Four-mode stabilized solid-state gyrolaser without blind region

The invention concerns solid-state gyrolasers used to measure rotation speeds or relative angular positions. This type of equipment is used, in particular, in aeronautical applications. The purpose of the invention is to complete the optic devices required to control the instability of ring-shaped solid-state lasers using specific optic devices that eliminate the blind region without adding a measurement bias. In this way, a "fully optic" solid-state laser is obtained, without moving parts, stable, and without blind region. These devices comprise in particular polarization separation optical devices (8, 9), reciprocal (4) and nonreciprocal (5, 13) optical rotators arranged so that four linearly polarized optical modes travel in the cavity (1) at sufficiently different frequencies to avoid mode locking.

Stabilized solid-state gyrolaser without blind region

The invention concerns solid-state gyrolasers used to measure rotation speeds or relative angular positions. This type of equipment is used, in particular, in aeronautical applications. The purpose of the invention is to complete the optic devices required to control the instability of lasers, using specific optic devices that eliminate the blind region. In this way, a "fully optic" solid-state laser is obtained, without moving parts, stable, and without blind regions. These devices comprise in particular reciprocal (6, 9) and nonreciprocal (5, 8) optical rotators, arranged so that two counter-propagating optical modes travel in the cavity (1) at sufficiently different frequencies to avoid mode locking.

Stabilized solid-state laser gyroscope with anisotropic medium

(EN) stabilized solid-state laser gyroscope with anisotropic medium

The invention relates to solid-state laser gyroscopes. One of the major problems inherent to that technology is that the optical emission of this type of laser is intrinsically highly power unstable. In order to reduce this instability, the invention provides for the introduction in the cavity (1) of controlled optical gains by installing an optical assembly comprising an anisotropic medium (19), a first optical element (7) and a second optical element with non-reciprocal effect (8) each acting on the polarization of the counter-propagating modes, at least one of those two effects being variable, for introducing controlled optical gains based on the direction of propagation of the counter-propagating optical modes. The invention also concerns several devices for implementing either the fixed effects of element (7) associated with variable non-reciprocal effects, or vice versa. Said devices are applicable in particular to monolithic cavity lasers.

Stabilized solid-state gyrolaser without blind region

Solid state gyrolaser with controlled optical pumping

The invention relates to a solid state gyrolaser with a controlled optical pumping comprising at least one ring-shaped optical cavity (1) comprising at least three mirrors (11, 12, 13, 14), a solid state amplifying medium (15) pumped by a laser diode (16) whose optical emission power is determined by a current supply source (17), the cavity (1) and the amplifying medium (15) being such that two so-called contra-rotating optical modes (5, 6) propagate in opposite directions to each other within the said optical cavity, the gyrolaser being a class B gyrolaser, the gyrolaser also comprising means (18) of measuring the difference in optical frequency existing between the two optical modes. The gyrolaser comprises means (20, 21) of measuring the total optical power circulating in the optical cavity and first means (22) of control of the current delivered by the supply source in such a way as to maintain the total optical power substantially constant in a narrow spectral band centred on therelaxation ...

Four-mode stabilized solid-state gyrolaser without blind region

Solid-state laser gyro with a mechanically activated gain medium

Stabilised solid-state gyrolaser

A solid-state gyrolaser (100) has a unit (30) for stabilizing the intensities to enable two counter propagating modes to be in the balance, and at least one unit (3) for calculating a measurement of rotation (OMEGA, I-OMEGA) based on the counter propagating modes, wherein the counter propagating modes have a frequency difference(DElLTAvmes), and the calculation is conducted if the frequency difference(DElLTA-v-mes) between two counter propagating modes is generated by the rotation of a cavity, the gyrolaser also comprises a unit (23) for measuring a control command (Co), a unit (21) for storing a behavior model (Mo) of a bias frequency (DELTA-v-b) induced by the unit (30) for stabilizing the intensities as a function of the control command (Co), a unit (22) for calculating the bias frequency (DELTA-v-b) induced by the unit (30) for stabilizing the intensities based on the value of the control command (Co) and the model (Mo), a unit (24) for calculating the bias (DELTA-OMEGA-b, DELTA-I-OMEGA-b ...

Solid-state laser gyro with a mechanically activated gain medium

The field of the invention is that of solid-state ring lasers or laser gyros. The laser gyro according to the invention comprises at least one optical cavity in the form of a ring and a solid-state amplifying medium which are designed so that two counterpropagating optical modes can propagate in opposite directions one with respect to the other inside said optical cavity and pass through the amplifying medium, said amplifying medium being coupled to an electromechanical device imparting on said amplifying medium a periodic translational movement along an axis substantially parallel to the direction of propagation of said optical modes. Thus, the population inversion grating, written by the standing wave into the amplifying medium, which disturbs the nominal operation of the laser gyro, isgreatly attenuated.

Laser gyro having a solid-state amplifying medium and an optical ring cavity

The laser gyro having a solid-state amplifying medium (MAES) and an optical ring cavity (COA) comprises an assembly (EE) containing the optical cavity (COA) and capable of undergoing an oscillatory rotational movement, together with at least one external longitudinal optical energy injection device (DEOILE) for injecting energy into the solid-state amplifying medium (MAES). The laser gyro also includes a fastening assembly (EF) designed to make said assembly (EE) containing the optical cavity and said external longitudinal optical energy injection device (DEOILE) undergo translational and rotational movement as one entity.

Solid state multi-oscillating gyrolaser using a cut crystalline gain medium 100

The invention relates to a ''multi-oscillating'' gyrolaser for measuring the angular speed or the relative angular position about a rotation axis, that comprises at least one annular optical cavity (1) and a solid-state amplifying medium (2) as well as a measuring device (6) arranged so that a first linear-polarisation propagation mode and a second linear-polarisation propagation mode perpendicular to the first mode can propagate in a first direction in the cavity, and so that a third linear-polarisation propagation mode parallel to the first mode and a fourth linear-polarisation propagation mode parallel to the second mode can propagate in the reverse direction in the cavity. The amplification medium is a cubic-symmetry crystal having an inlet face and an outlet face, said faces being substantially perpendicular to the crystallographic direction, and the different modes propagating in directions substantially perpendicular to said faces.

Scale-factor stabilized solid-state laser gyroscope

The invention relates to solid-state laser gyroscopes for measuring rotational speeds or angular positions which are used, in particular for aircraft engineering. A gyroscope performances depend on the temperature stability of the scale factor thereof (S) which is 4A/L, wherein L and A are the optical length and the area of the laser cavity, respectively and is a laser emission mean wavelength without the Sagnac effect. Conventionally, for gas lasers, each parameter of the scale factor is selected in such a way that it is temperature independent. The solid state lasers which are very different from the gas lasers are not treatable in the same manner. Said invention offers the laser cavity optical architecture based on the scale factor global conservation, wherein each parameter is temperature variable. An architecture which makes it possible to avoid optical mode hopes and several digital examples proving that inventive principles are applicable to standard materials are also disclosed.

