This book describes theoretical and modeling study of optical waveguide design, in straight and branched waveguide for ion-exchanged and silicon based materials. Physical parameters involved in the fabrication have been modeled to produce the highest possible evanescent field based on the material that they are using. Apart from that, optical properties such as polarization, beam spot size and wavelength are also studied to monitor their effects on the evanescent field. The compilation of research papers in this book can be used to fabricate an integrated waveguide with optimized condition. These simulation results demonstrate, that evanescent wave based, integrated optical devices for trapping are feasible and can be optimized; paving the way for real-life application devices to be realized.