Polarization-dependent saturation in semiconductor vertical-cavity lasers

Summary form only given. The nominal cylindrical symmetry of most vertical-cavity surface-emitting lasers (VCSELs) makes their optical polarization both interesting and fragile. As a result, the actual polarization state is determined by various optical anisotropies, of which linear birefringence, created by stress/strain and internal electric fields, is generally the dominant one. We have now measured the much weaker nonlinear anisotropies in VCSELs, which originate from the polarization dependence of the saturation. The experiments were performed on standard proton-implanted AlGaAs quantum-well VCSELs operating at a wavelength of 850 nm.