Reduction of polarization-fluctuation induced drift in resonator fiber optic gyro by a resonator integrating in-line polarizers

A method to decrease the polarization-fluctuation induced drift in a resonator fiber optic gyro (R-FOG) is demonstrated by inserting two in-line polarizers in a polarization-maintaining fiber resonator with twin 90° polarization-axis rotated splices. The in-line polarizers attenuate the unwanted resonance by introducing high loss for the unwanted eigenstates of polarization in the resonator. Compared to the resonator without in-line polarizers, the polarization-fluctuation induced drift is reduced by $6\times {10}^3$ times. The desired resonance in the resonator can keep excellent stability in a wide temperature range; thus the temperature-dependent polarization-fluctuation drift in the R-FOG is sufficiently suppressed. A typical bias stability of $4.7°/\mathrm{h}$ over 6500 s with an integration time of 10 s has been carried out. To the best of our knowledge, the long-term bias stability and high temperature stability are the best ever demonstrated in an R-FOG.