Versatile dispersion characteristics of water solution of glycerine in selective filling of holes in photonic crystal fibers.

Using a glycerine-water solution with various concentrations, we investigate the dispersion characteristics of photonic crystal fibers by selective filling of holes. Our analysis is based on a simple but accurate semi-vectorial solution of Helmholtz's equation by the finite difference method devised with a mode-field convergence technique and crosschecked by results with those from a deeply involved multipole method. Significantly, a better ultra-flatness but near-zero group velocity dispersion is revealed with a 20% glycerine-water solution that is superior to pure water of a very recent case when the holes of the first ring of the fiber are filled. This versatile effect in management of holes of identical diameter with liquid is expected to play a guiding role in studies of supercontinuum generation.