Electrode design to suppress thermal drift in lithium niobate modulators

In LiNbO₃ electro-optical devices, the symmetric design of the pair of ground-electrodes is an important factor in suppressing the thermal drift. Although conventional x-cut LiNbO₃ Mach-Zehnder modulators installed with identical ground-electrodes exhibit ⩽1 V in their bias change between 10 and 60°C, the asymmetric electrode design to narrow one ground-electrode (to approximately one-quarter in experiments) demonstrates that the bias change increases from 3 to 6 V