Suppressing polarization non-reciprocity error with reverse phase modulation in dual-polarization fiber optic gyroscopes

In a dual-polarization interferometric fiber optic gyroscope (IFOG), polarization non-reciprocity (PN) errors are significant, which degrades the IFOG performance due to the polarization coupling between two orthogonal axes. A dual-polarization IFOG with reverse phase modulation is proposed in which PN phase error can be sufficiently suppressed. In our scheme using a 2-km polarization maintaining coil with open-loop configuration, angle random walk of 4.62×10−4°/h and a bias instability of 4.6 × 10−4 °/h is demonstrated in detecting the Earth’s rotation rate.