COMPARISON OF OPTICAL LOSSES IN DIELECTRIC-APERTURED VERTICAL-CAVITY LASERS

The performance of vertical-cavity lasers (VCL's) employing dielectric apertures formed by lateral oxidation or wetetch undercutting of an A lAs layer on a common substrate are compared, Although both device typ es performed well, extracted optical losses from the wet-etch undercut structures exceed those of AlAs-oxide apertured lasers, The differenc e in performance is attributed to optical scattering losses specific t o the aperture fabrication method, enhanced by loss from the larger in dex of refraction discontinuity of the air-gap aperture relative to th e AlAs-oxide aperture.