Long-term DC drift in x-cut LiNbO3 modulators without oxide buffer layer

Long-term DC drift in x-cut LiNbO₃ modulators without any oxide buffer layer is examined by temperature accelerated biased aging tests. Based on the experiments at 140, 120 and 85°C, an activation energy of E_a=1.4 eV is proposed for estimation of log-term DC drift of x-cut LiNbO₃ modulators. Further, the normalised applied voltage A(t)=V(t)/V(0), in which V(0) is the initially applied DC voltage, is estimated to be less than 2, even after DC drift throughout 20 years of operation at 65°C