Fig. 1. The structure of the QD laser and the structure of the active region

Fig. 2. PL spectrum of the three QDs samples with growth temperature of 510℃，520℃ and 530℃

Fig. 3. Atomic force microscope （AFM）image of the three QDs samples （a）510 ℃，（b）520 ℃, and （c）530 ℃）

Fig. 4. P-I-V and WPE characteristics of the laser at CW mode

Fig. 5. Lasing spectrum at RT （The central wavelength is 1.3 μm）

Fig. 6. The power-current（P-I） characteristics in different temperature （5∼80℃） and the fitting curve between threshold current and temperature