Optimum amplifier location for wavelength division multiplexed dispersion managed solitons

Using a variational method, we analyze the residual frequency shifts due to cross-channel interactions in wavelength division multiplexed dispersion managed soliton transmission systems. We put forward a simple criterion for the optimal location of the amplifier based on the results of this analysis. This conclusion is explained in terms of the dependence of the propagation properties of a single pulse on the position of the amplifier and the optimality of the criterion is assessed, for some specific parameter values, using a commercial simulation software.