168 Gb/s/λ Direct-Detection 64-QAM SSB Nyquist-SCM Transmission over 80 km Uncompensated SSMF at 4.54 b/s/Hz net ISD using a Kramers-Kronig Receiver

Using the recently-proposed Kramers-Kronig receiver DSP scheme, we achieved 4×168 Gb/s 35 GHz-spaced WDM single-polarization direct-detection 64-QAM SSB Nyquist-SCM transmission over 80 km of uncompensated SSMF at a record net ISD of 4.54 b/s/Hz.