Resonant shape oscillations and decay of a soliton in a periodically inhomogeneous nonlinear optical fiber.

The propagation of a soliton in a nonlinear optical fiber with a periodically modulated but signpreserving dispersion coefficient is analyzed by means of the variational approximation. The dynamics are reduced to a second-order evolution equation for the width of the soliton that oscillates in an effective potential well in the presence of a periodic forcing induced by the imhomogeneity. This equation of motion is considered analytically and numerically. Resonances between the oscillations in the potential well and the external forcing are analyzed in detail