We demonstrate the generation and transmission of eleven channels with 224-Gb/s polarization-multiplexed, return to zero, 16-level quadrature amplitude modulation (POLMUX-RZ-16QAM) over 670 km of standard single mode fiber (SSMF) with 50-GHz channel spacing and a spectral efficiency of 4.2 b/s/Hz. We report a penalty of around 4.3 dB in the performance at back-to-back in comparison to the theoretical limits, and a margin of 1 dB in Q-factor below the forward error correction (FEC) limit (assumed to be at a bit error rate of 3.8x10-3) after transmission over 670 km of SSMF.
Alfiad, M. S., Kuschnerov, M., Jansen, S. L., Wuth, T., Borne, van den, D., & Waardt, de, H. (2010). 11 x 224 Gb/s POLMUX-RZ-16QAM transmission over 670 km of SSMF with 50-Ghz channel spacing. IEEE Photonics Technology Letters, 22(15), 1150-1152. https://doi.org/10.1109/LPT.2010.2051146