InGaN/GaN multi-quantum well LED array for short distance optical links

Abstract

Visible light communication is increasingly regarded as a pivotal complementary paradigm for emerging wireless infrastructures, while optical interconnects are widely acknowledged as a disruptive enabler of energy-efficient, ultra-dense data-center architectures. Based on this idea, we proposed an InGaN/GaN LED array for high-speed, short-distance optical links. By utilizing InGaN/GaN multi-quantum-wells (MQWs) devices and matrix electrode injection structures, the LED array (10×10) was fabricated for multi-channel communication under an on-off keying modulation scheme. Electroluminescence (EL), modulation bandwidth, and signal transmission properties of individual LED were thoroughly characterized. Experimental results demonstrate that the individual unit is about 200×200 μm in size, and it shows green emission peaked near 530 nm, achieving a -3 dB bandwidth in the region of 5.3 MHz to 13.7 MHz with a current region of 10 to 70 mA. The data rate can remain stable at 50 Mbps with bit error rate below 2×10-5, and can reach a limiting data rate exceeding 100 Mbps for driven current over 80 mA. We also confirm that these value are high enough to support video and audio transmission. Furthermore, as the LED array is designed in a row-common-ground configuration with individually addressable columns, the total data rate in a multiple-input multiple-output (MIMO) mode will theoretically exceed 500 Mbps. Our study reveals the promising potential of compact LED array for integrated optical links, with significant room remaining for improvement, particularly in reducing power consumption.