The effect of dispersion of the refractive index on the performance of mid-infrared quantum cascade lasers

• Published in: Journal of crystal growth 2001-07, Vol.227, p.313-318
• Main Authors: Li, A.Z, Chen, J.X, Yang, Q.K, Zhang, Y.G, Lin, C
• Format: Article
• Language: English
• Subjects: A1. Characterization; A3. Molecular beam epitaxy; B1. Phosphides; B3. Infrared devices; B3. Laser diode
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(01)00712-6

In this paper, we present the results of the calculation and design for waveguide and the dependence on the performance of mid-infrared InAlAs/InGaAs/InP quantum cascade (QC) lasers grown by gas source molecular beam epitaxy. The dispersion of refractive indices are calculated by taking into account the contribution of the free-carrier concentration absorption. We also report the first GSMBE grown InAlAs/InGaAs/InP QC lasers emitting at 5.1 μm, operated in pulse mode up to 130 K with T 0 of 208 K and J 0 of 2.6 kA/cm 2. For the QC laser designed with lower waveguide cladding InP concentration of 1×10 18 cm −3, it does not lase. Presented theoretical and experimental results indicate that the free-carrier absorption in both upper InGaAs contact layer and lower InP waveguide cladding does play an important role in the dispersion of the index of refraction of semiconductors at mid–far-infrared wavelengths and influence the performance of QC lasers.