Rate Equation Modeling of Interband Cascade Lasers on Modulation and Noise Dynamics

This work presents a rate equation model for interband cascade lasers, which is used for investigating modulation dynamics and optical noise properties. Through standard small-signal analysis of the rate equations, we analytically derive the resonance frequency, the damping factor, the relative intensity noise (RIN), and the frequency noise (FN) of the interband cascade lasers. It is shown that more cascading stages are beneficial for reaching a broad modulation bandwidth at a low pump current. On the other hand, fewer cascading stages are favorable to achieve low-RIN and low-FN (or narrow-linewidth) laser emission.