Search for: [Abstrakt = "In the present paper, an impact of localization of an oxide aperture within a vertical\-cavity surface\-emitting diode laser \(VCSEL\) on its threshold operation is analyzed. As expected, a shift of the aperture from the anti\-node position of the standing optical wave within a VCSEL cavity to the node position is followed by a drastic change of the wave guiding mechanism from the index guiding to the gain guiding. Index\-guided VCSELs have been found to exhibit much lower threshold currents, but any increase in their active\-region diameters over a relatively low critical value is followed by excitation of higher\-order modes. On the other hand, the fundamental\-mode operation is achieved in gain\-guided VCSELs with much larger active regions but at the expense of considerably higher lasing thresholds. Therefore, a new VCSEL design, i.e., the separate confinement oxidation \(SCO\) VCSEL, is proposed. The SCO VCSELs are expected to combine advantages of both previous oxide\-confined VCSELs, i.e., low lasing thresholds of index\-guided VCSELs with the fundamental\-mode operation of gain\-guided ones even in the case of large active regions."]

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