The field of optical computing and information processing is considered to be the most multidisciplinary field and requires collaborative efforts of many disciplines, ranging from device and optical engineers to computer architects, material scientists, and optical physicists for its success. The development of all-optical logic technology is important for a wide range of applications in all-optical networks, including high speed all-optical packet routing, optical encryption and optical computing. An important step in the development of this technology is a demonstration of optical logic elements and circuits, which can also operate at high speeds. The book reports the design of an extensive set of binary-logic based circuits that exploit an interferometric arrangement Terahertz Optical Asymmetric Demultiplexer (TOAD) as building unit in order to achieve enhanced signal processing functionality in the optical domain. The principle of operation has thoroughly been described and numerical simulations have been conducted. The theoretical models developed and the results obtained numerically are very useful to future all-optical information processing system.