A highly precise FBG sensor interrogation system with wavemeter calibration

Abstract Fiber Bragg grating (FBG) demodulators based on tunable lasers have been extensively applied in many fields. However, the tunable lasers can hardly avoid wavelength nonlinear tuning. Such problems and unexpected wavelength fluctuations may cause serious measurement errors. In this study, we propose a wavelength calibration scheme to solve this problem by incorporating a magneto-optic wavemeter into the interrogation system. We present experimental verification of real-time wavelength calibration of tunable lasers and measurement corrections. In the temperature measurement demonstrations, the experimental results show that the FBG interrogation accuracy was raised from ±3 pm to ±1 pm, and better long-term stability was achieved, corresponding to the temperature accuracy of ±0.1 °C.