Wide-Range Wavelength-Tunable Mode-Locked Fiber Laser Based on Fiber Bragg Grating

We demonstrated a wide-range wavelength-tunable passively mode-locked fiber laser based on the fiber Bragg grating (FBG) fabricated by femtosecond laser as the wavelength selection element. A ring fiber cavity with the nonlinear-optical loop mirror as its saturable absorber was employed for mode-locking operation. The peak wavelength of the fiber laser was 1547.9 nm with a spectral full-width-at-half-maximum of 0.90 nm at room temperature. The pulse duration of the fiber laser was about 2.94 ps closed to the Fourier-limited pulse duration of 2.80 ps by assuming sech ² pulse shape. The repetition rate was 860.5 kHz and the pulse peak power was about 56.2 W. The wavelength tuning range of the fiber laser achieved 14.2 nm by varying the FBG temperature from 25 °C to 1000 °C.