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By fiber or waveguide interferometer (e.g., Sagnac effect)

Subclass of:

356 - Optics: measuring and testing

356450000 - BY LIGHT INTERFERENCE (E.G., INTERFEROMETER)

356459000 - Rotation rate (e.g., ring laser gyros)

Patent class list (only not empty are listed)

Deeper subclasses:

Class / Patent application numberDescriptionNumber of patent applications / Date published
356461000 Resonant loop 21
356465000 Fiber coil winding 11
356464000 Having null feedback loop 9
356462000 Multi-axis (X-Y-Z) having multiplexing 3
20090015843FIBER OPTIC GYROSCOPE - A fiber optic gyroscope including an optical circulator in the path of said first and second beams for providing polarized first and second beams of identical polarization. A phase modulator couples the first and second beams to the first and second end respectively of the fiber loop, and couples for receiving the return first and second beams from the second and first ends respectively of the fiber loop. First and second photodiodes are coupled to the optical circulator for receiving the optical signal from the first and second return beams.01-15-2009
20090027684SEMICONDUCTOR RING LASER GYRO - A semiconductor ring laser gyro includes: a semiconductor laser for emitting light from each end of the gyro; at least one reflection prism comprising a plurality of reflection surfaces for forming an optical circuit, the at least one reflection prism adapted to receive and internally reflect the light emitted from the semiconductor laser; a transmissive mirror disposed at one of the plurality of reflection surfaces of the at least one reflection prism and adapted to transmit part of the light traveling clockwise and part of the light traveling counterclockwise through the optical circuit; and a beam multiplexing prism for multiplexing the light transmitted through the transmissive mirror.01-29-2009
20080291459Fiber optic gyroscope with integrated light source - An integrated module for a fiber optic gyroscope system includes a fiber optic sensing coil arranged to sense rotations about a sensing axis via the Sagnac effect comprises a substrate, an optical waveguide formed on the substrate, a light source comprising a doped waveguide formed on the substrate. The light source and the optical waveguide are arranged to produce counterpropagating light waves in the fiber optic sensing coil. The light source may be formed as a rare earth doped polymer waveguide or as a rare earth doped glass waveguide.11-27-2008
356463000 Multiple harmonic output 2
20100245834DETERMINATION OF OPTIMUM MODULATION AMPLITUDE TO SUPPRESS MODULATION-DISTORTATION-INDUCED ROTATION SENSING ERRORS IN A FIBER OPTIC GYROSCOPE - A method, implementable in a resonator fiber optic gyroscope (RFOG) having a first wave generator configured to produce a first resonance-detection modulating signal at a fundamental resonance frequency, includes generating with at least a second wave generator a second modulating signal at an even harmonic of the first modulating signal. The second signal is amplitude-modulated (AM) at a frequency that is harmonically unrelated to the first signal. The first signal is added to the second signal with a summing element to produce a resonator output bias error signal. An optimum amplitude is determined from the error signal. Subsequently, the amplitude of the first signal is controlled to the optimum amplitude.09-30-2010
20130135623DIGITAL SIGNAL PROCESSING METHOD AND DEVICE OF FIBER-OPTIC GYROSCOPE, AND FIBER-OPTIC GYROSCOPE - The present invention provides a signal processing method and device for the fiber-optic gyroscope, which can effectively expand the dynamic range of the fiber-optic gyroscope, improve the linearity of the scaling factor, and restrain the zero drift of the open-loop fiber-optic gyroscope, i.e., the dynamic fluctuation of the scaling factor. The fiber-optic gyroscope proposed by the present invention provides a first harmonic demodulation reference signal and a second harmonic demodulation reference signal, which are high in quality and synchronous in detection signal, to the signal processing device proposed by the present invention by the digital phase-locked loop technology.05-30-2013
Entries
DocumentTitleDate
20100039649OPTICAL SENSOR UTILIZING HOLLOW-CORE PHOTONIC BANDGAP FIBER WITH LOW PHASE THERMAL CONSTANT - An optical sensor includes an optical coupler. The optical sensor further includes a photonic bandgap fiber having a hollow core and an inner cladding generally surrounding the core. The photonic bandgap fiber is in optical communication with the optical coupler. Light signals counterpropagate through the photonic bandgap fiber and return to the optical coupler. The photonic bandgap fiber has a phase thermal constant S less than 8 parts-per-million per degree Celsius.02-18-2010
