Experimental Demonstration of an SFO-Robustness Scheme With Fast OFDM for IMDD Passive Optical Network Systems

A sampling frequency offset (SFO)-robustness scheme with zero padding (ZP)-fast orthogonal frequency-division multiplexing (FOFDM) is proposed and experimentally demonstrated in intensity-modulated and direct-detection (IMDD) passive optical network (PON) systems. It can be used to mitigate the impact of SFO-induced inter-carrier interference (ICI). The performance comparison between the proposed FOFDM scheme and conventional OFDM scheme in the presence of SFO is presented. Experimental results indicate that, as SFO-induced subcarrier phase offset (SPO) is compensated within the estimated error of ±0.1 ppm, at the same spectral efficiency (SE) and bandwidth granularity, the error vector magnitude (EVM) of ZP-FOFDM is superior to the OFDM at different received optical power (ROP). In addition, when the ROP is −1 dBm, the average error vector magnitude (EVM) of all the data subcarriers for ZP-FOFDM is 3.3-dB superior to that of OFDM. It means that the ZP-FOFDM scheme can effectively improve the SFO-robustness compared with OFDM.