Measurement of the intensity and phase of supercontinuum from an 8-mm-long microstructure fiber

We generate, measure, and model broadband continuum generation from a relatively short 8-mm-long microstructure fiber pumped by 40-fs pulses at 816 nm in the near infrared. Cross-correlation frequency-resolved optical gating is used to measure the spectral intensity and phase of the output continuum, and the results are shown to be in good agreement with numerical simulations. The output temporal intensity exhibits a distinct series of ultra-short sub-40-fs-duration sub-pulses, with these results directly revealing for the first time the temporal pulse breakup and soliton fission that is the dominant initial spectral broadening process underlying supercontinuum generation in microstructure fibers.