Single mode approaches for multijunction vertical cavity surface emitting lasers

The aim of this work is to fabricate high-power, single mode vertical cavity surface emitting lasers (VCSELs). Multiple junction VCSELs provide a pathway towards scaling optical output power. However, especially in the case of oxide confinement, these lasers have a greater tendency to exhibit multimode behavior when compared to their single junction counterparts. To achieve high-power, single mode multi-junction VCSELs, more advanced single mode strategies must be employed. A two-dimensional complex refractive index model was applied to model the transverse modes of photonic crystal VCSELs in order to determine the most suitable designs. Oxide confined VCSELs were fabricated using 850 nm single and double junction wafers, as well as 940 nm double and triple junction wafers. We report a maximum single mode power of 8.0 mW from the 850 nm double junction VCSELs and 10.7 mW from the 940 nm triple junction VCSELs. Double junction implant/oxide VCSELs were also fabricated and produced a peak single mode power of 8.1 mW.