20100033729BIAS-INSTABILITY REDUCTION IN FIBER OPTIC GYROSCOPES - A computer-implementable method of reducing bias instability in a fiber optic gyroscope includes receiving, with a computer, a first data set enabling the computer to generate a model of the gyroscope, including a light source, a photodetector, and a plurality of optical components and fiber sections coupling the light source to the photodetector, and a light signal to be propagated from the light source to the photodetector. The light signal has an associated wavelength spectrum. For each wavelength of the spectrum, the relative lightwave intensity reaching the photodetector is calculated. A signal-wave intensity and a spurious-wave intensity are determined from the calculated relative lightwave intensities. A scale factor is determined from the signal-wave intensity. The spurious-wave intensity is integrated over the wavelength spectrum of the light source to obtain a total spurious-wave intensity. A rate bias error is determined based on the total spurious-wave intensity and the scale factor.02-11-2010
20100073681BIAS-REDUCED FIBER OPTIC GYROSCOPE - A fiber optic gyroscope includes a light source, a coupler coupled to the light source, a photodetector coupled to the coupler, an integrated optic circuit (IOC) coupled to the coupler by a first element, and a sensing loop coupled to the IOC by second and third elements. At least one of the first, second and third elements includes a polarizing element.03-25-2010
20130083327MEMS based Ring Laser Gyroscope with Reduced Lock-in - 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.04-04-2013
20130088720OPTICAL GYROSCOPE - 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. By using periodically alternating coupling strengths and/or linearly chirped resonator circumferences, the gyroscope transmission has extremely narrow transmission resonances with slopes, corresponding to the responsivity to inertial rotations, that are large enough to yield shot noise limited sensitivities sufficient for inertial navigation in a device size less the 1 mm04-11-2013
20090091763MICROGYROSCOPE - A new high-performance, compact microgyroscope is implemented using a microlaser such as a microsphere laser or a microdisc laser that can be easily reduced in size. The microgyroscope includes a pumping unit for inputting pumping light for optical pumping, at least one microsphere or microdisc for oscillating a laser beam by performing optical pumping using light received from the pumping unit, an output coupler for receiving the oscillated laser beam from the microsphere or microdisc, and a photodetector for calculating a beat frequency due to interference between beams output from the output coupler to measure rotation. The pumping unit and the output coupler are constructed using a tapered optical fiber.04-09-2009
20130057870SYSTEMS AND METHODS FOR RESONATOR FIBER OPTIC GYROSCOPE INTENSITY MODULATION CONTROL - Systems and methods for improved resonator fiber optic gyroscope intensity modulation control are provided. In one embodiment, a resonant fiber optic gyroscope (RFOG) having a residual intensity modulation (RIM) controller is provided. The controller includes an intensity modulator optically coupled to receive a light beam from a laser source modulated at a resonance detection modulation frequency, and an optical tap device optically coupled to the intensity modulator. The controller also includes a feedback servo coupled to the optical tap device and the intensity modulator, the demodulating feedback servo generating a sinusoidal feedback signal to the intensity modulator. The feedback servo adjusts an amplitude and phase of the sinusoidal feedback signal provided to intensity modulator based on a residual intensity modulation detected by the demodulating feedback servo.03-07-2013
20110013194ALTERNATE MODULATION SCHEME FOR AN INTERFEROMETRIC FIBER OPTIC GYROSCOPE - An Interferometric Fiber Optic Gyro (IFOG) device for high accuracy sensing. An example IFOG includes an integrated optics chip (IOC) and a modulation component that modulates one or more light signals passing thru the IOC according to a bias-modulation waveform. A glitch pattern experienced at front-end components of the IFOG includes frequency content that has approximately zero amplitude at predefined sense harmonics. Frequency content of the bias-modulation waveform is below a predefined threshold value at the predefined sense harmonics.01-20-2011
