Microscopic theory of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers

The polarization eigenmodes of vertical-cavity surface-emitting lasers (VCSELs) are investigated theoretically. The study is based on a first-principles theory and includes a microscopic model for the optically active quantum well and a vectorial solution of the VCSEL cavity mode problem. The theory is evaluated for an anisotropically strained GaAs quantum well structure, interacting with two orthogonally polarized VCSEL eigenmodes. The dependence of the calculated input-output characteristics and polarization stability criteria on microscopic input parameters such as the value of the strain are discussed for various levels of sophistication of the microscopic many-body effects used in the analysis. The results of the stability analysis are consistent with recent experimental observations of polarization switching, suggesting that anisotropic strain of the active quantum well may be a dominant factor in those observations.