Abstract: Systems and methods are described for transmitting information optically. For instance, a system may include an optical source configured to generate a beam of light. The system may include at least one modulator configured to encode data on the beam of light to produce an encoded beam of light/encoded plurality of pulses. The system may include a spectrally-equalizing amplifier configured to receive the encoded beam of light/encoded plurality of pulses from the at least one modulator and both amplify and filter the encoded beam of light/encoded plurality of pulses to produce a filtered beam of light/filtered plurality of pulses, thereby spectrally equalizing a gain applied to the encoded beam of light. In some cases, the system may slice the beam of slight, to ensure a detector has impulsive detection. In some cases, the system may include a temperature controller to shift a distribution curve of wavelengths of the optical source.

Abstract: Some embodiments provide a method for separating the motion detection zone(s) of an A/V recording and communication device from the motion alert zone(s) of the A/V recording and communication device. For example, an A/V recording and communication device may be configured to generate motion alerts, and to record audio and video footage, when an event is detected within a selected motion alert zone (e.g., within a defined radius around the A/V recording and communication device). However, the A/V recording and communication device may not generate a motion alert for an event detected outside of the selected motion alert zone, even though the device may still record audio and video footage for the detected event (e.g., when the event is within a selected motion detection zone).

Abstract: An optical microtoroid resonator including one or more nanoparticles attached to a surface of the resonator and capable of receiving an input signal from a far-field source (via free-space transmission) and outputting light propagating within the optical apparatus. A method for coupling light into and out of an optical resonator using a nanoparticle or nanoparticles to interface with spatially separated far-field optical elements.

Abstract: A waveguide optical gyroscope (WOG) is disclosed, which may include: an emitter; an integrated interferometer disposed on a silica planar lightwave circuit (PLC) and comprising a multilayer waveguide loop disposed in a first cladding material and interposed between layers of at least a second cladding material having an index of refraction lower than an index of refraction of the first cladding material; a pump source configured to pump the first cladding material with a signal that compensates for a propagation loss in the multilayer waveguide loop; and a micro-optic component configured to receive an output of the emitter and to guide the output into the integrated interferometer.

Abstract: A ring laser gyroscope is provided. A light source is configured to generate light of a first wavelength. A plurality primary cavity mirrors are configured to route light of a second wavelength around a primary cavity to a readout device. One primary cavity mirror of the plurality of primary cavity mirrors includes a gain medium. The pumping mirror and the one primary cavity mirror including the gain medium is positioned and configured to reflect the light of the first wavelength back and forth in a pumping cavity through the gain medium, wherein the light of the first wavelength stimulates the gain medium to generate the light of the second wavelength that are reflected around the primary cavity to the readout device.

Abstract: 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.

Abstract: A dynamic optical microphone system may include an acoustic microphone that receives an audio signal and a laser microphone that transmits a laser beam and receives optical feedback from a human struck by the laser beam. The system may include a depth sensor that determines a distance to the human and a camera that tracks human faces. A processor may be communicatively coupled to the acoustic microphone, laser microphone, depth sensor, camera, and a memory storing computer executable instructions. The processor may determine a direction to a human, direct the laser beam at a voice box of the human, determine a distance to the human using the depth sensor, adjust an intensity of the laser beam based on the distance, receive optical feedback and isolate a voice signal through the optical feedback from background noise in the audio signal.

Abstract: A method for determining an operational characteristic of a vibrating structure gyroscope having a movable mass includes: driving the mass to oscillate along a first, predefined path; rotating the vibrating structure gyroscope so as to oscillate the mass along a second path, wherein the second path is different to the first, predefined path; sensing the oscillation of the mass along the second path so as to generate a sensing signal; converting the sensing signal into an in-phase signal and an out-of-phase signal using a demodulator, wherein the in-phase signal is in phase with the oscillation of the mass along the first path, and the out-of-phase signal is out of phase with the in-phase signal.

