High-Speed PS-PAM8 Transmission in a Four-Lane IM/DD System Using SOA at O-Band for 800G DCI

We experimentally demonstrate a high-speed intensity modulation and direct-detection (IM/DD) system with four wavelength division multiplexing (WDM) channels. With the aid of semiconductor optical amplifier (SOA) and probabilistic shaping (PS) technique, 1T (280Gbit/s×4) PS-PAM8 signals can be successfully transmitted over 40-km standard single mode fiber (SSMF). As a more precise performance criteria, the normalized generalized mutual information (NGMI) should be used to report the performance of PS shaped signals. In this experiment, each WDM channel can support 280Gbit/s/channel PS-PAM8 signals transmission with a NGMI larger than the threshold of a soft-decision forward error correction (SD-FEC) code of 0.83. Considering 25% FEC overhead, the net bit rate of each WDM channel is 220Gbit/s/channel. Therefore, the net transmission rate of the WDM system is 880Gbit/s, which can support the demand of 800G data connection. To the best of our knowledge, it is the first time to realize over 1Tbit/s PAM signal transmission over 40km in a four-lane IM/DD system.