| Entries |
| Document | Title | Date |
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| 20080218764 | METHODS 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 |
| 20090040526 | INTERFEROMETRIC 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 |
| 20090046294 | SAGNAC 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 |
| 20090079989 | OPTICAL 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 |
| 20090086212 | SEMICONDUCTOR 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 |
| 20090091763 | MICROGYROSCOPE - 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 |
| 20090195785 | LOW-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 |
| 20090201510 | DETERMINING 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 |
| 20090219545 | STITCHED 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 |
| 20090251703 | Optical nonliner evaluation device and optical switching element - An optical nonlinear evaluation device ( | 10-08-2009 |
| 20100033729 | BIAS-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 |
| 20100039649 | OPTICAL 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 |
| 20100073681 | BIAS-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 |
| 20100103428 | SIGNAL 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 |
| 20100123901 | Solid 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 |
| 20100128277 | RFOG 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 |
| 20100165349 | SYSTEMS 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 |
| 20100177317 | Matter-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 I | 07-15-2010 |
| 20100231919 | METHOD 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 |
| 20100238450 | FIBER 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 |
| 20100238451 | DEPOLARIZER 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 |
| 20100290056 | Abnormality 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 |
| 20100296100 | FIBER 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 |
| 20100296101 | ROTATIONAL 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 |
| 20100309473 | FIBER 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 |
| 20100309474 | GYROSCOPE 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 |
| 20100328673 | HIGH-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 |
| 20110013194 | ALTERNATE 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 |
| 20110102801 | DETERMINING 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 |
| 20110149293 | FIBER 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 |
| 20110181886 | SIGNAL 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 |
| 20110304852 | SYSTEM 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 |
| 20120062899 | BIAXIAL 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 |
| 20120113432 | CONSTANT 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 |
| 20120162658 | INTERFEROMETRIC 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 |
| 20120229811 | HIGH-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 |
| 20120281225 | OPTICAL 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 |
| 20120281226 | OPTICAL 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 |
| 20120300214 | GYROSCOPE 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 |
| 20120307251 | HIGH 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 |
| 20120307252 | RECYCLED 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 |
| 20130057870 | SYSTEMS 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 |
| 20130083327 | MEMS 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 |
| 20130088720 | OPTICAL 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 mm | 04-11-2013 |
| 20130188193 | GUIDED 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 |
| 20130201484 | OPTICAL 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 |
| 20130215430 | Suppression 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 |
| 20130293898 | INTEGRATED SILICON OPTOMECHANICAL GYROSCOPES (OMGS) - A system having an optomechanical gyroscope device. An optomechanical disk acts as an optical ring resonator and a mechanical disk resonator. A drive laser generates an optical drive signal. A drive channel acts as a waveguide for the optical drive signal and includes drive electrodes in a first proximity with respect to the optomechanical disk. The drive electrodes to excite the ring by evanescent coupling. A drive photodetector is configured to receive an output optical signal from the drive channel. A sense laser generates a optical sense signal. A sense channel acts as a waveguide for the optical sense signal and includes sense electrodes in a second proximity with respect to the optomechanical disk. A sense photodetector is configured to receive an output optical signal from the sense channel. | 11-07-2013 |
