Experimental determination of the temperature distribution in trench-confined oxide vertical-cavity surface-emitting lasers

We measured the temperature profile of operating vertical-cavity surface-emitting lasers by means of a contactless optical micro-probe technique, based on the analysis of spectral features in the spontaneous electroluminescence escaping the top Bragg mirror. Increasing the injected current above threshold in the range of 4-10 mA leads to a progressively nonuniform and bell-shaped distribution of temperatures with the laser center ~40% warmer than the edges. These results validate previous numerical calculations and show the usefulness of the proposed technique compared with the laser wavelength shift method.