Efficient Design of High-Capacity Dense Wavelength-Division Multiplex Systems

An efficient design methodology for high-capacity dense wavelength-division multiplexed systems is presented. In contrast to complex and time-consuming numerical simulations, analytical equations and heuristicapproximations are used to model the system performance. They facilitate first-order performance estimates and the identification of limiting effects even for multi-Tb/s systems within a few seconds. Taking into account local and accumulated group velocity dispersion, impairments due to fibre nonlinearities are described as a function of the average optical input power per channel. In combination with thedegradation of the optical signal-to-noise ratio caused by optical amplifier noise the maximum transmission distance versus optical input power can bedetermined. The validity of the models is verified by means of numerical simulations and system experiments. The dependence on data rate, modulation format, fibre type and dispersion compensation scheme is determined. Practical examples illustrate the usefulness of our design approach.