Thermal Effect Induced High-Bandwidth for Ring-Shaped Parallel Micro-LED Arrays Toward 10.25 Gbps Visible Light Communication

Micro-LED based optical communication shows promise as a 6G candidate but requires high speed and long distance. To overcome the trade-off between bandwidth and light output power of GaN micro-LEDs to achieve superior communication performance, a simple approach using a ringshaped parallel violet micro-LED array with high current density injection and better carrier confinement is presented in this study, demonstrating a significant increase in the -3 dB bandwidth with the increase in the number of parallel units. Specifically, a configuration of 9-parallel micro-LEDs achieved a -3 dB optical bandwidth of 1133 MHz at 6000 A/cm2, surpassing the 797 MHz bandwidth of a single micro-LED. An equivalent circuit model is proposed to explain the bandwidth improvement, suggesting that the reduction in carrier lifetime caused by thermal effects may be the underlying mechanism. Moreover, a record 10.25 Gbps data transmission rate was achieved using OFDM, attributed to the high bandwidth and light output power, marking the highest data rate reported for parallel micro-LEDs.