A bidirectional optical-carrying microwave resonance system based on a circulator structure and a method for detecting angular velocity by said system. A high-stability optical-carrying microwave of which polarization states in forward and reverse directions are perpendicular is generated in an optical fiber ring by utilizing a regenerative mold locking technology, a cavity length control technology, and a polarization state separation technology, and the optical-carrying microwave is used for measuring a rotational angular velocity. The circulator structure is adopted and the bidirectional optical-carrying microwave resonance is achieved by means of a bidirectional regenerative mode locking technology. A reciprocal bidirectional optical-carrying microwave resonance system is achieved on the basis of a non-reciprocal error elimination technology of a wide-spectrum optical interferometer. The polarization state separation technology is adopted to achieve dual-wavelength separation of optical signals and the perpendicular polarization state is adopted for opposite transmission in a sensitive ring, so that the detection capability of the sensitive ring is improved. The cavity length control technology is adopted to lock a microwave oscillation frequency in one direction to a high-stability standard-time reference source, so that a relative cavity length of an optical resonant cavity is stabilized. The system has the characteristics of high practicability, high measurement precision and the like.

A stabilized integrated optical circuit is presented. The stabilized integrated optical circuit includes at least one integrated optical chip formed from at least one inorganic material, a stabilizing-polarizable-fill gas, and an enclosure enclosing the at least one integrated optical chip and the stabilizing-polarizable-fill gas. At least one surface of the at least one integrated optical chip is modified by a treatment with at least one treatment gas selected to stabilize defects on the at least one surface. The stabilizing-polarizable-fill gas includes N.sub.2O and at least one polarizable material.

A ring cavity device includes a passive ring waveguide and an input/output waveguide horizontally coupled to the passive ring waveguide, including an active waveguide structure vertically coupled to the passive ring waveguide and/or the input/output waveguide. The active waveguide structure compensates for the loss of the passive ring waveguide. A method for fabricating a ring cavity device is also included. The ring cavity device may obtain part of the gain by vertical coupling or mixed coupling (vertical coupling followed by horizontal coupling) thus to compensate the loss in the ring cavity device. Hence, the quality factor of the ring cavity device is improved.

An optical waveguide structure for an optical gyroscope, the structure including a substrate; at least a first silicon nitride waveguide loop and a second silicon nitride waveguide loop connected to the substrate, the first silicon nitride waveguide loop and the second silicon nitride waveguide being disposed at different vertical distances from the substrate; at least one vertical coupler optically coupling the first silicon nitride waveguide loop to the second silicon nitride waveguide; and a plurality of air cavities defined in material below the first and second silicon nitride waveguide loops, no air cavities being defined in regions immediately below a coupling region defined around the at least one vertical coupler.

Improvements to optical power regulation in a gyroscopic system are described. The system can include an optical assembly (e.g., optical bench) which couples opposing optical signals to a resonator coil. The system can monitor the power of the optical signals through the resonator coil by including signal extraction optics in the optical assembly which are configured to extract a portion of the optical signals. The portions can be extracted via a single beamsplitter, wherein the beamsplitter reflects the portions at a single common surface, and can also reflect the portions to a respective photodetector in free space free from intervening optical components, such as polarizers or beamplitters. One or more processors can be coupled to the optical assembly, wherein the processor(s) are configured to adjust the power of the optical signals in response to detecting a power difference between the optical signals.

Disclosed are systems and methods that utilize multicore optical fibers for gyro coil winding. Particularly, the use of multicore fiber enables inherent thermal stability without the need for complex, tedious, and costly winding patterns. Enabling the use of level winding techniques eliminates the need for complex quadrupole winding patterns. This simplicity lends itself to advancements towards full automation of winding coils for multicore fibers, without sacrificing performance. This, in turn increases the production rate and overcomes current barriers to fiber optic gyroscope (FOG) market expansion. In accordance with the embodiments, multicore fiber can be utilized in various gyro coil winding techniques, including: level winding; Interrupted Level Wind (ILW); and Dual Axis Symmetric (DAS) winding. Furthermore, each of the multicore fiber gyro coil winding patterns can incorporate a multicore shuffle bridge. The multicore shuffle bridge is designed to provide multiple features, such as facilitating the rotation of mating cores.

Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.

A resonant fiber optic gyroscope (RFOG) comprises two integrated photonics interfaces coupling the optical resonator coil to the multi-frequency laser source that drives the RFOG; wherein the two integrated photonics interfaces comprise a first waveguide layer and a second waveguide layer wherein the first waveguide layer comprises two waveguide branches which come together to form a single waveguide branch; the second waveguide layer comprises two waveguide branches which remain separate from each other; and wherein the waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber.

Aspects of the present disclosure are directed to structural modifications introduced in a waveguide structure in order to more tightly pack adjacent waveguide turns in an optical gyroscope fabricated on a planar silicon platform as a photonic integrated circuit. Increasing number of turns of the gyroscope coil increases total waveguide length as well as enclosed area of the gyroscope loop, which translates to increased sensitivity to rotational measurement.

Aspects of the present disclosure are directed to configurations of compact ultra-low loss integrated photonics-based waveguides for optical gyroscope applications, and the methods of fabricating those waveguides for ease of large scale manufacturing. Four main process flows are described: (1) process flow based on a repeated sequence of oxide deposition and anneal; (2) chemical-mechanical polishing (CMP)-based process flow followed by wafer bonding; (3) Damascene process flow followed by oxide deposition and anneal, or wafer bonding; and (4) CMP-based process flows followed by oxide deposition. Any combination of these process flows may be adopted to meet the end goal of fabricating optical gyroscope waveguides in one or more layers on a silicon substrate using standard silicon fabrication technologies.