Domain inversion effects in Ti-LiNbO3 integrated optical devices

Abstract

Significant degradation in the cumulative electro‐optic effect attributable to domain inversion has been observed in integrated optical devices fabricated by Ti diffusion in c⁺‐LiNbO₃. The c⁻ surface was found to be considerably more immune to domain inversion than the c⁺ surface under similar diffusion conditions. Domain inversion was found to be dependent on diffusion temperature, time, and Ti concentration. A large increase in the V_π voltage was observed in Mach–Zehnder interferometers fabricated on c⁺ substrates compared to that of c⁻ substrates under the same fabrication conditions. The effect of domain inversion on crosstalk in directional coupler switches is also discussed.