Resonant waveguide-grating filters incorporating first-order feedback gratings

Summary form only given. Resonant waveguide-grating filters are of interest for a range of potential applications (Wang and Magnusson, 1993; Shin et al, 1998). Although such filters exhibit high reflectance under a plane wave incidence, reflectance reduction and spatial modification of the beam profile occur under a practical finite beam illumination. This stems from the narrow angular linewidth of the filter (Avrutsky and Sychugov, 1989). Incorporation of a first-order Bragg grating widens the angular aperture (Lemarchand et al, 1998) and improves filter properties as the calculations presented in this paper illustrate. The results presented pertain to TE-polarized beams at normal incidence.