Real-time experimental demonstration of a versatile optical OFDM symbol synchronisation technique using low-power DC offset signalling

A simple, low-power DC offset signalling-based optical OFDM symbol synchronisation technique is proposed and experimentally demonstrated, for the first time, in real-time end-to-end 11.25Gb/s 25km SMF IMDD systems using directly modulated DFB lasers. The technique is bandwidth overhead-free and suitable for high line rates. It can also support asynchronous receiver clocking, add extra network security at the physical layer, and more importantly, provide live symbol synchronisation in both point-to-point and point-to-multipoint.