Abstract

Performance of vertical-cavity surface-emitting lasers (VCSELs) has drastically improved using selective oxidation for current confinement[1]. Due to the lowered refractive index of the oxide the current aperture also induces lateral optical index guiding Proton implantation offers a planar device structure but the high energy implantation induces vacancies and centers for non-radiative recombnation at the perimeter of the active region. Therefore very small single mode devices with diameters below 5 μm an threshold currents below 100 μA can only be produced by selective oxidation. Thermal conductivity of the implanted material is reduced by a factor of two and a trade off between contact area and shading of the outcoupling facet has to be accepted. Optical guiding in proton implanted lasers is due to a superposition of gain guiding and thermally induced index guiding that changes for different driving conditions.

© 1996 IEEE