Comparison of SiO_2, Si_3N_4, As_2S_3, and Ge_(0.25)Se_(0.75) dielectric layers for InP- and GaAs-based material systems for midinfrared quantum cascade laser waveguides

摘要

We present in this paper a direct comparison of the optical properties of InP- and GaAs-based quantum cascade laser waveguides operating in the midinfrared wavelength range. The absorption loss and optical confinement were calculated using a two-dimensional electromagnetic finite-element method. The effect on the waveguide properties of SiO_2, Si_3N_4, As_2S_3, and Ge_(0.25)Se_(0.75) used as electrical insulation layers is investigated. The results indicate that a careful choice of this particular layer according to the geometrical structure and the emission wavelength should enhance the laser performance.