Design of waveguide-grating routers with minimal insertion-loss over all channels based on coupling between adjacent waveguides

Summary form only given. We utilize coupling between waveguides near the waveguide-opening region (WOR) where the arrayed-waveguides meet the free-propagation region of the second star-coupler. The coupling scheme used in the design of a waveguide-grating router (WGR) was proposed for the design of an integrated-optic star coupler for the purpose of transferring the input power uniformly to the waveguides of the output ports. Application of the same idea to the design of a WGR has not been completed because a few more parameters in addition to those for the design of a star coupler have not been considered to achieve the desired effect. In this work, we work out the problem based on the above idea for the specific designs of 16-, 32-, and 64-channel WGR's that have nearly ideal loss characteristics over all used channels within one complete span of the free spectral range.