Monolithic integration of photodetector with vertical cavity surface emitting laser

For the first time, monolithic integration of a photodetector with a vertical-cavity surface emitting laser (VCSEL) is demonstrated. The authors have designed and fabricated VCSELs with monolithically integrated pin photodetectors which dynamically monitor (and can thus control) the output power of the lasers. The VCSELs lase at room temperature and emit a highly coherent, low-divergence, circular beam directly from the top surface. The integrated photodetector shows a linear response to the laser emission with an effective responsivity of 0.25 A/W.