Low-threshold quantum well lasers grown by metalorganic chemical vapor deposition on nonplanar substrates

Low-threshold quantum-well lasers having as-grown optical and electronic confinement fabricated by a single-step growth on nonplanar substrates are discussed. Several devices using various approaches for delineating narrow active regions by this technique are described. Fully planar index-guided arrays grown over a nonplanar substrate exhibit a threshold current of 8 mA per element. A technology called temperature engineered growth, which permits the formation of submicrometer active-region widths and wide contacting regions in the same growth step, is introduced. Lasers having active regions as narrow as 0.5 mu m grown using this technology display stable single-transverse-mode operation. CW threshold currents as low as 2.5 mA at room temperature with differential quantum efficiencies of 34%/facet were measured for uncoated devices.>