Vertical cavity, surface-emitting laser with expanded cavity

摘要

A vertical-cavity, surface-emitting semiconductor laser having a substrate, an active layer of a semiconductor material which is adapted to generate light on a surface of the substrate, a pair of mirrors at opposite sides of the active layer and means for expanding the diameter of the output beam. Such means include a spacer layer of an optically passive material between the active layer and at least one of the mirrors, and mirror layers of reduced difference in index of refraction, interface layers having intermediate indices of refraction placed between mirror layers, in either case expanding the effective optical cavity length to at least 100 times the thickness of the active material in the active layer. Another means is anti-waveguiding which directly expands the diameter of the beam. The expanded cavity provides an output beam of larger diameter while maintaining stable single mode emission. The spacer layer may be a separate layer or region over the substrate or at least a portion of the substrate.