A quasi distributed fiber optic weight-displacement sensor using macro bends

A quasi distributed fiber optic weight - displacement sensor using Optical Time Domain Reflectometer (OTDR) is presented. Specially made triangular corrugations on aluminum block are used to create macro bends in a single mode fiber. The power loss created by the macro bend is measured by an OTDR. Initially corrugation of 5 mm pitch is used to study the weight-loss and displacement-loss characteristics. This set up is extended for the distributed studies in which three identical corrugations of 5 mm pitch are used. It is also observed that the loss introduced by the macro bend is sensitive to the period of corrugation and there is an optimum period of corrugation which gives highest sensitivity. The experiments are carried out at a wavelength of 1550 nm. Investigations exhibit higher sensitivity at 1550 nm compared to 1310 nm. The effect of number corrugation on the measurement is also a part our investigation.