15.64 Gbps High-Speed Visible Light Communication and Multiple-User Secure Communication Employing Red GaN Micro-LED Based Semi-Transparent Photodetector

In this paper, we developed a photodetector (PD) array based on red GaN micro-LEDs, where the n-GaN layers are electrically isolated from one another. We analyzed the factors affecting the transmittance of GaN micro-LED based PD when used as semi-transparent detector, examined the transmittance of different regions within the GaN micro-LED based PD, and proposed solutions to enhance overall transmittance. Additionally, we studied the gap between the absorption and electroluminescence (EL) spectra of the GaN micro-LED based PD, highlighting its benefits for future multifunctional application integration. Based on our research, we investigated its potential application in high-speed communication and multi-user secure communication based on semi-transparent PD. Furthermore, a record data rate of 15.64 Gbps was achieved based on the single GaN micro-LED based PD by employing an OFDM modulation scheme and a bit-loading algorithm with a 0.3 m transmission distance in free space. Finally, we employed our GaN micro-LED based PD as semi-transparent detector, and constructed a multiple user access system for secure communication, achieving a maximum data rate of 6.84 Gbps in all users.