A New Optical Gain Model for Quantum Wells Based on Quantum Well Transmission Line Modelling Method

This paper presents a new method for modelling the gain spectrum in quantum well structures based on the quantum well transmission line modelling (QW-TLM) method. In the QW-TLM method, three parallel RLC filters together with their associated weight coefficients constitute a QW-TLM unit, which represents the processes that electrons transit from the conduction band to the heavy hole band, the light hole band and the spin-orbit split-off band at a specific wave vector. Parallel QW-TLM units are adopted to describe the electron transitions in the wave vector space. Furthermore, the optical gain model of quantum wells based on the QW-TLM method is presented. The gain spectrum obtained through the QW-TLM method is agreeable with the gain spectrum calculated from the analytical expression in a large wavelength range from to . In order to reduce the computation time, under sampling QW-TLM is proposed to model the gain curve of quantum wells. The simulation result shows that the gain curve obtained from under sampling QW-TLM is consistent with the gain curve obtained through the theoretical derivation from to , which satisfies the requirement of studying the dynamic spectral characteristics of quantum well devices