InP-Based Integrated Circuits on SiC/Si Substrates for Terahertz Communications

This paper presents our series of research results on devices and circuits that are fabricated using SiC- and Si-substrate-based platforms as practical integration methods to realize high-performance, cost-effective terahertz (THz) systems. The performance of these integrated devices in different 300- GHz-band communications systems is evaluated by packaging them into conventional hollow metallic waveguides or Sidielectric waveguides. The SiC platform-based receiver module has been designed with a waveguide-input direct detector and balanced mixer modules that use Fermi-level managed barrier (FMB) diodes. Waveguide-output uni-traveling-carrier photodiode (UTC-PD) modules on the SiC platform exhibit unsaturated output power of much larger than 1 mW and are successfully applied to the self-heterodyne transmitter at 125 Gbit/s. SiC-UTC-PDs are integrated onto Si-dielectric waveguide platform and demonstrated as the transmitter in a heterodyne communication system at 210 Gbit/s. Finally, waveguide-input IQ homodyne receiver modules are developed using the Si-platform. By combining the IQ receiver with SiC-UTC-PD modules in both the transmitter and receiver, a fully-photonic RF amplifier-less 300-GHz-band wireless link is successfully demonstrated.