Development of a low-cost and miniaturized fiber Bragg grating strain sensor system

A fiber Bragg grating (FBG) strain sensor system that measures strains from reflected power changes of FBGs is presented. A laser diode used as a light source and a power meter are used in the system, which makes the FBG sensor system inexpensive and miniaturized. The reflected power of an FBG is expressed by the product of the reflectivity of the FBG and the optical power of the laser diode. Comparison of the strain applied in the experiment with that calculated from the reflected power shows that relative errors are within 5.1%, which verifies the feasibility of the strain sensor system proposed in this work. In addition, on the basis of this method, we fabricate a cantilever load cell using an FBG as the strain gauge instead of an electrical resistance, and also quantify the load range that can be measured by this load cell. (C) 2017 The Japan Society of Applied Physics