Performance Investigation of DFT-Spread OFDM Signal for Short Reach Communication Systems Beyond NG-PON2

In this paper, we investigate the performance of a discrete Fourier transform (DFT)-spread OFDM signal in an intensity-modulation/direct-detection system. We find that DFT-spread OFDM could reduce the peak-to-average power ratio effectively and hence improve the nonlinearity tolerance. Furthermore, DFT-spread OFDM also improves the receiver sensitivity performance and shows good robustness to nonlinearity distortion caused by low-bit resolution digital-to-analog converters and analog-to-digital converters. The measured bit error ratio of DFT-spread OFDM signal after a 40-km standard single mode fiber is well less than the forward-error correction limit of 3.8 × 10 -3 .