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.

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.

Aspects of the present disclosure are directed to process flow to fabricate a waveguide structure with a silicon nitride core having atomic-level smooth sidewalls achieved by wet etching instead of the conventional dry etching process.

The disclosed structures and methods are directed to a chip for an optical gyroscope and methods of manufacturing of the chip for the optical gyroscope. The chip comprises a substrate, a waveguide having a first waveguide cladding layer and a waveguide core; and a ring resonator having a first ring cladding layer and a ring resonator core attached to the first ring cladding layer. A side wall of the ring resonator core forms an obtuse angle with an upper surface of the substrate. The method comprises depositing a first cladding layer on an upper surface of a silicon substrate; depositing a core layer; depositing a resist mask pattern to define a form of a ring resonator core and a form of a waveguide core; etching the core layer outside of the resist mask pattern; and stripping the resist mask pattern off.

One example includes a FOG assembly including a spool that includes a flattened portion corresponding to a flange comprising an axial center corresponding to a sensitive axis about which an associated FOG system is configured to measure rotation. The FOG assembly also includes a magnetic shield arranged as a capped concentric cover about the sensitive axis and coupled to the spool and the flange to create a toroidal cavity between the magnetic shield and the flange. A fiber coil is disposed within the toroidal cavity and coupled to the flange. The fiber coil includes an optical fiber which is counter-wound in first and second orientations. The fiber coil has an axial dimension along the sensitive axis that is less than or equal to approximately 160% of a radial width corresponding to a difference between an outer radius and an inner radius of the fiber coil.

A stimulated Brillouin scattering gyroscope is provided. A pump laser generates continuous wave (CW) energy that travels through at least one bus waveguide to a waveguide resonator. A reflector is positioned within the waveguide resonator. The reflector is configured to pass at least some of the CW energy in a first direction and reflect at least some stimulated Brillouin scattering (SBS) energy in a second direction. A first detector is in operational communication with the at least one bus waveguide to detect CW energy. An output of the first detector used to at least adjust a pump laser frequency of the pump laser. A second detector is also in operational communication with the at least one bus waveguide. The second detector is used to determine phase shifts in detected SBS energy to determine at least rotation.

Disclosed herein 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.

An optical gyroscope includes, in part, an optical switch, a pair of optical rings and a pair of photodetectors. The optical switch supplies a laser beam. The first 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 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.

A fiber management assembly for a multi-axis fiber optic gyroscope (FOG) includes a mounting block. The mounting block includes an integrated optical circuit (IOC) mounting feature configured to permit mounting thereon an IOC. The mounting block further includes coil mounting features configured to permit mounting at least two optical fiber coils at the mounting block with the at least two fiber coils aligned in substantially different directions in three-dimensional space. The mounting block further includes an exterior surface having at least one substantially exterior, curved zone onto which connecting segments of respective optical fibers between the IOC and respective coils of the at least two optical fiber coils are routed and affixed.

One example includes fiber optic gyroscope (FOG) assembly. The FOG assembly includes a spool comprising a flange. The FOG assembly also includes an optical fiber comprising an optical fiber coil portion that is counter-wound in a first orientation and a second orientation opposite the first orientation. The optical fiber portion can be coupled to the flange. The optical fiber further includes a loopback portion with respect to the first orientation that is secured to the flange.