Experimental study of the combined mode and polarization control in VCSELs with a sub-wavelength surface grating

This study investigates the combined mode- and polarization-control in 850-nm oxide-confined VCSELs having a locally etched sub-wavelength surface grating with different geometries. A high polarization stable single-mode output power and low threshold current can be achieved for a wide range of duty cycles, which facilitates the fabrication. Moreover, no degradation of the far-field is observed for the ensemble of investigated devices.