Bit-error rate for a lightwave communication system incorporating an erbium-doped fibre amplifier

Abstract

The photon-number distribution at the output of an erbium-doped fibre amplifier (EDFA) with coherent light at the input is shown to obey the noncentral-negative-binomial (NNB) distribution. The use of this distribution in a binary on/off keying system gives rise to a lower bit-error rate (BER) than the Gaussian distribution, because the tails of these distributions differ (even for large mean input photon numbers).