宽带光源光谱不对称性对光纤陀螺性能的影响

摘要

Spectral asymmetry was one of the non-ideal characteristics of broadband light sources.The influence of this characteristic on scale factor was gradually manifested in high-precision fiber optic gyroscope.In order to analyze the spectral asymmetry and its influence on the fiber optic gyroscope,combined with the typical spectral parameters of the broadband light source used in the fiber optic gyroscope,the spectral asymmetry of the broadband light source was calculated theoretically,and the problems of the traditional quantitative spectral asymmetry were analyzed.And on the basis of this,a more accurate and reasonable quantitative index of spectral asymmetry was proposed.The results show that the spectral asymmetry can produce relative phase error and produce the apparent gain error in the modulation channel,which causes the gyro second feedback loop to "erroneously" adjust the gain of the modulation channel,causing the nonlinearity of the fiber optic gyroscope scaling factor.For class-like rectangles,when the asymmetry is less than 10-2,the non-linearity of the scale factor caused by the apparent gain error can reach 25x10-6.Therefore,in the light source design,the spectral asymmetry needs to be taken as a quantitative consideration indicator.%光谱不对称性是宽带光源的非理想特性之一,这种特性对标度因数的影响在中高精度光纤陀螺中会逐渐显现出来.为了分析光谱不对称性及其对光纤陀螺的影响,结合光纤陀螺所用宽带光源的典型光谱参数,对宽带光源的光谱不对称性进行了理论计算,分析了传统量化光谱不对称性方法存在的问题和局限性,并在此基础上提出了一种更加准确合理的光谱不对称性的量化指标.研究表明,光谱不对称性会产生相对相位误差,并在调制通道中产生视在增益误差,导致陀螺第二反馈回路“错误”调整调制通道的增益,引起光纤陀螺标度因数的非线性误差.对于类矩形光谱当不对称度小于10-2时,视在增益误差引起的标度因数非线性误差会达到25×10-6.因此在进行光源设计时需要将光谱不对称性作为一个定量考虑的指标.