Impact of fiber non-linearities in transmission across geographical optical networks

The introduction of a transparent optical level in a very large area transport network requires transmission through optical paths thousands of kilometers long. The Kerr effect in such networks causes nonlinear crosstalk due to Four-Wave Mixing (EWM) among channels, that is a quite detrimental, limiting the achievable spectral efficiency of the WDM transmission. Moreover, non-linear beating among the signals and optical noise are more dangerous than in point-to-point links. The aim of this work is to analyze the limitations imposed by the Kerr effect in fibers to the transmission performances of the WDM optical layer of wide area transport networks.