Low-noise balanced mixer for 300-GHz band based on Fermi-level managed barrier diode on SiC platform

Abstract

We developed a terahertz-wave balanced mixer fabricated on a SiC substrate using epi-layer-transferred InP/InGaAs Fermi-level managed barrier (FMB) diodes. The FMB diodes were monolithically integrated with waveguide couplers, a 90-degree hybrid circuit, and low-pass filters. The fabricated mixer was then assembled in a twoinput-port module with a broadband transimpedance amplifier and exhibited an intermediate frequency bandwidth of about 26 GHz with good inter-port isolations of more than 13 dB. The obtained minimum noise equivalent power was as low as 2  10 -19 W/Hz in the fundamental mixing mode at around 300 GHz for a local-oscillator power of about 400 W.

Single-channel 240-Gbit/s sub-THz wireless communications using ultra-low phase noise receiver

“…As future works for sub-THz wireless communications, total data rates should be increased to reach 1 Tbit/s not only by introducing multiplexing techniques such as 4x4 MIMO and polarization multiplex [28][29][30][31], but also by introducing highly sensitive receiver such as Fermi-level managed barrier diode receiver [32,33] to allow higher level modulation like 128QAM and 256QAM. Transmission distance should be further increased to 1 km by using sub-THz amplifiers and by increasing the output power from the photodiode.…”