Carrying the capacity of optical fiber into wireless space
The extremely wide bandwidth available at terahertz frequencies promises next-generation wireless communications with ultra-high speed and capacity.
Building on high-power SiC-based UTC-PDs and high-frequency module technology, we study higher-order modulation formats such as QPSK, 16QAM and 32QAM, frequency-division multiplexing (FDM) that uses multiple frequencies simultaneously, radio-over-fiber, and the integration of beam control with communications.
Recently, we generated two 16QAM signals at 257 GHz and 277 GHz simultaneously from a single high-power SiC-based UTC-PD and transmitted a total of 40 Gbit/s over a distance of about 16 m.
We are also extending this work to frequency-hopping communications that switch the terahertz frequency on a nanosecond timescale through fast optical wavelength control, making links resistant to jamming and eavesdropping.
Source: S. Ye et al., “Nanosecond-Hopping Multi-Channel Terahertz FHSS System Driven by Photomixing with a Tunable Laser for Enhanced Security,” IEICE Transactions on Electronics, Vol. E109-C, No. 8, pp. 293–296, 2026. DOI: 10.1587/transele.2025MTS0002