Transmission of 115×100G PDM-8QAM-OFDM Channels with 4bits/s/Hz Spectral Efficiency over 10,181km

4×1.15-Tb/s DP-QPSK superchannel transmission over 10,181-km of EDFA amplified hybrid large-core/ultra low-loss fiber spans with 2-dB FEC margin

“…Each 1.15-Tb/s superchannel is generated by aggregating 23 optical carriers at a spacing of 12. 5 GHz. An external cavity laser (ECL) with <100-kHz linewidth is modulated by a phase modulator (PM) driven with a 25-GHz sinusoidal wave.…”

“…The 424.2-km circulating loop testbed consists of seven 60.6-km spans using hybrid large-core/ultra low-loss fiber [5].…”

Performance Study of 100-Gb/s Super-Nyquist QPSK and Nyquist 8QAM over 25-GHz Spacing

“…Although 16-ary QAM has been demonstrated for ultra long-haul trans-oceanic transmission [2], the received uncoded bit error rate (BER) is very close to the forward-error correction (FEC) limit. To achieve sufficient system margin, dual-polarization (DP) quadrature phase-shifted keying (QPSK) and 8QAM are among promising modulation format candidates capable of reaching >3000 km reach at >= 4 b/s/Hz SE [3]- [5], equivalent to 100Gb/s over 25GHz channel spacing.…”

“…It is worth noting that super-Nyquist QPSK could reach an even longer distance by assuming soft-decision (SD) FEC [9]. On the other hand, 8QAM has received increased attention due to its potential to improve SE beyond 4 b/s/Hz without severely sacrificing reach [5], [10], [11]. Transoceanic transmission has been demonstrated by using dual-carrier 400G 8QAM with enhanced SD-FEC codes even with >100 km span length [10], [11].…”

54 Tb/s transmission over 9,150 km with optimized hybrid Raman-EDFA amplification and coded modulation

“…For example, transoceanic transmission using C+L bands has been demonstrated to provide significant increases in capacity and bandwidth [1][2][3] . Alternatively, hybrid Raman-EDFA designs can offer improved OSNR and longer repeater spacing while providing broad, continuous bandwidth [4][5][6][7] . Despite these advantages the most recent record setting capacity experiments used EDFA-only designs 3 .…”