Abstract: A fiber-optic interferometer is designed to receive and propagate a first single-mode wave along a first optical path and, respectively, a second single-mode wave along a second optical path, the second optical path being the reverse of the first optical path, and to form a first output wave and, respectively, a second output wave, having a modulated phase difference ??m(t). According to the invention, the modulated phase difference ??m(t) is equal to sum of a first periodic phase difference ???(t) having a level equal to ±?, a second periodic phase difference ??alpha(t) having a level equal to ±alpha and a third periodic phase difference ??beta(t) having a variable level between ?beta and +beta, said modulated phase difference ??m(t) comprising per modulation period T at least eight modulation levels among twelve modulation levels and said modulated phase difference between such that: ??m(t+T/2)=???m(t).

Abstract: A fiber-optic interferometer is designed to receive and propagate a first single-mode wave along a first optical path and, respectively, a second single-mode wave along a second optical path, the second optical path being the reverse of the first optical path, and to form a first output wave and, respectively, a second output wave, having a modulated phase difference ??m(t). According to the invention, the modulated phase difference ??m(t) is equal to sum of a first periodic phase difference ???(t) having a level equal to ±?, a second periodic phase difference ??alpha(t) having a level equal to ±alpha and a third periodic phase difference ??beta(t) having a variable level between ?beta and +beta, said modulated phase difference ??m(t) comprising per modulation period T at least eight modulation levels among twelve modulation levels and said modulated phase difference between such that: ??m(t+T/2)=???m(t).

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: 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: 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: 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: 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).

Abstract: An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving as input a light signal with input light power and delivering as output a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter (?R) 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, centred 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: 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.

Abstract: A fibre-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 fibre. For this reason, the fibre-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: An interferometric system includes a polarization separation element (10), a first polarization conversion element (11), a Mach-Zehnder interferometer (2) including a first (4) and second (5) arms connected to one another by a first (6) and second (7) ends in order for a first and second beams (20, 21) 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 (22, 23), a second polarization conversion element (11) for obtaining an interferometric beam (24), the polarization of which is converted, a polarization-combining element (10), and a detection element (8) suitable for detecting an output beam (25).

Abstract: 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.

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 bidirectional guided optical router includes an evanescent-field optical coupler having three input ports, three output ports, a first central waveguide, a second lateral waveguide and a third lateral waveguide and an evanescent-field-based optical coupling zone in which the first, second and third waveguides are disposed so as to allow evanescent-field-based coupling between the first central waveguide and either one of the lateral waveguides. The 3×3 optical coupler has a length L of between 3154×Leq and 2×Leq such that an optical beam coupled on the first input port having a power p and propagating on the first waveguide in the forward direction is distributed according to the following distribution: a first secondary beam having a power 90% of p/2 on the second output port, another secondary beam having a same power ?90% of p/2 on the third output port.

Abstract: An interferometric system includes a polarization separation element (10), a first polarization conversion element (11), a Mach-Zehnder interferometer (2) including a first (4) and second (5) arms connected to one another by a first (6) and second (7) ends in order for a first and second beams (20, 21) 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 (22, 23), a second polarization conversion element (11) for obtaining an interferometric beam (24), the polarization of which is converted, a polarization-combining element (10), and a detection element (8) suitable for detecting an output beam (25).

Abstract: The invention concerns a rectangular response optical filter for partitioning a limited spectral interval in a light flux with large spectrum comprising: a preferably monomode input optical fiber having one end; an array-reflector assembly in Litmann-Metcalf configuration; a converging optical system collimating at whose focus is set the input fiber end; a converging focusing optical system set between the array and the reflector; one or several output fibers of the same type as the input fiber. At least one reflector is placed in the focal plane of the focusing optical system and has a limited dimension in the dispersion plane, the position and the limited dimension of the dispersion plane determining the partitioned spectral interval.

Abstract: This invention relates to a continuously wavelength tunable monomode laser source with external cavity comprising a resonant cavity having a reflecting plane face, means for extracting a portion of the luminous flux and a retroreflecting dispersive device, an amplifier wave guide located inside the resonant cavity, means for controlling the retroreflecting dispersive device providing continuous tunability.

Abstract: The invention concerns an optical interferometer (1) with two waves defining two paths of different optical lengths and comprising at least a separator periscope (2, 3, 4) forming a Mach-Zender interferometer. The invention is characterised in that the interferometer (1) comprises, on the short path of the interferometer (1), a compensating plate (6) cut in glass of the same type as the separator periscopes (2, 3, 4) and having as thickness the difference of the glass thickness of the separator periscopes (2, 3, 4) traversed respectively by each of the waves. The invention is applicable to wavelength-multiplexed optical fibre transmission devices.