Weak guidance modal analysis of an infrared lightguide with a four‐lobed core cross section

Abstract

In this communication, we describe an analytical and computational study of the modal behavior, cutoff condition, and dispersion characteristics of a new kind of infrared optical waveguide having a core cross section with a four-lobed loop boundary. We introduce new and appropriate coordinates (ξ, η, z), and impose the boundary conditions under the weak guidance approximation. The modal characteristic equation has been derived, and from this, characteristic dispersion curves for some low-order modes are obtained in the low-attenuation window at λ0=1.3 and 1.55 μm. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 163–166, 1999.