Investigation of waveguides formed by diffusion of titanium in $Y$-cut lithium metaniobate

Waveguides were formed by diffusing titanium in argon, nitrogen, air, and vacuum. Their properties were investigated and it was found that those prepared by the diffusion in argon and vacuum had the lowest losses ($\lesssim$ 2 dB/cm). The greatest changes in the refractive index on the surface resulted from the diffusion in vacuum. There was no proportionality between the impurity concentration and the changes in the extraordinary or ordinary refractive indices. The electrooptic coefficients were identical with the bulk values.