Unrepeatered 100G Transmission Over 520.6 km of G.652 Fiber and 556.7 km of G.654 Fiber With Commercial Raman DWDM System and Enhanced ROPA

We report the results of 100G unrepeatered transmission aimed at achieving the longest distance without any inline active elements. The unrepeatered transmission system uses commercial distributed Raman pump modules, enhanced ROPA, and real-time processing coherent 100G transceivers (PM-QPSK) with soft-decision FEC. Two types of ultra-low loss fibers, G.652B and G.654B compliant, are fully characterized and used as span fiber. First, a single 100G channel is successfully transmitted over 520.6 km of G.652B fiber (86.2 dB) in a lab trial. Second, cabled large effective area, ultra-low loss G.654B fiber in a field environment is used as span fiber. A single 100G channel and four 100G channels are transmitted over 556.7 km (90.2 dB) and 523.2 km (84.8 dB), respectively.