Model for waveguide fabrication in glass by two-step ion exchange with ionic masking

A theory for optical waveguide fabrication processes, in which potassium ions exchanged into glass are used as a mask to regulate a subsequent silver-ion exchange, is presented. The model is used to examine the use of this technique in restricting the width of narrow-channel waveguides. The diffusion of silver through the potassium-ion mask is calculated, and a novel method of fabricating buried waveguides is described.