Magnetic error suppression in Polarization-Maintaining fiber optic gyro system with orthogonal polarization states

Abstract

In this paper, a polarization-maintaining fiber optical gyro (PMFOG) based on orthogonal polarization states is constructed. The clockwise light and counterclockwise light in the PMFOG pass through the same fiber coil with X/Y polarization and Y/X polarization respectively. Theory and experiments have shown that this system not only doubles the sensitivity of the PMFOG at the same length, but also suppresses the magnetic error obviously compared with the single-polarization PMFOG. The Poincare sphere model is established in the PMFOG with orthogonal polarization states under the radial magnetic field, which intuitively shows that magnetic error is opposite in the orthogonal polarization state, and can offset through each other. The radial magnetic error is suppressed from 0.112°/h/Gs to 0.011°/h/Gs, and the suppression reaches 10.07 dB. Meanwhile, the axial magnetic error is suppressed from 0.183°/h/Gs to 0.092°/h/Gs, achieving a suppression effect of 2.9 dB. The results of this research are of great significance to the miniaturization, the improvement of signal-to-noise ratio, and the optimization of environmental adaptability in fiber optic gyroscope.