| 摘要 |
A transducer (11) includes a fiber optic coupler (10) having a variable coupling efficiency. The fiber optic coupler (10) includes a first fiber (12a) and a second fiber (12b) and an interaction region (32) in which light propagating in one of the fibers (12a, 12b) is transferred to the other fiber (12a, 12b) by evanescent field coupling such that introducing light into one of the fibers (12a, 12b) may cause light to be output from both fibers (12a, 12b). Detectors (54), (56) detect the light output by the fibers (12a, 12b) and a ratio meter (58) produces an output proportional to the ratio of light intensity received by one of the detectors (54,56) to the light intensity received by the other detector (54, 56) the ratio being indicative of the coupling efficiency of the fiber optic coupler (10). In a first embodiment the coupling efficiency varies in response to the relative position of the fibers (12a, 12b), thereby providing a transducer 11 for measuring displacement. In a second embodiment the coupling efficiency is temperature-dependent, thereby providing a transducer (11) for measuring temperature. |
