Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 88: Lasers

HL 88.11: Talk

Friday, March 18, 2011, 13:00–13:15, POT 151

Investigation of heat dissipation in Mid-Infrared quantum cascade lasers — •Stefanie Mayer, Christian Schilling, Ralf Ostendorf, Quankui Yang, Rainer Lösch, Wolfgang Bronner, and Joachim Wagner — Fraunhofer Institut für Angewandte Festkörperphysik IAF, Freiburg, Deutschland

The output power and efficiency of quantum cascade lasers (QCL) is severely limited by self-heating effects of the device during operation. Therefore, a fundamental knowledge of the heat dissipation is essential for further device optimization.

We present modelling of heat transfer processes in GaInAs/AlInAs/ InP-based QCLs by finite elements analysis. The influence of different mounting techniques and of different heat spreaders on the temperature of the active region has been studied. The results indicate a significant reduction of the temperature (by about 40-50 %) inside the device by using diamond heat-spreaders and epi-down mounting due to improved heat dissipation. In addition we extended our analysis to QCL arrays and investigated thermal crosstalk between adjacent emitters of the array.

These results are confirmed by electro-optical measurements performed on QCL emitting at a wavelength of 4.7 µm. Here, an enhancement of 148.47 % in optical peak output power was observed in pulsed operation mode with 10 % duty cycle by using diamond heat-spreaders and epi-down mounting.