Integrated optical ring resonators made by silver ion-exchange in glass.

The first (to our knowledge) integrated optical ring resonators to be fabricated using silver ion-exchanged waveguides are reported. Both circular and racetrack shaped resonators have been made, both types being capable of high finesse (>15) and efficiency (>90%). The circular resonators are much more difficult to make, however, requiring a double-diffusion process and precise control of the ion-exchange. For this reason, the racetrack resonators have been the more successful and have behaved exactly as expected from the previous work on losses and directional couplers.