Abstract: According to one aspect, a multi-heterodyne system is disclosed, which comprises a first laser source for generating multi-mode radiation having a frequency spectrum characterized by a first plurality of phase coherent frequencies, and a second laser source for generating multi-mode radiation having a frequency spectrum characterized by a second plurality of phase coherent frequencies. The system further comprises at least one detector for detecting a combination of the multi-mode radiation generated by the first and second laser sources so as to provide a multi-heterodyne signal having a frequency spectrum characterized by a plurality of beat frequencies, each beat frequency corresponding to a pairwise difference in the first and second plurality of phase coherent frequencies.

Abstract: Bias error in a resonant fiber optic gyroscope (RFOG) is diminished by reducing polarization mismatch between a polarization Eigenstate of optical signals propagating inside of a resonator of the RFOG and the polarization of optical signals being injected into the resonator of the RFOG. The polarization mismatch is reduced by filtering the optical signals circulating in the resonator and the optical signals injected into the resonator with common polarizers.

Abstract: A transmitting optical module that includes multi-laser diode (LDs) and a planar lightwave circuit (PLC) to multiplex optical beams each output from the optical sources is disclosed. The PLC is mounted on a carrier through a WG carrier in upside down arrangement. The LDs are also mounted on the carrier through an LD carrier. The LDs and the PLC are optical coupled with two lenses each having respective optical axes offset from the other such that the optical coupling of the optical beam inputting the PLC becomes a maximum.

Abstract: A laser apparatus has a gain medium which has opposite ends, wherein the laser apparatus includes at least two independently controllable excitation sources, each one of the excitation sources being operable to produce an input beam to excite or pump the gain medium. Beam splitting arrangements are associated with the excitation sources are configured to split the input beam of its associated excitation source into at least two sub-beams. Beam guiding arrangements are associated with the excitation sources and are configured to direct a path of at least one of the split sub-beams from its associated excitation source, whereby each excitation source, its associated beam splitting arrangement, and beam guiding arrangement are arranged such that the sub-beams are respectively directed inwardly towards the gain medium at opposite ends.

Abstract: Systems and methods for dynamic PLC modulation are provided. In certain embodiments, a gyroscope system includes a block having cavities and passages that define a path; mirrors, each located in one of the cavities, direct light along the path defined by the cavities and the passages; a mirror drive coupled to one of the mirrors to change a position of the mirror, wherein the path's length is changed as the mirror's position changes; a photodetector that measures power of light along the path; and a controller that provides a control signal indicative of an amplitude of PLC modulation and a PLC frequency to the mirror drive; wherein the mirror drive, in response to the control signal, changes the position of the mirror at the frequency, wherein the mirror drive moves based on the amplitude; and wherein the controller changes the amplitude in relation to the measured power of the light.

Abstract: A semiconductor device that includes an optical resonator spaced from a waveguide structure to provide for evanescent-wave optical coupling therebetween. The optical resonator includes a closed loop waveguide defined by an epitaxial layer structure that includes at least one quantum well. The semiconductor device also includes circuitry configured to supply an electrical signal that flows within the epitaxial layer structure of the closed loop waveguide. The electrical signal affects charge density in at least quantum well of the closed loop waveguide and controls refractive index of the closed loop waveguide. In one embodiment, the electrical signal is a DC current signal that flows within a vertical thyristor structure of the closed loop waveguide to control refractive index of the closed loop waveguide such that resonance frequency of the closed loop waveguide corresponds to a characteristic wavelength of light.

Abstract: A RFOG, comprising: a master laser emitting a reference optical signal; first and second slave lasers emitting first and second optical signals; an optical resonator ring cavity coupled to the lasers, the first and second optical signals propagating in first and second directions through the optical resonator ring cavity; one or more signal generators to inject first and second modulation signals at first and second frequencies on both optical signals; first and second photodetectors that generate first and second signals; first and second demodulators to demodulate the first and second signals using first and second reference signals and the first and second frequencies; a differencing function to output the difference between resonance frequencies of the first and second signals; at least a third demodulator to detect reference phase errors; and at least one phase servo to adjust the phase of at least one of the first and second reference signals.

