Demonstration high-order QAM transmission based on one-bit delta-sigma modulation in radio-over-fiber system

Abstract

In the letter, we propose to use delta-sigma modulator (DSM) technology to transmit OFDM high-order QAM signals in a single-carrier radio-over-fiber (RoF) system, and conduct experimental verification. The experiment demonstrates the transmission of OFDM-256/1024/4096 QAM signals using one-bit DSM in the W band in a 20 km SSMF and 1 m wireless RoF system, and successfully realized that the BER of OFDM-256 and 1024 QAM after system transmission is lower than the hard decision forward error correction (HD-FEC) threshold of 3.8 × 10−3, and the BER after 4096 QAM transmission is lower than the soft decision forward error correction (SD-FEC) threshold of 4.0 × 10−2. The combination of DSM and the photonics-aided RoF solution can effectively solve the problem that the nonlinear damage caused by the bottleneck of the optoelectronic device in the RoF system limits the transmission of high-order QAM signals, and it is expected to be applied in the future 6G optical wireless network.