Bitrate(Gb/s) x Length(km): 

Bitrate(Gb/s)  at 100km

Bitrate as a function of dispersion

For MARS with dispersion at D=1.7, the bitrate exceeds the 1.25  Gb/s requirement

For the Nortel lasers used in NE MRTR transponders assume a spectral width of s=0.4 nm