Fabrication of variable bandwidth filters usingarrayed-waveguide gratings

Variable bandwidth filters have been fabricated using silica-based N × N arrayed-waveguide gratings. The centre wavelengths are λ0 = 1.55 µm for all channels. The 3 dB bandwidths are 40, 78, 116 and 154 GHz, for the filter with a path length difference ΔL = 63 µm. In the filter with ΔL = 8.6 µm, the 3 dB bandwidths are 414, 769, 1198 and 1608 GHz. The on-chip losses are 2.1 – 2.9 dB and sidemode suppression ratios are larger than 27 dB.