Anisotropic fibers with nonaligned optical (stress) axes

Propagation in anisotropic optical fibers is shown to have an isotropic fiber equivalent. This gives a clear physical description, particularly for the loss mechanism of leaky modes, and also allows for simple, approximate solutions by variational methods. The step-profile fiber with nonparallel core and cladding optical (stress) axes is solved exactly, showing that the fundamental modes are neither uniformly polarized nor geometrically perpendicular to each other. Slightly tilting the cladding’s optical axes relative to the core axes greatly amplifies the leakage reported previously for parallel optical axes.