Very low threshold and high power CW operation in1.55 µm gain-coupled DFB lasers with periodically etched quantum wells

The authors demonstrate extremely low threshold and high CW output power in 1.55 µm gain coupled DFB lasers. The structure is an MQW strain compensated active layer with first-order grating etched on the upper wells. The lowest thresholds of 2.5 mA at 20°C and 10 mA at 80°C are obtained using one HR facet coating. With an AR front facet, the CW output is increased up to 40 mW, while the threshold current remains < 10 mA.