Analysis of the compensation mechanism of a fiber-optic displacement sensor

Abstract This paper describes the evaluation of a fiber-optic displacement sensor that is compensated for variations in light-source intensity as well as for losses in the fibers. On the basis of the intensity distribution function of the output optical field formed by the source fiber end, the compensation mechanism of the twin-receiving-fiber displacement sensor is analyzed. It is shown theoretically that the ratio of the outputs of a pair of detecting fibers is independent of the light-source intensity and losses in the fiber system. Results are presented that confirm this.