A cubic nonlinear Schrodinger equation (NLS) with periodically varying disp
ersion coefficient, as it arises in the context of fiber-optics communicati
on, is considered. For sufficiently strong variation, corresponding to the
so-called strong dispersion management regime, the equation possesses pulse
-like solutions which evolve nearly periodically. This phenomenon is explai
ned by constructing ground states for the averaged variational principle an
d justifying the averaging procedure. Furthermore, it is shown that in cert
ain critical cases (e.g. quintic nonlinearity in one dimension and cubic no
nlinearity in two dimensions) the dispersion management technique stabilize
s the pulses which otherwise would be unstable. This observation seems to b
e new and is reminiscent of the well-known Kapitza's effect of stabilizing
the inverted pendulum by rapidly moving its pivot. (C) 2001 Published by El
sevier Science B.V.