Research on Axial Magnetic Field Sensitivity in the Polarization-Maintaining Optical Fiber Coil of Fiber Optic Gyroscope

The magnetic field sensitivity is the main source of errors in a fiber optic gyroscope (FOG) and the polarization-maintaining (PM) optical fiber coil is a major sensitive source. In this paper, a theory that an orthogonal magnetic field vertical to the light propagating direction in a PM optical fiber coil can induce a non-Faraday nonreciprocal phase difference in a FOG is presented. The theoretical simulation and experimental results show that the orthogonal magnetic drift proportional to the orthogonal magnetic field is the main cause of the axial magnetic field sensitivity in a FOG, which is closely related to the skeleton radius of the optical fiber coil and depends neither on the fiber coil's size nor the shape. Furthermore, the orthogonal magnetic field sensitivity will increase with decreasing skeleton radius. Aiming at the application demand of miniaturized gyroscope, the research results of this paper have certain guiding significance and engineering application value.