Etched Vertical-Cavity Surface Emitting Laser Diodes,

Vertical-cavity surface emitting lasers VCSELs are promising light sources for optical computing and interconnection due to their unique topology and two-dimensional array capacity. To date, VCSELs with monolithic distributed Bragg reflectors DBRs require current injection through the upper p-type DBR resulting in a large threshold voltage due to the concomitant series resistance. The voltage drop in the p-type DBR also leads to additional thermal effects which degrade the VCSEL performance. Various methods, such as introducing extra layers with intermediate composition into the quarterwave DBR or tapered doping in the p-type DBR have provided a reduction in the series resistance, but have lead to complicated DBR designs. We have developed a novel VCSEL structure, utilizing dry etching, in situ metallization, and ion implantation, which can avoid current injection through the upper DBR, and thus simplifies the required epilayers. We report a comparison between our etchedimplanted devices and VCSELs formed by a planar ion implantation process, all fabricated from the same wafer.