为了实现小巧紧凑且使用灵活的大量程位移测量, 提出了一种采用相位调制方法的光纤干涉仪。首先, 介绍相位调制方法, 分析内调制与外调制的特点, 指出由于内调制的局限性, 外调制更适于较大量程的位移测量。然后, 用数学推导和MATLAB仿真对已有的位移解算算法中的反正切法与微分交叉相乘法进行分析, 证明在毫米级量程的位移测量中反正切法优于微分交叉相乘法。最后, 搭建了采用相位调制方法的光纤干涉仪, 并进行了实验验证。实验结果表明: 相比于微分交叉相乘法, 反正切法更适用于毫米级以上量程的位移测量, 基于相位调制的光纤干涉仪在毫米级步进运动中的相对误差最大为255.21 nm, 标准差为78.56 nm, 基本满足高精度大量程的位移测量需求。

In order to realize compact and flexible wide-range displacement measurement, a fiber interferometer with the Phase Generated Carrier(PGC) method was proposed. First, the PGC method was detailed. The analysis on the internal and external modulations revealed the limitation of internal modulation and indicated that the external modulation was more suitable for wide-range displacement measurement. Then, two existing displacement calculation algorithms were analyzed by mathematical deduction and MATLAB simulation, proving that PGC-ATAN algorithm is better than PGC-DCM algorithm in millimeter-scale displacement measurement. A fiber interferometer based on the PGC method was established and tested experimentally. The results indicate that compared to PGC-DCM algorithm, PGC-ATAN algorithm is a better candidate for millimeter-scale displacement measurement. The maximum relative error of the interferometer in a millimeter-scale step motion is 255.21 nm with a standard deviation of 78.56 nm. It can satisfy the system requirements of high-precision and wide-range in displacement measurements.