Determination of refractive index profiles in diffused optical waveguides

An improved method for the reconstruction of diffused waveguide index profiles from experimental mode spectra is proposed. The method uses a parabolic approximation between successive points. It is tested on the example of an exponential profile, and applied to the reconstruction of index profiles in Ag⁺ ion-exchanged waveguides from measured mode spectra. This method appears to work well also in the cases of very few mode wave-guides.