Abstract: Described herein are isolated ring cavities that have refractive and heat-generating components physically separated and mechanically held by flexure mounts that are adapted to function in combination with the physically separated structure to moderate the thermal expansion effects of the heat generated by the refractive and other heat-generating elements (e.g., gain element) of the optical cavity. The flexure mounts may be configured as thinned portions of connective elements, reducing the effects of thermal expansion of the baseplate and allowing a thermal isolation from the baseplate. Multiple flexure mounts may be arranged to minimize further the effects of thermal expansion of the baseplate.

Abstract: A condition of at least one structural part (11?, 11?) of a working machine (10) is determined by detecting (201) a force of a changing magnitude to a first structural part (11?) or a structural part connecting the first structural part (11?) to the second structural part (11?), determining (203) a change in the position of the first structural part with respect to the second structural part as a function of the force detected, and determining (205) the condition on the basis of the change in the position of the first structural part with respect to the second structural part as a function of the force detected. At least a slope of the change in the magnitude of the force is detected.

Abstract: To isolate an active portion of a gyroscope resonator from mounting stresses propagating through a resonator attachment center, the resonator includes a stress isolation feature that includes alternating concentric symmetric regions of high and low stiffness. The resonator may be separated into a large number of thin, compliant spring elements and larger stiff mass elements, the aggregate areas of which optimized for an aggregate resonator spring constant (by selecting a width and a length of the spring elements), an aggregate mass (by selecting a size of the mass elements), a thermoelastic loss maximum (by selecting a width of the spring elements) and an operating frequency (by selecting a ratio of the aggregate spring to the aggregate mass).

Abstract: A ring laser gyroscope (RLG) block is provided. The RLG block includes a first corner bordered by a first portion of a first side and a first portion of a third side; a second corner bordered by a first portion of a second side and a second portion of the third side; and a third corner bordered by a second portion of the second side and a second portion of the first side. The first portion of the first side shifts the first corner laterally in a lasing plane of the RLG block, toward the second corner, and perpendicular to a first normal of a first mirror when a temperature change contracts the RLG block; and shifts the first corner laterally away from the second corner, and perpendicular to the first normal when the temperature change causes an expansion of the ring laser gyroscope block.

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: An apparatus, method and computer program wherein the apparatus includes at least one interferometer where the at least one interferometer is configured to cause interference of an electromagnetic input signal; wherein the at least one interferometer is configured to receive at least one sensor input signal from at least one sensor such that the sensor input signal controls the interference of the electromagnetic input signal by the at least one interferometer; wherein the at least one interferometer is configured to provide a plurality of outputs where each of the plurality of outputs is provided by the at least one interferometer responding to the at least one sensor input signal with a different sensitivity; and at least one detector configured to detect the plurality of outputs of the at least one interferometer and provide a digital output signal indicative of the at least one sensor input signal.

Abstract: A gyrolaser with optical cavity includes a plurality of mirrors, at least one photo-detector delivering two optical signals in phase quadrature, said signals being digitized, means for controlling the position of one of said mirrors by conversion of an electrical signal into a mechanical force, means for activating said gyrolaser in an oscillatory movement by conversion of an oscillation electrical signal into a mechanical force and means for measuring the angular velocity of said gyrolaser, and also includes: means for extracting the phase ? and the modulus ? or the square of the modulus ? from said optical signals; means for locking the length of the optical cavity; means for deriving said phase ? over a given period of time in order to produce a signal comprising the overall movement information for said gyrolaser; and means for locking the activation of said gyrolaser onto said oscillatory movement, receiving said signal, extracting from which an estimation of the oscillatory movement imparted on said gyr

Abstract: A method for detecting a complete or partial obstruction in a vessel through an intervening fluid includes receiving spectroscopic responses at different locations of a vessel wall, e.g., a vein or artery, through an intervening fluid, preferably blood. Spectroscopic responses are generated by irradiating the vessel wall at different locations and detecting spectra at those locations. In preferred embodiments, the radiation used is in the near infrared (NIR) region of the electromagnetic spectrum. The thrombus is located by determining whether fluctuations, spatial and/or spectral, of the spectral responses are indicative of thrombus.

Abstract: A RF-synchronization system includes a laser that creates pulse trains for synchronization. A modulation means transfers the timing information of the pulse train into an amplitude modulation of an optical or electronic system. A synchronization module changes the driving frequency of the modulation means until it reaches a phase-locked state with the pulse train.

Abstract: Dithering mechanism and method for eliminating the effects of zero-rate bias in a rate sensor or gyroscope. Both continuously moving and indexing embodiments are disclosed. The mechanism includes a first part mounted in a fixed position centered about a dither axis perpendicular to the input axis of the gyroscope, a second part disposed coaxially of the first part and affixed to the sensing element of the gyroscope, and a plurality of piezoelectrically driven quartz flexure beams extending radially between the first and second parts for dithering the second part about the dither axis. In some embodiments, the dithering mechanism is formed separately from and affixed to the sensing element of the gyroscope, and in others it is formed integrally with the sensing element.

Abstract: Dithering mechanism and method for eliminating the effects of zero-rate bias in a rate sensor or gyroscope. Both continuously moving and indexing embodiments are disclosed. The mechanism includes a first part mounted in a fixed position centered about a dither axis perpendicular to the input axis of the gyroscope, a second part disposed coaxially of the first part and affixed to the sensing element of the gyroscope, and a plurality of piezoelectrically driven quartz flexure beams extending radially between the first and second parts for dithering the second part about the dither axis. In some embodiments, the dithering mechanism is formed separately from and affixed to the sensing element of the gyroscope, and in others it is formed integrally with the sensing element.

Abstract: A ring laser gyroscope is described that includes at least one laser gyroscope block and a dither motor, where the gyroscope blocks are configured to engage the dither motor. The dither motor has an outer ring, a hub section, at least one radially extending reed extending between the outer ring and the hub section, and at least one piezoelectric transducer attached the reed. The piezoelectric transducer includes a common piezo-ceramic having a contiguous void line that allows for a separate electrical connection to be made to electrode surfaces on each side of the void line.

Abstract: Dither frequency analysis systems include a controller for directing a control signal and a dither frequency to an actuation driver. One or more sensors are used for receiving and relaying a signal downstream from an actuation element, which downstream signal includes the dither frequency. A frequency analysis device receives and analyzes the downstream dither frequency and directs the same to a controller that is configured to evaluate the analyzed downstream dither frequency, and evaluate whether the same indicates proper or improper actuation system operation. The downstream dither frequency is analyzed and evaluated at a frequency of less than about one second, and the frequency analysis device analyzes downstream dither frequencies in the range of from about 50 to 500 hertz. The system can include algorithms and test sequences to address and/or further evaluate improper actuation system operation.

Abstract: An actuating motion detection device for a mechanically actuated gyrolaser including at least one fastening ring coaxial with an actuation axis of the gyrolaser. The fastening ring includes a hub held at a center of a rim by radial flexible strips distributed about the hub, and the radial flexible strips are configured to act as springs and to vibrate under an actuating motion. The motion detecting device includes torsion detectors having a pair of piezoelectric plates disposed at a radial position along one radial flexible strip. The piezoelectric plates have respective remanent magnetic fields aligned in opposite directions, and each piezoelectric plate has two electrodes positioned on opposite sides of the piezoelectric plate with one of the two electrodes contacting the radial flexible strip. The electrodes are connected to a common output.