10 × 112-Gb/s PDM 16-QAM transmission over 630 km of fiber with 6.2-b/s/Hz spectral efficiency

We demonstrate ten-channel WDM transmission of 112-Gb/s 16-QAM (14-gigabaud, polarization-multiplexed) over 630 km of fiber. 16.7-GHz channel spacing yields a spectral efficiency of 6.2 b/s/Hz, fitting 1 Tb/s of information into a 1.2-nm optical bandwidth.