A demodulation method of FBG based on DFB laser and PID algorithm

A demodulation system for fiber Bragg grating (FBG) is designed based on distributed feedback (DFB) laser. By use of adjusting the internal temperature, wavelength tunable laser is achieved, and utilizing the laser and PID algorithm to realize the demodulation of FBG sensing signal. The system uses all-fiber structure, with fast response and high precision demodulation. Experimental results show that the method is accurate and stable to realize the demodulation of FBG sensing signal, the system minimum resolution can achieve 0.4 pm, dynamic range was up to 3 nm.