Recognition and Calibration Method for Delay-disorder FBG interrogation System based on FDML wavelength-swept Laser

Fourier domain mode-locked (FDML) has been used in fiber Bragg grating (FBG) interrogation for a high-speed and long-distance measurement. But the delays induced by long fiber result in non-neglected wavelength error and delay-disorder problem which disables system to address the location of sensors with corresponding wavelength-encoding characteristic. This letter proposes a novel delayed peak recognition and calibration method to confirm the relationship between delayed peaks and sensors with recognition parameters at two low rates, and eliminate wavelength error at two high rates. Experimental results show that this method recognizes the delayed peaks correctly and calibrates wavelength accurately with error below 10pm.