The solutions of nonaxisymmetric fields in SELFOC fibers with longitudinal imperfections

The solutions of nonaxisymmetric fields in SELFOC fibers with longitudinal imperfections are investigated. The refractive index is assumed to be of the form
K = \varepsilon/\varepsilon_{0} = K_{0} - K_{2}(z) r^{2}
(
K_{2}(z)
is a gradually varying function of
z
). The analytic solution is obtained. When K
2
is a constant, the solution is reduced to that of perfect SEL-FOC fibers, which is well known. Further the relations of modes conversion in imperfect fibers are obtained.