Figure 13: BER features (logarithmic scale) in eight channels (from 193.8 to 196.6 THz with 0.4 THz spacing) after experiencing the achievable maximum transmission distance described in Figure 10 caption. Results achieved with different lengths of fiber span are identified with corresponding groups of signs denoted in the graph text. Note that for fiber span from 30 to 45 km, the logarithmic scale of BER is -inf.