Automatic synthesis of light-processing functions for programmable photonics: theory and realization

Linear light-processing functions (e.g., routing, splitting, filtering) are key requiring configuration to implement on a programmable photonic integrated circuit (PPIC). In recirculating waveguide meshes (which include loop-backs), this is usually done manually. Some previous results describe explorations perform task automatically, but their efficiency or applicability still limited. paper, we propose an efficient method that can automatically realize configurations for many square-mesh PPIC. At its heart automatic differentiation subroutine built upon analytical expressions of scattering matrices enables gradient descent optimization functional synthesis. Similar the state-of-the-art synthesis techniques, our wide range functions, and multiple same PPIC simultaneously. However, do not need separate spatially into different subdomains mesh, resulting optimum have using part mesh. Furthermore, compared nongradient- numerical differentiation-based methods, proposed approach achieves 3× time reduction in computational cost.