Radiation pattern of light scattering from the core region of dielectric-slab-optical waveguides

The scattering from dielectric-slab-optical waveguides having refractive-index inhomogeneities in the core region has been studied by solving the Maxwell equations together with the use of a stationary phase method. The scattering phenomenon is of interest since it provides the radiation pattern in the far-field region which is characterized by the statistical scale of inhomogeneities in a waveguide. The anisotropic fluctuations of the refractive index in the directions parallel and perpendicular to the axis of light propagation have been assumed in the analysis. It is found that the strong multiple peaks in the forward direction occur in the substrate region when the correlation length of refractive-index inhomogeneities in the axial direction is much greater than the wavelength of light.