GaAs-based subwavelength grating on an AlOx layer for a vertical-cavity surface-emitting laser

Abstract

A GaAs-based subwavelength grating on a thick (∼3/4*λ at 1300 nm) AlO x layer is designed, fabricated, and characterized. The AlO x layer as a low-index medium is oxidized from a 640-nm Al 0.9 Ga 0.1 As layer. The layer contraction of the Al 0.9 Ga 0.1 As layer after wet oxidation to AlO x is 4.9%. We fabricated GaAs-based subwavelength gratings on the AlO x layer showing a high reflectivity of 90% in the 1300-nm wavelength range, consistent with the simulation results. Such GaAs-based subwavelength gratings can be used as high-contrast grating mirrors for narrow-linewidth VCSELs, improving the mechanical stability and simplifying the device fabrication.