Dynamic Modeling of Terahertz Quantum Cascade Lasers

In this paper, the influence of the simplifications made in the four-equation-based set of rate equations describing the dynamic behavior of a quantum cascade laser (QCL) is studied. Numerical simulations based on the set of four rate equations has been developed, enabling the theoretical study of the influence of different parameters on the direct modulation response of the laser. These equations have been then linearized in order to deduce a set of state system equations, which was written in a matrix formalism. Finally, an approximate second-order transfer function has been derived with the linearized dependence of its times constant.