Upcoming 6G wireless, superseding 5G and arriving possibly by 2030, is envisaged to function at hundreds of gigabits per second. Slowly, the technical advances needed are being made.
A hole in the tech development thus far has been at the interface between terahertz spectrum and hard, optical transmission lines. How does one connect terahertz (THz), which is basically through-the-air spectrum found between microwave and infrared, to the transmission lines that will be needed for the longer-distance data sends? The curvature of the Earth, for one thing, limits line of sight, so hard-wiring is necessary for distances. Short distances, too, can be impeded by environmental obstructions: blocking by objects, even rain or fog, becomes more apparent the higher in spectrum one goes, as wavelengths get shorter.