“…Although the accuracy of cut-offs calculated by effective index method needs to be improved, it does provide a good reference and approximation for us to shape the waveguide geometry far from the cut-offs in order to achieve a single-mode rib waveguide. In integrated optics, interferometric devices such as optical sensors and electro-optic amplitude modulators are often of the Mach-Zehnder interferometer (MZI) type (Krijnen et al, 1995). The proposed structure of the Ba 0.7 Sr 0.3 TiO 3 Mach-Zehnder modulator investigated in this work is shown schematically in Fig. 14.…”