Improvement of long-term stability of hollow-core photonic-crystal fiber optic gyro based on single-polarization resonator.

To improve long-term stability, we present a single-polarization resonator optic gyro based on a hollow-core photonic-crystal fiber (HCPCF), utilizing a micro-optical polarizing coupler formed by pairs of collimators and a series of polarization-dependent devices. We build the mathematical model of the polarization noise of the proposed gyro and experimentally validate the elimination of the undesired polarization eigenstate, which is the basis of the system's improved long-term stability. We use multi-modulation to suppress the backscattering noise and the closed-loop detection method to eliminate the effect of fluctuating output power on the gyro bias. A long-term bias stability of 20°/h is successfully demonstrated.