Controlled polarization switching in intra-cavity contacted VCSELs

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 direction, the polarization was set along while using the contacts along the polarization switches from the direction along to a direction making an angle of 25° to 90° towards. This peculiar result can be explained by the fact that the used VCSEL structure is not designed for intra-cavity contacting.