  To the best of our knowledge, we demonstrate for the first time the
generation of photon number squeezing by spectral filtering for ultra-broadband
light generated by microstructure fibers at 800 nm. A maximum squeezing of 4.6
dB is observed, corresponding to 10.3 dB after correcting for detection losses.
We numerically analyzed the quantum dynamics of ultrashort laser pulse
propagation through optical fibers by solving a nonlinear quantum Schrodinger
equation that included Raman scattering, especially for the quantum correlation
of photon number fluctuation among frequency modes in broadband pulses.
