G01C19/721

GYROSCOPE WITH REDUCED BIAS ERRORS DUE TO RESONANCE ASYMMETRIES

A resonator fiber optic gyroscope (RFOG) that includes at least one laser, a resonator and a resonator hopping control system is provided. The resonator is in operational communication with the at least one laser to receive a clockwise (CW) laser light and counterclockwise (CCW) laser light produced by the at least one laser. The resonance hopping control system is in communication with an output of the resonator and the at least one laser. The resonance hopping control system is configured to control an output of the at least one laser to periodically unlock, hop and lock frequencies of the laser light traveling in the CW and CCW directions in the resonator to resonance frequencies of the resonator to mitigate bias errors due to resonance asymmetries.

STIMULATED BRILLOUIN SCATTERING GYROSCOPE

A stimulated Brillouin scattering gyroscope is provided. A pump laser generates continuous wave (CW) energy that travels through at least one bus waveguide to a waveguide resonator. A reflector is positioned within the waveguide resonator. The reflector is configured to pass at least some of the CW energy in a first direction and reflect at least some stimulated Brillouin scattering (SBS) energy in a second direction. A first detector is in operational communication with the at least one bus waveguide to detect CW energy. An output of the first detector used to at least adjust a pump laser frequency of the pump laser. A second detector is also in operational communication with the at least one bus waveguide. The second detector is used to determine phase shifts in detected SBS energy to determine at least rotation.

Cladding-pumped waveguide optical gyroscope
11022440 · 2021-06-01 ·

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

RING WAVEGUIDE BASED INTEGRATED PHOTONICS OPTICAL GYROSCOPE WITH GAIN TUNING FOR ENHANCED PERFORMANCE
20210156687 · 2021-05-27 ·

An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first straight waveguide to receive incoming light and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing. The gyroscope comprises a first microresonator ring proximate to the first straight waveguide. Light evanescently couples from the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring. The guided beam evanescently couples back from the first microresonator ring to the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to guided beam to counter the propagation loss. In a coupled-ring configurations, the first microresonator ring acts as a loss ring, and optical gain is imparted to a second microresonator ring which acts as a gain ring.

Apparatus and method for an optical resonator with an integrated Bragg grating

An apparatus is provided. The apparatus comprises: an optical resonator including a surface; wherein a Bragg grating is formed at least part of the surface of the optical resonator; and wherein the Bragg grating has a Bragg frequency substantially equal to a center frequency of an Nth order Brillouin gain region capable of generating an Nth order Stokes signal.

MULTI-LAYER SILICON NITRIDE WAVEGUIDE BASED INTEGRATED PHOTONICS OPTICAL GYROSCOPE CHIP
20210140768 · 2021-05-13 ·

An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first portion with silicon nitride (SiN) waveguides that constitute a rotation sensing element; and, a second portion with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two portions can be stacked together to have a multi-layer configuration vertically coupled with each other. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than SiN and can be hybridly integrated to the SiN waveguide platform.

Sideband heterodyne switching for resonator fiber optic gyroscopes (RFOGs)

Systems and methods for performing SHD switching for RFOGS are provided herein. A system includes a resonator in which light resonates; at least one laser source that produces first and second optical beams; heterodyne modulators that modulate the first and second optical beams at a heterodyne frequency plus a modulation frequency offset to produce multiple sideband optical beams, wherein the modulation frequency offset has a different sign for the first and second optical beams; a frequency switching controller that alternatingly switches the signs of the modulation frequency offset applied to the first and second optical beams, wherein the heterodyne modulation of the first and second optical beams are on average at the heterodyne frequency; at least one coupler that couples the sideband optical beams into the resonator; a feedback control that detects the sideband optical beams transmitted from the resonator and, in response, adjusts frequencies of the optical beams.

RFOG resonance hopping

Systems and methods for performing resonator fiber optic gyroscope (RFOG) resonance hopping are described herein. For example, an RFOG includes a fiber optic resonator. The RFOG also includes a plurality of laser sources that each launch a respective laser for propagation within the fiber optic resonator. Further, the RFOG includes a threshold detector that determines when the operation of at least one laser source in the plurality of laser sources exceeds a threshold associated with the operational range of an aspect of the at least one laser source. Additionally, the RFOG includes a hop control logic that adjusts the frequency of at least one laser produced by the at least one laser source one or more resonant modes of the fiber optic resonator such that the aspect of the at least one laser moves away from the threshold towards a nominal value within the operational range.

Calibration circuit to mitigate fiber-optic gyroscope (FOG) bias error

One example includes a fiber-optic gyroscope (FOG) system that includes a fiber coil. The coil includes an optical fiber wound around a spool of a FOG. The optical fiber includes a first input and a second input. The system also includes an optical beam controller comprising an optical switch that provides a first optical beam to the first input and a second optical beam to the second input during a first switching state, and provides the first optical beam to the second input and the second optical beam to the first input during a second switching state. The system further includes a controller that mitigates bias error in determining rotation of the FOG based on comparing the first and second optical beams output from the FOG during the first and second switching states.

SIDEBAND HETERODYNE SWITCHING FOR RESONATOR FIBER OPTIC GYROSCOPES (RFOGS)

Systems and methods for performing SHD switching for RFOGS are provided herein. A system includes a resonator in which light resonates; at least one laser source that produces first and second optical beams; heterodyne modulators that modulate the first and second optical beams at a heterodyne frequency plus a modulation frequency offset to produce multiple sideband optical beams, wherein the modulation frequency offset has a different sign for the first and second optical beams; a frequency switching controller that alternatingly switches the signs of the modulation frequency offset applied to the first and second optical beams, wherein the heterodyne modulation of the first and second optical beams are on average at the heterodyne frequency; at least one coupler that couples the sideband optical beams into the resonator; a feedback control that detects the sideband optical beams transmitted from the resonator and, in response, adjusts frequencies of the optical beams.