We give numerical evidence that a singly resonant optical parametric oscill
ator is sensitive to noise in the single-pulse regime throughout the evolut
ion of the fields. The noise induces pulse jitter that can be eliminated by
use of either a small-amplitude injected field or an additional feedback c
avity. (C) 2000 Optical Society of America [S0740-3224(00)00801-8] OCIS cod
es: 190.4970, 190.7110.