Line-of-Sight Visible Light Communications With InGaN-Based Resonant Cavity LEDs

• Published in: IEEE photonics technology letters 2013-09, Vol.25 (18), p.1793-1796
• Main Authors: Tsai, Chia-Lung, Xu, Zhong-Fan
• Format: Article
• Language: English
• Subjects: InGaN; Light emitting diodes; line-of-sight optical link; Optical device fabrication; Optical fiber communication; Optical filters; Optical receivers; Optical reflection; Optical transmitters; resonant-cavity light emitting diodes (RCLEDs); visible light communications
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2013.2276105

Efficient InGaN-based resonant-cavity light-emitting diodes (RCLEDs) are investigated as potential light sources for visible light communications. Experimentally, InGaN multiple-quantum-well LEDs with a reasonable crystalline quality for blue light emission were grown by metal organic vapor phase epitaxy. A two-pair distributed Bragg reflector, along with a metallic Ag layer, was used to form a structure containing an optical cavity. The resulting InGaN RCLEDs exhibit improved performance over conventional LEDs in terms of light output power, external quantum efficiency, and directionality. In addition, two plano-convex lenses with facing convex surfaces were used to build a directed line-of-sight optical link between the transmitter and the receiver. Data transmission with rates up to 100 Mbit/s is demonstrated over a distance of 100 cm, implying the potential for indoor visible light communications with phosphor-converted white RCLEDs, provided that the slow-responding phosphorescent emission could be effectively filtered.