Abstract

A computer model was used to study important two-step ion-exchange processes for the fabrication of single-mode optical waveguides with fiber-like mode-field distributions. The ion-concentration distributions were solved from the ion-exchange equations by a finite-difference method¹ and were transformed into waveguide refractive-index profiles. The guided-mode solutions were then obtained by an iterative finite-difference method. As a first step, a field-assisted method was calculated to have better controllability than a diffusion method. As a second step, field-assisted burial was found to optimize the coupling loss to fiber to 0.05 dB, but losses lower than 0.2 dB were calculated for less complex diffusion-process steps. On thebasis of modeling, a solid-state fabrication process was proposed,¹ and the near-field distributions of fabricated waveguides were measured to confirm the model. Additional results are presented for a special two-step process that is an inverse ion-exchange method. This method has advantages in the control of the lateral dimension of waveguides.

© 1990 Optical Society of America