Vertical-cavity lasers for parallel optical interconnects

Continuing increases in efficiency, uniformity, and yield for low-threshold dielectrically Apertured Vertical-Cavity Surface-Emitting Lasers (VCSELs) suggest that this new generation of sources may be ready for insertion into practical parallel interconnect systems. This paper will review the recent evolution of these devices, pointing out key enabling advances and potential roadblocks yet to be addressed. Included will be advances that have led to record low optical losses as well as record high wall-plug efficiency at powers of a few hundred microwatts, desirable for massively parallel optical interconnects. The use of engineered oxide apertures is a key element in these cases. Experimental results will also include recent free-space and WDM fiber interconnects. Remaining issues to be addressed include some sort of lateral carrier confinement, such as a buried-heterostructure, to reduce carrier losses as devices are scaled to small lateral dimensions.