Self-Aligned Microlens-Integrated Vertical-Cavity Surface-Emitting Lasers

A novel method for fabricating microlens-integrated vertical-cavity surface-emitting lasers (VCSELs) by selective oxidation of composition-graded digital alloy AlGaAs was developed. Due to the simultaneous formation of a microlens and oxide aperture via single-step oxidation, self-aligned microlens-integrated VCSELs could be fabricated using standard intracavity-contacted VCSEL processing without additional process steps. The output beam from the oxide-buried and oxide-removed AlGaAs microlens-integrated VCSELs was strongly focused to a beam radius of 3.7 and 3.5 mum at a distance of about 25 and 15mum, respectively, from the surface of the VCSEL