Solid state multi-oscillating gyrolaser using a cut crystalline gain medium 100

The invention relates to a ''multi-oscillating'' gyrolaser for measuring the angular speed or the relative angular position about a rotation axis, that comprises at least one annular optical cavity (1) and a solid-state amplifying medium (2) as well as a measuring device (6) arranged so that a first linear-polarisation propagation mode and a second linear-polarisation propagation mode perpendicular to the first mode can propagate in a first direction in the cavity, and so that a third linear-polarisation propagation mode parallel to the first mode and a fourth linear-polarisation propagation mode parallel to the second mode can propagate in the reverse direction in the cavity. The amplification medium is a cubic-symmetry crystal having an inlet face and an outlet face, said faces being substantially perpendicular to the crystallographic direction, and the different modes propagating in directions substantially perpendicular to said faces.

Solid-state laser gyro having orthogonal counter-propagating modes

The invention concerns solid-state laser gyros used in inertial navigation unit. However, the design of this type of laser gyros involves some technical difficulties related partly to the fact that the counter-propagating waves interfere in the amplifying medium. The inventive laser gyro comprises at least one solid-state amplifying medium (2) and one ring optical cavity (1) including first optical means (4) enabling a first common linear polarization state to be imparted to the two counter-propagating optical waves in input and output of the zone containing the amplifying medium and second optical means (30, 31) enabling, inside the amplifying medium, a second linear polarization state to be imparted to the first optical wave and a third linear polarization state to the second optical wave, said polarization states being perpendicular, thereby eliminating all the inconveniences related to interferences.

OPTICAL PASSIVE RESONATOR GYRO WITH THREE BEAMS

The general field of the invention is that of passive resonator gyros comprising an injection laser emitting an initial optical beam at a first frequency and a fibre optic cavity. The gyro according to the invention operates with three optical beams at three different optical frequencies. A first beam is injected in a first direction of rotation, the second and the third beam are injected in the contrary direction. The gyro includes three slaving devices maintaining each optical frequency at a specific mode of resonance of the cavity. The gyro includes means for measuring the frequency differences existing between the different frequencies. Combined together, these differences are representative of the length of the cavity and the angular rotational velocity of the cavity along an axis perpendicular to its plane. 1. Passive resonator gyro comprising an injection laser emitting an initial optical beam at a first frequency and a cavity ,wherein the gyro includes:an optical splitter making it possible to divide the initial optical beam into a first optical beam, into a second optical beam and into a third optical beam, the first beam being injected into the cavity in a first direction, the second and third optical beams being injected into the cavity in the opposite direction;a first slaving device making it possible to slave the first frequency of the first optical beam to a first proper frequency corresponding to a first mode of resonance of the cavity or to slave a first proper frequency corresponding to a first mode of resonance of the cavity to the first frequency of the first optical beam;a second slaving device making it possible to slave the second frequency of the second optical beam to a second proper frequency corresponding to a second mode of resonance of the cavity;a third slaving device making it possible to slave the third frequency of the third optical beam to a third proper frequency corresponding to a third mode of resonance of the cavity, the three ...

Method for estimating scattering coefficients of a laser gyro in operation and associated gyroscopic system

An iterative method for determining scattering coefficients of the cavity of a laser gyro in operation supporting two counter-propagating modes, comprises steps of: determining a set of variables dependent on characteristic physical quantities of the laser gyro, one reference variable per dependency relationship being selected from the variables; measuring values of the characteristic physical quantities of the laser gyro in operation; determining measured values of the variables; estimating, via an iterative method, estimated values of the coefficients minimising a discrepancy between the measured values of the reference variables and estimated values of the reference variables, which are estimated from the values of the coefficients and the measured values of the variables other than the reference variables; and determining estimated values of the scattering coefficients from the estimated values of the coefficients.

COMPACT THREE-FREQUENCY RESONANT OPTICAL GYROSCOPE

A passive resonant optical gyroscope comprising a cavity and operating with three frequencies comprises: a first injecting laser to inject a first optical beam into the cavity in a first direction; a second injecting laser to inject a second optical beam into the cavity in an opposite direction; a third injecting laser to inject a third optical beam into the cavity in one of the aforementioned directions, one laser amongst the injecting lasers having a master frequency, the two other injecting lasers, called the first and second slave lasers, respectively having a first slave frequency and a second slave frequency; a master servocontrol device; a first servocontrol stage comprising first and second slave devices; and a second servocontrol stage comprising first and second optical phase-locking devices respectively comprising a first and second slave oscillator to generate a first radiofrequency offset signal and a second radiofrequency offset signal. 1. A passive resonant optical gyroscope comprising a cavity and operating with three frequencies , and comprising:a first injecting laser configured to inject a first optical beam into the cavity in a first direction;a second injecting laser configured to inject a second optical beam into the cavity in a direction opposite the first direction;a third injecting laser configured to inject a third optical beam into the cavity in one of the two aforementioned directions,one laser amongst one of the injecting lasers, which is selected as master laser, having a master frequency, the two other injecting lasers, which are respectively denoted the first and second slave lasers, respectively having a first slave frequency and a second slave frequency;a master servocontrol device configured to directly servocontrol the master frequency to an eigenfrequency corresponding to a resonant mode of the cavity or to servocontrol an eigenfrequency corresponding to a resonant mode of the cavity to the master frequency of the master laser;a ...

DEVICE FOR OPTICALLY RECEIVING A SIGNAL COMING FROM A PHASED ANTENNA ARRAY AND ASSOCIATED ANTENNA SYSTEM

The invention relates to an optical reception device for receiving a signal from an antenna array comprising: 1. An optical reception device , the reception device being able to receive a signal from a phased antenna array , the phased antenna array including N elementary antennas , N being an integer greater than 1 , the reception device including:a light source capable of generating an optical carrier at a reference frequency and M phased optical beams relative to a replica of the optical carrier and which are frequency-shifted relative to the reference frequency, M being an integer greater than 1,a collection circuit for the signals from the N elementary antennas, the collection circuit including N paths each connected to a respective elementary antenna, each path including a modulator able to modulate at least one of the phase and the amplitude of an incident signal according to a modulation,a beam-forming network connecting M+1 first ports to N second ports, each second port being connected to a respective path of the N paths, M first ports of the M+1 first ports being connected respectively to one of the M optical beams and the first port not connected to one of the M optical beams being a control port, the control port being connected to the other ports so that a maximum optical intensity on the control port corresponds to phased signals on the N second ports,a photodiode connected to the control port and able to measure the optical intensity of the signal of the control port at the reference frequency, anda controller able to control the modulation of each modulator as a function of the optical intensity measured by the photodiode.2. The reception device according to claim 1 , wherein the collection circuit includes two additional paths claim 1 , one of the paths being supplied by the optical carrier and the other paths supplying the light source with a replica of the optical carrier.3. The reception device according to claim 1 , wherein the controller is ...

Mode-locked laser

Mode-locked pulsed output is induced in a laser by introducing a varying frequency dependent loss in the cavity. The varying, frequency dependent loss allows a large number of longitudinal modes to oscillate. In one of the preferred embodiments of the subject invention, the varying frequency dependent loss is generated by reciprocating one of the mirrors of the resonator. In this embodiment, the laser has a resonator with a primary light path defined by first and second end mirrors. A gain medium is located between the end mirrors. A beam splitter is provided for redirecting the light into a secondary light path. A third mirror functions to feed back the light into the primary light path. Pulse formation is induced by varying the path length of one of the two paths by reciprocating an end mirror. Moving the mirror creates varying interference effects when the light energy is recombined at the beam splitter. The mirror is reciprocated relatively slowly, yet ultra-short pulses are generated.

