Studies of the dispersion characteristics and cutoff frequencies of a new lightguide having an Archimedian spiral core cross-section under the weak guidance condition

In this analysis we have taken the scalar wave approximation in the field u nder the weak guidance condition to study the modal behaviour, dispersion c haracteristics and cutoff frequencies of a new optical waveguide having an Archmedian spiral care cross-section. By choosing appropriate orthogonal co ordinates (xi, eta, z) and using the boundary conditions of the proposed wa veguide, the eigenvalue equation (characteristic equation) has been derived analytically. Using this equation model dispersion curves and cutoff frequ encies have been obtained for some low order modes.