Leakage-Assisted Transverse Mode Selection in Vertical-Cavity Surface-Emitting Lasers With Thick Large-Diameter Oxide Apertures

Cold-cavity 3-D transverse-vertical modes of 850 nm GaAs/AlGaAs vertical-cavity surface-emitting lasers with thick oxide aperture layers were simulated. Single fundamental mode operation at large aperture diameters is achieved by proper positioning of the layer with low Al content and thickness beyond a quarter-wavelength in the top distributed Bragg reflector above the aperture layers. This modification promotes the lateral leakage of the transverse higher-order modes along the oxidized layers and their discrimination due to increased gain thresholds at certain aperture diameters. At high leakage, even the fundamental mode exhibits confined spatially-modulated states due to coupling with the leakage field component.