Monolithically integrated surface and substrate emitting vertical cavity lasers for smart pixels

The authors present a way to monolithically integrate surface—and substrate—emitting vertical cavity surface emitting lasers (VCSELs) on a single substrate for use in smart pixel applications. Spatially selective oxidation is used to adjust the reflectivity of distributed Bragg reflectors to fabricate surface and substrate emitting VCSELs with threshold currents of 65–70 μA, far field FWHMs of 9°–16°, and slope efficiencies of 16%–18%. Threshold currents and far field angles for various aperture dimensions are measured and discussed.