Abstract: A ring laser gyroscope (RLG) assembly comprises an RLG block comprising: a first anode; a second anode; a cathode; and a cavity. The RLG assembly further comprises a current supply circuit coupled to the RLG block. The current supply circuit comprises a high voltage power supply to provide a high voltage signal; a first current path coupled between the high voltage power supply and the first anode to provide a first current to the first anode; and a second current path coupled between the high voltage power supply and the second anode to provide a second current to the second anode. The second current path is configured to mirror the first current such that the second current approximately matches the first current. Each component in the second current path is configured to operate based on power derived only from the high voltage signal.

Abstract: Systems and methods for a ring laser gyroscope with electrically isolated dither motor are provided. In one embodiment, a ring laser gyroscope, the gyroscope comprises: a laser block comprising a discharge gas filled chamber ring, a cathode, an anode and at least one other electrode; a dither motor mechanically coupled to the laser block and to a sensor chassis, wherein the laser block is secured to the sensor chassis by the dither motor; and an electrical isolator positioned between the dither motor and the laser block, wherein the electrical isolator electrically isolates the dither motor from the sensor chassis.

Abstract: A Fabry-Perot etalon is provided with first and second partially reflecting mirrors (12, 14) attached to a cuboidal spacer (16). The spacer (16) has a cylindrical bore (18) through its center and the mirrors (12, 14) are bonded, on axis, to opposite ends of this bore (18). Four support elements (22-28) are arranged symmetrically with respect to the axis in a tetrahedral configuration and constrain the cuboidal spacer (16) in all degrees of freedom. The cuboidal spacer (16) is flattened at its vertices, which results in modified distortion of the spacer (16) under the action of a compressive force acting through the supports. This structure of etalon provides insensitivity to inertial forces due to acceleration in all six degrees of freedom (three linear and three rotational) simultaneously with insensitivity to differential forces.

Abstract: In one aspect, the present disclosure provides a processor-implemented method of determining a bias for an axis of a gyroscope. The method includes: obtaining a temperature reading; maintaining a plurality of bias estimators for the axis, each bias estimator associated with a temperature and configured to estimate a bias at the associated temperature, the plurality of bias estimators including a number of short term bias estimators for estimating biases for recently obtained temperatures and a number of long term bias estimators for estimating biases for temperatures obtained over a comparatively longer period of time; and determining a bias for the axis of the gyroscope based on the temperature reading and one or more of the bias estimators.

Abstract: A monolithic semiconductor device that includes a waveguide structure optically coupled to an optical resonator. The optical resonator is adapted to process light at a predetermined wavelength. The optical resonator includes a closed loop waveguide having a plurality of straight sections that are optically coupled together by bend sections.

Abstract: Systems and methods for controlling the optical path length between a feedback enabled laser and a cavity, and hence the optical feedback phase. A phasor element, positioned along an optical path between the laser and the cavity coupling mirror, includes a gas medium within a volume defined by the phasor element. The phasor element is configured to adjust or control an optical path length of the laser light between the laser and the cavity coupling mirror by adjusting or controlling a density of the gas medium within the phasor volume.

Abstract: Systems for determining differential and average temperatures from resistive temperature devices are provided. In one embodiment, a device comprises a bridge network including a first node and second node, wherein the first node receives a constant current from a current source; a first branch coupled between a first node and a second node, the first branch including a first temperature sensing element of a first resistive temperature device; a second branch coupled in parallel with the first branch between the first node and the second node, the second branch including a second temperature sensing element of a second resistive temperature device; a first output that provides a signal representing a difference between a voltage developed across the first temperature sensing element and a voltage developed across the second temperature sensing element; and a second output that provides a signal representing a voltage developed across first node and the second node.

