A versatile SPICE model for quantum-well lasers

A SPICE equivalent-circuit model for the design and analysis of quantum-well lasers is described. The model is based on the three-level rate equations which include, in their characterization of charge dynamics, the role of gateway states at the quantum well. The model is versatile in that it permits both small- and large-signal simulations to be performed. Emphasis here is placed on validating the model via a comparison of simulated results with measured data of the small-signal modulation response, obtained over a wide range of optical output powers from two lasers with different lengths of the separate-confinement heterostructure (SCH). Using a set of tightly specified model parameters, all the important trends in the experimental data are reproduced. The consideration of gateway states is found to be important, with regard to predicting the small-signal response, only for the laser with the longer SCH. This highlights the significance of the interplay between the roles of transport through the SCH and capture/release via the gateway states at the quantum well.