US Patent 11175140 Resonator fiber optic gyroscope with integrated photonics interface

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.