Integrated Spectral Filters Consisting of Several Dielectric Ridges on the Surface of a Slab Waveguide

We study on-chip spectral filters comprising several dielectric ridges placed on a single-mode dielectric slab waveguide. The investigated filters work in reflection and carry out spectral filtering of obliquely incident TE-polarized modes of the waveguide. We show that by choosing the widths of the grooves separating the adjacent ridges, one can obtain nearly rectangular reflectance peaks using just a few ridges. The proposed filters are promising for the design of novel integrated spectral filters, sensors and optical computing devices.