MODAL DISPERSION CHARACTERISTICS OF A BRAGG FIBER HAVING PLASMA IN THE CLADDING REGIONS

The modal dispersion relation of electromagnetic waves in a Bragg fiber having plasma in the cladding regions is investigated analytically. The proposed Bragg fiber consists of a low index central region having air surrounded by a large number of periodic cladding layers of alternating high and low refractive indices of dielectric and plasma respectively. The modal dispersion relation is obtained by solving Maxwell wave equations using a simple boundary matching method. The analysis shows that the normalized frequency parameter (also called V -number) is frequency independent. This indicates that the proposed Bragg fiber may be used for single mode operation without high frequency limitation as well as with little loss of energy compared to the conventional dielectric waveguide.