10 × 224-Gb/s WDM transmission of 28-Gbaud PDM 16-QAM on a 50-GHz grid over 1,200 km of fiber

We demonstrate ten-channel wavelength-division-multiplexed long-haul optical networking of 28-Gbaud PDM 16-QAM signals on a 50-GHz grid (spectral efficiency of 4 b/s/Hz). We achieve transmission over 1,200 km of ultra-large-area fiber, including three wavelength-selective-switch passes.