FIBER COUPLER TRANSDUCER

摘要

A transducer includes a fiber optic coupler 10 having a variable coupling efficiency. The fiber optic coupler includes a first fiber and a second fiber and an interaction region in which light propagating in one of the fibers is transferred to the other fiber by evanescent field coupling such that introducing light into one of the fibers may cause light to be output from both fibers. Detectors detect the light output by the fibers and a ratio meter produces an output proportional to the ratio of light intensity received by one of the detectors to the light intensity received by the other detector, the ratio being indicative of the coupling efficiency of the fiber optic coupler. In a first embodiment the coupling efficiency varies in response to the relative position of the fibers, thereby providing a transducer for measuring displacement. In a second embodiment the coupling efficiency is termperature-dependent, thereby providing a transducer for measuring temperature.