Performance of a ULH single wide-band all-Raman DWDM transmission system over dispersion-managed spans

We evaluate the performance of an all-Raman ultralong-haul dense wavelength-division-multiplexing transmission system over 4160 km of dispersion-managed fiber. Enabling technologies include forward and backward-propagating Raman amplification and single-modulator return-to-zero transmitters. Large optical signal-to-noise ratio margins and small transmission penalties are achieved by means of a simple dispersion map.