Abstract

VCSELs most often emit linearly polarized light preferentially oriented along one of two perpendicular directions associated with the crystal axes. These two polarization modes have different optical frequencies split, typically by a few GHz, by the material birefringence For relatively low injection currents VCSELs commonly emit in the fundamental transverse mode, with a relatively abrupt switching between the states of linear polarization as the injection current is increased [1]. This general phenomenology has been explained with a model [2] that incorporates the vector nature of the laser field, saturable dispersion associated with the linewidth enhancement factor, and carrier dynamics associated with the different magnetic sublevels of the conduction and heavy hole valence bands. This theory also predicts elliptically polarized states as intermediates in the switching between the linearly polarized states.

© 1996 IEEE