A silicon waveguide in an electro-optic (EO) polymer cladding-based directional coupler switch was designed
and fabricated. Optimal dimensions for efficient coupling and minimal crosstalk are found analytically (coupled
mode theory) and numerically for 1550nm wavelength. Both coplanar electrode spacing and height are taken into
account for most effective poling conditions and performance. The design consists of two 255nm wide waveguides
separated by 500nm and is optimized for TE propagation. With an electrode separation of 4μm and coupling
length of 1.7cm, a switching voltage (<i>V<sub>s</sub></i>) < 10V at an <i>r</i><sub>33</sub> of 250pm/V is expected.