A simple fiber-optic sensor for use over a large displacement range

Abstract

An intensity-based fiber-optic displacement sensor has been developed and tested for static and dynamic response. The sensor incorporates an extremely simple design, light source and detector. Testing was done using quasi-static extension, a simple oscillating cantilever beam and a small shaker capable of frequencies up to 10 kHz. The sensor shows a response over a wide range of 410 mm. The response has two distinct linear regions with a central nonlinear region. For small displacements, the sensor shows excellent frequency response up to 10 kHz. At this stage, no attempt has been made to theoretically predict the light-loss behavior associated with this macrobend sensor [Marcuse, D., Journal of the Optics Society of America, 66 (3) (1976) 216–220; Lagakos, N., Cole, J. H. & Bucaro, Applied Optics, 26 (11) (1987) 2171–2180]; 1,2 rather this paper serves to demonstrate the basic function of the novel geometry of the sensing element.