Abstract: An interferometer is disclosed, such as may be incorporated into a hand-held spectrometer. The interferometer comprises enclosed path optics and a detector, the enclosed path optics comprise at least two reflecting elements and a beamsplitter, the beamsplitter is arranged to divide an input beam into first and second beams. The enclosed path optics are arranged to direct the first and second beams in opposite directions around paths enclosing an area and to output the first and second beams towards the detector. The enclosed path optics also focus the first and second beams onto the detector. The detector is arranged to detect a pattern produced by interference of the first and second beams. In a preferred embodiment the two reflecting elements are a pair of concave mirrors, and the enclosed path optics enclose a triangular area. The use of concave mirrors for both reflection and focussing provides the interferometer with compactness.

Abstract: A ring laser gyroscope configured to reduce alignment shifts in at least one critical alignment of the ring laser gyroscope is provided. The ring laser gyroscope includes reflective components configured to direct clockwise optical beams and counter-clockwise optical beams in at least one lasing plane; at least one ring-laser-gyro mounting feature having at least one respective through hole; and at least one minimally-threaded screw positioned in the at least one respective through hole. An unthreaded section of the minimally-threaded screw is contactlessly encased in the at least one respective through hole. A threaded-end of the at least one minimally-threaded screw is threaded in a respective at least one threaded hole in a gyro frame, the gyro frame spanning a reference mounting plane.

Abstract: The invention pertains to a frame element of a laser gyroscope comprising a substrate comprising mobile ions and an electrode fixed to the said substrate, comprising at least one electrically conducting element, connected electrically to the said electrode, and furnished with at least one distal part integrated into the said substrate and exhibiting at least one tip and/or at least one groove, forming at least one blind hole and/or at least one groove in the said substrate, of shape corresponding to that of the said distal part or parts, so as to obtain a tip effect.

Abstract: A ring laser gyro with no piezoelectric elements for dither detection includes a laser beam receiving unit for receiving a laser beam taken out of a gyro block, a laser beam intensity measuring unit for measuring the intensity of the laser beam received by the laser beam receiving unit, a dither mechanism, a dither control unit for driving the dither mechanism, and a gyro case housing the gyro block, wherein the laser beam receiving unit is secured to the gyro case, the laser beam receiving unit has a laser beam receiving surface for receiving the laser beam from the gyro block to detect a laser beam receiving position on the laser beam receiving surface and output positional information indicating the laser beam receiving position. The dither control unit drives the dither mechanism on the basis of information indicating the amplitude of the laser beam receiving position obtained from the positional information.

Abstract: A fiber-optic interferometer comprising an optical fiber wound to form a fiber coil into which two partial light beams of a first light source can be coupled. The Bragg structure is integrated into the fiber coil. Said Bragg structure comprises an optical fiber having a periodically varying refractive index. In a method for determining physical state parameters in the interior of a fiber coil of a fiber optic interferometer information about physical state parameters in the interior of the fiber coil is obtained on the basis of the reflection wavelength of a Bragg structure comprising an optical fiber having a periodically varying refractive index is integrated into the fiber coil.

Abstract: The present invention provides a laser processing method comprising the steps of attaching a protective tape 25 to a front face 3 of a wafer 1a, irradiating a substrate 15 with laser light L while employing a rear face of the wafer 1a as a laser light entrance surface and locating a light-converging point P within the substrate 15 so as to form a molten processed region 13 due to multiphoton absorption, causing the molten processed region 13 to form a cutting start region 8 inside by a predetermined distance from the laser light entrance surface along a line 5 along which the object is intended to be cut in the wafer 1a, attaching an expandable tape 23 to the rear face 21 of the wafer 1a, and expanding the expandable tape 23 so as to separate a plurality of chip parts 24 produced upon cutting the wafer 1a from the cutting start region 8 acting as a start point from each other.

Abstract: An all-fiber interferometric fiber optic gyroscope having a minimum reciprocal configuration is described. The gyroscope comprises a polarized light source, a light detector, a light source coupler, a fiber optic loop coupler, and a polarization maintaining fiber optic loop. A first port of the light source coupler is counter-axially coupled to an output end of the polarized light source, and a second port of the light source coupler on the same side as the first port is coupled to the light detector. A third port on the other side of the light source coupler is counter-axially coupled to the fiber optic loop coupler, and the fiber optic loop coupler is counter-axially coupled to the polarization maintaining fiber optic loop. The light source splits the input polarized light and polarizes the optical signal propagated along a transmission arm alone, where the first and third ports are on the same transmission arm.

