Elimination of Li2O out-diffusion waveguide in LiNbO3 and LiTaO3

Abstract
A novel technique was developed to eliminate the Li2O out‐diffusion waveguide in LiNbO3 and LiTaO3 incurred during the process of Ti in‐diffusion. The out‐diffusion waveguide can be suppressed by annealing the crystals in LiNbO3 powder at 900 °C in a flowing oxygen environment for 1 h or longer.