Reconstruction of refractive index profiles from multiple wavelength mode indices

A method is-presented whereby the refractive index profile of a planar, surface, dielectric optical waveguide may be reconstructed from sets of effective refractive indices, measured at different wavelengths. In order to allow for the dispersive nature of the glass, additional information from highly multi-mode guides, which are produced by the same manufacturing process as the guide under analysis, has been used in the method. The technique provides greater information about the profile than can be obtained from one measured set and is used here to analyse the profiles of potassium ion diffused guides formed in glass.