The influence of a nanoengineering procedure on the properties of single- and multi-layer self-assembled InAs quantum dot (QDs) has been studied using photoluminescence, transmission electron microscopy (TEM), and electroluminescence. Optical properties of QDs were optimized by shape engineering via adjustment of a GaAs overlayer thickness prior to a heating (truncation) step. TEM micrographs have confirmed that the employed growth procedure results in truncated pyramidal QDs covered entirely by AlAs with smooth top interfaces. Truncated QDs with two-monolayer-thick AlAs capping have demonstrated a strong blue shift of ground state (GS) energies and up to 10 meV larger separation between GS and first excited state energy levels as compared to non-capped QDs. We believe that AlAs capping, in combination with truncation procedure, results in significant suppression of carrier transport between QDs within the same layer as well as between QD layers. A record high characteristic temperature for GS lasing threshold, T0 = 380 K up to 55 °C, as well as a maximum saturated gain of 16 (5.3 per layer) cm−1, were measured for a 1.22 μm edge-emitting lasers with this truncated triple layer QD gain medium. A maximum saturated gain, 27 (3.9 per layer) cm−1, and T0 = 110 K have been demonstrated in a 1.19 μm lasers with truncated seven layer QD medium.