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.
Highlights
V ISIBLE light communications (VLC) is an emerging technology that has significant potential to supplement existing radio frequency (RF) based wireless communications
For example by reducing the light-emitting diodes (LEDs) active area, and thereby decreasing capacitance and increasing current density, we have previously reported modulation bandwidths in excess of 400 MHz [5]
Using single pixels from individually-addressable arrays of these LEDs, with a nominal peak emission wavelength of 450 nm, we demonstrate data transmission over free-space using on-off keying (OOK), pulse-amplitude modulation (PAM) and orthogonal frequency division multiplexing (OFDM) modulation schemes at data rates of 1.7, 3.4 and 5 Gbps, respectively
Summary
V ISIBLE light communications (VLC) is an emerging technology that has significant potential to supplement existing radio frequency (RF) based wireless communications. For example by reducing the LED active area, and thereby decreasing capacitance and increasing current density, we have previously reported modulation bandwidths in excess of 400 MHz [5] Such LEDs, with dimensions of 100 × 100 μm or less, have been used to demonstrate 3 Gbps transmission over free-space [6] and 5 Gbps along a polymer optical fibre (POF) [7]. Using single pixels from individually-addressable arrays of these LEDs, with a nominal peak emission wavelength of 450 nm, we demonstrate data transmission over free-space using on-off keying (OOK), pulse-amplitude modulation (PAM) and orthogonal frequency division multiplexing (OFDM) modulation schemes at data rates of 1.7, 3.4 and 5 Gbps, respectively These modulation bandwidths and data transmission rates represent, to the best of our knowledge, the highest yet reported for GaN LEDs
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