基于差动光纤干涉仪的位移测量方法

Displacement Measurement Method Based on Differential Optical Fiber Interferometer

为解决装置结构复杂与测量分辨率低的问题,提出了一种利用单模光纤和耦合器组成的位移测量系统,耦合器输出端两臂连接准直镜头,照射在被测物体正反两面形成差动结构。该结构使系统位移分辨率提高了2倍,达到1/4波长,且整个系统受温度的干扰较小。通过仿真分析和实验验证,证明了该方法的可行性,并使用多重希尔伯特变换方法进行位移重构。结果表明,该系统的位移重构精度也优于单通道系统,重构误差由111 nm降至60 nm。

A displacement measurement system based on a single mode fiber and a coupler is proposed.The two arms of the output end of the coupler are connected with a collimating lens to form a differential structure when irradiated to both sides of the measured object.The displacement resolution of the system is improved by two times,the resolution can reach a quarter of the wavelength,and the whole system is less disturbed by temperature.Through simulation analysis and experimental verification,the feasibility of this method is proved.Multiple Hilbert transform method is used to carry out displacement reconstruction.The results show that the displacement reconstruction accuracy of this system is also better than that of single-channel system,and the reconstruction error is reduced from 111 nm to 60 nm.