Low-threshold quasi-cw type-II quantum well lasers at wavelengths beyond 4 μm

Optically pumped InAs/InGaSb/InAs/AlSb type-II quantum well lasers emitting from 4.1 to 4.36 μm were operated up to 226 K with a characteristic temperature T0 of 30 K. The absorbed threshold pump intensity at 0.98 μm was 0.12 kW/cm2 at 100 K, and 3.25 kW/cm2 at 200 K with a pulse length of 5 μs and a repetition rate of 2 kHz. At 73 K, the peak output power was 250 mW per facet with a pulse length of 10 μs and a repetition rate of 10 kHz. A cw output power of 14.7 mW was observed at 74 K.