InAs/GaAs quantum dot lasers grown by gas-source molecular-beam epitaxy

We report on the InAs/GaAs quantum dot (QD) lasers grown by gas-source molecular beam epitaxy. Ridge waveguide lasers were processed on the grown structure consisting of five-stacked InAs QD layers formed by InAs layers with slightly different thicknesses. Continuous-wave operation was achieved up to 80 °C and more than 50 mW optical power was collected from one facet at 20 °C. The characteristic temperature of the QD laser was measured as high as infinity in the temperature range of 80-185 K. In addition, the lasing lines covered the wavelength window as wide as 26 nm at 20 °C and 52 nm at 80 K, respectively. By adjusting the cavity length, the lasing wavelength can be tuned in the range of 1.05-1.10μm. Both of the broad tuning wavelength and the wide lasing spectrum indicate that the QD lasers have very broad gain profile, which is highly desirable for making widely tunable lasers.