An analytical study of modal dispersion characteristics of helically clad crystal-cored optical fiber

摘要

The uniaxial crystal cored optical fiber, with optical axis parallel to the fiber axis, having helical cladding is proposed and a characteristic equation is derived. Employing helical boundary conditions, the characteristic equation is found and dispersion curves are drawn for different K_(co) (the ratio of longitudinal and transverse refractive index) values and for different modal order ν. The field components in the core region of the proposed fiber are found and a curve between effective-index vs. normalized frequency is drawn. Our studies show that the anisotropic parameter (K_(co)) influences the dispersion characteristics and modal cut-offs and the modal grouping occurs at different V number for different K_(co) values. It is also observed that the helix pitch angle ψ has no any pronounced effect on propagation characteristics of the proposed fiber.