Facilities

Directly modulated 1.3 μm quantum dot lasers epitaxially grown on silicon

We report the first demonstration of direct modulation of InAs/GaAs quantum dot (QD) lasers grown on on-axis (001) Si substrate. A low threading dislocation density GaAs buffer layer enables us to grow a high quality 5-layered QD active region on on-axis Si substrate. The active layer has p-modulation doped GaAs barrier layers with a hole concentration of 5 × 1017 cm3 to suppress gain saturation. Small-signal measurement on a 3 × 580 μm2 Fabry-Perot laser showed a 3dB bandwidth of 6.5 GHz at a bias current of 116 mA.

The importance of reducing threading dislocation density on laser lifetime is detailed in this paper.

We investigate the impact of threading dislocation density on the reliability of 1.3 lm InAs quantum dot lasers epitaxially grown on Si. A reduction in the threading dislocation density from 2.8108 cm2 to 7.3106 cm2 has improved the laser lifetime by about five orders of magnitude when aged continuous-wave near room temperature (35 C). We have achieved extrapolated lifetimes (time to double initial threshold) more than 10 106 h.