GYROLASER WITH STABILIZED SOLID STATE

PUMP LASER AND OPTIMIZED LASER MEDIA

GYROLASER SOLID STATE MULTIOSCILLATOR UTILIZING 100-CUT CRYSTALLINE GAIN MEDIA

Le domaine général de l'invention est celui des gyrolasers dits « multioscillateur » permettant la mesure de la vitesse angulaire ou de la position angulaire relative selon un axe de rotation déterminé, comportant au moins une cavité optique (1) en anneau et un milieu amplificateur (2) à l'état solide, et un dispositif de mesure (6) ; agencés de telle sorte qu'un premier mode de propagation polarisé linéairement et qu'un second mode de propagation polarisé linéairement perpendiculairement au premier mode puissent se propager dans un premier sens dans la cavité et qu'un troisième mode de propagation polarisé linéairement parallèlement au premier mode et qu'un quatrième mode de propagation polarisé linéairement parallèlement au second mode puissent se propager en sens inverse dans la cavité. Le milieu amplificateur est un cristal à symétrie cubique comportant une face d'entrée et une face de sortie, le cristal étant taillé de façon que lesdites faces soient sensiblement perpendiculaires à la direction cristallographique <100>, les différents modes se propageant dans des directions sensiblement perpendiculaires aux dites faces. On limite ainsi les effets de compétition entre modes à l'intérieur du cristal amplificateur. The general field of the invention is that of so-called "multioscillator" gyrolasers allowing the measurement of the angular velocity or of the relative angular position according to a determined axis of rotation, comprising at least one optical cavity (1) in a ring and an amplifying medium (2) in the solid state, and a measuring device (6); arranged such that a linearly polarized first propagation mode and a linearly polarized second propagation mode perpendicular to the first mode can propagate in a first direction in the cavity and a linearly polarized third propagation mode parallel to the first mode and that a fourth mode of propagation linearly polarized parallel to the second mode can propagate in the ...

LASER PUMP AND OPTIMIZED LASER MEDIUM

The invention concerns a longitudinally pumped laser comprising one or several active lasing media arranged in an optical cavity and pumping means (4) emitting at least a pump beam towards the active lasing media (3), means coupling (5) the beam(s) with the active medium. The invention is characterised in that at least one of the active lasing media comprises one or several non-homogeneously doped zones (8) and the dimension of said doped zones (8) and/or the distribution of the doping agents is selected on the basis of the desired transverse mode. Said laser is useful as amplifier.

GYROLASER WITH SOLID STATE FACTOR STABILIZED

Le domaine de l'invention est celui des gyrolasers à état solide utilisés pour la mesure des vitesses de rotation ou des positions angulaires. Ce type d'équipement est notamment utilisé pour les applications aéronautiques.Les performances d'un gyrolaser dépendent de la stabilité en température de son facteur d'échelle S qui vaut 4A/λ.L, L et A étant respectivement la longueur optique et l'aire de la cavité laser et λ la longueur d'onde moyenne d'émission laser hors effet Sagnac.Classiquement, dans les lasers à gaz, chaque paramètre du facteur d'échelle est choisi pour être indépendant de la température. Dans les laser à état solide qui sont de nature très différente de celle des lasers à gaz, on ne peut procéder ainsi.L'invention propose une architecture optique de cavité laser fondée sur la conservation globale du facteur d'échelle, chaque paramètre pouvant varier avec la température. Elle propose également une architecture permettant d'éviter conjointement les sauts de mode optique.Plusieurs exemples numériques montrant que les principes selon l'invention peuvent s'appliquer à des matériaux standards sont fournis. The field of the invention is that of solid state laser gyros used for measuring rotational speeds or angular positions. This type of equipment is used in particular for aeronautical applications. The performance of a laser gyro depends on the temperature stability of its scale factor S which is 4A / λ.L, L and A being respectively the optical length and l 'area of the laser cavity and λ the mean wavelength of laser emission excluding the Sagnac effect. Classically, in gas lasers, each parameter of the scale factor is chosen to be independent of the temperature. In solid state lasers which are very different in nature from gas lasers, this cannot be done. The invention proposes an optical architecture of a laser cavity based on the overall conservation of the scale factor, each parameter being able ...

SOLID STATE GYROLASER STABILIZED BY ACOUSTO-OPTICAL DEVICES

SOLID STATE GYROLASER WITH ORTHOGONAL PROPAGATION MODES

Le domaine de l'invention est celui des gyrolasers à état solide utilisés dans les centrales inertielles. Cependant, la réalisation de gyrolasers de ce type présente certaines difficultés techniques liées en partie au fait que les ondes contre-propagatives interfèrent dans le milieu amplificateur.Un gyrolaser selon l'invention comporte au moins un milieu amplificateur (2) à l'état solide et une cavité optique (1) en anneau comprenant des premiers moyens optiques (4) permettant d'imposer un premier état de polarisation linéaire commun aux deux ondes optiques contre-propagatives à l'entrée et à la sortie de la zone contenant le milieu amplificateur et des seconds moyens optiques (30, 31) permettant d'imposer, à l'intérieur du milieu amplificateur, un second état de polarisation linéaire à la première onde, optique et un troisième état de polarisation linéaire à la seconde onde optique, ces états de polarisation étant perpendiculaires. On supprime ainsi tous les inconvénients liés aux interférences. The field of the invention is that of solid state gyrolasers used in inertial units. However, the realization of gyrolasers of this type presents certain technical difficulties related in part to the fact that the counter-propagating waves interfere in the amplifying medium. A laser gyro according to the invention comprises at least one amplifying medium (2) in the solid state. and an annular optical cavity (1) comprising first optical means (4) for imposing a first state of linear polarization common to both counterpropagating optical waves at the input and at the output of the zone containing the amplifying medium. and second optical means (30, 31) for imposing, within the amplifying medium, a second state of linear polarization at the first optical wave and a third state of linear polarization at the second optical wave, these states polarization being perpendicular. This removes all the disadvantages associated with interference.

SOLID STATE GYROLASER STABILIZED WITHOUT BLIND AREA

OPTICALLY ACTIVE SOLID STATE GYROLASER THROUGH ALTERNATIVE BIAIS

Le domaine de l'invention est celui des gyrolasers à état solide utilisés pour la mesure des vitesses de rotation ou des positions angulaires relatives. Ce type d'équipement est notamment utilisé pour les applications aéronautiques. L'objet de l'invention est de compléter les dispositifs optiques nécessaires au contrôle de l'instabilité des lasers par des dispositifs optiques spécifiques permettant d'éliminer la zone aveugle. On obtient ainsi un laser à état solide " tout optique " sans pièces mobiles, stable et sans zone aveugle.A cet effet, le gyrolaser selon l'invention comporte notamment :. un ensemble optique (5) permettant d'introduire un déphasage optique non réciproque entre les modes contre-propageants ;. des moyens de commande (6) permettant de faire varier l'amplitude du déphasage de façon périodique autour d'une valeur moyenne très sensiblement nulle. The field of the invention is that of solid-state gyrolasers used for the measurement of rotational speeds or relative angular positions. This type of equipment is used in particular for aeronautical applications. The object of the invention is to supplement the optical devices needed to control the instability of lasers by specific optical devices to eliminate the blind area. Thus, an "all optical" solid state laser without moving parts, stable and without blind zone.For this purpose, the laser gyro according to the invention comprises in particular: an optical assembly (5) for introducing a non-reciprocal optical phase shift between the counter-propagating modes; control means (6) for varying the amplitude of the phase shift periodically around a very substantially zero average value.

