Nonlinear compression in a rod-type fiber for high energy ultrashort pulse generation.

We report the use of nonlinear compression in a very large mode-area rod-type photonic crystal fiber. This fiber allows the use of high energy pulses in the few microjoule range. We demonstrate the compression of 4 microJ, 338 fs pulses from a fiber chirped pulse amplification (FCPA) system down to 49 fs, 41 MW peak power pulses at a repetition rate of 200 kHz with an average power of 400 mW.