Gilbert-cell and photoreceiver circuits were designed for an integrated opt
ical phase-locked loop (OPLL) to generate stable channel offsets in dense w
avelength-division multiplexing (DWDM). These circuits were fabricated usin
g a p-i-n/heterojunction bipolar transistor layer structure. Various config
urations of an OPLL employing Gilbert-cell phase detectors and photoreceive
r circuits were tested, and wavelength separations from 1.0 to beyond 27.11
GHz were obtained.