MULTI-CURATOR SOLID STATE GYROLASER IS PASSIVELY STABILIZED BY A DOUBLE FREQUENCY CRYSTAL DEVICE

SOLID STATE GYROLASER STABILIZED WITHOUT BLIND AREA

Le domaine de l'invention est celui des gyrolasers à état solide utilisés pour la mesure des vitesses de rotation ou des positions angulaires relatives. Ce type d'équipement est notamment utilisé pour les applications aéronautiques.L'objet de l'invention est de compléter les dispositifs optiques nécessaires au contrôle de l'instabilité des lasers par des dispositifs optiques spécifiques permettant d'éliminer la zone aveugle.On obtient ainsi un laser à état solide « tout optique » sans pièces mobiles, stable et sans zone aveugle.Ces dispositifs comportent notamment des rotateurs optiques à effet non réciproque (6, 9) et réciproques (5, 8) agencés de sorte que les deux modes optiques contre-propageants circulent dans la cavité (1) à des fréquences suffisamment différentes pour éviter le couplage des modes. The field of the invention is that of solid state laser gyros used for measuring rotational speeds or relative angular positions. This type of equipment is used in particular for aeronautical applications. The object of the invention is to complete the optical devices necessary for controlling the instability of lasers by specific optical devices making it possible to eliminate the blind zone. thus an "all optical" solid state laser without moving parts, stable and without blind zone. These devices include in particular non-reciprocal (6, 9) and reciprocal (5, 8) optical rotators arranged so that the two modes counter-propagating optics circulate in the cavity (1) at sufficiently different frequencies to avoid mode coupling.

SOLID STATE GYROLASER WITH ORTHOGONAL PROPAGATION MODES

STABILIZED SOLID STATE GYROLASER WITH FOUR MODES WITHOUT BLIND AREA

Le domaine de l'invention est celui des gyrolasers à état solide utilisés pour la mesure des vitesses de rotation ou des positions angulaires relatives. Ce type d'équipement est notamment utilisé pour les applications aéronautiques.L'objet de l'invention est de compléter les dispositifs optiques nécessaires au contrôle de l'instabilité du laser en anneau à état solide par des dispositifs optiques spécifiques permettant d'éliminer la zone aveugle sans ajouter de biais de mesure. On obtient ainsi un gyrolaser à état solide « tout optique » sans pièces mobiles, stable et sans zone aveugle.Ces dispositifs comportent notamment des dispositifs optiques à séparation de polarisation (8, 9), des rotateurs optiques à effet non réciproque (4) et non réciproques (5, 13) agencés de sorte que quatre modes optiques polarisés linéairement circulent dans la cavité (1) à des fréquences suffisamment différentes pour éviter le verrouillage des modes. The field of the invention is that of solid state laser gyros used for measuring rotational speeds or relative angular positions. This type of equipment is used in particular for aeronautical applications. The object of the invention is to complete the optical devices necessary for controlling the instability of the solid state ring laser by specific optical devices making it possible to eliminate the blind area without adding measurement bias. The result is an “all-optical” solid-state laser gyro without moving parts, stable and without blind zones. These devices include in particular polarization-separation optical devices (8, 9), optical rotators with non-reciprocal effect (4) and non-reciprocal (5, 13) arranged so that four linearly polarized optical modes circulate in the cavity (1) at sufficiently different frequencies to avoid mode locking.

Solid state gyro laser for aeronautical application, has warning system with reciprocating effect and non-reciprocating effect devices acting on polarization state of two counter propagating modes

The laser has an optical ring cavity (1) with warning systems (4, 42, 43) having an optical unit at an interior of the optical cavity. The warning systems have reciprocating effect and non-reciprocating effect devices (7, 8) acting on polarization state of two counter propagating modes. The warning systems have a regulating unit to regulate the reciprocating or non-reciprocating effects of the respective devices. The ring cavity includes three mirrors (11-13), a solid state amplifier medium (19), and the warning systems, which are arranged to have two counter propagating modes.

SEMICONDUCTOR SOLID SOLID GYROLASER WITH VERTICAL STRUCTURE

OPTICAL AMPLIFICATION DEVICE

L'invention concerne un dispositif d'amplification optique comprenant un milieu amplificateur (m) insérés entre deux miroirs (M1 ) et (M2 ), et une source de pompage optique (P). Les miroirs (M1 ) et (M2 ) sont des miroirs confocaux dont le plan focal est situé au voisinage du centre du milieu non linéaire. Ce milieu (m) possède une forme de type allumette présentant un grand axe selon une direction (Dx ) faisant un angle ( alpha/2) avec l'axe optique de la cavité définie par les deux miroirs et le milieu amplificateur. Cette architecture permet le multipassage d'une onde optique incidente au sein du dispositif d'amplification conduisant à une augmentation des performances dudit dispositif. The invention relates to an optical amplification device comprising an amplifying medium (m) inserted between two mirrors (M1) and (M2), and an optical pumping source (P). The mirrors (M1) and (M2) are confocal mirrors whose focal plane is located in the vicinity of the center of the nonlinear medium. This medium (m) has a shape of matchstick having a major axis in a direction (Dx) forming an angle (alpha / 2) with the optical axis of the cavity defined by the two mirrors and the amplifying medium. This architecture allows the multipass of an incident optical wave within the amplification device leading to an increase in the performance of said device.

SOLID STATE GYROLASER WITH OPTICAL PUMP CONTROL

GYROLASER WITH SOLID STATE FACTOR STABILIZED

METHOD OF ESTIMATING THE DIFFUSION COEFFICIENTS OF AN OPERATING GYROLASER AND GYROSCOPIC SYSTEM THEREOF

STABILIZED SOLID STATE GYROLASER WITH FOUR MODES WITHOUT BLIND AREA

Method for controlling an optical device comprising a laser and a cavity making it possible to compensate for an amplitude modulation introduced by a phase modulator

