Super-high efficiency VCSELs

The vertical cavity surface emitting laser (VCSEL) is a light source of great importance for optical communication and sensing, enabling e.g. very high capacity interconnects in data centers and fast high resolution motion tracking in optical mice. The attractiveness of VCSELs is due to low operating current, excellent beam quality, high modulation speed at low current and low production cost. Still, the electrical-to-optical power conversion efficiency (PCE) of VCSELs is inferior to that of the most efficient edge emitting lasers. The limited PCE not only increases power consumption but also impacts several important performance parameters, most notably power and speed, since low efficiency translates into severe current induced self-heating. A significant increase of the PCE of VCSELs would therefore have an enormous impact on VCSEL technology and applications, enabling a reduction in power consumption (benefiting the global *green* photonics effort) and enabling VCSELs to operate with even higher output power and at even higher speed. It is the purpose of this project to increase the PCE of GaAs-based VCSELs to a level comparable to that of the most efficient edge emitters, aiming at a PCE of 80%. This ambitious goal represents considerable scientific and technical challenges, related to both VCSEL design and fabrication.