20100238450FIBER OPTIC GYROSCOPE USING A LOW-POLARIZATION AND POLARIZATION-MAINTAINING HYBRID LIGHT PATH - A fiber optic gyroscope using a low-polarization and polarization-maintaining hybrid light path comprises an optical meter head and a circuit signal processing part, The optical meter head comprises: a light source, a multi-functional integrated optic chip, a detector, a coupler and a fiber coil, wherein the light source is a low polarization light source and single mode fiber pigtail coupling; the input terminal of multi-functional integrated optic chip uses a single mode fiber, and the output terminal of multi-functional integrated optic chip adopts a polarization-maintaining fiber; the input fiber pigtail of the said detector is a single mode fiber; the coupler is a 2×2 polarization independence single mode fiber coupler; the fiber coil is a polarization-maintaining fiber. By adopting the scheme of the low-polarization and polarization-maintaining hybrid light path and the signal processing methods such as all-digital closed loop control and random overmodulation etc., the present invention can reduce the effect of light path polarization crosstalk, simplify the assembling technology, enable large scale production and guarantee the good scale factor linearity performance and the lower noise level. Furthermore, by temperature modeling and compensating, the invention enables the bias of the fiber optic gyroscope to drift more slightly within the all-temperature range, and therefore the fiber optic gyroscope with good performance and engineering application can be achieved.09-23-2010
20110102801DETERMINING AND COMPENSATING FOR MODULATOR DYNAMICS IN INTERFEROMETRIC FIBER-OPTIC GYROSCOPES - Determining linear modulator dynamics in an interferometric fiber-optic gyroscope may be accomplished by applying a stimulus at a point within the gyroscope, observing a response in an output of the gyroscope, and determining, from the observed response, the linear modulator dynamics.05-05-2011
20100296101ROTATIONAL SPEED SENSOR - The invention relates to a sensor for the determination of the rotational speed of a shaft. To provide a sensor improved with respect to known tachometers, it is proposed that the sensor has a stationary part (11-25-2010
20090195785LOW-NOISE FIBER OPTIC SENSOR UTILIZING A LASER SOURCE - A fiber-optic sensor includes an optical fiber coil and a laser source optically coupled to the coil. Light from the source is transmitted to the coil as a first signal propagating along the coil in a first direction and a second signal propagating along the coil in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the coil to generate a third signal. The laser source is frequency-modulated or can have a coherence length longer than a length of the coil.08-06-2009
20090219545STITCHED WAVEGUIDE FOR USE IN A FIBER-OPTIC GYROSCOPE - An integrated optical circuit includes a first waveguide portion of a first material. The first waveguide portion includes an input-port section terminating in a junction section from which first and second branch sections are formed. Second and third waveguide portions are respectively coupled to the first and second branch sections. The second and third waveguide portions are diffused with a second material different from the first material. First and second modulators are respectively coupled to the second and third waveguide portions. Each of the modulators provides respective modulating voltages generating respective electric fields. The second and third waveguide portions are coupled to the first and second branch sections at respective locations where the electric fields are substantially zero.09-03-2009
20110149293FIBER OPTIC INTERFEROMETER AND METHOD FOR DETERMINING PHYSICAL STATE PARAMETERS IN THE INTERIOR OF A FIBER COIL OF A FIBER OPTIC INTERFEROMETER - 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.06-23-2011
20090079989OPTICAL FIBER COATING SYSTEM AND MONITORING METHOD FOR IMPROVED THERMAL PERFORMANCE IN FIBER OPTIC SENSORS - A method and apparatus for reducing the thermal induced errors in an IFOG system. The apparatus including a highly thermally conductive material configured to encapsulate a waveguide of an interferometric fiber optic gyroscope (IFOG). The highly thermally conductive material more evenly distributes thermal changes encountered by a sensing coil of the IFOG thereby substantially reducing errors in the IFOG system.03-26-2009
20090046294SAGNAC SENSOR WITH NESTED WAVEGUIDES - Proposed optical device is based on counter-propagating optical fields within at least one nested waveguide-cavity loop, where the part of the waveguide loop is fold into the external waveguide loop. The nesting is performed using at least one waveguide crossing section. The invention may be used in Sagnac interferometer to measure various physical parameters, including rotation rate, electric current and mechanical perturbations. The invention also addressed a measurement method of such non-reciprocal parameters of interest. Optionally, the cavity includes a gain element, and the device operation may be switched discretely or gradually between passive and active regimes, thus changing the measurement characteristics.02-19-2009
20090201510DETERMINING AND COMPENSATING FOR MODULATOR DYNAMICS IN INTERFEROMETRIC FIBER-OPTIC GYROSCOPES - Determining linear modulator dynamics in an interferometric fiber-optic gyroscope may be accomplished by applying a stimulus at a point within the gyroscope, observing a response in an output of the gyroscope, and determining, from the observed response, the linear modulator dynamics.08-13-2009
