Simultaneously achieving sensitivity enhancement and relative intensity noise suppression in a closed-loop dual-polarization interferometric fiber optic gyroscope

Relative intensity noise (RIN) suppression and sensitivity enhancement are important means to reduce the bias instability (BI) and angular random walk (ARW) of interferometric fiber optic gyroscopes (IFOGs). In this study, a closed-loop dual-polarization IFOG with dual-polarization modulation and sensing technology is demonstrated. The phases of dual-polarization lights are modulated inversely to produce a complementary response at the same angular velocity. RIN in the two outputs is identical and synchronous because the two polarizations propagate in a fiber coil and experience a similar noise environment. Therefore, sensitivity enhancement and RIN suppression are obtained simultaneously through differential compensation. Compared with the single outputs, BI of the compensated output is reduced from 0.1°/h to 0.0069°/h, and ARW is decreased from 0.018°/h^1/2 to 0.00145°/h^1/2.