This application note describes how to design, simulate and layout an Arrayed Waveguide Grating (AWG) using OlympIOs. An INTERCONNECT compact model is initially used for quick analysis. The source code provided has been developped and tested for Matlab. The AWG model leverages Photon Design's experience in both waveguide modelling and free propagation region expansion to create an ultrafast simulation and design tool for the creation of bespoke wavelength division multiplexing devices. Optical and Quantum Electronics, 48, 1-11. 1007/s11082-016-0628-5 A submitted manuscript is the version of the article.