Comparing the performance of 980 nm VCSELs with different High-Contrast-Grating designs

The paper will present two possible ways of including a different high-contrast-grating (HCG) into a 980 nm vertical cavity surface emitting lasers (VCSEL). The device is composed of a GaAs cavity with five InGaAs quantum wells (QWs) at the center. The back mirror consists of 31 graded Al_xGa_1-xAs pairs with Al concentration from 0 to 1. The current is injected from the top, through an annular gold ring around the HCG and its oxide-base. To obtain current spreading and confinement, a reduced top distributed Bragg reflectors (DBR) is inserted between the cavity and the HCG. Current confinement is achieved by an aperture formed by an in-situ controlled wet oxidation process. This oxide apertures is placed at a field node, in order to minimize its effect on the field and reduce higher order mode appearance. This technology proves to be able to deliver good quality HCG, based on this scheme, as can be seen from some SEM images of preliminary processed gratings. A full set of design tools and guidelines will be presented and applied to the design of the structures.