Méthode d’asservissement d’un dispositif optique comprenant une cavité (C) présentant une résonance autour d’une fréquence centrale , un laser (L) et un modulateur de phase (PM), ladite méthode étant adaptée pour asservir ladite cavité (C) sur ledit laser (L) ou réciproquement et pour compenser une modulation d’amplitude introduite par ledit modulateur de phase (PM), ladite méthode comprenant entres autres, les étapes suivante : Faire varier un écart entre la fréquence optique du rayonnement laser et ladite fréquence centrale de manière à ce que ladite fréquence optique balaye ladite résonance, ledit écart étant contrôlé par un paramètre d’un élément dudit dispositif, et pour chaque écart Moduler, à une fréquence de modulation , une phase dudit rayonnement laser, par une phase de modulation , avec le modulateur de phase (PM), Injecter le rayonnement modulé en phase dans ladite cavité (C),Détecter, par une photodiode (PDt, PDr), un rayonnement réfléchis ou transmis par ladite cavité et générer un signal électrique (St, Sr) représentatif de l’intensité dudit rayonnement détecté,Démoduler ledit signal électrique à ladite fréquence de modulation en générant de manière synchrone un premier signal démodulé et un deuxième signal démodulé représentatif du signal électrique démodulé, respectivement à une première phase de démodulation et à une deuxième phase de modulation , avec différente de ladite première phase et en filtrant le premier et le deuxième signal de manière à conserver uniquement une composante continue du premier signal démodulé dit signal d’erreur 1 et du deuxième signal démodulé , dit signal d’erreur 2 [Fig.3A] Method for controlling an optical device comprising a cavity (C) having a resonance around a central frequency, a laser (L) and a phase modulator (PM), said method being suitable for controlling said cavity (C) on said laser (L) or vice versa and to compensate for an amplitude modulation introduced by said phase modulator (PM), said method comprising ...

OPTICALLY ACTIVE SOLID STATE GYROLASER THROUGH ALTERNATIVE BIAIS

DEVICE FOR OPTICALLY RECEIVING A SIGNAL FROM A PHASE CONTROL ANTENNA ARRAY AND ASSOCIATED ANTENNA SYSTEM

L'invention concerne un dispositif de réception optique (16) d'un signal d'un réseau antennaire (12) comportant : - une source lumineuse (62) générant une porteuse optique et M faisceaux optiques en phase et décalés en fréquence par rapport à la porteuse optique, - un circuit de collection (64) comportant N voies (74) reliées à une antenne (18), et comportant un modulateur (78) d'un signal incident, - un réseau de formation de faisceaux (66) reliant (M+1) premiers ports (86) à N deuxièmes ports (88) reliés à une voie (74), M premiers ports (90) étant reliés aux faisceaux optiques et un port de contrôle (92) relié aux autres ports (86, 88) de sorte qu'une intensité optique maximale sur le port de contrôle (92) corresponde à des signaux en phase sur les N deuxièmes ports (88). The invention relates to a device for optical reception (16) of a signal of an antenna array (12) comprising: - a light source (62) generating an optical carrier and M optical beams in phase and frequency-shifted with respect to the optical carrier, - a collection circuit (64) having N channels (74) connected to an antenna (18), and comprising a modulator (78) of an incident signal, - a beam forming network (66) connecting (M + 1) first ports (86) at N second ports (88) connected to a channel (74), M first ports (90) being connected to the optical beams and a control port (92) connected to the other ports (86) , 88) so that a maximum optical intensity on the control port (92) corresponds to in-phase signals on the N second ports (88).

Solid-state laser gyro having orthogonal counter-propagating modes

The invention concerns solid-state laser gyros used in inertial navigation unit. However, the design of this type of laser gyros involves some technical difficulties related partly to the fact that the counter-propagating waves interfere in the amplifying medium. The inventive laser gyro comprises at least one solid-state amplifying medium (2) and one ring optical cavity (1) including first optical means (4) enabling a first common linear polarization state to be imparted to the two counter-propagating optical waves in input and output of the zone containing the amplifying medium and second optical means (30, 31) enabling, inside the amplifying medium, a second linear polarization state to be imparted to the first optical wave and a third linear polarization state to the second optical wave, said polarization states being perpendicular, thereby eliminating all the inconveniences related to interferences.

Gyrolaser for aeronautic application, has optical unit and rotator with non-reciprocal effect, both acting in polarization state of counter-propagating modes, where effects of either optical unit or rotator are adjustable

The gyrolaser has an anisotropic laser medium (19) and a follow-up system (4, 42, 43) with, inside a monolithic cavity, an optical assembly. The assembly has an optical unit (7) acting in polarization state of counter-propagating modes and a rotator (8) with non-reciprocal effect also acting in the polarization state of the modes. The effects of either the optical unit or the rotator are adjustable. The follow-up system includes an electronic coupling module (4), two photo-detectors (42) and two semi-reflecting blades (43).

SOLID STATE GYROLASER WITH MECHANICALLY ACTIVE GAIN MEDIUM.

GYROLASER WITH STABILIZED SOLID STATE

Gyrolaser (100) à état solide comportant un dispositif (30) de stabilisation des intensités permettant de maintenir l'équilibre des deux modes contre-propageants, un moyen (3) de calcul d'une mesure de rotation (Ω, IΩ) dudit gyrolaser à partir des modes optiques dits contre-propageants, présentant entre eux une différence de fréquence (Δνmes), en supposant que cette différence est induite uniquement par la rotation de la cavité, comprenant en outre : - un moyen (23) pour mesurer la commande de réglage (Co), - un moyen (21) pour mémoriser un modèle (Mo) de comportement d'un biais en fréquence (Δvb) induit par le dispositif (30) de stabilisation des intensités en fonction de la commande de réglage (Co), - un moyen (22) pour calculer le biais en fréquence (Δvb) induit par le dispositif (30) de stabilisation des intensités à partir de la valeur de la commande de réglage (Co) et du modèle (Mo) , - un moyen (24) pour calculer le biais (ΔΩb, ΔIΩb) sur la mesure de rotation (Ω, IΩ), induit par le biais en fréquence (Δνb) - un moyen (25) pour compenser le biais (ΔΩb, ΔIΩb) sur la mesure de rotation (Ω, IΩ). A solid-state laser gyro (100) having an intensity stabilizing device (30) for maintaining the balance of the two counter-propagating modes, a means (3) for calculating a rotation measurement (Ω, IΩ) of said laser gyro from so-called counter-propagating optical modes, having a frequency difference between them (Δνmes), assuming that this difference is induced solely by the rotation of the cavity, further comprising: - means (23) for measuring the control setting device (Co); - means (21) for storing a frequency bias pattern (Δvb) model (Mo) induced by the intensity-stabilizing device (30) according to the setting control (Co) ), - means (22) for calculating the frequency bias (Δvb) induced by the intensity stabilization device (30) from the value of the adjustment control (Co) and the model (Mo), - a means (24) for calculating the bias (ΔΩb, ΔIΩb) on the ...

Device for optical amplification

The apparatus includes a laser pump source (P), e.g. an array of semiconductor laser diodes, placed perpendicular to the main axis of the medium (m), e.g. YAG, and may be linked by optical fibres. Mirrors (M1, M2) are parabolic or spherical but compensated for astigmatism and may be integrated into the medium. The surfaces perpendicular to the optical axis of the device may have a curved part to form a mirror and a flat part, transparent to the optical beam to be amplified and cut at the Brewster angle of incidence. Equally the surface may be covered partially by a mirror and partially by an antireflecting layer which is transparent to the beam.

