Transform-limited 100 μJ, 340 MW pulses from a nonlinear-fiber chirped-pulse amplifier using a mismatched grating stretcher-compressor

We report on a compact double-stage ytterbium-doped-fiber chirped-pulse amplifier system delivering high temporal quality 270 fs pulses of 100 mu J energy at a repetition rate of 300 kHz resulting in a peak power of 340 MW. The recompression down to 1.1 times the Fourier limit is based on the exploitation of nonlinear phase shifts associated with mismatched stretcher-compressor units. A 1-m-long ytterbium-doped 80 mu m core diameter photonic crystal fiber is implemented as the power amplifier and allows the production of 143 mu J pulses before compression with an accumulated B integral of 17 rad throughout the amplification stages. (C) 2008 Optical Society of America.