Three-level rate-equations-based model of quantum cascade lasers with a single solution regime

Abstract

The three-level rate-equations-based QCL models can possess multiple DC solution regimes for nonnegative values of injection currents. We show that using the proposed variable transformation, the three-level rate-equations based models, considering the gain-saturation terms, can possess single solution regime and hence, the circuit-level simulation results will always converge to the positive laser output powers. By using the proposed equivalent circuit-level model, the effects of injection current on QCL static and dynamic behaviors are investigated. It has been shown that the proposed circuit-level model accurately predicts the operating characteristics of the QCLs.