Investigation of Photorefractive Waveguides Fabricated by Excimer Laser Ablation and Ion-Implantation

The fabrication of thin films optical waveguides of photorefractive materials is particularly desirable for applications in integrated optics. It is also of interest because the guided-wave intensity-length product can be considerably larger than in bulk media because of the optical confinement within the waveguide. The increased intensity-length product may therefore allow much faster response times than in the bulk (typically by a factor of ≈103-l04). Thin crystalline films can be fabricated by a variety of techniques such as RF sputtering, flash evaporation, molecular beam epitaxy and liquid phase epitaxy. However, the films grown are often of the incorrect (or variable) composition and phase and are rarely of good optical quality. We discuss here two methods that we have investigated for producing optical waveguides in several different photorefractive materials.