Modeling and characterization of embedded electrode performance in transverse electrooptic modulators.

A mathematical model with experimental verification is presented to characterize the performance of surface and embedded electrodes in 2-D electrooptic modulators. From the solution of a discretized integral equation for the electrode surface charge, the electrode capacitance and the electric field penetration and uniformity are related to the switching voltage, speed, and uniformity of the electrooptic modulation. Fabricated surface and embedded electrodes in 9/65/35 PLZT are then evaluated with respect to the predictions of the model and the saturated quadratic response of the electrooptic material. These results provide important insight into the design trade-offs of switching speed, halfwave voltage, switching energy, and modulation uniformity of surface and embedded modulator geometries.