Bias error in a resonant fiber optic gyroscope (RFOG) is diminished by reducing polarization mismatch between a polarization Eigenstate of optical signals propagating inside of a resonator of the RFOG and the polarization of optical signals being injected into the resonator of the RFOG. The polarization mismatch is reduced by filtering the optical signals circulating in the resonator and the optical signals injected into the resonator with common polarizers.

A chip-scale ultrasensitive ring laser gyroscope that utilizes the physics of exceptional points. By exploiting the properties of such non-Hermitian degeneracies, the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed (.sup.1/2), thus enhancing the sensitivity to low angular rotations by orders of magnitudes. At its maximum sensitivity limit, the measurable spectral splitting is independent of the radius of the cavity rings involved. Binary and ternary systems and associated methods are described.

To reduce or eliminate crosstalk between adjacent integrated optical waveguides, an embodiment of an integrated structure includes, between the optical waveguides, a metal isolation region configured to redirect a signal leaking from one waveguide away from the other waveguide, to absorb the leaking signal, or both to redirect and absorb respective portions of the leaking signal. For example, such an integrated structure includes a cladding, first and second optical cores, and a metal isolation region. The optical cores are disposed in the cladding, and the isolation region is disposed in the cladding between, and separate from, the cores. Including a metal isolation region between adjacent optical waveguides can reduce crosstalk between the waveguides more than coating the waveguides with a metal because the metal coating typically is not thick enough to redirect or absorb enough of a leakage signal to reduce crosstalk to a suitable level.

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.

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 reducing polarization-related bias errors in RFOGS are described herein. In certain implementations, an RFOG system includes a fiber optic resonator, one or more laser sources, wherein light from the laser sources launches first and second optical beams into the fiber optic resonator in opposite directions, and an electro-optically tunable devices in the resonator path configured to modulate the phase difference between polarization components in the first and second optical beams as the optical beams propagate within the fiber optic resonator. The system further includes at least one photodetector, wherein the polarization components of the first and second optical beams are incident on the photodetector, wherein the at least one photodetector provides an electrical signal, and at least one processing unit configured to receive the electrical signal and calculate a rotation rate for the RFOG and provide a drive signal for the electro-optically tunable device.

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.

Bias error in a resonant fiber optic gyroscope (RFOG) is diminished by reducing polarization mismatch between a polarization Eigenstate of optical signals propagating inside of a resonator of the RFOG and the polarization of optical signals being injected into the resonator of the RFOG. The polarization mismatch is reduced by filtering the optical signals circulating in the resonator and the optical signals injected into the resonator with common polarizers.

An optical resonator is provided. The optical resonator comprises: an optical resonator coil comprising a first port and a second port; wherein the optical resonator coil comprises antiresonant nodeless fiber; a resonator loop closure optics system; and wherein the antiresonant nodeless fiber has a length such that the resonant frequencies the optical resonator of the desired polarization state of light and of the undesired polarization state of light are separated by between a tenth of a free spectral range and nine tenths of a free spectral range to minimize gyroscope errors.

An integrated photonics optical gyroscope front-end chip is fabricated on a waveguide platform made of electro-optic materials. The front-end chip launches light into and receive light from the rotation sensing element, that can be a fiber spool or a waveguide coil/microresonator ring. The waveguide coil/microresonator ring can be made of the same electro-optic material platform or a different material platform. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than the electro-optic material and can be hybridly integrated or otherwise coupled to the waveguide platform. Additional phase shifters can be made of piezo-electric material or can be thermal phase shifters.