Hello and welcome, while this is way over my head, we DO have a scientist or two as members.
Maybe "Cyparagon" could help you out, I bet he could at least shove you in the right direction, or know someone who could.
What kind of autocorrelator did you use? A simple linear autocorrelator only gives the spectral width. With a SHG autocorrelator you can see if the phase is flat ans what the pulse length is, but you'd still have to make assumptions on the pulse shape. A FROG or GRENOUILLE can give the full intensity/time or phase/time profile of a pulse.