All-optical digital physical-layer network coding for DPSK mm-wave Radio-over-Fiber networks

We demonstrate the first all-optical digital physical-layer network coding (AOPNC) for Differential Phase Shift Keyed (DPSK) Sub-Carrier Modulated (SCM) signals in mm-wave Radio-over-Fiber (RoF) networks. AOPNC is performed at the Central Office (CO) by employing a Delay Interferometer (DI) for phase-to-amplitude conversion, two Semiconductor Optical Amplifier-Mach Zehnder Interferometers (SOA-MZIs) performing the XOR and XNOR operation between the OOK converted signals and a third SOA-MZI for the phase regeneration of the encoded phase-formatted XOR signal. Encoding and decoding are evaluated via simulations for 2.5 Gb/s NRZ-DPSK data modulated on 60 GHz SC for both synchronous and asynchronous operation.