Waveguide dispersion characteristics of two kinds of triple-clad single-mode (bers named WI and WII were examined in this paper. In view of the impossibility to deduce the expression of waveguide dispersion directly due to the complexity of the characteristic equations, a feasible approach to calculate waveguide dispersion was established. The calculated results indicate that the adjustable range of the zero-dispersion point of the triple-clad WI-and WII-type single-mode (bers is obviously wider than that of the conventional doubly clad W-type single-mode (bers in the same conditions. The in8uences made by the geometric parameters and optical parameters on the waveguide dispersion and cuto9 characteristics of low-order modes for WI-and WII-type (bers were analyzed. The method presented to calculate waveguide dispersion can be applied to multi-clad fibers.

A doubly clad optical fiber with an inner cladding made of a uniaxial crystal material whose optical axis is parallel to the fiber axis was proposed, and exact characteristic equations of vector modes were derived. The influence of the ratio (kcl) of the extraordinary to the ordinary ray indexes upon the waveguide dispersion was examined in detail. In view of the impossibility to deduce the expression of waveguide dispersion directly due to the complexity of the characteristic equations, a feasible approach to calculate waveguide dispersion was established. The calculated results indicate that the values of waveguide dispersion can be effectively changed through variation of kcl without changing the geometrical and optical parameters (S and R). The influences of kcl, S and R on the propagation and cutoff characteristics of the low order modes are also analyzed.