A theoretical investigation of the influence of noise in a passively mode-l
ocked semiconductor laser with a slow saturable absorber is presented. Diff
erence equations for the pulse energy and jitter are derived. We find that
noise leads to increased pulse durations and considerable jitter. The influ
ence of noise, for systems with and without self-phase modulation and group
velocity dispersion, on the pulse energy and stability regions is discusse
d. (C) 1999 American Institute of Physics. [S0003-6951(99)03133-2].