20100103428SIGNAL LIGHT GENERATING APPARATUS USING OPTICAL FIBER AND ROTATION SENSING APPARATUS - A light signal generating apparatus including an erbium-doped optical fiber is provided. The signal light generating apparatus includes a optical fiber which is a gain medium, a light source to emit pump light, a stabilizing unit to compensate for changes of a mean wavelength of the signal light with respect to temperature change in the optical fiber to thereby stabilize the mean wavelength of the signal light, and an optical coupler to transmit the pump light from the light source to the optical fiber and to output signal light returning from the optical fiber and signal light returning from the optical fiber via the stabilizing unit by which the single light is stabilized. Accordingly, the apparatus can lower the change of the mean wavelength with respect to temperature and lower a pump power required of the pump light source.04-29-2010
20100123901Solid State Gyrolaser with Controlled Optical Pumping - 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.05-20-2010
20090251703Optical nonliner evaluation device and optical switching element - An optical nonlinear evaluation device (10-08-2009
20090086212SEMICONDUCTOR RING LASER GYRO - A semiconductor ring laser gyro comprises: A semiconductor ring laser gyro comprises: a closed optical circuit, the closed optical circuit comprising a plurality of reflection members; a semiconductor laser element disposed in the closed optical circuit and emitting laser light from each end thereof, the semiconductor laser element having a luminous region with a width that is at least ten times as large as a wavelength of the laser light; and a pair of optical systems for forming a shape of the laser light emitted from each end of the semiconductor laser element.04-02-2009
20100177317Matter-Wave Rate Gyro Integrated onto an Atom Chip and Associated Accelerometer - The general field of the invention is that of rate gyros, of the matter-wave type, allowing the measurement of a speed of rotation in a given direction of measurement. This type of rate gyro works by the Sagnac effect and uses ultracold atoms to perform the measurement. It necessarily comprises an atom trap allowing a cloud of ultracold atoms to be immobilized in a given configuration and means for separation-displacement-recombination of the cloud into two packets of atoms so as to make them trace out a given area. The device according to the invention combines both of these two functions onto one atom chip notably comprising a first conducting wire through which a DC current I07-15-2010
20100165349SYSTEMS AND METHODS FOR MONITORING ANGLE RANDOM WALK - A gyroscope for determining an angular rate output. The gyroscope includes a first demodulator configured to demodulate an angular rate measurement at a first bias modulation frequency to determine the angular rate signal and a second demodulator configured to demodulate the angular rate measurement at a second bias modulation frequency to provide a signal with ARW information. The gyroscope further includes an ARW estimator that provides an output that is proportional to ARW that is then stored in a memory. The second bias modulation frequency is an even order harmonic of the first bias modulation frequency.07-01-2010
20090040526INTERFEROMETRIC FIBER OPTIC GYROSCOPE WITH OFF-FREQUENCY MODULATION SIGNALS - Interference in a rotation rate detector signal of an interferometric fiber-optic gyroscope from a bias phase modulator signal may be reduced or substantially avoided by transmitting one or more off-frequency signals having a frequency other than the eigenfrequency of the gyroscope towards a bias phase modulator, generating the bias phase modulator signal having a frequency substantially equal to the eigenfrequency of the gyroscope, and driving the bias phase modulator with the bias phase modulator signal.02-12-2009
20130215430Suppression of quantization noise in a fiber-optic sagnac interferometer - In the case of a fiber-optic Sagnac interferometer, the output of an analog/digital converter and thus output signals processed in a main control circuit as well as a phase resetting signal for a phase modulation encompass a first word width. An input of a digital/analog converter and thus a resetting signal, which acts on the phase modulator, encompasses a second word width, which is smaller than the word width, with which the resetting and modulation signal is computed. A residual value signal comprising a third word width, which can be added to the output signal of the analog/digital converter via an adder, is obtained from the surplus, low-value bits.08-22-2013
20100238451DEPOLARIZER FOR A FIBER OPTIC GYROSCOPE (FOG) USING HIGH BIREFRINGENCE PHOTONIC CRYSTAL FIBER - An environmentally robust fiber depolarizer for a fiber optic gyroscope. The depolarizer includes substantially a clockwise propagating leg and a counterclockwise propagating leg, distally coupled at opposite ends of a gyroscope sensing coil. The fiber depolarizer is formed of high birefringence photonic crystal fiber bonded segments. The fiber depolarizer reduces Shupe effect in a FOG and/or depolarizes the light anywhere in the optical circuit of a FOG. The Shupe effect reduction depolarizers may be packaged apart from the FOG sense coil, or wound in a symmetric pattern on the outer diameter of the FOG sense coil.09-23-2010
