A Full-Duplex Radio-Over-Fiber Link Based on a Dual-Polarization Mach–Zehnder Modulator

A simple and low-cost full-duplex radio-over-fiber (RoF) link implementing wavelength reuse for short-range applications is proposed and demonstrated based on a dual-polarization Mach-Zehnder modulator (DPol-MZM). In the center unit, a continuous-wave optical carrier is sent to a DPol-MZM to generate an optical signal with data modulation along one polarization direction and an unmodulated optical carrier along the other orthogonal polarization direction. In the remote antenna unit, a polarization beam splitter is used to separate the modulated signal for downstream service and the unmodulated optical carrier for upstream signal remodulation. A proof-of-concept experiment is carried out. Performance of the established full-duplex RoF link operated at 18 GHz is investigated. The measured bit error rate and the error vector magnitude confirm that the proposed architecture is a promising candidate for future high-speed and low-cost short-range applications.