All-fiber laser seeded femtosecond Yb:KGW solid state regenerative amplifier*

A high efficiency compact Yb:KGW regenerative amplifier using an all-fiber laser seed source was comprehensively studied. With thermal lensing effect compensated by the cavity design, the compressed pulses with energy of 1 mJ at 1 kHz and 0.4 mJ at 10 kHz in sub-400-fs pulse duration using chirped fiber Bragg grating (CFBG) stretcher were demonstrated. A modified Frantz-Nodvik equation was developed to emulate the dynamic behavior of the regenerative amplifier. The simulation results were in good agreement with the experiment. Numerical simulations and experimental results show that the scheme can be scalable to higher energy of multi-mJ, sub-300 fs pulses.