Mode Characteristics of the Strongly Anisotropic $a$ -Axis Single-Crystal Fiber

The mode theory of the strongly anisotropic a axis step-index single-crystal fiber is studied in this paper. The electromagnetic field equations of the a axis step-index single-crystal fiber are solved under the strongly anisotropic condition, and the transverse electric field components are obtained. The dispersion equations far from cutoff, near cutoff, and in the guided mode region are discussed, respectively. Numerical results of the mth-order elementary modes are presented for the strongly anisotropic a axis step-index single-crystal fiber.