Ion exchange as a new tool to evaluate and quantify glass homogeneity

The homogeneity of glasses is an important factor in many application fields but particularly in photonics. Here, we present a simple approach for evaluating the homogeneity of optical glasses based on a study of ion-exchanged optical waveguides. For that, silicate glasses doped with erbium ions were used as the substrate glasses. Such glasses are going to be widely used in optical telecommunication systems as optical amplifying components and that is why their good homogeneity is of particular significance. For the study, glasses with deliberately different (even poor) homogeneity were melted as the substrate glasses, with optical waveguides being prepared in them by ion exchange. The properties of the waveguides were characterised by mode spectroscopy measurement and the results were evaluated using statistical procedures, which enabled us to determine and compare the measures of glass homogeneity.Our results proved that ion exchange could serve as a useful tool for rating glass homogeneity. The paper also presents our suggestions for the fabrication of good homogeneity small samples of erbium-containing silicate glasses.