Rapid simulation-driven design optimization of photonic directional couplers using variable-fidelity EM simulations

A methodology for fast design optimization of photonic couplers is discussed. Our approach exploits variable-fidelity EM simulations and adaptively-adjusted design specification (AADS) technique for accommodating misalignment between the low- and high-fidelity coupler model. As demonstrated using an example of a 195 THz coupler, an optimum design can be obtained at the cost corresponding to only about 13 high-fidelity EM simulations of the structure.