980 nm quantum dot lasers with very small threshold current densities

Quantum dot lasers based on a single active layer with total external quantum efficiencies of up to 80% (>1 W/A) and threshold current densities as low as 54 A/cm(2) have been realized. By direct comparison with a quantum well reference structure the effect of the active layer on important device properties is demonstrated. The difference in the gain properties has a direct impact on the length dependence of the threshold current density and makes quantum dot lasers superior in the case of long cavities. Furthermore, the differences in the sensitivity of emission wavelength and threshold current density to operation temperature: have been investigated.