Moment-generating function method used to accurately evaluate the impact of the linearized optical noise amplified by EDFAs

摘要

In a nonlinear optical fiber communication (OFC) system with signal powermuch stronger than noise power, the noise field in the fiber can be describedby linearized noise equation (LNE). In this case, the noise impact on thesystem performance can be evaluated by moment-generating function (MGF) method.Many published MGF calculations were based on the LNE using continuous wave(CW) approximation, where the modulated signal needs to be artificiallysimplified as an unmodulated signal. Results thus obtained should be treatedcarefully. More reliable results can be obtained by improving the CW-based LNEwith the accurate LNE proposed by Holzlohner et al in Ref. [1]. In this work weshow that, for the case of linearized noise amplified by EDFAs, its MGF can becalculated by obtaining the noise propagation information directly from theaccurate LNE. Our results agree well with the experimental data of multi-spanDPSK systems.