Real Time Monitoring of Structural Health Using Fiber Bragg Grating Sensors Based on Arrayed Waveguide Grating Demultiplexing

Abstract

In order to monitoring the health of the structure, a quasi-distributed fiber Bragg grating (FBG) interrogator based on two-channel theory of the arrayed waveguide grating (AWG) demultiplexer is presented. As is known, a slightly change of the temperature or strain or other related parameters applied on the FBG will lead to a shift of the Bragg wavelength of the FBG, which makes sense on the precisely temperature and strain monitoring of structures, including viaduct bridges, towers, railway, skyscraper, etc. It can be interrogated by the relative intensity of two-adjacent-channel of the AWG-based demultiplexer, which offers a low-cost, high sensitivity for the interrogation of FBG distributed sensors.