High-performance integrated-optical chip for a broad range of fiber-optic gyro applications

A high-performance integrated-optical device for a broad range of fiber-optic gyro applications is reported. The circuit contains four directional couplers and six phase modulators that form the fiber-loop coupler, the bias and serrodyne phase modulators, and an on-chip interferometric serrodyne phase detector. The chip was fabricated by the annealed-proton-exchange method in X-cut LiNbO(3), which yielded a highly polarizing guided circuit with a polarization extinction ratio of at least 60 dB. Other performance parameters include low half-wave voltages (3.5-5.5 V) at 1.3 microm and splitting and tapping directional coupler parameters well within the design needs required by application.