Ultra-long unrepeatered transmission over 607 km at 100G and 632 km at 10G.

This paper reports record unrepeatered transmission results using forward and backward distributed Raman amplifications, large effective area ultra-low loss fiber and enhanced ROPAs with additional pumping fibers. Coherent 100 Gb/s with PM-QPSK modulation format and OOK 10G transmission are demonstrated over 607 km (97.2 dB) and 632 km (101.

150 x 120 Gb/s unrepeatered transmission over 409.6 km of large effective area fiber with commercial Raman DWDM system.

15 Tb/s unrepeatered transmission is achieved over 409.6 km (68.2 dB) of large effective area fiber using forward and backward distributed Raman amplification and a remotely-pumped erbium-doped optical amplifier.