High‐Speed Blue Laser Diodes with InGaN Quantum Barrier for Beyond 36 Gbps Visible Light Communications

Abstract Laser‐based visible light communication (VLC) is emerging as a crucial technology for future applications like the Internet of Things and artificial intelligence. However, the data transmission rate is limited by the modulation bandwidth of visible laser diodes (LDs). This paper presents the design and fabrication of blue GaN‐based short‐cavity (300 µm/500 µm) LDs with InGaN quantum barrier (QB) and a narrow ridge width of 2 µm for high‐speed VLC systems. Theoretical analyses of the band structure and carrier distribution, along with experimental results, reveal significant improvements in electro‐optical performance and frequency response of the demonstrated blue LDs with InGaN QB. A high slope efficiency of 1.85 W A −1 , a wall‐plug efficiency of 29%, and an intrinsic 3 dB bandwidth exceeding 8 GHz are achieved. By using the high‐speed blue LD as a transmitter, the VLC system achieves a record data rate of 36.5 Gbps. The system shows a larger operation window for high speed and better temperature adaptability, marking a substantial advancement for high‐speed VLC links.