Domain inversion effects in Ti-LiNbO3 integrated optical devices

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 Vπ 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.