A 3D DPG Maxwell Approach to Nonlinear Raman Gain in Fiber Laser Amplifiers

TL;DR

This paper introduces a fully vectorial 3D Maxwell-based model for Raman gain in fiber laser amplifiers, utilizing an ultraweak DPG formulation and nonlinear iteration to improve accuracy in high-frequency wave propagation.

Contribution

It presents a novel full-vectorial formulation and application of the DPG Maxwell approach to nonlinear Raman gain modeling in fiber lasers.

Findings

Qualitative agreement with experimental data

Effective modeling of Raman gain in fiber amplifiers

Enhanced accuracy over traditional beam propagation models

Abstract

We propose a three dimensional Discontinuous Petrov-Galerkin Maxwell approach for modeling Raman gain in fiber laser amplifiers. In contrast with popular beam propagation models, we are interested in a truly full vectorial approach. We apply the ultraweak DPG formulation, which is known to carry desirable properties for high-frequency wave propagation problems, to the coupled Maxwell signal/pump system and use a nonlinear iterative scheme to account for the Raman gain. This paper also introduces a novel and practical full-vectorial formulation of the electric polarization term for Raman gain that emphasizes the fact that the computer modeler is only given a measured bulk Raman gain coefficient. Our results provide promising qualitative corroboration of the model and methodology used.