Analysis of avalanche diode receivers by saddlepoint integration

The error probability in a binary fiber-optical communication system whose receiver utilizes an avalanche-diode detector is calculated by applying the method of numerical saddlepoint integration to Laplace inversion integrals for the probabilities of errors of the first and second kinds. It is shown how to choose the contours of integration for efficient numerical quadrature. The effects of shot noise, intersymbol interference, and additive Gaussian noise are taken into account, and the decision level on the receiver output is set to minimize the average probability of error. Examples show how the method can be used in receiver design to select system parameters such as the output pulsewidth and the sampling time in order to minimize the probability of error