High-speed visible light communication using light-emitting diodes embedded with photonic crystals

Abstract

Recent research and progress have shown that using light-emitting diodes (LEDs) as a high-speed transmitter is a promising candidate in a high-speed data system. The photonic crystal (PhC) LED (PhCLED) can improve the performance of the devices for visible light communication (VLC) due to its unique spatial and temporal management of photonic modes. In this research, the dynamic behaviors of PhCLEDs at both small- and large-signal modulation are studied. The PhC-induced radiative recombination enhancement is demonstrated by both small-signal modulation and BERT. A PhCLED with an electrical-to-optical (E-O) −3-dB bandwidth of 347MHz is demonstrated, which corresponds a 55% enhancement compared to a convention LED. Moreover, an error-free transmission was tested under a PRBS at 200 Mbps with a BER < 10−10. Better signal integrity is also shown in digitally modulated eye patterns up to 500 Mbps. Our study implies the limit of scaling down LEDs to achieve high-frequency operation since πrec has to be decreased accordingly to maintain high efficiency in the light output power. For the best E-O -3-dB bandwidth and transmitted signal quality, the PhCLED with a larger period and a larger air-hole portion is suggested in this work. The discussion above demonstrates the potential of PhCLEDs for high-speed transmission.