Terahertz communications using effective-medium-slot waveguides

All-dielectric effective-medium-clad waveguides have been widely exploited in terahertz communications owing to their extremely low loss, low dispersion, and broad bandwidth. Here, we propose a substrateless effective-medium-slot waveguide. In addition, we introduce a taper-free interface that allows terahertz waves to directly couple from a metallic hollow waveguide without requiring dielectric insertion. We achieve a 3-dB bandwidth of 40% with a maximum coupling efficiency of 90% in the WR-2.2 band (330–500 GHz). By employing a broadband uni-traveling-carrier photodiode transmitter and sub-harmonic mixer receivers, we demonstrate an aggregated data rate of 0.8 Tbit/s with quadrature amplitude modulation schemes across 14 channels from 330 to 600 GHz. The effective-medium-slot waveguide platform yields robust broadband coupling with enhanced mechanical protection, offering reliable interconnects for ultra-high-speed terahertz integrated systems.