Cross-coupling drift between magnetic field and temperature in depolarized interferometric fiber optic gyroscope

We propose a theory of cross-coupling drift in depolarized interferometric fiber optic gyroscopes (D-IFOGs) under the joint influence of magnetic field and temperature. The magnetic field and temperature cross-coupling drift (MTCD) originates from the interaction of the nonreciprocal circular birefringence produced by the magnetic field, the thermal stress birefringence from the varying temperature, and the inherent residual birefringence in the fiber coil. The MTCD is much greater than the sum of the individual drifts induced by magnetic field and temperature. We established a relevant theoretical model and carried out numerical simulations, and verified the results experimentally. For a typical D-IFOG, the experimental results showed a cross-coupling degree exceeding 170% when the temperature varied from -20 °C to 60 °C, as predicted in the simulations.