Dynamics of Semiconductor Casers for Optical Communications

Abstract

Abstract The objective of this work is to study the dynamic behavior of quantum well semiconductor laser used in optical fiber communication systems. This study is mainly motivated by the superior features offered by these lasers, such as its narrow line-width, low threshold current and high modulation bandwidth. The optimum use of such properties in optical communication systems requires a robust model of the laser dynamics that account for the different physical parameters and could be integrated in a system-oriented simulation environment. To attain that objective the semiconductor laser dynamics have been studied in depth as well as different techniques used for the modeling of these dynamics. Based on this study we found that the laser dynamics, which can be accurately described by carriers, photons and phase rate equations, depends strongly on the laser physical parameters and more specifically on its differential optical gain. We have then focused on the gain calculation in quantum well semiconductor lasers as key parameter for dynamics understanding. A semi-classical model that accounts for the strain effects in multiple quantum well structures is then used to evaluate the gain and its variation with both the carrier density and the photon energy.