Inverse Design of a High-Performance Wavelength Division Multiplexer Using Topology-Optimized Photonic Crystals

Topology optimization techniques have been adopted in designing devices with flexible and exotic functions from microwave to optical frequencies that cannot be conceived by physical intuitions. This article introduces topology optimization theory into the design of topological photonic crystals, aiming to achieve the inverse design of microwave wavelength division multiplexers. We set the topological characteristics of photonic crystals as the primary objective functions and enhance their performance by extending specific band gaps. The research results show that by constructing domain walls between different configurations of photonic crystals, unidirectional transmission and high transmittance characteristics can be achieved. Therefore, we propose a method for designing and optimizing electromagnetic devices, which are of significant importance for the design of multi-port wavelength division multiplexers.