| 20140029011 | OPTICAL 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 loop having a length and a laser source optically coupled to the loop. The laser source has a coherence length. Light from the source is transmitted to the loop as a first signal and a second signal counterpropagating along the loop. 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 counterpropagating through the loop to generate a third signal. A ratio of the coherence length to the length of the loop is greater than 1. | 01-30-2014 |
| 20140071455 | STABILIZED PUMP LASER OUTPUT SYSTEM AND METHOD - A system includes a light source that generates a coherent output signal. A light stabilizer comprising an optical fiber can be configured to pass one axis of propagation of the coherent output signal from the light source to a Bragg grating to generate a stabilized pump output signal for the system. | 03-13-2014 |
| 20140132961 | FIBER OPTIC GYROSCOPE WITH FRONT END POLARIZER - A fiber optic gyroscope (FOG) is provided. The FOG comprises a depolarizer that receives light from a light source, a multifunction integrated optic chip (MIOC) and a sensing coil coupled to outputs of the MIOC. The FOG also includes a polarizer coupled between an output of the depolarizer and an input of the MIOC. The polarizer mitigates polarization non-reciprocity (PNR) bias error and enhances the polarization extinction ratio (PER) of the FOG. | 05-15-2014 |
| 20140168655 | BROADBAND FIBER LIGHT SOURCE WITH HIGH WAVELENGTH STABILITY UNDER RADIATION FOR IFOG APPLICATIONS - A rare-earth-doped-fiber light source with wavelength stability includes a rare-earth doped fiber and an undoped fiber placed in proximity to each other and having the same host material and the same cross-sectional structure, a coupler configured to direct a first portion of pump power from a pump laser to the undoped fiber so the first portion of pump power was twice passed through the coupler; and a wavelength division multiplexer configured to input a second portion of pump power from the pump laser to the rare-earth doped fiber. The rare-earth doped fiber is an active medium for the broadband light source and includes a fiber core doped with rare-earth ions. The undoped fiber includes a rare-earth-dopant-free fiber core. The length of the undoped fiber is one of the same as that of the doped fiber or optimized to match a radiation sensitivity of the doped fiber. | 06-19-2014 |
| 20140185053 | OPTICAL INTERFEROMETRIC APPARATUS - An optical interferometric apparatus comprises a light source emitting a coherent light, a polarizing beam-splitting element splitting the light into a first light and second light which travel along an optical fiber element and then are combined. Then, a beam-splitting element split the combined light into a third light and a fourth light, and a first phase-modulation element and a second phase-modulation element respectively are disposed on the optical paths of the third and fourth lights. A first polarization element and a second polarization element respectively superpose the P wave and S wave of the third and fourth lights, and a first detection element and a second detection element respectively detect the third and fourth lights to respectively generate a first polarized signal and a second polarized signal. A demodulation computing element is used to calculate and determine phase information according to the first and second polarized signals. | 07-03-2014 |
| 20140198317 | STABLIZED PUMP LASER WITH OUTPUT REFLECTOR ON POLARIZING OPTICAL FIBER - A laser apparatus comprises a pump laser device, and a polarizing optical fiber having a proximal end and a distal end, with the polarizing optical fiber coupled to the pump laser device at the proximal end. At least one output reflector is written on the polarizing optical fiber toward the distal end. Only one polarization mode is supported when a laser beam is transmitted through the polarizing optical fiber from the pump laser device. | 07-17-2014 |
| 20140211210 | FIBER OPTIC GYROSCOPE MIXED SIGNAL APPLICATION SPECIFIC INTEGRATED CIRCUIT - A system comprising a fiber optic gyroscope and a mixed signal application specific integrated circuit (ASIC) connected to the gyroscope is provided. The mixed signal ASIC comprises a digital logic unit, a relative intensity noise (RIN) analog-to-digital converter (ADC) coupled to the digital logic unit and configurable to receive a signal from a RIN detector, and a rate ADC coupled to the digital logic unit and configurable to receive a signal from a rate detector. The mixed signal ASIC also includes a light source digital-to-analog converter (DAC) coupled to the digital logic unit, and a thermo-electric cooler DAC coupled to the digital logic unit, both of which are configurable to send control signals to a light source of the gyroscope. The mixed signal ASIC further includes an integrated optical chip DAC, an eigen-frequency servo DAC, and a heater servo DAC, all of which are coupled to the digital logic unit. | 07-31-2014 |
