An interferometric optical fibre sensor comprises optical fibre defining an optical circuit configured to propagate a first optical wave via an environment in which the optical fibre can be exposed to a stimulus that modifies the first optical wave, and a second optical wave, and to combine the first optical wave and the second optical wave to create an interference signal containing information about the stimulus, wherein optical fibre propagating either or both of the first optical wave and the second optical wave comprises hollow core optical fibre configured to propagate the optical wave or waves by an antiresonant optical guidance effect.

Systems and methods for reducing rotation sensing errors from laser source signal and modulation cross-talk are provided herein. An RFOG includes a fiber optic resonator; a first laser source that produces a first light wave at a first carrier frequency and a first cross-talked portion at a second carrier frequency wave for propagating in a first direction, wherein a second cross-talked portion propagates in a second direction that is opposite to the first direction; a second laser source that produces a second light wave for propagating in the second direction at a second carrier frequency, and having a third cross-talked portion that propagates in the first direction, a first modulator that modulates the first light wave by suppressing light at the first carrier frequency and the second cross-talked portion at the second carrier frequency, and photodetectors that generate signals from the modulated first light wave and the second light wave.

A fiber-optic interferometer is designed to receive and propagate a first single-mode wave along a first optical path and, respectively, a second single-mode wave along a second optical path, the second optical path being the reverse of the first optical path, and to form a first output wave and, respectively, a second output wave, having a modulated phase difference Δϕ.sub.m(t). According to the invention, the modulated phase difference Δϕ.sub.m(t) is equal to sum of a first periodic phase difference Δϕ.sub.π(t) having a level equal to ±π, a second periodic phase difference Δϕ.sub.alpha(t) having a level equal to ±alpha and a third periodic phase difference Δϕ.sub.beta(t) having a variable level between −beta and +beta, said modulated phase difference Δϕ.sub.m(t) comprising per modulation period T at least eight modulation levels among twelve modulation levels and said modulated phase difference between such that: Δϕ.sub.m(t+T/2)=−Δϕ.sub.m(t).

Systems and methods for reducing rotation sensing errors from laser source signal and modulation cross-talk are provided herein. An RFOG includes a fiber optic resonator; a first laser source that produces a first light wave at a first carrier frequency and a first cross-talked portion at a second carrier frequency wave for propagating in a first direction, wherein a second cross-talked portion propagates in a second direction that is opposite to the first direction; a second laser source that produces a second light wave for propagating in the second direction at a second carrier frequency, and having a third cross-talked portion that propagates in the first direction, a first modulator that modulates the first light wave by suppressing light at the first carrier frequency and the second cross-talked portion at the second carrier frequency, and photodetectors that generate signals from the modulated first light wave and the second light wave.

The present disclosure relates to integrated photonics-based optical gyroscopes with silicon nitride (SiN) waveguide-based microresonators. SiN microresonators are fabricated either on a fused silica platform or on a silicon substrate with oxide cladding. A narrow linewidth high-Q laser is hybridly integrated on a silicon photonics platform. The laser is tuned with a first SiN microresonator, and the rotational sensing component of the gyroscope comprises another SiN microresonator. The silicon photonics front-end chip has components for a balanced detection scheme to cancel noise in the optical signal coming back from the rotational sensing component.

Photonic devices and methods for operation thereof are disclosed. A photonic device may include a laser configured to generate light. The photonic device may also include a weak value device having a ring resonator. The weak value device may receive the light from the laser and modify the light using the ring resonator to form return light. The photonic device may further include a stabilizing structure configured to generate a tuning signal based on the return light and control one or both of the laser or the ring resonator using the tuning signal to lock a frequency of the laser to a resonance frequency of the ring resonator.

Systems and methods for an injection locking RFOG are described herein. In certain embodiments, a system includes an optical resonator. The system also includes a laser source configured to launch a first laser for propagating within the optical resonator in a first direction and a second laser for propagating within the optical resonator in a second direction that is opposite to the first direction, wherein the first laser is emitted at a first launch frequency and the second laser is emitted at a second launch frequency. Moreover, the system includes at least one return path that injects a first optical feedback for the first laser and a second optical feedback for the second laser, from the optical resonator, into the laser source, wherein the first and second optical feedbacks respectively lock the first and second launch frequencies to first and second resonance frequencies of the optical resonator.

The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a rotation sensing element, which can be a fiber coil or a sensing coil/micro-resonator ring on a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in the fiber coil or the sensing chip, where the sending chip is coupled to the front end chip. Electrical and/or thermal phase modulators are integrated with the integrated photonics chip. 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 passive resonant optical gyroscope comprising a cavity and operating with three frequencies comprises: a first injecting laser to inject a first optical beam into the cavity in a first direction; a second injecting laser to inject a second optical beam into the cavity in an opposite direction; a third injecting laser to inject a third optical beam into the cavity in one of the aforementioned directions, one laser amongst the injecting lasers having a master frequency, the two other injecting lasers, called the first and second slave lasers, respectively having a first slave frequency and a second slave frequency; a master servocontrol device; a first servocontrol stage comprising first and second slave devices; and a second servocontrol stage comprising first and second optical phase-locking devices respectively comprising a first and second slave oscillator to generate a first radiofrequency offset signal and a second radiofrequency offset signal.

Systems and methods for resonance switching RFOGs with feed-forward processing are provided. In one embodiment, a system comprises: a fiber optic resonator; first and second laser sources coupled to the resonator, wherein the first source launches a first beam into the resonator and the second source launches a second beam into the resonator in an opposite direction; a first servo loop that locks the first beam to a first resonant mode of the resonator during a first state and to a second resonant mode of the resonator during a second state; a second servo loop that locks the second beam to the second resonant mode during the first state and to the first resonant mode during the second state; a feed-forward rate processor coupled to the servo loops that calculates a FSR average across a prior resonance switching cycle of resonant frequency measurements and applies the average to current measurements.