Optically pumped InAs/InGaSb type-II quantum-well lasers

High-power mid-infrared (MIR) lasers are highly desirable for a variety of applications such as remote chemical sensing, infrared countermeasures, environmental monitoring etc. We will report the recent progress in the development of optically pumped Mid-IR lasers based on InAs/InGaSb/InAs/AlSb type-II quantum wells (QWs) for high power applications. The potential of achieving Watts of quasi-cw output power by improving the material quality and device design will be discussed. The performance of our previous devices was mainly limited by the rising of internal loss vs, temperature, even though the internal quantum efficiency was > 70% at temperatures up to 150 K. The internal loss rose from 10 cm-1 at 80 K to 19.2 cm-1 at 140 K, which was mainly due to inter-valence subband absorption. With such a high internal loss, power scaling by increasing device length is limited. At high temperatures, while lasing was possible under intensive and short pulses, the lasing efficiency and average output power were not sufficient for many high-power applications. For this device, the maximum peak output power was 0.98 W per facet with a pulse length of 0.05 ms. The net external quantum efficiency before thermal roll off was as high as 23.5% with an estimated pump power absorption of 87% in the 0.82-mu m active region.