Abstract: An exemplary resonator fiber optic gyroscope comprises a resonator having an optical fiber loop; a light source configured to generate a light beam; and an intensity modulation circuit coupled between the light source and the resonator. The intensity modulation circuit is configured to modulate the intensity of the light beam from the light source to output an intensity modulated signal to the resonator. The intensity modulation circuit is configured to produce the intensity modulated signal such that harmonics of the intensity modulated signal which overlap a primary wave of a counter-propagating light beam in the resonator have an amplitude below a predetermined threshold. Amplitudes below the predetermined threshold are negligible.

Abstract: A temperature sensor package includes a temperature sensor having a first side and a second side, wherein the first side of the temperature sensor includes an active region configured for coupling with a target area for temperature measurement of an object. The temperature sensor package further includes a circuit board having a first side and a second side, the first side of the circuit board coupled to the second side of the temperature sensor, wherein the circuit board provides thermal insulation between the active region of the temperature sensor and an environment on the second side of the circuit board.

Abstract: A gyrolaser comprises: a ring-shaped optical cavity and a gaseous medium, and at least three electrodes in contact with the gas of the amplification medium, the electrodes generating charges when ignition voltage is applied; the cavity and distribution of the electrodes comprising at least one plane of symmetry perpendicular to the plane of the cavity and passing through the electrode of first type; at least one conductive ignition element set at a predetermined potential, the shape and arrangement being such that symmetry is maintained; the electrically conductive element generating an electric field locally for guiding the charges so they are distributed symmetrically in a first flow and second flow in the first and second discharge areas respectively when the ignition voltage is applied, in such a way that a first plasma and a second plasma are initiated simultaneously, respectively, in the first discharge area and in the second discharge area.

Abstract: In a laser gyroscope, an activation wheel has a polygonal cylindrical hub formed by continuous assembly of vertical walls, wherein two adjacent walls of the cylindrical hub between them form a dihedron. Each radial plate of the activation wheel is connected to the cylindrical hub along the edge of a dihedron. The walls are formed with bulging portions, serving for plane-to-plane fixing of one face of the tulip to an optical block, and thin parts allowing a radial displacement degree of freedom of the fixing parts relative to the rim when there is a differential thermal expansion between the tulip and activation wheel. The activation wheel may be produced in a material having a thermal expansion coefficient higher than the tulip, for example steel, with plane-to-plane fixing of the tulip to the activation wheel hub, advantageously by screws, the assembly effectively accommodating the thermal expansion differential between the two materials.

Abstract: The invention relates to a laser gyro that comprises an optical block comprising a glass-ceramic first material comprising apertures, electrodes placed in the apertures of the optical block, and seals) ensuring the hermeticity of the optical block in the location of the apertures. The seal comprises indium of a first redox potential. The laser gyro furthermore comprises, making contact with the seal, at least one sacrificial electrode comprising a second material of a second redox potential, the second redox potential being lower than the first redox.

Abstract: An optical gyroscope is provided for measuring a small angular difference. The gyroscope includes a laser, a pre-selection polarizer, a first beam splitter, a coil of optical fiber, a second beam splitter, a post-selection polarizer, a spectrometer and an analyzer. The laser emits a pulse beam of coherent photons. The beam has pulse duration ?. The pre-selection polarizer pre-selects the photons, and the first beam splitter separates the photons by their horizontal |+ and vertical |? polarization eigenstates. These beams are launched into a fiber optical coil of radius r, which preserves polarization. The coil rotates by a difference rotation angle ??. The second beam splitter recombines the polarized photon beams as they exit the coil. The post-selection polarizer post-selects the photons. The spectrometer captures the post-selected photons and measures the associated frequency translation ??.

