Generalized Gaussian approximation for single-mode fibers

A variational method is presented that generalizes well-known Gaussian method for single-mode fibers. This method uses only simple elementary functions to approximate the fundamental mode fields. By applying it to practical cases such as step index and clad parabolic index fibers, where exact solutions can be found, it is demonstrated that the method is essentially simple and that it is accurate for the analysis of single-mode fibers and devices. This approximation provides much better eigenvalues and, in particular, evanescent fields than the traditional Gaussian. Significantly, the present approximation´s range of applicability covers the whole single-mode range, while being only slightly more complicated than the modified Gaussian method