Optical Physical-Layer Digital Network Coding for 2.5-Gb/s RoF-Based FiWi Networks

We demonstrate the first digital optical physical-layer network coding (OPNC) scheme for 2.5-Gb/s ON/OFF keyed (OOK) subcarrier modulated (SCM) signals suitable for the application in fiber-wireless networks. The proposed OPNC scheme employs all optical XOR logic gates that rely on cross-phase modulation-based Semiconductor Optical Amplifier (SOA) Mach-Zehnder interferometers to perform encoding and decoding operations. The proposed encoding and decoding scheme is targeting deployment at the central office and the clients site at the remote antenna units, respectively. Proof of concept verification is experimentally demonstrated for 2.5-Gb/s OOK-SCM data using a 10-GHz subcarrier. Both synchronous and asynchronous operations are evaluated, achieving error free operation.