Transfer-printed yellow and red InGaN micro-LEDs on diamond for ultra-low-power high-speed optical interconnects

The rapid growth of computing demand requires high-speed transmission with low power consumption. Micro-light-emitting diodes (micro-LEDs), offering high modulation bandwidth, low-power operation, and array integration, are promising transmitters for next-generation interconnects. Here, we show yellow and red InGaN micro-LEDs, optimized through superlattice strain engineering and a three-period quantum well design, which were transfer-printed onto diamond, with microlenses fabricated by two-photon lithography for coupling optimization. The 20 µm yellow micro-LED achieved an electrical-to-optical bandwidth of 2850.4 MHz at 6.25 A/cm², while the 20 µm red device reached 2593.4 MHz at 50 A/cm². With on–off keying (OOK) modulation through a 1 m fiber link, 20 µm and 40 µm yellow devices achieved 1.5 Gbps at 25 µA (6.25 A/cm²) and 50 µA (3.125 A/cm²), with energy efficiencies of 0.056 pJ/bit and 0.110 pJ/bit, respectively. This study demonstrates the potential of InGaN yellow and red micro-LEDs for energy-efficient high-speed optical interconnects. The authors demonstrate transfer-printed yellow and red InGaN micro-LEDs on diamond substrates. These devices achieve a 1.5 Gbps data rate with an energy efficiency of 0.056 pJ/bit, enabling low-power, high-speed optical interconnects.