Numerical modeling of field-assisted Ag+–Na+ ion-exchanged channel waveguides using varied explicit space charge density approach

This article presents a numerical model of field-assisted Ag⁺–Na⁺ ion exchange in glass, used to determine Ag⁺ ion concentration contours in cross-sections of channel waveguides. Space charge density was used as a modeling parameter, with different values adopted separately under the mask and in the region of the mask window. Based on the results of simulations, it can be stated that the space charge distribution under the mask has a decisive influence on the diffusion range of Ag⁺ ions into the glass and on the shape of silver ion concentration contours corresponding to the maximum range of Ag⁺ ions diffusion. Charge generated within the diffusive structure influences the shape of silver ion concentration contours near the mask’s edge and affects the thickness of the polarized layer under the mask within the waveguide’s optical structure. Modeling results indicate a significant influence of factors affecting space charge density distribution in glass on the results of forming channel waveguides in the field-assisted process.