20100128277RFOG WITH REDUCED POLARIZATION MODE INDUCED BIAS ERROR - Hollow core fiber RFOG having symmetric M-(or W-)shape, three-(or two-)mirror configurations. These symmetric configurations help to cancel out polarization error induced bias of the RFOG even when light of the unwanted ESOP is present. The RFOG resonator with optical components forming substantially small cross-coupling angles between their polarization axes, and/or with polarizing elements inserted into the resonator, and/or with resonator mirrors having identical reflectivity for light of different polarization states, can effectively reduce the polarization mode induced bias error.05-27-2010
20120307252RECYCLED LIGHT INTERFEROMETRIC FIBER OPTIC GYROSCOPE - Interferometric fiber optic gyroscope. The gyroscope includes a pulsed light source for generating light pulses and a sense coil for receiving and trapping the light pulses travelling in clockwise and counter clockwise directions for a selected number of times around the sense coil. A detector receives the counter propagating light pulses to determine the phase shift between the two counter propagating light pulses, the phase shift being proportional to rotation rate of the sense coil.12-06-2012
20120307251HIGH PERFORMANCE HOLLOW-CORE OPTICAL-FIBER FILTER FOR OPTICAL ROTATION SENSING - A hollow-core optical-fiber filter is provided. The hollow-core optical-fiber filter includes a hollow-core optical fiber having a first end-face and an opposing second end-face. The first end-face and the second end-face set a fiber length. The hollow-core optical-fiber filter also includes a first reflective end-cap positioned at the first end-face and a second reflective end-cap positioned at the second end-face. When an optical beam from a laser is coupled into one of the first end-face or the second end-face, an optical output from the opposing end-face has a narrow linewidth and low frequency noise fluctuations.12-06-2012
20110304852SYSTEM TO REDUCE GYROSCOPIC ERRORS WITH LIMITED POWER SUPPLY QUALITY IN A FIBER OPTIC GYROSCOPE - One embodiment is directed to a power supply for a fiber optic gyroscope that comprises at least one main power supply, at least one demodulator local power supply to operatively couple the main power supply to a demodulator included in the fiber optic gyroscope, and at least one modulator local power supply to operatively couple the main power supply to a bias modulator included in the fiber optic gyroscope. The demodulator local power supply comprises a first current source to source current to the demodulator and a first shunt regulator coupled across a load associated with the demodulator. The modulator local power supply comprises a second current source to source current to the bias modulator and a second shunt regulator coupled across a load associated with the bias modulator.12-15-2011
20120062899BIAXIAL OPTICAL GYROSCOPE - A biaxial optical gyroscope is provided, which realizes mode separation using the waveguide devices with different material, and the biaxial optical gyroscope includes: a surface Plasmon Polariton Y-type mode splitter (03-15-2012
20120113432CONSTANT OPTICAL POWER SENSOR USING A LIGHT SOURCE CURRENT SERVO COMBINED WITH DIGITAL DEMODULATION INTENSITY SUPPRESSION FOR RADIATION AND VIBRATION INSENSITIVITY IN A FIBER OPTIC GYROSCOPE - Systems and methods for fiber-optic gyroscopes are provided. In one embodiment, a fiber-optic gyroscope comprises: a light source current servo coupled to a light source that transmits light through an optic path, wherein the light source current servo controls intensity of light through the optic path via a light source current drive that supplies current to power the light source; and an intensity control signal processor coupled to the optic path via a photo detector, wherein the intensity control signal processor outputs an intensity control signal to the light source current servo, wherein the intensity control signal is a function of intensity of light as received at the photo detector; wherein the light source current servo compares the intensity control signal against a stable analog voltage reference to adjust the light source current drive and drive optical power at the photo detector towards a constant level.05-10-2012
20120300214GYROSCOPE UTILIZING TORSIONAL SPRINGS AND OPTICAL SENSING - A gyroscope and a method of detecting rotation are provided. The gyroscope includes a structure configured to be driven to move about a drive axis. The structure is further configured to move about a sense axis in response to a Coriolis force generated by rotation of the structure about a rotational axis while moving about the drive axis. The structure further includes at least one first torsional spring extending generally along the drive axis and at least one second torsional spring extending generally along the sense axis. The gyroscope further includes an optical sensor system configured to optically measure movement of the structure about the sense axis.11-29-2012
