Quasi 2-bit 32-QAM OFDM based Digital RoF Link by Delta-sigma Modulation at 2.5 Gbit/s

We experimentally implemented and discussed the quasi 2-bit delta-sigma modulated 32-QAM OFDM based DRoF link in detail. Optically constructing the delta-sigma modulated 2-bit QAM-OFDM data mitigated the impact of nonlinearity in optical links. After optimization, the quasi 2-bit delta-sigma modulated 32-QAM OFDM was successfully transmitted over 15-km SMF with a raw data rate of 2.5 Gbit/s at the lowest receiving power of −15.10 dBm. The proposed DRoF link structure boosted the robust anti-nonlinearity and cost-effective RRHs, which was appropriate for the beyond 5G applications.