Plasmonic modulator enabling kilometer-range high-throughput sub-THz links for radio access networks

Future radio access networks must accommodate growing mobile data traffic. Capacity between mobile devices and remote radio units (RRUs) must increase by using higher wireless carrier frequencies. Higher frequencies reduce reach, requiring RRU densification and high-capacity front- and backhaul connections. Optical fiber offers high throughput, but deployment can be expensive or unfeasible. Here we show an all-photonic sub-THz wireless link at 226 GHz over 1400 m, achieving a record-high net-rate-distance product of 214.2 Gbit s^-1 km. Broadband photonic and plasmonic components enabled flat frequency response at high speeds. A novel dual-sideband receiver increased signal-to-noise ratio by 2 dB. We assessed power variations due to atmospheric turbulence; the scintillation index remained below 0.019 under strong turbulence, confirming sub-THz link resilience. A theoretical comparison with free-space optical links highlights the turbulence resistance. In this work, we show sub-THz links offer high capacity, resilience to weather and turbulence, and cost-effective deployment for wireless front- and backhaul.