The phase-noise performance of a low-noise preamplified two-channel op
tical downconverting link is measured for the first time. The downconv
erter is capable of operation over a 2-18-GHz bandwidth with a fixed i
ntermediate frequency of 160 MHz. Results show that a two-channel conf
iguration used as a remote microwave phase detector exhibits performan
ce equivalent to a typical microwave mixer.