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 secondorder intensity noise, and the other exhibits enhanced complementarity owing to the reverse modulation between HPL and VPL. Experimentally, thermal strain introduces lowfrequency 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°/h1/2 to 0.005°/h1/2, respectively. Such innovative error-compensation mechanisms may find important applications in high-precision IFOGs.