Design for non-uniformly doped Erbium-doped waveguide amplifiers in the propagation direction

A novel scheme is proposed to improve the gain performance of Erbium-doped waveguide amplifiers (EDWAs) by non-uniformly doping Er+3 ions along the propagating direction. Dependence of gain and pump efficiency on Er concentration is studied through an adaptive method based on the finite element method (FEM). Numerical results suggest that the optimized distribution of Er concentration operated by gain and pump efficiency can improve, in a certain degree, the gain value, i.e., the gain maximum, for a certain limited length.