Method for analysis of real commercially available optical fibers with large core diameter

Abstract

This work presents method for computing dispersion parameters of guided modes propagating in commercially available telecommunication silica optical fibers with large core diameter. These real optical fibers differ from model ideal representation by non-symmetric geometry of transversal cross-section in both radial coordinates and refractive index profile form. We propose solution for detailed reconstruction of researched optical fiber 3D-structure by limited data from the protocols of refractive index profile measurement by conventional lab kits of optical fiber analyzers over conditional transversal cross-sections “X” and “Y”. It is based on irregular mesh with nodes laying on cross-section semi-axes corresponding to refractive index profile extremums that provides following implementation of triangularization procedure to form the adaptive mesh for researched fiber representation during its analysis by rigorous numerical methods. We performed computing of guided mode staff transmission parameters for commercially available sample of multimode optical fiber 50/125 of Cat. OM2 with great core asymmetry and strong refractive index profile distortions by recently developed modification of mixed finite element method adapted for analysis of optical fibers with large core diameter. Computation results were compared with data of analysis proceed by the same approach for model ideally symmetric multimode optical fiber with structure repaired also from the same sample measurement data but considered only from the one semi-axis.