STRAIN MEASUREMENT AT CANTILEVER BEAM WITH FIBER BRAGG GRATING SENSORS AND COLLIMATORS AND ITS CORRECTION METHOD

Abstract

Recently, Fiber Bragg Grating(FBG) sensors are being used in various fields. However, it has difficulty to measure at the place where it is not possible to connect fibers each other physically. In this study, using FBG a collimator, we have measured strains with a single optical fiber with many FBG sensors where FBG sensors on one optical fiber line is installed on the beam and the other optical fiber line is connected with an optical interrogator installed at stationary side. The optical fiber lines between an optical fiber line with FBG sensors on the beam and the other optical fiber line on the stationary part are connected by the collimator which makes the use of light's unique characteristic - light travels through space. The experiment showed that the wave length of the light were changed to be linear as strains increased, and the accurate strains were measured by applying the collimator collection factor, which was proposed in this paper.