The Influence of Pyroelectric Effect on the Stability of Optical Parameters in Ti:LiNbO3 Modulators

In this letter, we present the results of the study of the pyroelectric effect in Ti:LiNbO3 titanium diffusion waveguides formed on an X-cut substrate, which are the basis for the creation of phase modulators. This letter presents an analysis of the contribution of pyroelectric phase drift, its magnitude, and the relaxation time characteristics of the charges causing the drift. The measurements were carried out interferometrically in the circuit of a fiber-optic Mach-Zehnder interferometer. The final part of the experimental study shows the results of significant suppression of the pyroelectric effect in the modulator. Moreover, reductive annealing of the crystal in hydrogen-nitrogen medium does not deteriorate the optical transmission properties of the waveguide. The prospective application of this method in the fabrication of Ti:LiNbO3 phase modulators is also evaluated.