding nominal model Mo(q?1) or Mo(k) previously identified, the control law with an internal model and disturbance observer is implemented in real time, a modifier block ?(q?1) or ?(k) is applied to and associated with the nominal model, and the nominal model remains the same during the variations of the current configuration of the electroacoustic system, and the modifier block is varied in real time during these variations.

Abstract: A method and a device are based on the application of an active correcting system with central corrector and Youla parameter for the attenuation of essentially monofrequency mechanical vibratory perturbations generated in a material structure by a rotating machine. Previously, a control law corresponding to a block modeling of the system is established and calculated, the blocks being, on the other hand, those of the central corrector and, on the other hand, a Youla parameter block, the modeling being such that only the Youla parameter, in the form of an infinite impulse response filter, has coefficients dependent on the vibratory perturbation frequency. During a phase of use, in real time, the frequency of the current perturbation is determined and the control law is calculated using for the Youla parameter the stored coefficients of a determined perturbation frequency corresponding to the current perturbation frequency.

Abstract: A fiber optic interferometric measurement system includes a light source; first and second optical transmission elements; first and second Sagnac-ring interferometers, respectively, including first and second fiber optic coils, and, respectively, having lengths L1 and L2; and first and second individual integrated optical circuits, respectively, connected to the first and second optical transmission elements, and to the two ends of the first and second optic coils, respectively. The interferometric system includes a multiple integrated optical circuit integrating, on a single substrate, the first and second individual integrated optical circuits, and the difference ?l between the optical length of the first optical transmission elements and the optical length of the second optical transmission elements is higher than the maximum of ?Nb1×L1 and ?NB2×L2, in which ?Nb1 and ?Nb2, respectively, are the group birefringence index difference of the first and second fiber optic coils, respectively.

Abstract: A method of calibration of a navigation and pointing system (10) including a navigation unit (11) integrally connected to a pointing device (12), the navigation unit being configured to measure the orientation of a navigation reference system (21), the pointing device (12) being configured to measure a signal in a pointing reference system (22). The calibration method includes the following steps: selecting a first planar surface (8) and a second planar surface (9); acquiring measurements via the system by directing the pointing direction towards the first planar surface (8), and respectively towards the second planar surface (9), according to a plurality of predetermined orientations; applying an algorithm for processing the measurements acquired at the previous step to extract therefrom the misalignment angles between the navigation reference system (21) and the pointing reference system (22).

Abstract: An electroacoustic transducer submersible in an immersion fluid (8) for underwater acoustic communications, includes two horns (3a, 3b), a counterweight (4), two electroacoustic motors (1a, 1b), aligned along an axis of symmetry (6), the opposite ends of the motors being respectively connected to a horn, the unit consisted by the electroacoustic motors, the counterweight and the horns being able to generate a longitudinal electroacoustic resonance mode. The transducer includes a rigid and hollow cylindrical part (5) extending around the counterweight, the cylindrical part having an axis merged with the symmetry axis of the transducer, the inside of the cylindrical part forming a fluid cavity able to be filled with the immersion fluid, the electroacoustic motors and the cylindrical part being so dimensioned that the fluid cavity forms an acoustic coupling between the longitudinal electroacoustic resonance mode and a circumferential resonance mode of the cylindrical part.

Abstract: A method of manufacturing a radiation-resistant optical fiber and a thus-obtained radiation-resistant optical fiber, the method includes the following steps: a) manufacturing a silica optical fiber preform; b) forming, in the preform, a longitudinal cavity; c) drawing the preform so as to form an optical fiber (1) including a core (2), an optical cladding (6) and at least one longitudinal cavity (3) having at least one opening (13) at one end of the optical fiber (1); d) applying, during step c) of fiber drawing, a gas-tight coating (4); e) exposing the optical fiber (1) to a gaseous substance, including preferably gaseous hydrogen and/or gaseous deuterium, in such a way to incorporate the gaseous substance in silica via the opening (13); and f) closing any opening (13) at both ends of the optical fiber.

Abstract: A fiber-optic measurement device (10) includes a SAGNAC ring interferometer (20) having a proper frequency fp. The aim is to improve response time while maintaining high precision across the measurement range. Biasing elements (130) are used to produce: a first biasing phase-differential modulation component ??b1(t) (34) which is periodic in time-slots, having levels +? and ??, at a first biasing modulation frequency fb1 such that fb1=(2k1+1) fp, k1 being a natural number; and a second periodic biasing phase-differential modulation component ??b2(t) (35), having extreme amplitudes +?/a and ??/a, a being a non-zero real number such that |a|>1, at a second biasing modulation frequency fb2 such that fb2=(2k2+1) fp, k2 being a non-zero natural number such that k2>k1. A gyrometer including such a measurement device and a navigation or inertial-stabilization system including at least one such gyrometer are also described.

Abstract: A fibre-optic interferometric measurement device (100) intended to measure a physical parameter (QR), includes: a wide-spectrum light source (103); a SAGNAC fibre-optic interferometer (110), in which there propagate two counter-propagating light waves (101, 102) including measurement elements (1140) sensitive to the physical parameter that results in a non-reciprocal phase difference ??? between the two light waves; and a detector (104) delivering an electric signal representative of the physical parameter. The measurement elements include a ring resonator (1143) in transmission mode including a first coupler (1141) and a second coupler (1142) respectively, which couple a first arm (111) and a second arm (112) respectively of the SAGNAC interferometer to the ring resonator, in such a way that the two light waves travel in opposing directions of travel (1143H, 1143AH).