Waveguide Dispersion in a Strongly Biaxial Anisotropic Fiber: An Analytical Solution

In this paper, modal propagation along anisotropic biaxial step-index homogeneous optical fibers is considered and wave equations are derived in a cylindrical coordinate system, coaxial with the z-axis. It is assumed that the core is a strongly biaxial dielectric medium, with diagonal ε in rectangular coordinates, surrounded by an isotropic cladding that extends to infinity in the radial direction. The computational algorithm uses Frobenius´ series expansions, both in the core and cladding, and is fully derived here. Dispersion lines are presented for a particular case, showing novel effects, not found in the weakly anisotropic case.