Application of evolution strategies in optimal design problems involving diffraction gratings

Dielectric gratings with a piecewise constant surface profile are designed as beam splitters and star couplers. In each design problem, the diffraction efficiencies are used to formulate a target function, which has to be optimized. A rigorous grating theory is employed to compute the target function efficiently for each real-valued parameter vector comprising the design variables of the grating. Due to the multi-modal behavior of the target functions, an evolution strategy (ES) is applied as optimization technique. The numerical design examples demonstrate the usefulness of the proposed approach.