MODAL CUTOFF PROPERTIES OF A FIBER WITH A TREFOIL CROSS-SECTION UNDERTHE WEAK GUIDANCE APPROXIMATION

In this paper, we present a theoretical analysis of the propagation of electromagnetic waves through a fiber with a trefoil cross section. T his may be regarded as a preliminary study of a waveguide in which thr ee cares are embedded in a common cladding. By choosing an appropriate coordinate system, the scalar wave equation is solved, and thereby th e characteristic equation for the guided modes under the weak guidance approximation is derived. To understand the basic modal properties in a simple manner; the cutoff equation is derived and the modal cutoff properties of some modes are determined numerically. (C) 1997 John Wil ey & Sons, Inc.