Systematic and robust design of photonic crystal waveguides by topology optimization

A robust topology optimization method is presented to consider manufacturing uncertainties in tailoring dispersion properties of photonic crystal waveguides. The under, normal and over-etching scenarios in manufacturing process are represented by dilated, intermediate and eroded designs based on a threshold projection.

The objective is formulated to minimize the maximum error between actual group indices and a prescribed group index among these three designs. Novel photonic crystal waveguide facilitating slow light with a group index of n(g) = 40 is achieved by the robust optimization approach. The numerical result illustrates that the robust topology optimization provides a systematic and robust design methodology for photonic crystal waveguide design.