Efficient multi-body shape optimization of on-chip nanophotonic neural network
摘要
Inverse design of on-chip nanophotonic neural networks (ONNs) is often hindered by the prohibitive cost of repeated three-dimensional (3D) full-wave simulations, especially when the optimization is performed in a high-dimensional geometric design space. Here, we employ a computationally efficient multi-body shape optimization framework and integrate it with a wave-based linear-decoupling strategy to address this challenge. By reconstructing input-specific responses from pre-computed characteristic states, our approach bypasses the need for exhaustive, repetitive full-wave solutions of Maxwell’s equations inside the optimization loop. We utilize elliptical scatterers to enable anisotropic control over optical fields, reducing the nominal design-variable count by hundreds of times for the studied devices compared to an equivalent 40-nm pixel-based topology-optimization baseline. 3D finite-difference time-domain simulations on the Iris and MNIST classification benchmarks validate that the proposed framework yields compact ONN classifiers with high inference accuracy and significantly lower training cost. This work establishes a scalable, fabrication-aware methodology for high-performance on-chip photonic neural processors.