Abstract: An all-fiber interferometric fiber optic gyroscope having a minimum reciprocal configuration is described. The gyroscope comprises a light source, a light detector, a light source coupler, a fiber optic loop coupler, and a polarization maintaining fiber optic loop. A first port of the light source coupler is coupled, with polarization axis alignment, to an output end of the light source, and a second port of the light source coupler on the same side as the first port is coupled to the light detector. A third port on the other side of the light source coupler is coupled, with polarization axis alignment, to the fiber optic loop coupler, and the fiber optic loop coupler is coupled, with polarization axis alignment, to the polarization maintaining fiber optic loop. The light source splits the input light and polarizes the optical signal propagated along a transmission arm alone, where the first and third ports are on the same transmission arm.

Abstract: Optical gyroscope devices based on optical whispering gallery mode resonators that measure rotations based on rotation-induced optical phase shift in optical whispering gallery mode resonators.

Abstract: Embodiments of the present invention provide improved systems and methods for external frit mounted components on a sensor device. In one embodiment, a method for fabricating a sensor device comprises securing at least one component stack on a sensor body over at least one opening in the sensor body, wherein the at least one component stack comprises a plurality of components and applying a frit to the plurality of components in the at least one component stack and the sensor body. The method further comprises heating the frit, the at least one component stack, and the sensor body such that the frit melts and cooling the frit, the at least one component stack, and the sensor body such that the at least one component stack is secured to the sensor body.

Abstract: A laser gyro includes a cylindrical solid amplifier bar having an axis of revolution. The laser gyro also includes: an annular piezoelectric element for exciting said solid amplifier element at a predetermined frequency f, along said axis of revolution, said annular piezoelectric element being mounted fixed on one of the two end cross sections of the cylindrical solid amplifier bar so that its axis of revolution coincides with said axis of revolution of said cylindrical solid amplifier bar; and an annular dynamic counterweight mounted fixed on the free end cross section of said annular piezoelectric element so that its axis of revolution coincides with said axis of revolution of said cylindrical solid amplifier bar; said cylindrical solid amplifier bar being dimensioned so as to be considered nondeformable at said excitation frequency f.

Abstract: The invention pertains to a frame element of a laser gyroscope comprising a substrate comprising mobile ions and an electrode fixed to the said substrate, comprising at least one electrically conducting element, connected electrically to the said electrode, and furnished with at least one distal part integrated into the said substrate and exhibiting at least one tip and/or at least one groove, forming at least one blind hole and/or at least one groove in the said substrate, of shape corresponding to that of the said distal part or parts, so as to obtain a tip effect.

Abstract: A microfabricated optical gyroscope that utilizes a linear array of micron scale optical ring resonators closely spaced to allow evanescent coupling of electromagnetic fields in adjacent resonators. Within each resonator, the optical Sagnac effect produces a phase difference between clockwise and counterclockwise propagating light that is proportional to the inertial rotation rate perpendicular to the plane of the resonator. The disclosure enhances the overall sensitivity to rotations by varying the strengths of the evanescent coupling between resonators and/or the circumferences of the resonators. The size and coupling strengths control the optical interference between resonators.

Abstract: A temperature sensor package includes a temperature sensor having a first side and a second side, wherein the first side of the temperature sensor includes an active region configured for coupling with a target area for temperature measurement of an object. The temperature sensor package further includes a circuit board having a first side and a second side, the first side of the circuit board coupled to the second side of the temperature sensor, wherein the circuit board provides thermal insulation between the active region of the temperature sensor and an environment on the second side of the circuit board.

Abstract: A ring laser gyroscope (RLG) includes moveable minors and a Micro-Electro-Mechanical Systems (MEMS) actuator coupled to the moveable minors to cause a respective displacement thereof that induces a phase modulation on counter-propagating light beams relative to one another. The induced phase modulation creates an optical path difference between the counter-propagating light beams corresponding to a virtual rotation that reduces the lock-in of the RLG.

