The step azimuthal optical fiber

摘要

We present a new kind of optical fiber by introducing a perturbation of the classical core-cladding fiber design. The azimuthal symmetry of the refractive index is modified by a narrow parabolic perturbation. The perturbation acts like an azimuthal potential well against the propagating pulse. Theoretical calculations lead to a strong selection of the azimuthal modes. We show that by conveniently choosing the parameters, the fundamental mode is not reflected as a result of its radial field distribution.