Analysis of Polarization Error of the Half-Wave Plate in Photon-Entangled Fiber Optic Gyroscope

This paper derives the principle of the photon-entangled fiber gyro’s optical path, simulates and compares the effect of the rotation angle of the half-wave plate (HWP) optical axis on the output state quantum interference efficiency, and performs a simulation analysis of the polarization entanglement error in the photon-entangled fiber gyro. It is proven that the rotation angle of the half-wave plate’s optical axis has a significant impact on the quantum interference efficiency, with the maximum quantum interference efficiency corresponding to a half-wave plate optical axis rotation angle of 22.5°. When there is a deviation in the rotation angles of the two half-wave plates, it does not lead to non-reciprocal phase errors.Still, it lowers quantum interference efficiency and increases measurement difficulty. Excessive errors in the rotation angle of the half-wave plate’s optical axis may reduce the accuracy performance of the gyroscope. The polarization error generated by the entire optical path may lead to the inability to break through the shot noise limit (SNL), and in the case of existing background noise, the polarization error has a more severe impact on the accuracy of the entangled gyroscope.