Investigation of thermal properties of mid-infrared AlGaAs/GaAs quantum cascade lasers

Abstract

We report on detailed experimental investigation of thermal properties of AlGaAs/GaAs quantum cascade lasers (QCLs) emitting at wavelength of 9.4 μm. Different mounting options and device geometries are compared in terms of their influence on the relative increase of the active region temperature. High resolution, spatially resolved thermoreflectance is used for mapping temperature distribution over the facet of pulse operated QCLs. The devices’ thermal resistances are derived from experimental data. We also develop a numerical thermal model of QC lasers, solving heat transport equation in 2D and 3D, which includes anisotropy of thermal conductivity. By combining experimental and numerical results, an insight into thermal management in QCLs is gained. Thermal optimization of the design focuses on improving heat dissipation in the device, which is essential to increase the maximal operation temperature of the devices.

Monte Carlo modeling applied to studies of quantum cascade lasers

“…Gao et al (2006Gao et al ( , 2007a investigated influence of electron leakage to X valleys and compared the performance with other structures (Sirtori et al 1998(Sirtori et al , 1999. We would like to notice that this particular structure design has been a basis for fabrication of QCL by Prof. M. Bugajski research group at Institute of Electron Technology, Warsaw, Poland (Kosiel et al 2009(Kosiel et al , 2011, and extensively investigated experimentally (Pierściński et al 2010(Pierściński et al , 2012Bugajski et al 2013Bugajski et al , 2014. In collaboration with this project microscopic description of electron behavior (Borowik et al 2010) and investigation of space-charge effect (Konupek et al 2011;Borowik et al 2012) have been performed by MC technique.…”

Examination of thermal properties and degradation of InGaN - based diode lasers by thermoreflectance spectroscopy and focused ion beam etching

“…24 Therefore, it needs to be determined experimentally in case of each device. The TR has been previously extensively applied to study facet heating of different type semiconductor devices (edge emitting lasers, 25 laser bars, 26 vertical external-cavity surface emitting laser -VECSELs 27 and quantum cascade lasers -QCLs 28,29 ) based on the GaAs or InP material system. The application of TR spectroscopy to investigate the temperature distribution on the front facet of GaN based DL devices was presented for the first time in the paper.…”

Heat Dissipation Schemes in AlInAs/InGaAs/InP Quantum Cascade Lasers Monitored by CCD Thermoreflectance

“…The CCD TR [14,19], in which a lamp with narrow bandpass filters or a LED illuminator is used to produce the probe light (spectrally narrow) and the whole thermal image is stored in one snapshot by CCD camera. In the other configuration, known as classical or focused laser beam configuration [20][21][22], the appropriate laser line is used as a probe beam for examining the structure. The thermal image is registered by scanning the sample surface point by point.…”