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 behaior, cutoff condition, and disper- sion characteristics of a new kind of infrared optical waeguide haing a core cross section with a four-lobed loop boundary. We introduce new () and appropriate coordinates j , h, z , and impose the boundary condi- tions under the weak guidance approximation. The modal characteristic equation has been deried, and from this, characteristic dispersion cures for some low-order modes are obtained in the low-attenuation window at l s 1.3 and 1.55 mm. Q 1999 John Wiley & Sons, Inc. Microwave 0 Opt Technol Lett 23: 163)166, 1999.