Modal analysis of an infrared lightguide with a three-lobed core cross-section under the weak guidance approximation

Abstract

This paper gives in brief the theoretical and computational investigation of a new infrared lightguide having a three-lobed core cross-section. This structure is here introduced for the first time and may be conceived as a distortion of a triangular core cross-section. Using the scalar wave approximation, the modal characteristic equation for the lowest order mode (v=0) has been analytically derived. From this equation the modal dispersion curves are obtained at two operating wavelengths λ0 = 1.55 μm and λ0 = 1.30 μm.