In order to improve wavelength demodulation precision of fiber Bragg grating（FBG） demodulation system and satisfy the need of high precision measurement practically

based on F-P tunable filter and wavelength standard device

a processing technique that combines correlation spectrum method with linear interpolation method is presented.This method not only can restrain noise effectively

but can detect wavelength drift quantity accurately.Experiments indicate that wavelength resolution of Bragg grating and demodulation precision both can be improved well compared with conventional peak detection method

and wavelength resolution is 1pm

temperature measureing precision is ±0.2 ℃.