20100290056Abnormality detection appraratus of optical fiber gyro - The numbers of pulses of the CW signal and the CCW signal of the optical fiber gyro during a predetermined sampling duration are detected by samplers. An abnormality determiner determines that the optical fiber gyro is normal if at least one of the pulse numbers is greater than or equal to a threshold value. If both pulse numbers are smaller than the threshold value, the abnormality determiner determines that an abnormality, such as a circuit break, a bad connection, etc., has occurred, and outputs the result of determination to an output unit. The abnormality determiner may determine an abnormality on the basis of the presence/absence of quantization noise.11-18-2010
20110181886SIGNAL CONDITIONING TO PROVIDE OPTIMUM GAIN AND NOISE REDUCTION FOR RESONATOR FIBER OPTIC GYROSCOPES - A resonator fiber optic gyroscope includes a first light source configured to generate a light signal. A resonator element is configured to generate a optical signal based on the light signal. A photodetector is configured to generate a first electrical signal based on the optical signal. The first electrical signal includes an oscillating signal, a direct-current (DC) signal, an even-harmonic signal including components at even harmonics of the oscillating signal, and an odd-harmonic signal including components at odd harmonics of the oscillating signal. A filtering element is configured to attenuate the DC signal, at least one even-harmonic component, and an odd-harmonic component to produce a second electrical signal. An amplifier is configured to amplify the second electrical signal. An analog-to-digital converter (ADC) is configured to digitize the amplified second electrical signal.07-28-2011
20120229811HIGH-LINEARITY SIGNAL-PROCESSING AMPLIFIER - A clamp-point active circuit is provided. The clamp-point active circuit includes a rate amplifier configured to receive an output from a device transitioning between at least two levels. The clamp-point active circuit has at least one switching device configured to receive an output from the rate amplifier. The at least one switching device is in at least one respective feedback loop of the rate amplifier. A switching of the at least one switching device causes the rate amplifier to amplify with high linearity in a desired operating range and to clamp outputs received from the transitioning device that are outside the desired operating range to a fixed level.09-13-2012
20120162658INTERFEROMETRIC PATH AND/OR ROTATION MEASURING DEVICE - The present invention relates to an interferometric path and/or rotation measuring device having a transducer unit (06-28-2012
20100328673HIGH-INDEX CONTRAST WAVEGUIDE OPTICAL GYROSCOPE HAVING SEGMENTED PATHS - A waveguide optical gyroscope is disclosed. The waveguide optical gyroscope includes a laser, two detectors, a set of couplers and a set of waveguides. The laser generates a light beam. A first waveguide guides the light beam to travel in a first direction, and a second waveguide guides the light beam to travel in a second direction. The first and second waveguides are coupled to several ring waveguides via the couplers. The first detector detects the arrival of the light beam traveling from the first waveguide, and the second detector detects the arrival of the light beam traveling from the second waveguide.12-30-2010
20100231919METHOD FOR DETERMINING LOADS ON A MECHANICAL STRUCTURE AND THE RESULTANT DAMAGE - A method for determination of loads in a mechanical structure and/or of damage or states in the mechanical structure which result from the loads in the mechanical structure. Rotations of a part of the mechanical structure caused by loads/damage in the mechanical structure are measured by a fiber optic rotation sensor that is rigidly connected mechanically to the structural part. The loads/damage/states in the mechanical structure are deduced from the measured rotations.09-16-2010
20080218764METHODS AND SYSTEMS FOR FIBER OPTIC GYROSCOPES VIBRATION ERROR SUPPRESSION - Systems and methods for performing vibration error suppression in a fiber optic gyro sensor. An example system includes a light source, a sensing loop assembly, a photo detector, and a processing component. The light source generates a light signal that is then modulated by the sensing loop assembly and applied to a fiber optic coil in the assembly. The photo detector receives a modulated light signal that is an output of the sensing loop assembly (coil) and generates an analog signal. The processing component converts the generated analog signal into a modulated digital signal, determines an average of the modulated digital signal, determines an intensity modulation amplitude based on the determined average of the modulated digital signal, and re-scales the modulated digital phase signal based on the determined intensity modulation amplitude.09-11-2008
