Reduction of polarization-fluctuation induced drift in resonator fiber optic gyro by a resonator with twin 90 degrees polarization-axis rotated splices.

A method to suppress polarization-fluctuation induced drift in resonator fiber optic gyro (R-FOG) is demonstrated by a polarization-maintaining fiber (PMF) resonator with twin 90 degrees polarization-axis rotated splices. By setting the length difference of the fiber segments between two 90 degrees polarization-axis rotated splicing points to a half of the beat-length of the fiber, a single eigen-state of polarization (ESOP) is excited with incident lightwave linearly polarized along the polarization-axis of the fiber. Compared to the previously reported resonator employing single 90 degrees polarization-axis rotated splice [1], in which two ESOPs are excited, our new scheme avoids the effect from the unwanted ESOP and thus suppresses the polarization-fluctuation induced drift in R-FOG output significantly.