Low-Threshold and High-Bandwidth Green InGaN Hybrid QW-QD-Like VCSELs for Visible-Light and Chip-to-Chip Optical Interconnects

The increasing demand for high-speed data transmission in artificial intelligence computing and data-center architectures has accelerated the development of compact optical interconnect technologies. In this work, a green InGaN hybrid quantum well-quantum-dot like vertical-cavity surface-emitting laser (hybrid QW-QD-like VCSEL) operating near 510 nm is demonstrated. The device incorporates an InGaN active region and a nanoporous GaN distributed Bragg reflector (NP-DBR) to form a vertical resonant cavity. Optical characterization indicates strong carrier localization behavior and hybrid QW-QD-like recombination in the active region. The fabricated device with a 12 μm aperture exhibits a low threshold current of 1.032 mA (0.9125 kA/cm2) and stable lasing near 510 nm. High-speed modulation measurements show a −3 dB bandwidth of 3.18 GHz, and data transmission experiments achieve a bit-error rate of 2.6 × 10−3 at 4.5 Gb/s, below the forward-error-correction limit. These results demonstrate the potential of green InGaN hybrid QW-QD-like VCSELs for visible-light communication (VLC) and short-reach optical interconnect applications.