COMPUTATIONALLY EFFICIENT METHODS FOR BIT-ERROR RATE EVALUATION IN WEAKLY COHERENT OPTICAL-SYSTEM

A semianalytical method to estimate the bit-error rate performance of nonsynchronous ASK and FSK optical heterodyne systems is presented. Th is approach takes into account numerous system details with an accurac y similar to Monte-Carlo simulation, but with a computation time reduc ed by several orders of magnitude. An analytical approximation, based on a closed-form expression for the decision variable moment generatin g function, is also presented. The results obtained with the semianaly tical method and the analytical approximation are compared to Monte-Ca rlo simulation results and to measurements obtained on a practical FSK system.