Minimizing the linewidth enhancement factor in multiple-quantum-well semiconductor optical amplifiers

Semiconductor optical amplifiers (SOAs) often exhibit pronounced phase noise owing to their inherently high linewidth enhancement factor (LWEF). The signal to noise ratio of a SOA is often decreased due to refractive index fluctuations in the gain medium causing distorted phase relationship between the generated photons, which is quantified by the LWEF. A simple and precise theoretical model that offers a prescription for minimizing the LWEF in SOAs is unavailable in the literature. In this study, we have developed an inclusive yet simple algorithmic model that aims to both represent the variation and to provide a strategy for minimizing the LWEF in multiple-quantum-well (MQW) based SOAs. The results of the presented model were verified via a reasonable agreement with experimental results. This study provides a theoretical description of how to adjust the LWEF through tuning of the most critical MQW SOA parameters in the design stage.