Stabilizing the Pereira-Stenflo Solitons in Nonlinear Optical Fibers

We study in detail stability of exact chirped solitary-pulse solutions in a model of a filtered nonlinear optical fiber, in which stabilization of the pulses is achieved by means of an extra lossy core, parallel-coupled to the main one. We demonstrate that, in the model's three-dimensional parameter space, there is a vast region where the pulses are fully stable, for both signs of the group-velocity dispersion. These results open way to a stable transmission of optical solitons in the normal-dispersion region and, thus, to an essential expansion of the bandwidth offered by the nonlinear optical fibers for telecommunications. In the cases when the pulses are unstable, we study the development of the instability, which may end up by either a blowup or decay to zero.