Previous work has shown that the overlap between Fabry–Perot resonances and gain spectra explain some polarization state behaviors in vertical-cavity surface-emitting lasers (VCSELs). In this article, this approach is complemented for devices whose resonance is blueshifted relative to the peak gain. A simple phenomenological model is introduced that assumes the existence of a uniaxial strain in the quantum well layers making the material gain anisotropic. Measurements of the polarization anisotropy in spontaneous emission spectra confirm the hypothesis. Using rate equations, which include the demonstrated anisotropy, the polarization-state behavior of even externally coupled cavities VCSELs is predicted.

No abstract