Strain sensor based on fiber bragg grating bonded with polymer plates

Abstract

In this study, the FBG is embedded in between two polymer plates and then lateral force is applied to create a compression that produces slight curvature on the plates. The purpose of this study is to measure the output operating voltage of reflected spectrum of FBG for different grating position and lateral displacement applied to these plates. Furthermore, the relationship of the output voltage with applied strain was studied. This study only involves compensation of strain without the influence of temperature on the FBG. Passive detection scheme was used as interrogation in this study using power detection method. This system uses an SM-28 FBG (1549.39 nm) with 3.59 cm head sensor, a broadband light source (SLD), a circulator, photodetector, and oscilloscope. The oscilloscope provides the voltage reading of the reflected spectrum received by the photodetector. The graph of output voltage against lateral displacement and applied strain against the output voltage were obtained. The sensitivity of the FBG changes with both different lateral displacement applied to it and the length of the distance from mounting position of the plates to the point of stress, L. The output voltage changes linearly with the lateral displacement and strain applied to the plates.