Measurement of internal quantum efficiency and temperature dependence of gain and loss in interband cascade lasers near room-temperature

We demonstrate that the loss coefficient of 6 and 12 cascade IC lasers is temperature independent over the temperature range of 240 to 300 K. These lasers have an n-doped 200 nm symmetrical separate confinement region. A loss coefficient of 7-8 cm^-1 is demonstrated, which compares to the best loss results obtained so far. Measurement on a 12 cascade IC laser with a p-doped separate confinement region indicates a cavity loss of 14 cm^-1, in agreement with the expectation of higher losses for p-doped layers. An internal quantum efficiency of 80 % is measured at 240 K. A temperature dependence of the gain coefficient given by T_O = 44.5 K is measured and is in agreement with the known threshold dependence on temperature in these lasers. This suggests that Auger recombination is playing an important role in these lasers.