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.

A stimulated Brillouin scattering (SBS) gyroscope comprises a resonator; a first laser in communication with the resonator and configured to emit a first optical signal propagating in a first direction, the first optical signal producing a first SBS signal counter-propagating in a second direction; a second laser in communication with the resonator and configured to emit a second optical signal propagating in the first direction, the second optical signal producing a second SBS signal counter-propagating in the second direction; a third laser in communication with the resonator and configured to emit a third optical signal propagating in the second direction, the third optical signal producing a third SBS signal counter-propagating in the first direction. At least one photodetector is coupled to the resonator and receives the SBS signals, which are combined in the photodetector to produce electrical signals that include rotational rate information encoded in frequencies of the electrical signals.

A microelectromechanical systems (MEMS) device comprises an optical directional coupler comprising: a first waveguide having a first and a second end, wherein a light beam is introduced into the first end; a second waveguide having a third and a fourth end, wherein the light beam is evanescently coupled between the two waveguides in the central region; a first photodetector to detect first optical power in the light beam at the second end; and a second photodetector to detect second optical power in the light beam at the fourth end; a vibrating proof mass adjacent to the coupler in a first direction from the coupler, wherein when inertial forces are applied to the MEMS device in a second direction, the proof mass moves in the first direction; a processor to determine the displacement of the proof mass from the coupler as a function of the first and the second optical power.

In an aspect, a pressure sensor for determining pressure in an environment comprises: a source for emitting a coherent reference light characterized by a reference light frequency; a first lock-in mechanism configured to send an electrical signal to the source based on a reference resonance frequency; a reference cavity; wherein the reference cavity is characterized by the reference resonance frequency; a modulator configured a reference light to generate at least a first sideband frequency such that an output of said modulator is a measurement light characterized by at least the first sideband frequency; a frequency synthesizer configured to drive the modulator; a second lock-in mechanism configured to send an electrical signal to the frequency synthesizer based on a measurement resonance frequency; and a measurement cavity configured to receive at least a portion of the measurement light; wherein the measurement cavity is characterized by the measurement resonance frequency; and wherein the pressure of the environment is determined based on the reference resonant frequency and the measurement resonance frequency.

A stimulated Brillouin scattering (SBS) gyroscope comprises a resonator; a first laser in communication with the resonator and configured to emit a first optical signal propagating in a first direction, the first optical signal producing a first SBS signal counter-propagating in a second direction; a second laser in communication with the resonator and configured to emit a second optical signal propagating in the first direction, the second optical signal producing a second SBS signal counter-propagating in the second direction; a third laser in communication with the resonator and configured to emit a third optical signal propagating in the second direction, the third optical signal producing a third SBS signal counter-propagating in the first direction. At least one photodetector is coupled to the resonator and receives the SBS signals, which are combined in the photodetector to produce electrical signals that include rotational rate information encoded in frequencies of the electrical signals.

A resonant fiber optic gyroscope comprises: a ring resonator including a fiber coil fabricated from a first type of hollow core fiber; a light source to produce at least two light beams, wherein a first light beam is configured to travel in a clockwise direction in the ring resonator and a second light beam is configured to travel in a counterclockwise direction in the ring resonator; a filter resonator assembly coupled between the light source and the ring resonator including: at least two short pieces of optical fiber shorter in length than the fiber coil, the at least two short pieces of optical fiber fabricated from the first type of hollow core fiber; and wherein prior to the beams entering the ring resonator, a plurality of reflective devices are configured to condition the beams such that they excite the fundamental mode of the hollow core fiber within the ring resonator.

A method is provided. The method comprises: receiving a first optical signal and a second optical signal; injecting the first optical signal into an optical resonator so that the first optical signal propagates in a first direction through the optical resonator; injecting the second optical signal into the optical resonator so that the second optical signal propagates in a second direction through the optical resonator, which is opposite to the first direction; filtering an optical signal propagating in the first direction of the optical resonator with a first common polarizer having the first polarization; and filtering an optical signal propagating in the second direction of the optical resonator with the first common polarizer.

A hyperbolic modulation offset reducer circuit for a resonator fiber optic gyro (RFOG) is provided. The circuit includes a first demodulation circuit that is configured to demodulate a received transmission signal from a resonator at twice a sideband heterodyne detection modulation frequency to reject signals due to backscatter. A slave resonance tracking loop of the circuit is coupled to an output of the first demodulation circuit. The slave resonance tracking loop is configured to create an offset frequency signal from the transmission signal that is applied to an optical phase lock loop of a RFOG. A hyperbolic modulator offset control loop is also coupled to the output of the first demodulation circuit. The hyperbolic modulator offset control loop is configured to create a subharmonic common modulation signal from the transmission signal that is coupled to a common phase module in a silicon photonics chip of the RFOG.

An optical sensor includes an optical device including a microresonator, laid out to guide a light beam along a closed loop optical path, and an injection and/or extraction waveguide, optically coupled to the microresonator; a photodetector, arranged at the output of the injection and/or extraction waveguide; and an analysis device, receiving a signal supplied by the photodetector, and deducing therefrom information relative to a displacement. The microresonator is constituted of a plurality of elementary waveguides spaced apart from each other, and arranged one after the other according to a loop shaped layout. The optical sensor offers increased sensitivity to the measurement of nanometric displacements.

Various embodiments may provide an optical gyroscope. The optical gyroscope may include a ring resonator, an input source configured to generate or provide a first light beam and a second light beam to the ring resonator, and a switching pathway having an input end and an output end coupled to the ring resonator, and may include a plurality of switches. The optical gyroscope may include a control circuit configured to control the plurality of switches to allow the first light beam to propagate from the input end to the output end along the switching pathway during a first time interval, and allow the second light beam to propagate from the input end to the output end along the switching pathway during a second time interval. The optical gyroscope may additionally include a detector loop configured to receive the first light beam and the second light beam from the ring resonator.