Real-time reception of four channels 50 Gb/s class high-level QAM-DMT signal in short reach

We demonstrated 4-channel high level QAM-DMT transmission over 20-km SMF-28 with real-time reception. 58.72-Gb/s 256QAM-DMT and 56.4-Gb/s 128QAM-DMT signal transmission within 25-GHz grid is achieved with the BER under 2.4×10-2 and real-time reception.