Photonic downconversion for coherent phase-modulated radio-over-fiber links using free-running local oscillator

A digital coherent receiver employing photonic downconversion is presented and experimentally demonstrated for phase-modulated radio-over-fiber optical links. Photonic downconversion adds additional advantages to optical phase modulated links by allowing demodulation of signals with RF carrier frequencies exceeding the bandwidth of electrical analog-to-digital converter. High spurious-free dynamic range is observed for RF carriers at 5 GHz photonically downconverted to 1 GHz.

► Phase modulated optical links for the transparent transport of wireless signals.
► Coherent detection with digital signal processing for detection and demodulation.
► Photonic downconversion enables detection of high RF carrier frequencies.
► High linearity achieved for high RF frequencies.