he AWG demultiplexer loss). As usual the design starts from the power budget, considering that no dispersions have to be optically compensated. The power budget equations are e=Pt+Gp+G-AT-A-Arec (all in dB) (6.98) (all in dB) TABLE 6.17 Parameters of the Single Span Systems with Electronic Pre-Distortion at 10 Gbit/s Channel speed 10 Gbit/s Optical bandwidth of the DWDM comb Extended C band Modulation IM NRZ Number of channels Channel spacing 100 GHz Transmitting chain Source laser emitted power Source laser linewidth Mach Zehnder lithium niobate IM modulator loss Multiplexer (multistage AWG X 80) loss Patchcords, connectors, monitoring taps loss Detection chain High-efficiency PIN sensitivity @ 10 Gbit/s -20dBm Demultiplexer (multistage AWG X 80) loss Patchcords, connectors, monitoring taps loss Power per channel on the PIN -15 dBm Telecommunication Networks where the symbols have the usual meanings. It is to underline that, also in this case, there exists a maximum peak power per channel that can be injected into the line due to the fact that the pre-distortion device has an upper limit in its equalizing capability and if the non- linear distortion is too pronounced or if it starts to involve nonlinear polarization rotation pre-compensation is no more possible. The value of Pmax is much higher than in the case of previous sections and, looking at the practical implementations of electronics pre-distortion and suitably scaling the presented results [43], it can be set at 34 mW (15.4 dBm) per channel if we target a system length much longer than the effective length, that is almost always the case. From the second power budget equation it results Gb = 16.77 dBm, the total input power being 12.77 dBm and the output power 29.54 dBm. This is not an impossible amplifier, but it is for sure not a standard booster, especially for the very high output power. It is pos- sible that a double stage amplifier is needed, but in any case, we will assume that such an amplifier will be available. In the second power budget equat