Four-mode stabilized solid-state gyrolaser without blind region

The invention concerns solid-state gyrolasers used to measure rotation speeds or relative angular positions. This type of equipment is used, in particular, in aeronautical applications. The purpose of the invention is to complete the optic devices required to control the instability of ring-shaped solid-state lasers using specific optic devices that eliminate the blind region without adding a measurement bias. In this way, a “fully optic” solid-state laser is obtained, without moving parts, stable, and without blind region. These devices comprise in particular polarization separation optical devices, reciprocal and nonreciprocal optical rotators arranged so that four linearly polarized optical modes travel in the cavity at sufficiently different frequencies to avoid mode locking.

PASSIVE OPTICAL GYROMETER RESONANT TO THREE BEAMS

Le domaine général de l'invention est celui des gyromètres passifs résonants comprenant un laser d'injection (1) émettant un faisceau optique initial à une première fréquence et une cavité fibrée (2). Le gyromètre selon l'invention fonctionne avec trois faisceaux optiques à trois fréquences optiques différentes. Un premier faisceau (F1) est injecté dans un premier sens de rotation, le second et le troisième faisceau (F2, F3) sont injectés dans le sens contraire. Le gyromètre comporte trois dispositifs d'asservissement (10, 12, 13, 14, 20, 22, 23, 24, 25, 30, 32, 33, 34, 35) maintenant chaque fréquence optique sur un mode de résonance spécifique de la cavité. Le gyromètre comporte des moyens de mesure des différences de fréquence existant entre les différentes fréquences. Ces différences combinées entre elles sont représentatives de la longueur de la cavité et de la vitesse de rotation angulaire de la cavité selon un axe perpendiculaire à son plan. The general field of the invention is that of resonant passive gyrometers comprising an injection laser (1) emitting an initial optical beam at a first frequency and a fiber cavity (2). The gyroscope according to the invention operates with three optical beams at three different optical frequencies. A first beam (F1) is injected in a first direction of rotation, the second and the third beam (F2, F3) are injected in the opposite direction. The gyro has three servo devices (10, 12, 13, 14, 20, 22, 23, 24, 25, 30, 32, 33, 34, 35) holding each optical frequency in a specific resonance mode of the cavity . The gyrometer comprises means for measuring the frequency differences existing between the different frequencies. These combined differences between them are representative of the length of the cavity and the angular rotation speed of the cavity along an axis perpendicular to its plane.

Coupling device for hollow-core optical fibers comprising a coupling element

Dispositif (D) de couplage pour fibres optiques comprenant : une première fibre optique (FO1) à cœur creux à couplage inhibé comprenant une première gaine microstructurée (SCF1) comprenant une pluralité de premier motif tubulaire confinant (MCF1), répartis en anneau et entourant, au moins partiellement, un premier cœur (C1) de manière à confiner au moins un rayonnement à une longueur d’onde dans ledit premier cœur,une deuxième fibre optique (FO2) à cœur creux à couplage inhibé, comprenant une deuxième gaine microstructurée (SCF2) comprenant une pluralité de deuxième motif tubulaire confinant (MCF2), répartis en anneau et entourant, au moins partiellement, un deuxième cœur (C2) de manière à confiner ledit rayonnement lumineux dans ledit deuxième cœur,un élément couplant (SCP) agencé entre le premier et le deuxième cœur, ledit élément couplant comprenant au moins un motif tubulaire couplant (MCP, MCP1, MCP2, MTa) compris au moins partiellement dans ladite première gaine microstructurée et/ou ladite deuxième gaine microstructurée et présentant une épaisseur de paroi dite épaisseur de couplage et un indice de matériau dit indice de couplage, un agencement de l’élément couplant, l’épaisseur de couplage et l’indice de couplage étant adaptés de manière à créer un canal de fuite pour ladite longueur d’onde permettant un couplage du rayonnement guidé par la première fibre optique vers la deuxième fibre optique et/ou de la deuxième fibre optique vers la première fibre optique. Figure pour l’abrégé : [Fig.3] Coupling device (D) for optical fibers comprising: a first hollow-core optical fiber (FO1) with inhibited coupling comprising a first microstructured sheath (SCF1) comprising a plurality of first confining tubular pattern (MCF1), distributed in a ring and surrounding, at least partially, a first core (C1) so as to confine at least one radiation at a wavelength in said first core,a second hollow-core optical fiber (FO2) with inhibited coupling, comprising a second ...

Compact three-frequency resonant optical gyroscope

A passive resonant optical gyroscope comprising a cavity and operating with three frequencies comprises: a first injecting laser to inject a first optical beam into the cavity in a first direction; a second injecting laser to inject a second optical beam into the cavity in an opposite direction; a third injecting laser to inject a third optical beam into the cavity in one of the aforementioned directions, one laser amongst the injecting lasers having a master frequency, the two other injecting lasers, called the first and second slave lasers, respectively having a first slave frequency and a second slave frequency; a master servocontrol device; a first servocontrol stage comprising first and second slave devices; and a second servocontrol stage comprising first and second optical phase-locking devices respectively comprising a first and second slave oscillator to generate a first radiofrequency offset signal and a second radiofrequency offset signal.

DEVICE FOR OPTICALLY RECEIVING A SIGNAL FROM A PHASE CONTROL ANTENNA ARRAY AND ASSOCIATED ANTENNA SYSTEM

L'invention concerne un dispositif de réception optique (16) d'un signal d'un réseau antennaire (12) comportant : - une source lumineuse (62) générant une porteuse optique et M faisceaux optiques en phase et décalés en fréquence par rapport à la porteuse optique, - un circuit de collection (64) comportant N voies (74) reliées à une antenne (18), et comportant un modulateur (78) d'un signal incident, - un réseau de formation de faisceaux (66) reliant (M+1) premiers ports (86) à N deuxièmes ports (88) reliés à une voie (74), M premiers ports (90) étant reliés aux faisceaux optiques et un port de contrôle (92) relié aux autres ports (86, 88) de sorte qu'une intensité optique maximale sur le port de contrôle (92) corresponde à des signaux en phase sur les N deuxièmes ports (88). The invention relates to a device for optical reception (16) of a signal of an antenna array (12) comprising: - a light source (62) generating an optical carrier and M optical beams in phase and frequency-shifted with respect to the optical carrier, - a collection circuit (64) having N channels (74) connected to an antenna (18), and comprising a modulator (78) of an incident signal, - a beam forming network (66) connecting (M + 1) first ports (86) at N second ports (88) connected to a channel (74), M first ports (90) being connected to the optical beams and a control port (92) connected to the other ports (86) , 88) so that a maximum optical intensity on the control port (92) corresponds to in-phase signals on the N second ports (88).

GYROLASER WITH SOLID CONDITION AND RING OPTICAL CAVITY AMPLIFIER

Le gyrolaser à milieu amplificateur à état solide (MAES) et à cavité optique en anneau (COA), comprend un ensemble (EE) englobant la cavité optique (COA) et apte à subir un mouvement de rotation oscillant, ainsi qu'au moins un dispositif optique externe d'injection longitudinale d'énergie (DEOILE) dans le milieu amplificateur à état solide (MAES). Le gyrolaser comprend également un ensemble de fixation (EF) adapté pour rendre solidaire en translation et en rotation ledit ensemble (EE) englobant la cavité optique et ledit dispositif optique externe d'injection longitudinale d'énergie (DEOILE). The solid state amplifier (MAES) and ring optical cavity (COA) gyrolaser comprises an assembly (EE) encompassing the optical cavity (COA) and capable of undergoing an oscillating rotational movement, as well as at least one external optical longitudinal energy injection device (DEOILE) in the solid state amplifier medium (MAES). The laser gyro also comprises an attachment assembly (EF) adapted to render said translation unit (EE) integral in translation and in rotation, encompassing the optical cavity and said external optical longitudinal energy injection device (DEOILE).

