800 Gb/s (8 × 100 Gb/s) Nyquist Half-Cycle Single-Sideband Modulation Direct-Detection Transmission Over 320 km SSMF at C-band

Direct detection shows great attraction in short- and medium-reach transmission for its low cost and easy integration. Especially, single-sideband (SSB) Nyquist subcarrier modulation is a promising technology due to its high spectral efficiency and strong tolerance to chromatic dispersion. In this paper, we experimentally demonstrate 800 Gb/s (8 × 100 Gb/s) direct-detection wavelength-division multiplexing (WDM) transmission over 320 km standard single-mode fiber (SSMF) with Nyquist 16-ary quadrature amplitude modulation (16-QAM) and half-cycle SSB subcarrier modulation. Each channel carries 25 Gbd 16-QAM SSB signal and the channel spacing is 35 GHz. The nonlinear performance is discussed for both single channel and WDM systems. The bit error rate of the WDM system transmitting over 320 km SSMF is 6.73 × 10-3. Considering 20% hard-decision forward error correction and frame redundancy, a net bit rate of 650.4 Gb/s is achieved with a spectral efficiency of 2.32 b/s/Hz. With this spectral efficient modulation technique, our study achieves C-band high-capacity direct-detection WDM systems with metro distance transmission as long as 320 km SSMF.