Abstract

Empirically based models are currently in use for predicting the refractive-index distribution from dopant concentrations in ion exchanged glass for waveguide and gradient-index applications.^1-3 Two of these models predict, either explicitly³ or when applied with the appropriate parameters,¹ a linear variation of refractive index with silver dopant concentration. Five silver-doped aluminosilicate glass samples were fabricated by ion exchange to test the models. A wide range of dopant distributions was made with local compositions up to 14-mole % silver and exchange depths up to 3.3 mm. Concentration distributions were measured by energy dispersive spectroscopy.⁴ Refractive-index distributions were measured by ac interferometry.⁵ The measured refractive index (0.6471 μm) is linear with concentration for small (<1.0-mole % silver) dopant levels but otherwise departs significantly from the model. The index model should be improved by the inclusion of compressive stress due to the unequal radii of the exchange ions.

© 1987 Optical Society of America