Laser doubler modular laser architecture comprises folded construction active laser regions single pump beam fed using progressive reflections

The laser beam architecture has several active laser regions (5a,5b) placed in an optical cavity. The laser architecture is folded, a single pump beam is progressively reflected to cover each of the active laser regions.

Optical amplification device

Disclosed is an optical amplification device comprising an amplifier medium inserted between two mirrors and an optical pumping source. The mirrors are confocal mirrors whose focal plane is located in the vicinity of the center of the non-linear medium. This medium has a match-stick shape with a large axis in one direction forming an angle alpha/2 with the optical axis of the cavity defined by the two mirrors and the amplifier medium. This architecture enables an incident optical wave to pass several times within the amplification device leading to an increase in the performance characteristics of said device.

OPTICAL BEAM SHAPING SYSTEM

OPTICAL AMPLIFICATION DEVICE

Solid-state gyrolaser stabilised by acousto-optical devices

Le domaine de l'invention est celui des gyrolasers à état solide. Un des problèmes majeurs inhérents à cette technologie est que la cavité optique de ce type de laser est par nature fortement instable. Pour réduire cette instabilité, l'invention propose d'introduire dans la cavité (1) des pertes optiques contrôlées dépendantes du sens de propagation par la mise en oeuvre de dispositifs acousto -optiques. Plusieurs dispositifs sont décrits mettant en oeuvre différentes configurations de dispositifs acousto-optiques. Ces dispositifs s'appliquent notamment aux lasers à cavités monolithiques et, en particulier, aux lasers de type Néodyme-YAG.

Stabilised solid-state laser gyroscope

A major problem with solid-state laser gyroscopes is that the optical cavity is by its nature very unstable. According to the invention, this instability may be reduced by the introduction of controlled optical losses into the cavity (1), dependent on the direction of propagation, by means of providing an optical unit comprising a polarising element (71), a first element with a reciprocal effect (7), acting on the polarisation of the waves and a second element with a non-reciprocal effect (8), also acting on the polarisation of the wave, whereby at least one of the two effects is variable and said losses are electronically controlled to follow the intensity difference between the counter-propagating effects. Several devices are disclosed using either fixed reciprocal effects and variable non-reciprocal effects or vice versa. Said devices are of application to monolithic cavity lasers and in particular lasers of the Neodymium-YAG type as well as lasers with a fibre cavity.

SEMICONDUCTOR SOLID SOLID GYROLASER WITH VERTICAL STRUCTURE

Le domaine de l'invention est celui des gyrolasers à état solide utilisés dans les centrales inertielles. Ce type d'équipement est notamment utilisé pour les applications aéronautiques.Il est possible de réaliser un gyrolaser à état solide à partir de milieux semi-conducteurs pompés optiquement ou électriquement. Les gyrolasers actuels de ce dernier type sont monolithiques et sont de dimensions réduites. Ils ne permettent pas d'une part d'atteindre des précisions comparables à celles des gyrolasers gazeux et d'autres part d'implémenter des méthodes optiques pour supprimer le couplage en fréquence à faibles vitesses de rotations ou les dérives en température.L'objet de l'invention est un gyrolaser à état solide comportant un milieu semi-conducteur et constitué d'éléments discrets assemblés, offrant ainsi la possibilité de réaliser des cavités de grande dimension permettant d'atteindre les précisions voulues.Plus précisément, le gyrolaser comporte une cavité optique en anneau et un milieu amplificateur semi-conducteur à cavité externe à structure verticale comportant un empilement de zones de gain planes et parallèles entre elles, les dimensions de la cavité étant sensiblement supérieures à celles du milieu amplificateur, ledit milieu amplificateur étant utilisé en réflexion. The field of the invention is that of solid state gyrolasers used in inertial units. This type of equipment is used in particular for aeronautical applications. It is possible to produce a solid state laser gyro from optically or electrically pumped semiconductor media. Current gyrolasers of the latter type are monolithic and have small dimensions. On the one hand, they do not make it possible to achieve precision comparable to those of gaseous laser gyros and on the other hand to implement optical methods to eliminate frequency coupling at low rotational speeds or temperature drifts. of the invention is a solid state laser gyro comprising a semiconductor ...

OPTICAL BEAM SHAPING SYSTEM

The invention concerns an optical beam-shaping system comprising: a first segment with parallel faces (L1) whereof the surfaces (10 and 11) are reflecting towards the segment inside such that various portions of the incident optical beam (F1) in a first input zone perform different numbers of reflection between the two faces and those various beam portions are offset in mutually parallel planes in first output zones; a second segment with parallel faces (L2) whereof the surfaces are likewise reflecting towards the segment inside such that on receiving in the second input zones the various beam portions transmitted by the first segment, said various portions perform different numbers of reflection between the two faces and are offset in second output zones, parallel to said planes so as to be aligned along a direction perpendicular to said planes. The invention is useful for coupling a laser source to an optical fibre.

Pumped laser and optimized lasing medium

A longitudinally pumped laser including one or more active lasing media arranged in an optical laser cavity and at least one pumping device emitting at least one pumping beam toward the at least one active lasing medium. The pumped beam or beams is coupled with the active medium. At least one of the active lasing media includes one or more non-homogeneously doped zones, and the dimension of the doped zones and/or the distribution of the dopants is chosen on the basis of the desired transverse mode of the laser cavity. Such a laser can be used as an amplifier.

GUIDED PROPAGATION OPTICAL AMPLIFICATION DEVICE AND MANUFACTURING METHOD

Methode d'asservissement d'un dispositif optique comprenant un laser et une cavite permettant de compenser une modulation d'amplitude introduite par un modulateur de phase

Méthode d'asservissement d'un dispositif optique comprenant une cavité (C) présentant une résonance autour d'une fréquence centrale f c , un laser (L) et un modulateur de phase (PM), ladite méthode étant adaptée pour asservir ladite cavité (C) sur ledit laser (L) ou réciproquement et pour compenser une modulation d'amplitude introduite par ledit modulateur de phase (PM), ladite méthode comprenant entres autres, les étapes suivante : A. Faire varier un écart δv entre la fréquence optique du rayonnement laser et ladite fréquence centrale de manière à ce que ladite fréquence optique balaye ladite résonance, ledit écart étant contrôlé par un paramètre d'un élément dudit dispositif, et pour chaque écart δvi i. Moduler, à une fréquence de modulation f mod , une phase dudit rayonnement laser, par une phase de modulation Φ pmod , avec le modulateur de phase (PM), ii. Injecter le rayonnement modulé en phase dans ladite cavité (C), iii. Détecter, par une photodiode (PD t , PD r ), un rayonnement réfléchis ou transmis par ladite cavité et générer un signal électrique (St, Sr) représentatif de l' intensité dudit rayonnement détecté, iv. Démoduler ledit signal électrique à ladite fréquence de modulation f mod en générant de manière synchrone un premier signal démodulé et un deuxième signal démodulé représentatif du signal électrique démodulé, respectivement à une première phase de démodulation et à une deuxième phase de modulation ϕ dem,2 ϕ dem,2 ≈ ϕ dem,1 k , avec k ϵ [0; 2TT] différente de ladite première phase et en filtrant le premier et le deuxième signal de manière à conserver uniquement une composante continue du premier signal démodulé Vϵ 1 dit signal d'erreur 1 et du deuxième signal démodulé Vϵ 2 , dit signal d'erreur 2

Festkörperlaserkreisel mit optisch kontrollierter pumpfunktion.

