Fiber optic gyroscope

The gyroscope has an optical system that has a fiber optic coupler (52) and single mode optical fibers (51,53) connected from a light source (10) to an optical integrated circuit (14). A polarization maintaining optical fiber (54) is connected to the input-output end of the optical integrated circuit to produce a difference in group delay time between two orthogonal polarization modes. The polarization maintaining optical fiber has a predetermined length (L), and connected nearer the light source in the optical system to the optical integrated circuit. The polarization maintaining optical fiber produces a difference in group delay time that exceeds the coherence length of light from the light source.