Guided wave all-optical logic devices

The main advantage, that guided wave optics offers for all-optical logic devices based on third-order optical nonlinearities, is that the necessary high intensities can be maintained over longer distances. This means that the interaction lengths are absorption limited rather than diffraction limited. An other advantage is the general compatibility of guided wave optics with the optical fibres used in communication systems. Two all-optical logic device concepts, the nonlinear directional coupler and the asymmetric Mach-Zehnder interferometer are explored and two different types of nonlinear material, semiconductor doped glass and epitaxial layers of AlGaAs/GaAs, are discussed