Abstract: A system includes a downconverter, an optical transmitter, an optical receiver, and an upconverter. The downconverter includes an LO1 circuit and a mixer. The LO1 circuit generates an LO1 signal synchronized with an LO synchronization signal. The mixer receives RF signals in first frequency bands and downconverts them to second frequency bands by mixing the RF signals with the LO1 signal. The optical transmitter modulates the downconverted RF signals and the LO synchronization signal onto optical beams and transmits the modulated optical beams over a fiber. The optical receiver demodulates the modulated optical beams to reconstruct the downconverted RF signals and the LO synchronization signal. The upconverter includes an LO2 circuit and a mixer. The LO2 circuit generates an LO2 signal responsively to the reconstructed LO synchronization signal. The mixer mixes the reconstructed RF signals with the LO2 signal to reconstruct the RF signals in the first frequency bands.