1引言位移测量是各种测量的基础，利用单膜光纤干涉仪测量位移，是当前世界各国科技界的研究热点之一，由于它具有以下优点，所以得到世界各国的高度重视。（1）分辨率高，例如光纤位移传感器，其灵敏度在理论上为10－13m。（2）为无源器件，对被测对象不产生影响。（3）频带宽 1 Introduction Displacement measurement is the basis of various surveys. Using single-fiber optical interferometer to measure displacement is one of the research hotspots in the field of science and technology in various countries all over the world. Because of its following advantages, it has won great attention of all countries in the world. (1) high resolution, such as optical fiber displacement sensor, the sensitivity is theoretically 10-13m. (2) is a passive device, does not affect the measured object. (3) bandwidth