Recursive function theory and logic

This application describes a single-mode dielectric waveguide for guiding electromagnetic wave energy. The guide comprises a low-loss dielectric substrate in which a thin, low-loss, dielectric strip of higher refractive index is embedded. In general, such a guide is capable of supporting a plurality of modes of two orthogonally-polarized families of modes. To limit the waveguide to single-mode operation, the cross-sectional dimensions are limited so that the guide is incapable of supporting modes higher than the fundamental mode of each of the two families of modes. One of two fundamental modes is then supported by either placing a lossy material along one surface of the guiding strip, thereby making the guide much lossier to one of the two fundamental modes or, alternatively, by placing a higher refractive index material along the strip, thereby destroying the guiding capability of the waveguide with respect to one of the two fundamental modes.