New Approach to Transverse Mode Control in VCSELs

Abstract

A theme of current VCSEL research is the quest for single-transverse mode operation, especially at high power levels. Monomode output is required for many VCSEL applications using both free-space propagation and the superior fibre-coupling properties of VCSELs. The oxide aperture approach has been remarkably successful in this respect, and a record single-mode power of 4.8 mW has been reported. Here we investigate the potential of a somewhat simpler approach - that of patterning the top reflector in a VCSEL in order to obtain sufficient waveguiding to confine a single transverse mode.