Photonic crystal circuits: Localized modes and waveguide couplers

Localized modes and waveguide couplers in photonic crystal circuits are discussed. Emphasis is placed on circuit geometries which include waveguide channels containing dielectric barriers, channel bends, or junctions with other waveguides. Photonic crystal circuits composed of waveguide channels of both linear and nonlinear dielectric materials are treated. A waveguide coupler which allows energy to be transfered from one waveguide channel to another through weak interchannel interactions is studied.