Fiberoptic displacement sensor with a short hollow metal optical waveguide

A fiberoptic displacement sensor is described that is based on a combinatio n of a pair of emitter and receiver fibers and a short hollow metal wavegui de. The role of the hollow metal waveguide and its influence on the sensor characteristics are studied experimentally. It is shown that adding such a waveguide changes the shape of the sensor's output signal and increases its amplitude by more than a factor of two. The optimum length of the metal op tical waveguide that ensures improved sensor's parameters is also estimated . The proposing sensor scheme can modify and improve the parameters of a la rge variety of fiber optic sensors that employ the same emitter-receiver fi ber arrangement. (C) 1999 American Institute of Physics. [S0034-6748(99)035 04-2].