VOLTERRA SERIES APPROACH FOR OPTIMIZING FIBEROPTIC COMMUNICATIONS-SYSTEM DESIGNS

A new methodology for designing long-haul fiberoptic communication sys tems is presented. We derive the overall Volterra series transfer func tion of the system including linear dispersion, fiber nonlinearities, amplified spontaneous emission (ASE) noise from the fiber amplifiers, and the square-law nature of the direct detection (DD) system. Since a nalytical expressions for the probability of error are difficult to de rive for the complex systems being used, we derive analytical expressi ons for an upper bound on probability of error for integrate-and-thres hold detection at the receiver. Using this bound as a performance crit erion, we determine the optimal dispersion parameters of each fiber se gment required to minimize the effects of linear dispersion, fiber non linearities and ASE noise from the amplifiers. We study the dependence of optimal dispersion parameters on the average power levels in the f iber by varying the peak input power levels and the amplifier gains, A nalytical expressions give us the freedom to choose system parameters in a practical manner, while providing optimum system performance. Usi ng a simple system as an example, we demonstrate the power of the Volt erra series approach to design optimal optical communication systems. The analysis and the design procedure presented in this work can be ex tended to the design of more complex wavelength division multiplexed ( WDM) systems.