Abstract
We propose a new method for fabricating optical waveguides with nonuniform thickness by controlling the electrical field distribution during the field-assisted ion-exchange. We refer to this method as distributed-field-assisted ion-exchange. The distribution of the intensity of the electrical field was simulated for different electrode configurations, and was compared with experimental diffusion depth distribution of K+-Na+ exchange in sodalime slide glass. A unique bath was designed for the distributed-field-assisted ion-exchange. Using a three-electrode configuration, we obtained, for instance, a 2 cm-long spot size converter with thickness changes of from 12 μm to 2 μm. This technique can be used to fabricate waveguides for optical chemical sensors.
