Raman pre-amplifier performance comparison in two 320 Gbps transmission systems

The purpose of this paper is to evaluate system performance dependence on channel spacing and data rate per channel if a single discrete Raman pre-amplifier is used for loss compensation. For comparison to make sense both systems are designed to have the same data rate, i.e. 320 Gbps, modulation, i.e. binary differential phase shift keying and equal spectral efficiency with 1.6 THz total occupied bandwidth. First system under study consists of 32 channels, each with 10 Gbps data rate and 50 GHz channel spacing. Second system under study consists of 8 channels, each with 40 Gbps data rate and 200 GHz channel spacing. Transmission distance in both cases is 100 km. Both systems have a single discrete Raman pre-amplifier where highly nonlinear fiber is used as gain medium.