Spectral inverse scattering theory for inhomogeneous dielectric waveguides and devices

The authors review electromagnetic inverse scattering theory for inhomogeneous dielectric waveguides and devices. Typically the parameters of these system components are expressed as functions of frequency or wavenumber, so that spectral, i.e. time-harmonic, methods are appropriate. Spectral, i.e. time-harmonic, inverse scattering theory is reviewed using the propagation of electromagnetic waves in inhomogeneous dielectric waveguides as a physical model. Permittivity profiles are reconstructed from scattering matrix data. Applications to the design of couplers, logical gates, and nonuniform transmission lines are discussed