20130201484OPTICAL DETECTION SYSTEMS AND METHODS OF USING THE SAME - An optical detection system. The optical detection system includes a host node having (a) an optical source for generating optical signals, and (b) an optical receiver. The optical detection system also includes a plurality of fiber optic sensors for converting at least one of vibrational and acoustical energy to optical intensity information, each of the fiber optic sensors having: (1) at least one length of optical fiber configured to sense at least one of vibrational and acoustical energy; (2) a reflector at an end of the at least one length of optical fiber; and (3) a field node for receiving optical signals from the host node, the field node transmitting optical signals along the at least one length of optical fiber, receiving optical signals back from the at least one length of optical fiber, and transmitting optical signals to the optical receiver of the host node.08-08-2013
20100296100FIBER OPTIC GYROSCOPE ARRANGEMENTS AND METHODS - This disclosure provides methods, systems and devices that may be used to measure, calculate, and orient a device such as a drill bit in a downhole environment. To that end, disclosed are fiber optic gyroscopes, wherein the fiber optic gyroscopes comprise elliptical fiber optic cable coils in a mutually orthogonal arrangement that is tilted relative to a length of a supporting shaft, e.g., tube. Light travels in opposite directions within each of the elliptical fiber optic cable coils, and, subsequently, sensors detect differences in time for each light path of the light that traveled in opposite directions within each one of the elliptical fiber optic cable coils. The elliptical nature of the fiber optic cable coils minimizes the cross-sectional area of the mutually orthogonal arrangement, and thereby makes it well-suited for use in downhole environments where space is at a premium. This disclosure also may provide an inertial measurement unit.11-25-2010
20100309474GYROSCOPE UTILIZING MEMS AND OPTICAL SENSING - A gyroscope and a method of detecting rotation are provided. The gyroscope includes a structure configured to be driven to move about a drive axis. The structure is further configured to move about a sense axis in response to a Coriolis force generated by rotation of the structure about a rotational axis while moving about the drive axis. The gyroscope further includes an optical sensor system configured to optically measure movement of the structure about the sense axis. In certain embodiments, the gyroscope is a microelectromechanical system (MEMS) gyroscope.12-09-2010
20100309473FIBER OPTIC CURRENT SENSOR AND METHOD FOR SENSING CURRENT USING THE SAME - An apparatus and method for sensing current. The apparatus includes an optical fiber having first and second opposing ends, a recirculator configured such that when light propagates from the respective first and second ends of the optical fiber, at least some of the light is reflected, directed or passed by the recirculator into the respective opposing ends of the optical fiber to propagate through the optical fiber and form an optical loop having an opening there through.12-09-2010
20120281226OPTICAL SENSOR USING A HOLLOW CORE WAVEGUIDE - An optical sensor includes at least a portion of an optical waveguide having a hollow core. The optical waveguide substantially confines a first optical signal and a second optical signal within the hollow core as the first optical signal and the second optical signal counterpropagate through the optical waveguide. Interference between the first optical signal and the second optical signal is responsive to perturbation of the at least a portion of the optical waveguide.11-08-2012
20120281225OPTICAL SENSOR HAVING A NON-NEGLIGIBLE SOURCE COHERENCE LENGTH - An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the waveguide to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.11-08-2012
20130188193GUIDED MATTER-WAVE SAGNAC INTERFEROMETER - The present invention provides an interferometer apparatus comprising a matter-wave guide enclosing an area, wherein a flux of particles may be guided in the matter-wave guide in at least two opposite paths, the matter-wave guide is rotatable relative to an inertial frame of reference; a first beam splitter to split the first beam to at least second and third beams, each of the second and third beams is to be guided in another path of the two opposite paths; and a second beam splitter allowing particles of the second and third beams to exit the matter-wave guide in a first probability and to stay in the matter-wave guide in a second probability.07-25-2013

Patent applications in class By fiber or waveguide interferometer (e.g., Sagnac effect)

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