Line-of-sight visible light communications with InGaN-based resonant cavity LEDs

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.