Thermal Analysis for Quantum Cascade Lasers using Experiments, Simulations and Structure Function Obtained by Static Measurement

In order to increase the output of quantum cascade lasers (QCLs), it is important to improve the heat dissipation. For investigating the relationship between the device structure and heat dissipation properties, three kinds of different QCL devices were prepared as follows. One is a device which has the ridge covered with SiO2 and thin Au, another is a device which has the ridge covered with SiO2 embedded with Au, and the other is a device which has the ridge covered with SiO2 embedded with Cu. The temperature distributions was measured with a thermos-viewer. In addition, relationship between structure and heat dissipation properties in these structure devices are analysed with a three-dimensional model. As a result, it was clarified from experiments and simulations to improve heat dissipation properties by embedding ridge with Au or Cu. Furthermore, the thermal properties of the QCL device was measured by the statics method to separate the thermal resistance of the ridge, that of substrate, and that of mount parts. It was shown that the thermal resistance improves by more than 2 K/W from 9.3 K/W to 6.9 K/W by embedding ridge with Au or Cu.