Utilizing High-Intensity Optical Subcarrier Signal for Conversion Gain Enhancement of a UTC-PD-Integrated HEMT Photonic Double-Mixer

We experimentally investigated the effect of high-intensity subcarrier signal input to the UTC-PD-integrated HEMT photonic double-mixer for optical-to-wireless carrier frequency down-conversion. The conversion gain linearly increased with increasing the subcarrier signal intensity from +0.63 dBm to +6.63 dBm without saturation. As a result, the conversion gain enhancement of about +6 dB from −51.0 dB to −44.2 dB was achieved.