Impact of electron-beam lithography irregularities across millimeter-scale resonant grating filter performances.

We investigated the impact of electron-beam lithography writing imperfections on the performance of two-dimensional resonant grating notch filters. This large area photonic device provides an interesting benchmark to assess the acceptable limits of unavoidable fabrication errors. We found that field stitching errors up to 100 nm have no detrimental effect on the filter linewidth, whereas a 2.5 nm electron-beam writing resolution, responsible for digitization disorder, is tolerable only for high-index contrast filter designs. Such an electron-beam writing strategy could also be beneficial for photonic crystal guiding structures or any periodic nanopatterned device with which the optical mode interacts with a large number of periodic elementary units.