Polarization dynamics in vertical-cavity surface-emitting lasers with optical feedback through a quarter-wave plate

Square-wave switching of the intensities of the orthogonal linearly polariz ed components of the output of a vertical-cavity surface-emitting laser (VC SEL) found previously in experiments with polarization-changing optical fee dback, is not found in rate equation models incorporating only birefringenc e and gain anisotropy, but is found in the model for VCSELs developed by Sa n Miguel, Feng, and Moloney [M. San Miguel, Q. Feng, and J.V. Moloney, Phys . Rev. A 52, 1729 (1995)]. The dynamics is sensitive to both the feedback s trength and the relaxation rate of the magnetization in the quantum well su blevels. (C) 1999 American Institute of Physics. [S0003-6951(99)03806-1].