1.3 μm emitting, self assembled quantum dot lasers

The performance of lasers with self assembled quantum dot active regions is dependent on both the number of dot states present and the population of those states. Here we describe design approaches to both maximise the number and population of the states at an energy separation corresponding to 1.3 μm emission. This involves careful control of the growth parameters, particularly temperature and the use of p-modulation doping and thin InAlAs layers to maximise carrier population. We present results that include a low threshold current density in longer devices, a low (or even negative) temperature dependence of threshold current and demonstrate CW operation at 1.3 μm for 1 mm long devices with uncoated facets. We also show that the negative T₀ (reducing threshold current density with increasing temperature) obtained around room temperature in our p-doped devices is due to the temperature dependence of the gain