Buried-glass waveguides by ion exchange through ionic barrier

Fabrication of buried single-mode glass waveguides by ion exchange through the ionic barrier is studied. In this process, an unmasked potassium ion exchange is first performed to form an ionic barrier. The purpose here is to reduce sodium concentration near the surface (not to make a waveguide). The waveguides are formed in the second step of the process by masked silver ion exchange through this leaky ionic barrier. The calculated waveguide index profiles and both calculated and measured mode profiles are presented.