Theory and simulation of a two coupled-cavities fiber laser

摘要

In this work we develop a theoretical model to analyze the response of a two coupled-cavities fiber laser. This setup operates as an additive pulse mode-locking (APM) laser and its design is based on the combined action of an active cavity and a passive cavity. The first one is generated with an erbium-doped fiber and two fiber Bragg gratings (FBGs) as reflective components, while the passive cavity is built with a fiber pigtail being the corresponding mirrors one of the FBGs and the Fresnel reflection at the fiber end. It is proposed a numerical model that solves the Non-Linear Schrodinger Equation (NLSE) by using the Split-Step Method (SSM) together with the T-Matrix Method (TMM) to calculate the coupling factor on each reflective component. The main parameters are: the group velocity dispersion (GVD), the self-phase modulation (SPM), the gain and/or loss factors of the fibers including self-saturation effect and the reflectivity and dispersion characteristics of each FBG. The dependence of both, temporal and frequency behaviour of the generated emission with the several involved setup parameters are analyzed. The numerical results produced by applying the theoretical model are compared with previously obtained experimental results, and a good agreement between them is observed.