宽谱光源相对强度噪声及对闭环光纤陀螺影响研究

Relative Intensity Noise Characteristic of Broadband Sources and its Effect on Performance of Closed-Loop Fiber Optic Gyroscope

宽谱光源相对强度噪声(RIN)的定量评估及其对光纤陀螺(FOG)性能的影响机理是进一步提高FOG精度的关键问题。搭建实验测试系统对4种不同谱型、不同偏振态宽谱光源的RIN进行了独立测试,基于3种不同等效谱宽定义分别计算4种宽谱光源的RIN,通过对比确定了基于功率加权平均谱宽的强度噪声计算模型;在此基础上,对FOG的随机游走系数(RWC)模型进行了修正。搭建光电分离式高精度FOG实验系统,采用4种光源,分别测试了FOG的RWC,同时利用修正模型估算了RWC,实测值与估算值吻合较好。结果表明,光源的功率加权平均等效谱宽和偏振度是影响宽谱光源RIN的主要因素,该研究为光源RIN的评估和高精度FOG的优化设计提供了重要的理论和实践依据。

The accurate evaluation of relative intensity noise （RIN） of broad-band sources and its effect mechanism on a fiber optic gyroscope （FOG） are key factors to further improve the performance of FOGs. An intensity noise measurement system is constructed and RINs of four sources with different spectral shapes and degree of polarizations are tested. Then the RINs are calculated with three different effective bandwidths and the accurate RIN model is confirmed by employing the power weighted average （PWA） bandwidth. Based on this research, the random walk coefficient （RWC） model of FOG is modified. A photoelectric detachment high precision FOG is constructed, and the RWC of FOG is tested with four broadband sources and calculated by using the modified model. It is shown that the calculation results are consistent with the experiment results. This indicates that the power weighted average bandwidth and the degree of polarization are key factors determining the RIN of broadband sources and this research is of great value in evaluating the RIN characteristics of different sources and designing high performance FOGs.