Design methodology of refractive index engineering by implantation of high-energy particles in electro-optic materials

Slab waveguides were constructed in K1−xLixTa1−yNbyO3 crystals by the implantation of C+412 ions at 30 MeV and O+516 ions at 30 and 40 MeV. The waveguides were characterized by a prism coupler setup. A refractive index drop of 10.9% was observed in a layer formed by the implantation of O+516 ions at 30 MeV. The carbon-implanted waveguides were found to be thermally stable after annealing at 450 °C. A semiempirical formula for predicting the change in the refractive index given the parameters of the implantation process was developed. It is argued that the combination of the basic implantation process with the semiempirical formula can be developed to become a generic method for constructing complex electro-optic circuits with a wave-guided architecture.