Abstract

This thesis introduces coupled mode theory and uses it to study the transfer characteristics of multiple guide optical couplers. Two and three guide couplers are examined to determine their effectiveness as power transfer devices, and the implementation of two and three guide switches is discussed. A novel approach to designing a three guide coupler is introduced, where a feedback loop is placed around one of the guides. It is demonstrated that this device exhibits desirable characteristics that are not available by current passive coupler designs: splitting any fraction of a signal between two separate waveguides while maintaining a zero phase shift between the outputs, as well as combining two signals of arbitrary amplitude and phase. The wavelength dependence of this device is examined, and its potential as a wavelength selective filter or wavelength division multiplexer is demonstrated. Various computer programs have been developed to aid in the analysis of optical couplers including one that animates the eigensolutions of the device as signals propagate though its length. The technique of eigensolution decompositions is used to illustrate the relationship between coupling parameters of multiple N-guide couplers such that they may either achieve complete transfer of power between guides or act as interferometers.