Based on the principle of tunable fiber Fabry-Perot（TF F-P） filter which scans the reflected peak of fiber Bragg grating（FBG）

aimed at the nonlinearity and nonrepeatability between the transmitted wavelength and control-voltage of the TF F-P filter

a novel wavelength demodulation system based on reference FBG is presented.The system adopts reference FBG which placed in the unchanged temperature environment to get steady wavelength.The wavelength and control-voltage of the TF F-P filter is linearized in a narrow wavelength range

which achieves high performance.Demodulation system is used to detect a FBG temperature sensor at the range of 30

1

30 ℃

the experimental comparison results show that average temperature error is less than 0.52 ℃.