Automated suppression of polarization-fluctuation in resonator fiber optic gyro with twin 90° polarization-axis rotated splices

Automated suppression of polarization-fluctuation in a fiber optic gyro made of a polarization-maintaining fiber (PMF) resonator with twin 90° polarization-axis rotated splices is experimentally demonstrated. The y-axis polarized component in the output of the resonator is detected to generate the feedback signal to adjust the length difference of the two fiber segments between the two 90° polarization-axis rotated splicing points. When the length difference becomes a half of the beat-length of the PMF, only one eigen state of polarization is excited linearly polarized in x-axis direction, ensuring the suppression of polarization-fluctuation induced bias drift.