Ultra-Long-Haul High-Capacity Super-Nyquist-WDM Transmission Experiment Using Multi-Core Fibers

This paper describes promising techniques for approaching the capacity-distance product over 1 Exabit/s×km in the transoceanic-class optical fiber transmission. One is the Super-Nyquist wavelength-division multiplexing (WDM) technique based on poly-binary-pulse shaping with maximum likelihood sequence estimation, in which it is possible to multiplex optical signals with WDM spacing of less than the signal baudrate. Another technique is the space-division multiplexing technique based on multi-core fibers (MCFs) with multi-core Erbium-doped fiber amplifiers (EDFAs), in which the fiber capacity can be increased when the number of cores of MCF is increased. Finally, we present a demonstration of 140.7-Tbit/s, 7 326-km transmission of 201-channel 25-GHz-spaced Super-Nyquist-WDM 100-Gbit/s optical signals using seven-core fibers and full C-band seven-core EDFAs.