Comparision of Bit-loading and DFT-Spread DMT Signal Transmission in O-band IM/DD System utilizing DML

Abstract

In this paper, we experimentally compared the performance of bit-loading discrete multi-tone (DMT) signal and discrete-Fourier-transform spread (DFT-Spread) DMT signal with pre-equalization in Intensity Modulation with Direct Detection (IM-DD) system. We first experimentally demonstrated that the bit error ratio (BER) of DFT-Spread DMT signal with optimized Quadric Curve (QC) fitting-based pre-equalization outperforms Zero-Forcing based pre-equalization in O-band over 20-km transmission utilizing directly modulated laser (DML). We also experimentally demonstrated that DFT-Spread DMT signal with optimized QC fitting pre-equalization shows better BER performance than bit-loading DMT signal in 95Gbit/s signal transmission with 19GHz bandwidth. The BER of bit-loading DMT signal and DFT-Spread DMT signal with optimized QC fitting pre-equalization after 20-km SSMF transmission at -1 dBm received optical power (ROP) are 5.8×10-3 and 1.8×10-3, respectively.