Abstract: A method and system for transmitting source light to a plurality of Sagnac interferometers includes a first directional coupler that splits the source light into a second light beam and a third light beam. The second light beam supplies light to a first Sagnac interferometer and the second light beam supplies light to a second directional coupler, and the first directional coupler also delivers light returning from the first Sagnac interferometer to a first detector that is used to indicate rotation of the first Sagnac interferometer. The second directional coupler splits the third light beam into a fourth light beam and a fifth light beam, and the fourth light beam supplies light to a second Sagnac interferometer. The second directional coupler delivers light returning from the second Sagnac interferometer to a second detector, and the second detector provides a signal indicative of rotation of the second Sagnac interferometer.

Abstract: The general field of the invention is that of gyrolasers comprising at least one ring-shaped optical cavity comprising at least three mirrors, a solid state amplifying medium pumped by a laser diode whose optical emission power is determined by a current supply source, the cavity and the amplifying medium being such that two so-called contra-rotating optical modes propagate in opposite directions to each other within the said optical cavity, the gyrolaser being a class B gyrolaser, the gyrolaser also comprising means of measuring the difference in optical frequency existing between the two optical modes. The gyrolaser comprises means of measuring the total optical power circulating in the optical cavity and first means 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 the relaxation frequency of the laser.

Abstract: A microlaser system, including a microlaser, having an elongated generally cylindrical substrate, a thin dopant film encircling at least a portion of the substrate, and a pumping laser positioned to shine onto the thin film. The thin film is between about 2 and about 10 microns thick. When the pumping laser shines on the thin film, the thin film lases in whispering gallery mode. The dopant is preferably selected from the group including transition metals and rare-earth elements. In a most preferred embodiment, the thin film is titanium-doped amorphous aluminum nitride.

Abstract: Solid-state gyrolaser having a device for stabilizing the intensities making it possible to maintain equilibrium of the two counter-propagating modes having at least a means for calculating a rotation measurement (?, I?) of the gyrolaser on the basis of the counter-propagating modes having a frequency difference (??mes) between them, by assuming that the frequency difference (??mes) between the two counter-propagating modes is induced only by the rotation of the cavity.

Abstract: A guided coherent atom source (1) includes elements for generating neutral atoms in a gaseous state (2), elements for cooling the atoms gas (3), elements for generating a magnetic field (4), including an electro-magnetic micro-chip (6) deposited on a surface (18) of a substrate (14), and capable of condensing the atoms in a magnetic trap, elements for generating an electro-magnetic RF field capable of extracting the condensed atoms, optical elements (10) for emitting and directing an optical coherent beam (12) toward the condensed atoms able to guide the condensed atoms, characterized in that the optical elements (10) and the electro-magnetic micro-chip (6) are integrated onto the same substrate (14). An atomic interferometer using such a source is also disclosed.

Abstract: In a laser gyroscope, an activation wheel has a polygonal cylindrical hub formed by continuous assembly of vertical walls, wherein two adjacent walls of the cylindrical hub between them form a dihedron. Each radial plate of the activation wheel is connected to the cylindrical hub along the edge of a dihedron. The walls are formed with bulging portions, serving for plane-to-plane fixing of one face of the tulip to an optical block, and thin parts allowing a radial displacement degree of freedom of the fixing parts relative to the rim when there is a differential thermal expansion between the tulip and activation wheel. The activation wheel may be produced in a material having a thermal expansion coefficient higher than the tulip, for example steel, with plane-to-plane fixing of the tulip to the activation wheel hub, advantageously by screws, the assembly effectively accommodating the thermal expansion differential between the two materials.

Abstract: Methods are disclosed wherein the structural health of a civil structure, such as, but not limited to, a bridge or the like is measured by electronic distance measurement (EDM) from a plurality of stable locations to a plurality of cardinal points on the structure in a methodical manner. By measuring the coordinates of the cardinal points, the dynamic and long-term static behavior of the structure provide an indication of the health of the structure. Analysis includes: comparison to a Finite Element Model (FEM); comparison to historical data; and modeling based on linearity, hysteresis, symmetry, creep, damping coefficient, and harmonic analysis.