Exact performance evaluation of lightwave systems with optical preamplifier

In this paper the performances of a direct-detection receiver with optical doped fiber preamplifier are investigated. All the sources which contribute to the global noise are taken into account, namely the shot noise, the excess noise due to the randomness of the gain, the amplified spontaneous emission (ASE) noise, and finally the thermal noise generated by the receiver. The approach is based on a probabilistic model of the amplifier that enables us to give the complete statistics of the noises. Comparisons with results previously obtained by different methods are presented. The effects of the amplifier gain, the spontaneous emission factor, the optical bandwidth, and the thermal noise on the error probability are examined and discussed.