Comparison between multilayered InAs quantum dot lasers with different dot densities

This letter describes the dependence of the dot density per layer on laser performance for 1.3-μm range multilayered InAs quantum dot (QD) lasers having 12-QD layer in order to increase the maximum modal gain of the ground state (GS). Twelve-QD lasers with almost identical photoluminescence (PL) intensities and full width at half maximum (FWHM) were prepared, with a dot density per layer in the range of (1.4–3.0)×1010cm−2. Results for the undoped 12-QD lasers reveal that the lasers with almost the same PL intensity and FWHM have an almost identical relationship between the threshold current density (Jth) and the mirror loss and have much the same maximum mirror loss from which lasers can oscillate from the GS. This is probably due to the fact that the Jth of dot lasers fabricated by the self-assembled method are strongly dominated by the gain width that is governed by the nonuniformity of QDs.