Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

We present a comprehensive numerical model to simulate self-heating effects of oxide-confined vertical-cavity surface-emitting lasers (VCSELs) under continuous-wave operation. The model self-consistently accounts for the close interaction between optical, electrical, and thermal processes in VCSELs. In particular, hot carriers and nonequilibrium optical phonons in the quantum wells are modeled by solving a carrier energy balance equation and an optical phonon rate equation. Our numerical simulations reveal that they are responsible for aggravated thermal rollovers in VCSELs´ L-I characteristics. Detailed comparisons are made and good agreement is obtained between simulations and experiments for the L-I-V and lasing wavelength characteristics of VCSELs with varying oxide aperture size. Various mechanisms that result in the L-I thermal rollover behavior are also investigated with the aid of simulations.