High Bandwidth GaN-Based Micro-LEDs for Multi-Gb/s Visible Light Communications

TLDR

GaN-based LEDs provide highly efficient illumination and enable visible light communications by exploiting a large, licence‑free optical spectrum. The study reports progress in developing micro‑scale GaN LEDs optimized for visible light communications. They fabricate micro‑LEDs with design enhancements tailored for high‑speed VLC. The micro‑LEDs achieve electrical‑to‑optical bandwidths exceeding 800 MHz and support free‑space data rates of 1.7, 3.4, and 5 Gb/s using OOK, PAM, and OFDM, respectively.

Abstract

Gallium-nitride (GaN)-based light-emitting diodes (LEDs) are highly efficient sources for general purpose illumination. Visible light communications (VLC) uses these sources to supplement existing wireless communications by offering a large, licence-free region of optical spectrum. Here, we report on progress in the development of micro-scale GaN LEDs (micro-LEDs), optimized for VLC. These blue-emitting micro-LEDs are shown to have very high electrical-to-optical modulation bandwidths, exceeding 800 MHz. The data transmission capabilities of the micro-LEDs are illustrated by demonstrations using ON–OFF-keying, pulse-amplitude modulation, and orthogonal frequency division multiplexing modulation schemes to transmit data over free space at the rates of 1.7, 3.4, and 5 Gb/s, respectively.