Enhancing Stability of an Integrated Fiber Optic Gyroscope Employing a Dual-Polarization Thin Film Lithium Niobate Modulator Chip

Recent advances in integrated optical gyroscopes focus on the development of on-chip waveguide devices and noise suppression─both critical for higher integration density and measurement accuracy. In this work, we demonstrate a novel, to our knowledge, integrated fiber optic gyroscope (FOG) based on a dual-polarization (DP) scheme incorporating a z-propagating thin-film lithium niobate (TFLN) modulator chip. This chip enables consistent transmission efficiency across all polarization states through an expanded SiON butt-coupling interface and a bilayer inverse taper. By leveraging the complementarity between orthogonal polarized lights, the DP scheme effectively suppresses polarization nonreciprocity and backscattering noise, particularly that arising from chip mode hybridization and sidewall scattering. The integrated DP-FOG achieves a breakthrough bias instability of 0.018 deg/h for a TFLN-based gyroscope, using a polarization-maintaining fiber coil as short as 300 m, with clear detection of the Earth’s rotation. This noise compensation mechanism promises to find significant applications in future monolithic FOGs.