Chirped pulse amplification of a femtosecond Er-doped fiber laser mode-locked by a graphene saturable absorber

In this work we demonstrate for the first time, to our knowledge, a chirped pulse amplification (CPA) setup utilizing a graphene mode-locked femtosecond fiber laser as a seed source. The system consists of a mode-locked Er-fiber oscillator operating at 1560 nm wavelength, a grating-based pulse stretcher, two-stage amplifier and a grating compressor. The presented setup allows the amplification of the seed up to 1 W of average power (1000 times amplification) with linearly polarized 810 fs pulses and 20 nJ pulse energy at a 55 MHz repetition rate. The whole design is based on single-mode fibers, which allows one to maintain excellent beam quality, with M-2 less than 1.17.