Femtosecond pulse delivery through large-core microstructured fibers

Summary form only given. Recently developed microstructured fibers (MF) offer new possibilities for delivery of energetic pulses. Utilization of large-mode-area single-mode MF is not possible due to prohibitively large bend losses, however robust single-mode operation of multimode MF appears attainable. Input pulses centered at 800 nm were generated by a commercial Ti:sapphire laser. The temporal pulsewidth of the output was measured with an intensity autocorrelator based on a two-photon photodiode. The input chirp was adjusted to produce the shortest output pulses at the lowest powers. Maintaining the distance between gratings constant, we measured the duration of the output pulses as a function of power. For 2.5-nanojoules-energy pulses, we measured output pulse widths shorter than 300 fs.