Laser Characteristics of 1.3-μm Quantum Dots Laser With High-Density Quantum Dots

We have reported the effects of using an As₂ source and gradient composition-strain reducing laser (GC-SRL) to fabricate InAs quantum dot (QD) structures. The coalescence of the coherent QDs was reduced under the As₂ source. We have realized high density (8.0 times10¹⁰ cm^-2 per sheet) measured by SEM and high uniformity (full-width at half-maximum: 23 meV measured by photoluminescence at room temperature) QDs using an As₂ source and the GC-SRL technique. Further, we have demonstrated nine- stack QD lasers with high-density and high-uniformity QDs for the first time. We achieved a large modal gain of 54 cm^-1 at a ground state emission of beyond 1.3-mum. A very low threshold current can be realized by a quantum effect for further equalization of QDs. We believe that the method of fabricating this QD laser with high density, high uniformity, and high modal gain will qualify as a novel technique.