Transmission Performance of a 485-Gb/s CO-OFDM Superchannel With PDM-16QAM Subcarriers Over ULAF and SSMF-Based Links

We experimentally compare the transmission performance of a 485-Gb/s coherent optical orthogonal frequency-division-multiplexed (CO-OFDM) superchannel with PDM-16QAM subcarrier modulation over two types of fiber links, one based on ultra-large-area fiber (ULAF) spans, and the other on standard single-mode-fiber (SSMF) spans. Two amplification schemes, hybrid Raman/erbium-doped fiber amplifier (EDFA) and EDFA-only, are studied. We find that the optimum signal launch power is about 2 dB higher in ULAF than in SSMF for transmitting over 20 80-km spans under both amplification schemes. With EDFA-only amplification, the ULAF offers ~2-dB higher optimum Q² factor than the SSMF after 1600-km transmission. With hybrid Raman/EDFA amplification, a transmission distance of 1600 km is achieved at Q² = 9.2 dB by using the ULAF spans, which is 67% longer than that obtained with the SSMF spans.