High-Modulation Bandwidth and Low-Conversion Loss UTC-PD Optoelectronic Mixer

The optoelectronic mixer is a critical component in millimeter-wave (MMW) and terahertz (THz) systems, facilitating the integration between optical fiber and wireless communication technologies. This study elucidates the optoelectronic mixing principles of the uni-traveling carrier photodiode (UTC-PD) and design a structure with high modulation bandwidth and low conversion loss. The designed mixer achieves a modulation bandwidth of 28.1 GHz with a conversion loss of 9.5 dB at a local oscillator (LO) signal frequency of 60 GHz. At LO signal frequency of 100 GHz, the modulation bandwidth decreases to 26.8 GHz, with a corresponding conversion loss of 16.4 dB.