Gaussian approach to the performance assessment of optical multiplexer/demultiplexer concatenation in transparent optical networks

A Gaussian approach (GA) with two equivalent optical filters, one for the noise and the other for the signal, is proposed for analytically evaluating the transparent optical network (TON) performance for arbitrary TON topologies, optical multiplexers/demultiplexers and electrical filters. This GA helps in identifying, in a fast computational way, the different mechanisms that contribute to TON performance degradation. The accuracy of estimates obtained through the GA is assessed in comparison with an exact method. In the case of no laser misalignment, the estimates given by the GA are very accurate, with maximum discrepancies of 0.5 dB observed for infinite extinction ratio. With extinction ratio reduction, the accuracy of GA estimates is further improved. With laser misalignment, for an extinction ratio of 10, the GA estimates are reasonably accurate, and for infinite extinction ratio, the accuracy is slightly reduced, but TON Q-factor behaviour is well assessed by the GA. Only for optical filters with large bandwidth and some laser misalignment, can GA estimates diverge, with discrepancies not exceeding 2.6 dB in the range of parameters investigated.