M. Joshi et al., Lightguides with core cross-section bounded by two spirals: Effect of curvature on dispersion curves, OPTIK, 111(8), 2000, pp. 375-377
Recently Sing ct at. [1-2] investigated the dispersion characteristics and
cutoff conditions of a wave guide whose guidng cross-section was assumed to
be bounded by two spirals, r=ce-theta(2)/2 and r=be -theta(2)/2. In that p
aper [2] the width (b - c) is allowed to change by changing the parameter b
and keeping c fixed at 2.0 mu m. Here in this paper, we want to study how
the dispersion characteristic change with curvature considering a few more
fixed values of c. We choose c = 4.0 mu m and c = 6.0 mu m, so that the ave
rage curvature may be less than curvature corresponding to c = 2.0 mu m. It
is found that as the curvature of the guide decreases the number of sustai
ned modes for a given value V shows a tendency to decrease.