1.3 GHz E-O bandwidth GaN-based micro-LED for multi-gigabit visible light communication

Abstract

The data rate of a visible light communication (VLC) system is basically determined by the electrical-to-optical (E-O) bandwidth of its light-emitting diode (LED) source. In order to break through the intrinsic limitation of the carrier recombination rate on E-O bandwidth in conventional c-plane LEDs based on InGaN quantum wells, a blue micro-LED with an active region of nano-structured InGaN wetting layer is designed, fabricated, and packaged to realize a high-speed VLC system. The E-O bandwidth of the micro-LED can reach up to 1.3 GHz. Based on this high-speed micro-LED, we demonstrated a data rate of 2 Gbps with a bit error rate (BER) of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>1.2</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> with simple on-off keying signal for a 3-m real-time VLC. In addition, a 4-Gbps VLC system using quadrature phase shift keying-orthogonal frequency-division multiplexing with a BER of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mn>3.2</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> is also achieved for the same scenario. Among all the point-to-point VLC systems based on a single-pixel LED, this work has the highest distance-bandwidth product of 3 GHz·m and the highest distance-rate product of 12 Gbps·m.