A mini-staged multi-stacked quantum cascade laser for improved optical and thermal performance

In this paper, a mini-staged multi-stacked quantum cascade laser structure with a designed wavelength of 4.7 mu m is presented. By introducing five 0.5 mu m thick high thermal conductivity InP interbuffer layers, the 60-stages active region core of the quantum cascade laser is divided into six equal parts. Based on simulation, this kind of quantum cascade laser with a 10 mu m ridge width gives nearly circular two-dimensional far-field distribution (FWHM = 32.8 degrees x 29 degrees) and good beam quality parameters M-2 = 1.32 x 1.31 in the fast axis (growth direction) and the slow axis (lateral direction). Due to the enhancement of lateral heat extraction through the interbuffer layers, compared to the conventional structure, a decrease of about 5-6% for the maximum temperature in the active region core of the mini-staged multi-stacked quantum cascade laser with indium-surrounded and gold-electroplated packaging profiles is obtained at all possible dissipated electrical power levels.

National Science Fund for Distinguished Young Scholars of China 60525406 National Natural Science Foundation of China 60736031 60806018National Basic Research Program of China 2006CB604903 National High-tech R&D Program of China 2007AA03Z446 This work was supported by the National Science Fund for Distinguished Young Scholars of China (contract number: 60525406) the Key Program of National Natural Science Foundation of China (contract number: 60736031) the National Natural Science Foundation of china Youth Fund (contract number: 60806018) National Basic Research Program of China (contract number: 2006CB604903) and National High-tech R&D Program of China (contract number: 2007AA03Z446).