Time-dependent model for vertical-cavity surface-emitting laser

Two models have been developed to simulate a vertical-cavity surface emitting laser. The first model is a 2D time-dependent bulk dielectric and absorption coefficients. These bulk coefficients depend upon the material, lattice temperature, and carrier concentration. This field model is coupled with a frequency-dependent gain model that describes the quantum well regions in the time domain. Treatment of frequency-dependent media in a finite-difference time-domain code is computationally intensive. On the other hand, because the volume of the active region is small relative to the volume of the distributed laser cavity, the computational overhead is reasonable. A semi-empirical transport model is used to describe the bult transport, which drives the quantum well transport. In addition, the semi-empirical model provides a spatial distribution for the lattice temperature and carrier concentrations. The second model is a 3D solution of Maxwell's equations. The 3D model can be used for cold cavity calculations. The 2D code generates the dielectric and absorption coefficients assuming azimuthal symmetry, providing the initial conditions for the 3D calculation.