57 W, 27 fs pulses from a fiber laser system using nonlinear compression

We report on the generation of 27 fs pulses with an average output power of 57 W and a repetition rate of 78 MHz. The pulses are generated by combining a high average power fiber chirped pulse amplification (FCPA) system with a microstructured large-mode-area fiber for nonlinear compression. The FCPA system delivers 270 fs pulses in a linearly polarized beam with diffraction-limited quality. Nonlinear compression is achieved by launching the pulses into a short (few cm) piece of microstructured fiber and subsequent compression by a pair of chirped mirrors.