300-GHz Beam-Steering Wireless Communication Enabled by 4-Array InGaAs UTC-PD on SiC Substrate and Optical Phased Array

This paper presents a high-performance 4-array InGaAs UTC-PD fabricated on a silicon carbide (SiC) substrate, designed to improve thermal management and enhance output power for terahertz (THz) wave applications. The developed 4-array UTC-PD configuration enables precise beam steering at 300 GHz, demonstrating multi-directional wireless communication utilizing On-Off Keying (OOK) modulation. The SiC substrate with thermal conductivity approximately seven times higher than that of conventional indium phosphide (InP) substrates suppresses device overheating, preventing thermal damage and performance degradation even under high photocurrent conditions, while significantly enhancing THz output power. Furthermore, we successfully demonstrated the real-time transmission of uncompressed 4K video, underscoring the feasibility of this system for high-capacity THz wireless communication applications. Finally, Beam-Switching Time Division Multiplexing (BS-TDM) was also implemented and evaluated, demonstrating its potential for efficient resource allocation in next-generation wireless systems.