Analysis of single mode step index fibres using finite element method.

Abstract

Single mode step index fibres are the most common waveguides employed in optical communication systems. To design and study such fibres, analytical methods are not sufficient and hence more advanced mathematical techniques such as finite element methods (FEM) are used. In this paper we employed the FEM software, COMSOL Multiphysics® (version 4.3) to study the effect of varying the core radius of a glass single mode step index fibre on the electric field intensities propagated from the core to the cladding region. The results show that with a cladding radius of 40 μm, it is possible for the single mode step index fibre to sufficiently support the propagation of the fundamental mode for core radii in the range 2.5 to 6 μm. The optimum core radius was found to be 4 μm.