Combined numerical and analytical method of calculating microbending losses in single-mode fibers with arbitrary index profiles

Using a multilayer approximation of the index distribution, analytical solutions of the microbending losses according to Petermann´s approach for single-mode fibers with arbitrary index profiles can be derived. It is shown that less than 20 layers are required to ensure satisfying accuracy for graded-index single-mode fibers. For single-cladded fibers, simple profile-independent formulas for the ω01and ω02spots sizes are presented. These make it possible from the Laplace spot size at the zero dispersion wavelength to derive the spectral microbending losses without knowing the index profile.