Low thermal resistance high-speed top-emitting 980-nm VCSELs

Increasing copper plated heatsink radii from 0 to 4 mum greater than the mesa in vertical-cavity surface-emitting lasers (VCSELs) reduced the measured thermal resistance for a range of device sizes to values 50% lower than previously reported over a range of device sizes. For a 9-mum diameter oxide aperture, the larger heatsink increases output power and bandwidth by 131% and 40%, respectively. The lasers exhibit a 3-dB modulation frequency bandwidth up to 9.8 GHz at 10.5 kA/cm². The functional dependence of thermal resistance on oxide aperture diameter indicates the importance of lateral heat flow to mesa sidewalls