High-power femtosecond Yb-doped fiber amplifier

We report on the generation of linearly chirped parabolic pulses with 17-W average power at 75 MHz repetition rate and diffraction-limited beam quality in a large-mode- area ytterbium-doped fiber amplifier. Highly efficient transmission gratings in fused silica are applied to recompress these pulses down to 80-fs with an efficiency of 60%, resulting in a peak power of 1.7 MW. Power scaling limitations given by the amplifier bandwidth are discussed. (C) 2002 Optical Society of America.