RETRACTED: A new 90-degree bend in a two-dimensional photonic crystal waveguide using topology optimization

Topology optimization is a promising method for systematic design of optical devices. As an example we demonstrate how the method can be used to design a new 90-degree bend in a two-dimensional photonic crystal waveguide with a transmission loss of less than 0.3%. This method is used to maximize the energy flow through the waveguide and thus reduce unwanted reflections from the waveguide bend to a minimum. We specify a design area in the vicinity of the waveguide and distribute the material in this domain to maximize the energy flow. The flow through the waveguide is found by computing the poynting vector at the output waveguide port. Topology optimization can directly be applied to the design of other optical devices e. g., multiplexers and wave splitters with optimized performance.