Dispositif de couplage pour fibres optiques a coeur creux comprenant un element de couplage

Dispositif (D) de couplage pour fibres optiques comprenant : - une première fibre optique (FO1) à cœur creux à couplage inhibé comprenant une première gaine microstructurée (SCF1) comprenant une pluralité de premier motif tubulaire confinant (MCF1), répartis en anneau et entourant, au moins partiellement, un premier cœur (C1) de manière à confiner au moins un rayonnement à une longueur d'onde λ ορ dans ledit premier cœur, - une deuxième fibre optique (FO2) à cœur creux à couplage inhibé, comprenant une deuxième gaine microstructurée (SCF2) comprenant une pluralité de deuxième motif tubulaire confinant (MCF2), répartis en anneau et entourant, au moins partiellement, un deuxième cœur (C2) de manière à confiner ledit rayonnement lumineux dans ledit deuxième cœur, - un élément couplant (SCP) agencé entre le premier et le deuxième cœur, ledit élément couplant comprenant au moins un motif tubulaire couplant (MCP, MCP1, MCP2, MTa) compris au moins partiellement dans ladite première gaine microstructurée et/ou ladite deuxième gaine microstructurée et présentant une épaisseur de paroi tcp dite épaisseur de couplage et un indice de matériau n cp dit indice de couplage, un agencement de l'élément couplant, l'épaisseur de couplage t cp et l'indice de couplage ncp étant adaptés de manière à créer un canal de fuite pour ladite longueur d'onde λ ορ permettant un couplage du rayonnement guidé par la première fibre optique vers la deuxième fibre optique et/ou de la deuxième fibre optique vers la première fibre optique.

Method for servocontrolling an optical device comprising a laser and a cavity, making it possible to compensate for an amplitude modulation introduced by a phase modulator

A method for the servo control of an optical device includes a cavity exhibiting resonance around a center frequency ƒ c , a laser and a phase modulator, the method being designed to servo-control the cavity to the laser or vice versa and to compensate for an amplitude modulation introduced by the phase modulator, the method comprising, inter alia, the following steps: A. varying a difference δν between the optical frequency of the laser radiation and the center frequency, such that the optical frequency scans the resonance, the difference being controlled by a parameter of an element of the device, and for each difference δν i i. modulating, at a modulation frequency ƒ mod , a phase of the laser radiation, through a modulation phase ϕ mod , with the phase modulator, ii. injecting the phase-modulated radiation into the cavity, iii. using a photodiode to detect radiation reflected or transmitted by the cavity and generating an electrical signal (St, Sr) representative of the intensity of the detected radiation, iv. demodulating the electrical signal at the modulation frequency ƒ mod by synchronously generating a first demodulated signal and a second demodulated signal representative of the demodulated electrical signal, respectively at a first demodulation phase ϕ dem,1 and at a second modulation phase ϕ dem,2 ϕ dem,2 ≈ϕ dem,1 k, where k∈[0; 2π] is different from the first phase, and by filtering the first and the second signal so as to retain only a DC component of the first demodulated signal Vϵ 1 , called error signal 1, and of the second demodulated signal Vϵ 2 , called error signal 2.

Convertisseur de faisceau d'onde et son procede de fabrication

Un faisceau d'onde est employé de manière d'autant plus efficace que son étendue géométrique est proche de la symétrie de révolution. Pour cela, un système peut utiliser un convertisseur d'un ou plusieurs paramètres d'un faisceau d'onde comportant N sous-faisceaux (N entier ≥ 1), caractérise en ce qu'il comporte au moins un matériau massif comportant au moins: une première extrémité comportant au moins N entrées, chacun des N sous-faisceaux étant reçu par l'une des N entrées, et une deuxième extrémité comportant au moins une sortie délivrant le faiceau dont le ou les paramètres de conversion ont une ou des valeurs prédéterminées. Le paramètre converti peut être l'étendue géométrique afin de satisfaire la condition d'efficacité.

Convertisseur de faisceau d'onde et son procede de fabrication

Un faisceau d'onde est employé de manière d'autant plus efficace que son étendue géométrique est proche de la symétrie de révolution. Pour cela, un système peut utiliser un convertisseur d'un ou plusieurs paramètres d'un faisceau d'onde comportant N sous-faisceaux (N entier ≥ 1), caractérise en ce qu'il comporte au moins un matériau massif comportant au moins: une première extrémité comportant au moins N entrées, chacun des N sous-faisceaux étant reçu par l'une des N entrées, et une deuxième extrémité comportant au moins une sortie délivrant le faiceau dont le ou les paramètres de conversion ont une ou des valeurs prédéterminées. Le paramètre converti peut être l'étendue géométrique afin de satisfaire la condition d'efficacité.

Coupling device for coupling hollow-core optical fibres comprising a coupling element

A device for coupling optical fibers, includes a first coupling-inhibited hollow-core optical fiber comprising a first microstructured cladding comprising a plurality of first confining tubular features distributed in a ring and encircling, at least partially, a first core so as to confine at least radiation at a wavelength λop to the first core, a second coupling-inhibited hollow-core optical fiber comprising a second microstructured cladding comprising a plurality of second confining tubular features distributed in a ring and encircling, at least partially, a second core so as to confine the light radiation to the second core, a coupling element arranged between the first and second cores, the coupling element comprising at least one coupling tubular feature comprised at least partially in the first microstructured cladding and/or the second microstructured cladding and having a wall thickness tcp called the coupling thickness and a material index ncp called the coupling index, an arrangement of the coupling element, the coupling thickness tcp and the coupling index ncp being configured so as to create a leakage channel at the wavelength λop allowing the radiation guided by the first optical fiber to be coupled to the second optical fiber and/or the radiation guided by the second optical fiber to be coupled to the first optical fiber.

Optical passive resonator gyro with three beams

The general field of the invention is that of passive resonator gyros comprising an injection laser emitting an initial optical beam at a first frequency and a fiber optic cavity. The gyro according to the invention operates with three optical beams at three different optical frequencies. A first beam is injected in a first direction of rotation, the second and the third beam are injected in the contrary direction. The gyro includes three slaving devices maintaining each optical frequency at a specific mode of resonance of the cavity. The gyro includes means for measuring the frequency differences existing between the different frequencies. Combined together, these differences are representative of the length of the cavity and the angular rotational velocity of the cavity along an axis perpendicular to its plane.