G01C19/721

Pulse per second signal generation using a fiber optic gyroscope

A fiber optic gyroscope inputs laser light into opposing ends of a fiber optic coil and detects light at the same ends of the optical fiber. A pulse-per-second signal is generated by determining the phase difference between the two opposing laser light signals, and generating electrical pulses based on this detected phase difference. The fiber optic gyroscope may become a source of one or more PPS signals used by a vehicle.

Interlaced spiral optical gyroscope

An optical gyroscope includes, in part, an optical switch, a pair of spiral optical rings and a pair of photodetectors. The optical switch supplies a laser beam. The first spiral optical ring delivers a first portion of the beam in a clockwise direction during the first half of a period, and a first portion of the beam in a counter clockwise direction during the second half of the period. The second spiral optical ring delivers a second portion of the beam in a counter clockwise direction during the first half of the period, and a second portion of the beam in a clockwise direction during the second half of the period. The first photodetector receives the beams delivered by the first and second optical rings during the first half of the period. The second photodetector receives the beams delivered by the first and second optical rings during the second half of the period.

SENSOR THERMAL MANAGEMENT AND STABILIZATION UTILIZING VARIABLE CONDUCTANCE
20210080198 · 2021-03-18 · ·

A system for sensor thermal management and stabilization comprises a sensor block, one or more sensors mounted on the sensor block, one or more heaters mounted on the sensor block, a chassis coupled to the sensor block, a thermal conductor moveably coupled between the sensor block and the chassis, and a thermal control actuation mechanism operatively connected to the thermal conductor. The thermal control actuation mechanism is operative to cause the thermal conductor to vary a total thermal conductance from the sensor block to the chassis by moving the thermal conductor toward the chassis or away from the chassis. The total thermal conductance is varied to provide an optimized thermal stability and optimized environmental range of applicability for the one or more sensors.

Ring waveguide based integrated photonics optical gyroscope with gain tuning for enhanced performance
11060869 · 2021-07-13 · ·

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.

Weak value amplification Coriolis vibratory gyroscope

A weak value amplification (WVA) Corolis vibratory gyroscope (CVG) is provided for measuring angular rate. The WVA CVG includes a vibratory structure that induces a deflection; an optical weak value amplifier that amplifies the deflection as an amplified signal; and a weak value detector to measure the amplified signal to determine the angular rate. Further exemplary embodiments provide first and second plates, a laser, a polarizing filter, a beam-splitter, left and right mirrors, a half-wave plate, a retarder and a detector. The laser emits an emission beam of photons. The polarizing filter polarizes the emission beam. The beam-splitter divides the beam into left and right beams reflected by the left and right mirrors. The retarder imposes a phase difference between the left and right beams. The detector measures the left and right 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.

SYSTEMS AND METHODS FOR CORRECTING ERRORS IN GYROSCOPES

Techniques are provided for correcting for time varying changes to a gyroscope incorporating a resonator and/or to an environment in which the gyroscope is located, and which affect the resonator. Free spectral range of the gyroscope, which varies with such changes, is determined and is used to correct at least one of gyroscope bias and scale factor.

SYSTEM ARCHITECTURE FOR INTEGRATED PHOTONICS OPTICAL GYROSCOPES
20210010811 · 2021-01-14 ·

The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in a fiber coil or a sensing chip having a waveguide coil or ring resonator, where the sending chip is coupled to the front end chip. Strip waveguides are designed to primarily select TE mode over TM mode when laser light is coupled into the integrated photonics chip. A plurality of mode-selective filters, based on multi-mode interference (MMI) filter, a serpentine structure, or other types of waveguide-based mode-selective structure, are introduced in the system architecture. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.

Second-order passive ring interferometer sensor and method

A passive ring interferometer sensor includes an electromagnetic ring path configured to receive a pair of electromagnetic waves from an electromagnetic radiation source and to direct the waves to be counter-propagating within the ring path toward respective ends of the path. A combination junction receives the waves from the respective ends and combines the waves to be co-propagating within a coupling path. Polarization elements are configured to set the waves to be mutually co-polarized within the electromagnetic ring path and to be mutually cross-polarized within the coupling path. A detector is configured to receive the mutually cross-polarized waves from the coupling path and to detect second-order coherence. Embodiments can sense rotation rate as fiber-optic gyroscopes or serve as other types of sensors such as gravitational wave sensors. Embodiments may have greatly increased unambiguous range and decreased sensitivity to any centroid wavelength shift.

Multilayer waveguide optical gyroscope
10852137 · 2020-12-01 · ·

A waveguide optical gyroscope includes a multilayer waveguide rotation sensor fabricated on a substrate. The multilayer waveguide rotation sensor includes one or more overlaying non-intersecting, spiraling coils that are vertically separated to reduce or eliminate optical cross coupling. The waveguides are optically coupled by a vertical waveguide and are optically coupled to the other components of the optical gyroscope, including a light source and detector, which may be integrated or fabricated on the substrate. A lithium niobate phase modulator chip may be disposed on the substrate and optically coupled to the waveguides in the multilayer waveguide rotation sensor. The multilayer waveguide rotation sensor enables a small cross section for the guiding channels thereby achieving a high coil density in a small volume.