Controlled polarization switching in intracavity contacted VCSELs

Abstract

We have investigated the potential of asymmetric current injection for polarization switching in GaAs-based intracavity contacted vertical cavity surface emitting lasers using two sets of p-and n-contacts per device. We simulated the current paths in both symmetric and asymmetric contacted devices. A large lateral current component is present in the asymmetric case; this induces a certain anisotropy in comparison to the symmetric case, possibly able to stabilize the polarization in one direction. Intra-cavity devices are processed on a standard air-post VCSEL wafer. When using the contacts set along the ] 0 1 1 [ direction, the polarization was set along [110] while using the contacts along [110] the polarization switches from the direction along [110] to a direction making an angle of 25° to 90° towards [110]. This peculiar result can be explained by the fact that the used VCSEL structure is not designed for intra-cavity contacting.