Blue-and green-emitting quantum dots have been characterized and ridge waveguide lasers incorporating such quantum dots into the active region have been realized. The laser heteroscturctures were grown by plasma assisted molecular beam epitaxy. Injected carrier lifetimes in the quantum dots have also been measured by temperature dependent and time resolved photoluminescence. A threshold current density of 930 A/cm(2) in the blue-emitting lasers was measured under pulsed bias. A tunnel injection scheme to inject holes has been incorporated in the design of the green quantum dot lasers, and a threshold current density of 945 A/cm(2) in the green-emitting lasers has been measured under pulsed bias. Slope efficiencies of 0.41 W/A and 0.25 W/A have been measured, corresponding to differential quantum efficiencies of 13.9% and 11.3%, in the blue and green lasers, respectively. (c) 2013 Elsevier B.V. All rights reserved.