Hong Wei, Hu Xudong, Zang Zerun, Zhang Pei, Lou Shaofeng, Huang Bo, Li Yunjiao, Zhang Mianzhi
Appl Opt. 2023 Jun 1;62(16):E109-E118. doi: 10.1364/AO.483537.
The pure Shupe effect is substantially reduced in a fiber optic gyroscope (FOG) with symmetrical windings. However, the effect of the temperature-induced nonuniformity of the stress in the coil depends on the mean temperature derivative (T-dot). Research on precision winding technology has discovered that the symmetry of optical fiber rings affects the temperature performance of fiber optic gyroscopes. Optical fiber rings with good symmetry also have good temperature performance. This paper first establishes a temperature drift model of optical fiber rings that includes the Shupe effect and T-dot effect and then uses finite element simulation to analyze the drift error of optical fiber rings in a variable temperature environment. Analysis shows that this drift is caused by the variation and uneven distribution of the fiber length and the refractive index in the positive and negative winding of the optical fiber ring, which results in a residual phase difference that is directly related to the symmetry of the optical fiber ring. Simulation and analysis show that balancing the residual phase difference of the optical fiber ring can be achieved by cutting the length of the optical fiber ring at both ends. This paper uses optical frequency domain reflectometry (OFDR) technology to precisely test the symmetry of the optical fiber ring, ensuring accurate adjustment of the lengths at both ends of the optical fiber ring. Experimental tests on two gyroscopes have shown that the optical fiber ring with a smaller drift error can be obtained after testing and adjusting its length. The experimental data indicates that the bias stability of two laboratory gyros are increased by 23.6% and 18.1%, and the bias range are reduced by 22.4% and 30.0%.
在具有对称绕组的光纤陀螺仪（FOG）中，纯舒佩效应会大幅降低。然而，线圈中温度引起的应力不均匀性的影响取决于平均温度导数（T点）。对精密绕组技术的研究发现，光纤环的对称性会影响光纤陀螺仪的温度性能。具有良好对称性的光纤环也具有良好的温度性能。本文首先建立了包含舒佩效应和T点效应的光纤环温度漂移模型，然后利用有限元模拟分析了变温环境下光纤环的漂移误差。分析表明，这种漂移是由光纤环正反绕组中光纤长度和折射率的变化及分布不均引起的，导致了与光纤环对称性直接相关的残余相位差。模拟分析表明，通过切割光纤环两端的长度可以平衡光纤环的残余相位差。本文采用光频域反射仪（OFDR）技术精确测试光纤环的对称性，确保对光纤环两端长度进行精确调整。对两个陀螺仪的实验测试表明，在对其长度进行测试和调整后，可以获得漂移误差较小的光纤环。实验数据表明，两个实验室陀螺仪的偏置稳定性分别提高了23.6%和18.1%，偏置范围分别减小了22.4%和30.0%。
