Optic Fiber Interferometer For Absolute Distance Measurement

A new optic fiber interferometer system for measuring absolute distance longer than 1 meter by means of a short distance (100mm) slide-way is presented. It consists of positioning interferometer and scanning interferometer. The positioning interferometer is used to position the target by quasi-white light, and the scanning interferometer is used to measure the distance. In order to expand the measurement range, several couples of fiber are employed in the positioning interferometer, and the optical path difference of each couple can be calibrated by the system itself. The experimental results show that the measuring accuracy may be approached to 10^-5.