Effect of absorption loss on the saturation characteristics of semiconductor optical amplifier

Abstract

Semiconductor optical amplifiers (SOAs) as nonlinear devices always work in the gain saturation region. Therefore, the saturation gain is an important parameter of SOAs. However, the existing theoretical gain formula greatly deviates from the experimental measurements. We find experimentally that the effect of the absorption loss on the SOA gain cannot be neglected, especially when the SOA is biased into the saturation region. In this paper, considering the influence of the absorption loss, we propose a modification to the SOA gain formula in common use. We are able to validate the revised formula against the experimental measurements. Thus the theoretical formula after modification can be accurately applied to evaluate the SOA gain in practice.