In situ measurement of ionic concentration during fabrication of ion-exchanged waveguides

In this paper we describe a concentration cell for the measurement of Ag+ ion concentration useful for fabrication of Ag+ − Na+ exchanged waveguides in glass. The scheme is adaptable to other ion exchanges as well. High measurement accuracy (±2 mV) and assured repeatability are possible by standardizing the reference electrode and experimental conditions. Use of such a cell with appropriate analog signal processing should facilitate on-line concentration control by periodic pumping of the exchanging ion into the molten salt bath.