Sub-50fs GHz Pulse Burst with Average Power Beyond 20W

We report a high power pulse burst polarization-maintaining fiber amplification system that enables 22 W, 1MHz pulse bursts with sub-pulse duration of ~41 fs and repetition rate of ~1 GHz. The seeded GHz pulses are generated from GHz mode-locked fiber laser, and its power is further boosted by a hybrid scheme combining chirped-pulse amplification and self-similar amplification. Because the common double-cladding Yb ³⁺ -doped fiber is used as gain fiber, the simple fusion operation makes the system more compact and reliable.