Planar Waveguide Add/Drop Wavelength Filters Based on Segmented Gratings

Abstract

We investigate the application of segmented reflection gratings in planar devices that can function as either a single- or two-wavelength add/drop filter. The role of the segmented gratings is analogous to that of a blazed grating, but can provide a higher reflectivity level at the Bragg wavelength, eliminate back reflection into the fundamental mode, and provide arbitrarily close channel spacing in the two-wavelength case.