High-Power Photomixer Arrays

Toward higher terahertz output power

Raising the output power of photomixers is a key challenge in putting terahertz waves to practical use in communications and sensing.

We integrate UTC-PDs on thermally conductive SiC substrates with ultra-high-frequency circuits, and we arrange multiple UTC-PDs into arrays whose terahertz outputs are coherently combined.

An 8×1 UTC-PD array that integrates eight UTC-PDs, a T-junction power combiner and an antenna achieved an output increase of about 16 dB at 300 GHz compared with a single UTC-PD.

By combining two UTC-PD/SiC photomixer modules in a terahertz waveguide, we have also achieved output power at the 5.3 mW level.

Angular dependence of relative intensity with eight-channel combining and with a single channel — Coherently combining the outputs of eight UTC-PDs increases output by about 16 dB compared with a single UTC-PD.

Source: H. Ssali et al., “Generating Enhanced THz Power via an 8 × 1 UTC-PD Array Integrated with a T-Junction Combiner,” 2025 Asia-Pacific Microwave Conference (APMC), DOI: 10.1109/APMC65046.2025.11378753

Frequency response and output linearity of a single photomixer and of waveguide combining — Terahertz waves from two photomixer modules are combined inside a waveguide, achieving output at the 5.3 mW level. Comparison of a single photomixer and waveguide combining: (a) frequency response, (b) output linearity.

Source: Y. Kamiura et al., “300-GHz Photonic Wireless Link with 5.3-mW Output Using Waveguide-Combined UTC-PD/SiC Photomixers,” The 51st European Conference on Optical Communication (ECOC2025), No. 135.

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