Beyond 300-Gb/s optical interconnect over 10-km SSMF at C band enabled by optical vestigial sideband signal

Using only a linear feed-forward equalizer in the receiver, we experimentally demonstrate a single-wavelength 120 Gbaud PAM4 vestigial sideband (VSB) signal transmission over 10 km standard single-mode fiber (SSMF) at C band under the 7% overhead (OH) hard-decision forward error correction (HD-FEC) bit error rate (BER) threshold. An optical filter is used to generate the VSB signal by optically filtering one sideband signal after the modulator. In order to further increase the data rate, a pre-emphasis equalizer, and a simplified second-order nonlinear equalizer are then employed to combat both the linear and nonlinear distortion introduced in the transmission link. Using probabilistic constellation shaping PAM8 signal, the achieved maximum line data rate is more than 350 Gb/s, below the 19% OH soft-decision forward error correction (SD-FEC) BER threshold, providing a potential solution for 10 km optical interconnect at C band with a data rate of more than 200 Gb/s per wavelength.