Spectral shifts and line-shapes asymmetries in the resonant response of grating waveguide structures

The resonant spectral response that grating-waveguide structures display in the transmitted and reflected intensities, is analyzed with the aid of a newly developed wave interference model. The resonant response is shown to be generally accompanied by wavelength shifts for the transmitted and reflected intensities, resulting in asymmetric resonance line-shapes. A simple rule that relates the ratio of these resonant shifts to the reflected intensity from the structure away from resonance is obtained. The predicted results from the model were confirmed experimentally viith both dielectric as well as metal based grating-waveguide structures. (C) 1998 Elsevier Science B.V.