Monolithic polarization control of multimode VCSELs by a dielectric surface grating

Based on design guidelines from a three-dimensional, fully vectorial model, we have fabricated vertical-cavity surface-emitting lasers (VCSELs) with a monolithically integrated dielectric surface grating for polarization control. For VCSELs with emission wavelengths of 850 and 980 nm we have achieved orthogonal polarization suppression ratios (OPSRs) above 15 dB for all modes up to thermal rollover, which very well agrees with theory. It is shown both theoretically and experimentally that the grating has no influence on the emission far-field. The surface grating has also been combined with a surface relief to stabilize the polarization and to increase the fundamental mode output power at the same time.