RF/FSO Mixed Communication System Incorporating Photonic Aggregation for Improved Spectral Efficiency and Suppressed Co-frequency Interference

A radio frequency (RF)/free-space optical (FSO) mixed communication system incorporating photonic aggregation is proposed and experimentally demonstrated. Four co-frequency binary phase shift keying (BPSK) microwave signals received by four antennas are aggregated to a single polarization 16 quadrature amplitude modulation (16QAM) optical signal, and the optical signal with octuple spectral efficiency is transmitted over a free-space link. On the receiver side, the 16QAM signal from four microwave channels is decoded simultaneously by a single optical coherence receiver. A proof-of-concept experiment is conducted to verify the effectiveness of the proposed technique. An RF/FSO mixed communication system incorporating photonic aggregation supporting wireless communications at a baud rate of 1 G-baud is demonstrated. The error vector amplitude (EVM) is measured to be 5.68%.