A system for a resonant fiber optic gyroscope, the system comprising: at least two fiber-to-waveguide optical couplers, each of the at least two fiber-to-waveguide optical couplers having a proximal end (212, 222) and a distal end (214, 224), each of the at least two fiber-to-waveguide optical couplers having a waveguide structure including, a first waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the first waveguide layer including a first waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a second waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler, and a second waveguide layer separated from the first waveguide layer, the second waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the second waveguide layer including a including a third waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a fourth waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler; an optical resonator coil comprised of turns or windings of optical fiber, further comprising a first port and a second port, wherein the first port is optically coupled to the proximal end (212, 222) of a first fiber-to-waveguide optical coupler of the at least two fiber-to-waveguide optical couplers and the second port is optically coupled to the proximal end (212, 222) of a second fiber-to-waveguide optical coupler of the at least two fiber-to-waveguide optical couplers, and the distal end of the first fiber-to-waveguide optical coupler being optically coupled to the distal end of the second fiber-to-waveguide optical coupler to form at least one waveguide; and wherein the or each waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber. at least two fiber-to-waveguide optical couplers, each of the at least two fiber-to-waveguide optical couplers having a proximal end (212, 222) and a distal end (214, 224), each of the at least two fiber-to-waveguide optical couplers having a waveguide structure including, a first waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the first waveguide layer including a first waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a second waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler, and a second waveguide layer separated from the first waveguide layer, the second waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the second waveguide layer including a including a third waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a fourth waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler; a first waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the first waveguide layer including a first waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a second waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler, and a second waveguide layer separated from the first waveguide layer, the second waveguide layer extending from the proximal end to the distal end of the fiber-to-waveguide optical coupler, the second waveguide layer including a including a third waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler and a fourth waveguide branch that extends from the proximal end to the distal end of the fiber-to-waveguide optical coupler; an optical resonator coil comprised of turns or windings of optical fiber, further comprising a first port and a second port, wherein the first port is optically coupled to the proximal end (212, 222) of a first fiber-to-waveguide optical coupler of the at least two fiber-to-waveguide optical couplers and the second port is optically coupled to the proximal end (212, 222) of a second fiber-to-waveguide optical coupler of the at least two fiber-to-waveguide optical couplers, and the distal end of the first fiber-to-waveguide optical coupler being optically coupled to the distal end of the second fiber-to-waveguide optical coupler to form at least one waveguide; and wherein the or each waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber.