Polarization locking of vertical cavity surface-emitting lasers using amorphous Si subwavelength transmission gratings

Summary form only given. The output light of a vertical-cavity surface-emitting laser (VCSEL) can exist in two linearly polarized modes. Under normal operation, one of the modes will dominate over the other and, depending on the injection current, switching between the two modes can occur. Efforts have been made to control the polarization by use of anisotropic transverse cavity geometry, stress from an elliptical window, asymmetrical active layers, and metal gratings as the bottom reflector. In this paper we report the first demonstration of locking the polarization of VCSELs by putting a ultrathin amorphous silicon subwavelength transmission grating in front of the output window of a VCSEL.