Effciency of an integrated optic modulator/switch depends on the overlap integral between the applied electric field and the optical mode. In this work, the field distribution of electrodes is analysed to determine the maximum overlap integral affected by the parameters of electrode width, interelectrode gap and optical mode size etc.. The results of the optimal electrode and waveguide design for Ti:LiNbO 3 modulators/switches are presented by utilizing a systematic optimization of all the necessary parameters according to the available technology.