Design and operation of different optical fiber sensors for displacement measurements

Design and operation of different intensity modulated extrinsic optical-fiber sensors are reported. A cantilever fiber-to-fiber, as well as a fiber-lens-fiber design is arranged and studied experimentally. The third scheme introduces a fiber-lens-double fiber design in which a double fiber is used for the light detection. In each case, a stepper motor driven micrometer system is used for the small displacement variations of the cantilever fiber or the ball lens. The results obtained for these sensors are checked against each other, advantages and disadvantages are explored, and the optimum sensor design for such a measurement is proposed. (C) 1999 American Institute of Physics. [S0034-6748(99)00806-0].