Temperature dependence of 4.1 μm mid-infrared type II “W” interband cascade lasers

The thermal properties of 5-stage “W” Interband-Cascade Lasers emitting at 4.1 μm at room temperature (RT) are investigated by measuring the lasing and spontaneous emission properties as a function of temperature and hydrostatic pressure up to 1 GPa. Experiments show that at RT more than 90% of threshold current of these devices is due to non-radiative loss processes. We also find that the threshold current density dependence on temperature can be fitted with a single exponential function over a wide temperature range with a characteristic temperature, T0, of 45 K. The relatively high temperature sensitivity in these devices is attributable to the large non-radiative current contribution coupled with non-pinning of the carrier density above threshold.