Analysis of wavelength-switched high-density WDM networks employing wavelength conversion by four-wave-mixing in semiconductor optical amplifiers

In this paper transmission through an optical transparent network layer in which very high capacity data streams are processed without optical to electrical conversion is considered. Highly-dense WDM is assumed. The optical layer is superimposed to an electrical network layer in which the high capacity streams are processed at lower digital transmission hierarchies. Photonic switching is realized inside the optical layer by means of wavelength translators based on four-wave-mixing in traveling wave semiconductor optical amplifiers. The transmission performance of the network is theoretically analyzed exploiting an accurate model of the wavelength converter. ASE and phase noise accumulation along the signal path through the network, linear crosstalk and nonlinear effects during fiber propagation are taken into account. Due to the adopted method to perform wavelength conversion, chirping/dispersion induced penalties result to be greatly reduced and homo-wavelength crosstalk inside the network nodes is almost eliminated. This allows very good transmission performances to be attained even for very high capacity networks, as demonstrated by the reported theoretical results