Abstract

Proton-implanted vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively high series electrical resistances. Initially, these were attributed to the high series resistance of p-type Bragg mirrors. However, even in the case of devices with stepped,¹ graded-superlattice,² or continuously graded³ mirrors, the series resistance remains very high in comparison to that of common stripe-geometry lasers. We examine what role is played in high resistance of proton-implanted VCSELs by current spreading in the upper section of the device. Three different top-contact geometries are considered: annular, circular, and broad-area. Closed-form analytical solutions are obtained for each case. The results demonstrate that low values of series resistance can be achieved by using the broad-area contact configuration.

© 1992 Optical Society of America