二次偏振串扰对光纤陀螺零偏稳定性的影响

The Influence of Second-Order Polarization Crosstalk on the Zero-Bias Stability of Fiber Optic Gyroscope

保偏光纤环是保偏型光纤陀螺(FOG)的关键组成部分。偏振光在保偏光纤环内发生的二次偏振串扰在FOG干涉输出端会产生很多次干扰项引入相位误差,从而影响FOG的静态参数,如零偏稳定性。文章设计了一套实验夹具用于对保偏光纤环精准施压,通过控制两个夹具在保偏光纤的消偏长度内施压产生大量的二次串扰高点。测得光纤环的偏振串扰数据,并进行仿真计算得到零偏仿真值,与实际测试得到的零偏数据对比,理论仿真值与实际测试值一致。随着施压产生的二次串扰强度增大,FOG的零偏稳定性也随之恶化,施压产生的二次串扰点强度最大时,与未施压时相比,实验环1的零偏稳定性从0.006 3°/h恶化到0.015 1°/h,实验环2的零偏稳定性从0.012 5°/h恶化到0.017 1°/h。

Polarization-maintaining fiber coil is the core component of polarization-maintaining Fiber Optic Gyroscope (FOG). The second-order polarization crosstalk occurs within the polarization?maintaining fiber coil of the polarized light will produce many second order interference terms in the interference output end of the FOG, which may introduce phase error and affect the static parameters of the FOG, such as zero-bias stability. In this paper, we design a set of experimental fixture to produces high crosstalk points by exert precision pressure on the polarization-maintaining fiber coil. By controlling the two fixtures exert pressure in polarization-maintaining fibers depolarize length to produce a large number of second order crosstalk, the crosstalk points data is extracted for simulation calculation. Compared with the zero-bias stability data obtained from the actual test, the theoretical simulation value is consistent with the actual test value. As the pressure increases the intensity of the second-order crosstalk, zero bias stability of the FOG is worsening. The maximum intensity of second-order crosstalk produced by pressure is compared with that without pressure. The experimental results show that the zero bias stability of coil 1 is deteriorated from 0.006 3°/ h to 0.015 1°/ h, and zero bias stability of coil 2 is deteriorated from 0.012 5°/ h to 0.017 1°/ h.