High-speed Visible Light Communication Systems Based on Si-substrate LEDs with Multiple Superlattice Interlayers

Abstract

High-speed visible light communication (VLC), as a cutting-edge supplementary solution in 6G to traditional radio-frequency communication, is expected to address the tension between continuously increased demand of capacity and currently limited supply of radio-frequency spectrum resource. The main driver behind the high-speed VLC is the presence of light emitting diode (LED) which not only offers energy-efficient lighting, but also provides a cost-efficient alternative to the VLC transmitter with superior modulation potential. Particularly, the InGaN/GaN LED grown on Si substrate is a promising VLC transmitter to simultaneously realize effective communication and illumination by virtue of beyond 10-Gbps communication capacity and Watt-level output optical power. In previous parameter optimization of Si-substrate LED, the superlattice interlayer (SL), especially its period number, is reported to be the key factor to determinate the output optical power by influencing the wall-plug efficiency. However, few efforts were made to investigate the influence of SLs on VLC performance. Therefore, we for the first time investigated the impact of the SL period number on VLC system through experiments and theoretical derivation. The result shows more SL period number is related to higher signal-to-noise ratio (SNR) via improving the wall-plug efficiency. Further, by using Levin-Campello bit and power loading technology, we achieved a record-breaking data rate of 3.37 Gbps over 1.2-m free-space VLC link under given optimal SL period number, which, to the best of our knowledge, is the highest data rate for a Si-substrate LED-based VLC system.

10 Mbps in-plane green light communication system made by InGaN/GaN MQWs device

“…For the past few years, InGaN/GaN multiple quantum wells (MQWs) LEDs has gained significant interest for high-speed VLC applications due to their outstanding features, sunch as low-power consumption, integration of illumination and transmission, and offering multiplexing options for wavelengths [6] . To our best knowledge, the data rate of lnGaN/GaN MQWs VLC system has achieved Gb/s level [7] , the modulation bandwidth up to 1.53 GHz [8] .…”