Visible light communication (VLC) based on the micro light emitting diode (micro-LED) has attracted increasing attention owing to its high bandwidth, low power consumption, and high security. Compared with semi-polar or non-polar micro-LEDs, the commercial polar micro-LED has the advantages of low cost and more mature epitaxy technique. In this study, green micro-LEDs with different indium tin oxide (ITO) sizes are fabricated based on the commercial c-plane LED epitaxial wafer. The transmission performance of 80, 100, and 150 µm devices has been studied in detail. A partial pre-equalization scheme is utilized to increase data rates. Finally, the VLC system with a 100 µm green micro-LED as the transmitter could achieve a maximum data rate of 3.59 Gbit/s. Such a result will be beneficial to promote the further development of low-cost, high-speed VLC devices in the future.

A sunlight communication system is proposed that uses Sr₂Si₅N₈:Eu²⁺ phosphors to concentrate sunlight signals in strong background light noise; thus, a wide spectrum sunlight communication system is converted into a narrow spectrum one. A communication method is proposed to enable compression to the dark line H-α (656.28 nm) spectrum. A 50% solar energy conversion efficiency is achieved with a 0.3 μs code delay, a 0.2 μs code rise time (20%–80%), and a 96% optical transmittance. Experimental results show that phosphors enhance the sunlight intensity 1.5 times with the same distance. This method has immense potential in future long-distance sunlight communication.