180 Gbps Multi-Channel 300 GHz Communications Enabled by Photonically-Driven Low-Barrier Mixers

Abstract

Wireless communications at 300 GHz are expected to play an important role in the deployment of 6G and beyond networks. Multiple electronic and photonic technologies compete in this regard, each bringing its own particular benefits. While purely optoelectronic links are interesting for incorporating photonic advantages in signal transmission and reception, electronic receivers typically based on Schottky mixers are far superior in conversion efficiency. Thus, the link signal-to-noise ratio (SNR) is improved, and higher throughput can be achieved. Here, we demonstrate a fully optoelectronic 300 GHz band multi-channel link using a novel low-barrier Schottky mixer driven with a photonically generated local oscillator (LO) signal in the receiver using a modified uni-travelling-carrier photodiode (MUTC-PD). This combines the efficient down-conversion of Schottky-based mixers and the advantages of photonic LO signals such as tuneability, remote generation and distribution, and the reuse of coherent technology used in fibre networks. Up to three frequency channels are generated in the transmitter which is also based on a MUTC-PD photomixer, achieving a maximum aggregated line rate of 180 Gbps over 1.5 m under SD-FEC limit using 16-QAM format and optical intensity modulation. To the best of the authors' knowledge, this is an unprecedented data rate for fully optoelectronic terahertz communications.