Theoretical analysis of a coated single-mode fiber termination

The antireflection efficiency of a single layer coating in front of an abruptly terminated monomode optical fiber is treated analytically by means of an integral equation, that is appropriate to solve the corresponding boundary value problem. Both guided and radiation modes are taken into account, when describing the field inside the optical fiber region. Then the integral equation is solved approximately by a Neumann series procedure giving highly accurate results when the weakly guidance condition holds, which is a case of practical interest in the optical communications area. The reflection coefficient and the radiation pattern of this configuration are computed. Numerical results are given for several values of the parameters of the geometry under consideration.