MODELING THERMAL EFFECTS ON THE LIGHT VS CURRENT CHARACTERISTIC OF GAIN-GUIDED VERTICAL-CAVITY SURFACE-EMITTING LASERS

Heating effects on the light power vs current characteristic of planar top-emitting vertical-cavity laser diodes analyzed by thermal, optica l and electrical modeling. The two-dimensional finite element thermal- electrical simulation considers the spatial current funneling in the t op p-doped distributed Bragg reflector and a current density dependent resistivity of the hetero-barrier. Layered regions are described by a nisotropic material parameters. Non-uniform refractive index temperatu re coefficients of the semiconductor materials are applied in the vert ical optical modeling. The strongly inhomogeneous temperature distribu tion causes thermal increases of emission wavelength and reflectivity as well as decreases of threshold gain and external quantum efficiency with rising current. Finally, the calculated maximum light power is f ound to be decisively affected by the temperature coefficients of the refractive indices,