  We investigate polarisation squeezing of ultrashort pulses in optical fibre,
over a wide range of input energies and fibre lengths. Comparisons are made
between experimental data and quantum dynamical simulations, to find good
quantitative agreement. The numerical calculations, performed using both
truncated Wigner and exact $+P$ phase-space methods, include nonlinear and
stochastic Raman effects, through coupling to phonons variables. The
simulations reveal that excess phase noise, such as from depolarising GAWBS,
affects squeezing at low input energies, while Raman effects cause a marked
deterioration of squeezing at higher energies and longer fibre lengths. The
optimum fibre length for maximum squeezing is also calculated.
