Polarization control of vertical-cavity surface-emitting lasers through use of an anisotropic gain distribution in [110]-oriented strained quantum-well structures

An analysis of the in-plane optical matrix elements connected with the gain distribution of (In,Ga)As-GaAs quantum-well structures on [110] GaAs substrates is presented. The in-plane gain distribution is found to be anisotropic-with a maximum directed along the [110]-[110] crystallographic axis. Optically-pumped vertical-cavity surface-emitting lasers on the [110] surface with these quantum wells in the cavity exhibit stable, well-defined polarization states; this stability is believed to be a consequence of the predicted anisotropic gain distribution on the [110] surface. Of the two orthogonal eigen polarizations observed, the one with the higher optical intensity, for a given pump power, was found to be stabilized along the [110] crystallographic axis; this is in agreement with the analysis.>