| 20140218739 | INTERFEROMETER EMPLOYING A MULTI-WAVEGUIDE OPTICAL LOOP PATH AND FIBER OPTIC ROTATION RATE SENSOR EMPLOYING SAME - An interferometer employed, in part, as a Sagnac interferometer or fiber optic gyro (FOG) includes a light source that provides a source light wave that is split into first and second light waves that are directed to traverse a defined optical loop path in opposite directions. The defined optical loop path in accordance with the present invention is provided by multiple waveguides wound into a coil such that the opposite traveling first and second light waves serially travel through all of the waveguides in opposite directions around the optical loop path. | 08-07-2014 |
| 20140268164 | Suppression of lock-in effect due to a MIOC frequency response in a fiber-optic sagnac interferometer - A fiber-optic Sagnac interferometer in a rotation rate sensor comprises a multifunctional integrated optical chip (MIOC) with a MIOC transfer function. A digital filter is connected upstream to the multi-functional integrated optical chip, whose filter transfer function corresponds basically to the inverse MIOC transfer function such that the MIOC transfer function is compensated by the filter transfer function. Corresponding coefficients of the filter transfer function may be determined in a main control loop. | 09-18-2014 |
| 20150009505 | FIBER-OPTIC MEASUREMENT DEVICE, GYROMETER, AND NAVIGATION AND INERTIAL-STABILIZATION SYSTEM - A fiber-optic measurement device ( | 01-08-2015 |
| 20150022818 | LASER-DRIVEN OPTICAL GYROSCOPE WITH PUSH-PULL MODULATION - A system and method for reducing coherent backscattering-induced errors in an optical gyroscope is provided. A first time-dependent phase modulation is applied to a first laser signal and a second phase modulation is applied to a second laser signal. The phase-modulated first laser signal propagates in a first direction through a waveguide coil and the phase-modulated second laser signal propagates in a second direction opposite the first direction through the waveguide coil. The first time-dependent phase modulation is applied to the phase-modulated second laser signal after the phase-modulated second laser signal propagates through the waveguide coil to produce a twice-phase-modulated second laser signal. The second time-dependent phase modulation is applied to the phase-modulated first laser signal after the phase-modulated first laser signal propagates through the waveguide coil to produce a twice-phase-modulated first laser signal. The twice-phase-modulated first and second laser signals are transmitted to a detector. | 01-22-2015 |
| 20150022819 | FIBER OPTIC GYROSCOPE DEAD BAND ERROR SUPPRESSION - Embodiments described herein provide a method of modulating an input light beam of a fiber optic coil of an IFOG. The method includes intermittently jumping the phase step of a feedback signal to suppress dead band. Jumping the phase step includes: creating a jumped phase step during a first cycle of the IFOG, the jumped phase step having a whole value configured to cause a phase jump in the feedback signal and a fractional value corresponding to the fractional value from a phase step of a cycle immediately preceding the first cycle. Jumping the phase step also includes generating the feedback signal from a sum of the bias modulation value and the jumped phase step. | 01-22-2015 |
| 20150070706 | Ring Mirror Optical Rotation Sensor - An optical rotation sensor includes a Fabry Perot laser having an active gain medium for generating first and second light beams, a closed optical path through which the first and second light beams counter-propagate and first and second mirrors coupled to respective ends of the closed optical path. The first minor is a ring mirror having a complex valued reflectivity that varies with a rotation rate of a frame within which the optical rotation sensor is placed. A detector is coupled to an output of the Fabry Perot laser to measure an output intensity thereof. | 03-12-2015 |
| 20150116722 | DISPERSION MANAGED INTERFEROMETRIC FIBER OPTIC GYROSCOPE - A dispersion managed interferometric fiber optic gyroscope comprising: a coupler coupled to the broadband light source via a first input fiber; an IOC comprising: a beamsplitter that directs the input signal to a first output and a second output; a combiner configured to combine a first return signal from the first output and a second return signal from the second output into a combined return signal; an integrated optical circuit input coupled to the coupler via a second input fiber; a fiber optic gyroscope sensing coil coupled to a first pigtail fiber and second pigtail fiber, the sensing coil comprising sensing fibers, wherein at least one dispersion slope of at least one of the first input fiber, second input fiber, first pigtail fiber, second pigtail fiber, and the sensing fibers is selected such that the signals at the IOC input has a second order coherence substantially equal to two. | 04-30-2015 |
| 20150131102 | INTERFEROMETRIC MEASUREMENT SYSTEM WITH OPTICAL FIBRE AND INERTIAL GUIDANCE OR NAVIGATION SYSTEM INCLUDING SUCH AN INTERFEROMETRIC MEASUREMENT SYSTEM - A fiber optic interferometric measurement system includes a light source; first and second optical transmission elements; first and second Sagnac-ring interferometers, respectively, including first and second fiber optic coils, and, respectively, having lengths L | 05-14-2015 |
