Unrepeatered Transmission of 3.2-Tb/s (32 $\,\times\,$ 120-Gb/s) Over 445-km Fiber Link

We demonstrated 3.2-Tb/s (32 × 120-Gb/s) unre-peatered transmission over 445-km fiber with A eff -managed-span. This was achieved by employing co-propagating second-order pumped Raman amplification and remote optically pumped amplifier, which was counter-propagating second-order Raman pumped. This letter also discusses design tradeoff on the nonlinear tolerance and Raman gain efficiency within A eff -managed-span for performance enhancement of unrepeatered transmission.