We report the thermal analysis of short wavelength strain-compensated InxGa1-xAs/InyAl1-yAs quantum cascade lasers (QCLs) operating at lambda similar to 3.8-4.3 mu m by a two-dimensional heat transfer model using heat source densities obtained from experimental measurements in continuous-wave mode. The heat fluxes and temperature profiles are analyzed for various QCL structures with different bonding schemes, extracting thermal conductance (G(th)). The use of buried heterostructure (BH) enhances the lateral heat dissipation from the active core region of QCLs. The heatsinking structure in epilayer-down configuration using diamond submount exhibits high G(th) values with less temperature dependence. For epilayer-down bonded single ridge waveguide 11 mu m wide and 4 mm long BH QCLs at lambda similar to 3.8 mu m and lambda similar to 4.3 mu m on diamond submount, the improved G(th) values of 292 W/K cm(2) and 409 W/K cm(2) at 298 K are obtained, respectively. The highly strained InGaAs/InAlAs structure gives a low G(th) value due to the reduced thermal conductivity. The theoretically calculated results are compared with the existing G(th) data obtained experimentally, thus showing a good agreement. (C) 2010 Elsevier Ltd. All rights reserved.