| 20150316380 | FIBER OPTIC GYROSCOPE DEAD BAND ERROR SUPPRESSION - Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. During a first cycle, a first cycle raw rate is stored and a feedback signal is generated based on a jumped phase step. During a second cycle, a second cycle raw rate is stored and a feedback signal is generated based on the jumped phase step. During a third cycle, a third cycle phase step is generated by accumulating the first cycle raw rate with a second cycle phase step, and a feedback signal is generated from the third cycle phase step. During a fourth cycle, a fourth cycle phase step is generated by accumulating the second cycle raw rate with the third cycle phase step, and a feedback signal is generated from the fourth cycle phase step. | 11-05-2015 |
| 20150316381 | FIBER OPTIC GYROSCOPE DEAD BAND ERROR SUPPRESSION - Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. If a bit flip was clocked into a digital to analog converter generating the feedback signal at the beginning of a cycle in which the jumped phase step is implemented, the method includes at least one of re-introducing a rate difference corresponding to the bit flip, altering the timing of the bit flip, or altering the timing of the generating a feedback signal based on the jumped phase step. | 11-05-2015 |
| 20150345949 | INTERFEROMETRIC MEASUREMENT DEVICE COMPRISING A FILTERING INTERFEROMETER - An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving as input a light signal with input light power and delivering as output a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter (Ω | 12-03-2015 |
| 20150369591 | OPTICAL 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. | 12-24-2015 |
| 20160069686 | OPTOMECHANICAL DISK VIBRATORY GYROSCOPES - An integrated optomechanical disk vibratory gyroscope device includes a mechanical oscillator having a substantially circular structure. The substantially circular structure is supported by a pillar, and mechanically isolated from a surrounding structure by a gap or slot. One or more actuators are coupled to the mechanical oscillator across the gap or slot. Each of the one or more actuators is configured to excite the mechanical oscillator in a driving mode. One or more optomechanical cavities are disposed substantially in a plane defined by the mechanical oscillator. At least one component of the one or more optomechanical cavities is disposed on or in the substantially circular structure. Each of the at least one or more optomechanical cavities configured to measure a displacement of the mechanical oscillator in a sensing mode. A method of manufacture is also described. | 03-10-2016 |
| 20160076891 | SYSTEM AND METHOD FOR REDUCING COHERENT BACKSCATTER IN A STITCHED WAVEGUIDE INTEGRATED OPTIC CIRCUIT - An integrated optical circuit comprises a first waveguide section of a first material having a first index of refraction, a second waveguide section diffused with a second material, different from the first material, the second waveguide section having a second index of refraction; and a third waveguide section of the first material. A portion of the first waveguide section at a first interface is angled at a first angle and a portion of the second waveguide section is angled at the first angle. A portion of the first waveguide section at a second interface is angled at a second angle and a portion of the third waveguide section is angled at the second angle. The first angle and second angle are selected such that the angle of incidence of light at the first and second interfaces is greater than the Brewster's angle. | 03-17-2016 |
| 20160153782 | Integrated Optical Coupler and Fibre-Optic System Having Such an Integrated Optical Coupler | 06-02-2016 |
| 20160178375 | Active Waveguide Optical Gyroscope | 06-23-2016 |
| 20160202063 | ENERGY-EFFICIENT OPTIC GYROSCOPE DEVICES | 07-14-2016 |
| 20160377436 | DIVERGING WAVEGUIDE ATOMIC GYROSCOPE - Waveguide includes fork with first and second bifurcated ends coupled to loop section and separated by angle determined based on velocities of portions of quantum mechanical wavefunction of atoms traveling above waveguide. Waveguide propagates blue-detuned laser having first evanescent field that repels atoms away from waveguide and red-detuned laser having second evanescent field that attracts atoms toward waveguide, together creating potential minimum/well. Laser cooling atoms, causing atoms positioned in potential minimum/well to move toward first fork section following potential minimum/well. Atomic state initialization section initializes atomic states of atoms to known ground-state configuration. Beam splitter section splits quantum mechanical waveform of each atom above surface of diverging waveguide into first portion at first velocity that travels into first end of first fork section into first loop section and second portion at second velocity that travels into second end of first fork section into first loop section. | 12-29-2016 |
