Coupling Efficiency and Reflectance Analysis of Graded Index Expanded Beam Connectors

Abstract

This article deals with coupling efficiency and reflectance analysis of graded-index expanded-beam connectors. We point out the best conditions to take advantage of expanded beam connectors for relaxing lateral offset tolerances without going down to critical angle misalignments tolerances. The influence of manufacturing defaults and coupling misalignments by lateral offset and tilt angle on coupling efficiency and reflectance are theoretically analyzed, investigated, and compared to experimental results. The study explains an interesting reflectance of expanded beam connectors compared to standard single-mode fibers. We demonstrate and explain why we can both obtain high coupling efficiency and low reflectance.