High bit rate dense dispersion managed optical communication systems with distributed amplification

In this paper we have investigated optical pulse propagation in a dense dispersion managed (DM) optical communication system operating at a speed of 100 Gb/s and more taking into account of the effects of third order dispersion, intra-pulse Raman scattering and self steepening. Using perturbed variational formulation, we have obtained several ordinary differential equations for various pulse parameters. These equations have been solved numerically to identify launching criteria in the first DM cell of the system. Full numerical simulation of the nonlinear Schrodinger equation has been employed to identify effects of higher order terms on pulse propagation and to investigate the intra-pulse interaction. The roles played by these higher order linear and nonlinear effects have been identified. It has been found that the shift of the pulse centre due to intra-pulse Raman scattering increases with the increase in the distance of propagation and average dispersion. We have noticed that for higher value of average dispersion pulses travel less distance before collision than for lower average dispersion.