Numerical analysis of injected current effects on thermal characteristics of vertical-cavity surface-emitting laser

Abstract

The present study aims to numerically investigate thermal characteristics of the Vertical-cavity surface-emitting lasers (VCSELs) considering current flows, non-radiative recombination, spontaneous emission transfer, and heat generation. The finite-volume method is used for discretizing the governing equations, and the comparison between prediction and measurement is made to evaluate the simulation code developed in this study. From literature, the numerical models are established for resistive heating inside Bragg reflector and contacts, non-radiative recombination between electrons and holes in the active region, and absorptive heating of created photons, and spontaneous emission. It is found that the numerical prediction shows good agreement with experimental data of temperature rise, and local heating exists mainly near the active layer of VCSEL during operation. Near the active region, thermal sources and temperature increase with injected current, whereas the electrical potential is mainly distributed in the active and p-mirror regions. Also, the maximum temperature rise appears in the active region owing to non-radiative recombination and reabsorption of spontaneous light emission. Even though the heat source significantly increases at the edge of the active region and high resistive regions, the temperature does not change much because of the small size of the active region. Moreover, the resistive and active heating, and total heating dissipation increase with injected currents. The resistive heating dissipation is larger than the active heat dissipation because of high resistivity materials.