Process optimization of buried Ag(+)-Na(+) ion-exchanged waveguides: theory and experiment

We report optimization of the processing conditions for fabrication of single-mode Ag(+)-Na(+) ion-exchanged waveguides in a soda-lime glass. The surface-index change, the mobility and diffusion coefficient of Ag(+) have been measured at low melt concentrations and the results used for calculation of the index profile using a new simple numerical method for solving the diffusion equation in a two-step process where the index profile is buried by applying an electric field in the second step. The calculated profile is in agreement with that measured. This correlation allows solution of the Helmholtz equation for given process parameters. Single-mode waveguides with desired mode-field distribution have been designed and fabricated with optimized performance and fiber compatibility at 1.3 microm.