Polarization and transverse mode behaviour of VCSELs under optical injection

A theoretical analysis of the polarization and transverse modes of Vertical-cavity Surface-emitting lasers with external optical injection is performed. We show that, for single-mode operation, weak injection of linearly polarized light can lead to stable output power in the injected polarization. We also show that, for multitransverse mode operation, weak injection of linearly-polarized light can lead to stable emission of the fundamental transverse mode in the injected polarization over wide current ranges. The previous selection can occur when the transverse modes have parallel or orthogonal polarizations.