Radio-over-Fiber System With Multiple-Optical-Source-Based Microwave Photonic Filter Performing as a Subcarrier Demultiplexer

A simple and cost-effective demultiplexing approach for a subcarrier multiplexed radio-over-fiber (RoF) system is proposed, analyzed, and experimentally demonstrated. A microwave photonic filter based on multiple optical sources is integrated into the RoF system, and by simply controlling the time delay in the remote antenna unit, the subcarrier with desirable frequency can be filtered out, and undesirable ones are suppressed. An experimental demonstration has been carried out by implementing a two-optical-source-based microwave photonic filter in an RoF downlink transmitting a 2.5-GHz subcarrier modulated with 150-Mb/s on-off keying (OOK) data, showing that it works well as a subcarrier demultiplexer. The proposed demultiplexing approach enjoys high flexibility, tunability, and cost-effectiveness and has good potential applications in the multiplexed RoF systems.