FIBEROPTIC DISPLACEMENT SENSOR WITH 0.02 MU-M RESOLUTION BY WHITE-LIGHT INTERFEROMETRY

A system of fiber-optic displacement sensors is described. Interferometric transducers and recievers are linked in various combinations by multimode fibers. Michelson and Fabry-Perot interferometers serve as the transducers. Receivers are of the Michelson type, scanned either mechanically to provide a wide range (20 mm) at low repetition (1/s), or electronically with a CCD photodiode array, offering fast read-out (< 10 ms) over a limited displacement range (140-mu-m). The sensor operation is independent of variations of the fiber losses. We discuss the performance of this system, its resolution, absolute accuracy, noise and multiplexing.