Suppressing Polarization Non-Reciprocity and Backscattering Noise in Dual-Polarization Modulation and Sensing Interferometric Fiber Optic Gyroscope

Dual-polarization interferometric fiber optic gyroscopes (DP-IFOGs) have recently emerged as an attractive high-performance IFOG. However, suppression of polarization non-reciprocity (PN) and backscattering noise (BS) is necessary for improving system stability. In this article, a dual-polarization modulation and sensing IFOG (DPMS-IFOG) with a mid-positioned DP-modulator is proposed and demonstrated. When horizontally and vertically polarized light (HPL and VPL) have balanced intensities, PN manifests identical magnitude but opposite sign. For BS, a part is converted into negligible second-order intensity noise, and the other exhibits enhanced complementarity owing to the reverse modulation between HPL and VPL. Experimentally, thermal strain introduces low-frequency PN, and bias instability (BI) reduces from 0.49 °/h of the uncompensated output to 0.05 °/h of the compensated output. The laser-driven DPMS-IFOG demonstrated 15.66-fold and 33.34-fold improvements in BI and angular random walk (ARW), decreasing from 0.94 °/h to 0.06 °/h and from 0.1667°/h^1/2 to 0.005°/h^1/2, respectively. Such innovative error-compensation mechanisms may find important applications in high-precision IFOGs.