There currently exists no universal design software for photonic circuits, which are needed to support sensor systems used for national security applications. This means that the design and optimization of photonics for custom applications can be costly and time consuming. The development of a photonics design tool would enhance the expansion and availability of this technology sector while reducing the cost. This project will develop an integrated optics design tool that runs on a desktop PC or over a network. The tool will have wide applicability, and allow end users to design custom photonic circuits without becoming experts in all aspects of the physics involved. Phase I will develop an accurate and efficient simulation of beam propagation through waveguides and various components, the heart of a robust photonics design tool, using previous results from multi-level sub-wavelength diffractive optics. A mini-design tool with a web user interface will be constructed. Commercial Applications And Other Benefits as described by awardee: Photonic circuits are becoming a widely used component in the telecommunications industry. Photonics can replace many ordinary chips with the advantage of requiring less power with increasing speed.