Rate Equation Modeling of Interband Cascade Lasers

Abstract

Interband cascade lasers (ICLs) are power-efficient mid-infrared laser sources for applications in sensing of numerous molecules and in free-space optical communications. The static performances of ICLs including the lasing threshold and the output power have been significantly improved since its first demonstration by R. Yang [1]. GaSb-based ICLs have optimal performance in the spectral range of 3–4 μm which is hard to reach for the quantum cascade laser counterpart [2]. This work proposes a rate equation model for studying dynamical characteristics of ICLs including the intensity modulation (IM) response, the relative intensity noise (RIN), and the frequency noise (FN). Taking into account carrier dynamics in the W-shape active region while ignoring those in the electron and hole injectors [3], the rate equations for the carrier number N, the photon number S, and the phase ϕ of the electric field read.