Study Of The Stability Of The Wavelength Demodulating Of Fiber Bragg Grating

Fiber Bragg Grating sensor becomes a new hot spot of sensor field with its unique advantage. It has the very good application prospect in shipping, aviation, civil engineering, power industry, earth dynamics and oil industry. Study a FBG senor system which is accuracy, low cost, stability is of great significance.The main content of this thesis:1) We devise a method with the optic absorptive gas which is stored in the box and a reference FBG to calibrate the demoulation system. The absorption line of the gas would not be interfered by temperature of the environment. We chose acetylene gas as the absorbing gas, because the absorption spectrum of the acetylene gas is fitted to the FBG sensors.2) The demoulation system is composed of ASE wide band light source, 2X2optical coupler, PIN photodetectors and DSP module. The absorption line of the gas would not be interfered by temperature of the environment, so the optic absorptive gas can improve the accuracy of the wavelength demodulating.3) Experiments with the wavelength analysis system and the FBG sensors are described. Strain data of FBG sensors are gathered and compared with electrical sensors. We calibrated the temperature FBG senor with the demodulation system. The experimental result prove the system is stable.