Researchers from the University of Illinois Urbana-Champaign and the University of Notre Dame have demonstrated a gallium nitride micro-LED that operates at an optical modulation bandwidth of 2.75 GHz while consuming just 25 mW of power. The breakthrough, reported in IEEE Electron Device Letters, could lower electricity and cooling costs for short-range optical links inside data centers.
Current data-center interconnects rely on tiny lasers that, although effective, draw substantial power and generate heat. In facilities with thousands of such lasers, both electricity and air-conditioning expenses rise sharply.
Lead author Abdelghany Abouelnagga explained that the team set out to test the belief that smaller devices are always faster. They examined micro-LEDs ranging from 100 µm down to 2 µm in diameter, finding that a 5-µm device offered the best compromise between bandwidth and power consumption.
The achievement resulted from detailed semiconductor modeling of material defects and parasitic effects, allowing the researchers to fine-tune the design before fabrication rather than relying on trial-and-error.
According to Abouelnagga, roughly 90% of data-center traffic travels less than 10 meters between racks, yet most transmitters are still lasers that waste energy and produce heat. Micro-LEDs could handle the same data loads with far less power.
The team envisions arranging these emitters in two-dimensional arrays, each delivering an independent data stream. Such a compact chip could dramatically increase capacity without enlarging the footprint, a benefit for large operators like Google, Microsoft, Meta and Amazon as workloads expand.
