Diffraction from oxide confinement apertures in vertical-cavity lasers

Direct measurement of scattered fields from oxide confinement apertures in vertical-cavity lasers is presented. Diffraction fringes associated with each transverse lasing mode are detected in the far field from devices with varying oxide aperture dimensions and with quantum efficiencies as high as 48%. The diffracted pattern symmetries match the rectangular symmetry of the oxide apertures present in the devices and fringe locations are compared to Fraunhofer theory. The fraction of power diffracted from the lasing mode remains roughly constant as a function of relative pump rate, but is shown to depend on both transverse mode order and oxide aperture size.