Characteristics of 1.3μm quantum-dot lasers with high-density and high-uniformity quantum dots

The authors realized a five-layered $1.3\mu \mathrm{m}$ InAs quantum dot (QD) with a high density and uniformity of $8.0\times {10}^{10}{\mathrm{cm}}^{-2}$ /sheet and $23\mathrm{meV}$ , respectively, by employing an ${\mathrm{As}}_2$ source and a gradient-composition strain reducing layer. Further, the authors demonstrated the $1.3\mu \mathrm{m}$ wavelength emission of this five-layered QD laser with a $0.5\mathrm{mm}$ cavity length and cleaved facet at room temperature. Moreover, the authors could achieve a high modal gain of $43{\mathrm{cm}}^{-1}$ at $1.3\mu \mathrm{m}$ because of the high density and uniformity of the QDs.