Dispersion-Managed Solitons and Optimization of the Dispersion Management

Abstract

We overview recent progress in dispersion-managed (DM) fiber optic communications. Wavelength-division-multiplexing transmission of a DM soliton (or more general return-to-zero (RZ) formatted data) is an attractive way to realize middle- and long-distance ultra-high-capacity fiber communication systems. We present a theory of the DM optical soliton and a simple basic theory of the general DM RZ transmission. Two ordinary differential equations for the root-mean-square pulse width and chirp (momentum equations) describe the fast (during compensation period) evolution of the DM pulse. Applying chirped Gauss–Hermite orthogonal functions we derive a path-averaged propagation equation governing both the shape of the DM soliton and the slow (average) evolution of any chirped DM pulse. We describe the breathing dynamics of the self-similar core and oscillating tails of the DM optical pulse propagating in a fiber line with an arbitrary dispersion map. Based on the developed theory we describe the basic system principles, the design, and the optimization rules for DM fiber links. We demonstrate how to determine the energy enhancement of the DM soliton and optimal (chirp-free) points for launching of the signal, and how to evaluate the characteristics of a carrier signal for specific system parameters. DM solitons in systems with in-line filtering and Bragg gratings are also studied. Analytical results are illustrated by numerical simulations for a number of specific dispersion maps actively used in practice.