Refractive index profile of fused-tapered fiber couplers

Abstract

We investigate the refractive index profile evolution during the tapering of fused couplers. We assume the refractive index to be a linear function of the dopant concentration. The evolution of the refractive index profile is obtained by solving the diffusion-convection equation. The couplers are cleaved at different positions along the coupler axis, and the real refractive index profiles, measured using Refracted-Near-Field technique, are compared with the numerical solutions.