Research Of Fiber Bragg Grating Sensors And Design Of Conditioning Circuits

Optical fiber grating is a new type of passive fiber component which is widely investigated and applied recent years in the world. Optical fiber Bragg grating (FBG) sensor is a functional optical fiber sensor which uses FBG as the sensing unit. It can take measurement of temperature and strain directly and also detect other physical and chemical variables indirectly. It has many advantages such as lightweight, corrosion resistance, anti - interference of electromagnetic, small size of probe, easily connecting with optical fiber, easily forming sensing network and so on. Because of these superiorities, the optical fiber Bragg sensor is widely used in all fields.This paper discussed the principle of FBG sensors in theory and technique and then studied the wave length demodulation method and the realization. Based on the analysis, a kind of FBG demodulation system was put forward and the electric circuit modules of photoelectricity system were designed. Specially, the turnable FFT scan circuit and the weak signal amplification circuit for FBG reflection light were successfully completed. The entire FBG photoelectric system was connected and tested. This paper gave emphasis to the study on FBG sensors and a kind of high sensitive temperature sensor which used metal substrate was designed. Through the finite element analysis method, the strain under a variety of force was analyzed and the coupling effect of strain on temperature sensor was discussed. Furthermore, the characteristics of nude FBG sensor and the metal substrate sensor were tested under the static and dynamic temperature change. The result of experiment was given.