POTASSIUM-DOUBLE-ION-EXCHANGED AND SILVER-DOUBLE-ION-EXCHANGED SLAB GLASS WAVE-GUIDES - CHARACTERIZATION AND MODELING

Double-ion-exchanged glass waveguides are made first by a potassium-io n exchange followed by a silver-ion exchange. The inverse WKB method i s used to determine the index profile. It is shown that a combination of a truncated quadratic function and a complementary error function r epresents the refractive index best. A direct WKB method is employed t o find the maximum index change and the diffusion coefficient of the s econd exchange process. The concentration of silver, potassium, and so dium ions are measured by an x-ray photoelectron spectroscopy techniqu e. The results agree well with the index profile when a quadratic func tion is used.