Wideband arrayed waveguide grating with three low-loss maxima per passband

By using a novel multisection three-waveguide directional coupler, we significantly improve the performance of a passband-flattened arrayed waveguide grating router that uses a three-arm interferometer connected to the input. Each pass-band has three low-loss maxima. For a 16-channel demultiplexer, we achieve a 1- to 20-dB passband-width ratio of 0.62 and a fiber-to-fiber insertion loss of 2.5-3.6 dB.