Dispersion Measurement of Chirped Fiber Bragg Grating Using a Tunable Mode-Locked Laser

An accurate dispersion measurement approach for chirped fiber Bragg gratings (CFBGs) based on a wavelength-tunable mode-locked fiber laser is proposed and demonstrated. The relationship between group delay and the mode-locked laser’s repetition rate is analytically derived. Dispersion information and the tunning ranges of 2^nd and 3^rd dispersion coefficients of a commercial tunable CFBG are determined experimentally, which are agree well with the specifications provided by the manufacturer. Compared with other techniques, the proposed method is straightforward to operate. The retrieved high-order dispersion information of CFBGs will be greatly benefit to the fiber chirped-pulse amplification system and ultrafast laser techniques.