Highly stable FBG wavelength demodulation system based on F-P etalon with temperature control module

Wavelength of Fiber Bragg Grating(FBG) changes with ambient temperature and pressure. If change of wavelength is detected, then ambient temperature and pressure can be calculated. In this paper, a highly stable Fiber Bragg Grating(FBG) wavelength demodulation system based on F-P etalon with tempe-rature control module was proposed. The theory of the FBG wavelength demodulation system was discussed and the reason of high stability was analyzed. In this system, a Fabry Perot(F-P) etalon with temperature control module was introduced for real-time wavelength calibration. Wavelengths of F-P etalon can be inquired by the specification. Wavelength of FBG can be calculated by linear interpolation. The temperature control module can ensure temperature of the etalon changes within 0.01℃, so that wavelengths of the etalon can be regarded as constant values. In the end the stability of the system was experimented by measuring wavelengths of FBG which was in a water-bath. The system was also compared with the MOI corporation optical sensing interrogator sm125 on the stability. Experimental results demonstrate that the system can achieve a long-term stability of 0.15 pm in 20 h, while sm125 was 3 pm.