Self-starting widely tunable ps pulses generation from Yb-doped double-clad fiber laser

The cw pumped self-staring, widely tunable ps pulses Yb³⁺-doped double-clad fiber laser is experimentally studied. In experiments, the 20 m single mode Yb³⁺-doped double-clad fiber worked as gain medium. And we used 77 MHz RF signal AOM and a grating which formed external cavity to provide feedback, and made the laser linewidth narrower. We obtained 1 GHz repetition rate with highest output power 56.3 mW pulses, whose width was smaller than 60 ps. Also, the fiber laser was tunable over 40 nm from 1072.9 nm to 1113.7 nm.