60GHz CMOS-APD optoelectronic mixers with optimized conversion efficiency

A harmonic optoelectronic mixer based on CMOS avalanche photodiode is designed for optimized conversion efficiency in 60-GHz band. By reducing P-N junction capacitance in the avalanche photo-detection region and parasitic n-well/substrate capacitance, the supplied 30-GHz LO is efficiently converted to the 60-GHz harmonic LO signal and generates up-converted RF signals from optical IF. In addition, the silicide layer under the metal contact reduces the parasitic resistance and enhances the mixer conversion efficiency.