🤖 AI Summary
This work proposes the first monolithic free-space all-optical graph neural network to overcome the efficiency limitations of existing physics-informed neural networks in graph-structured tasks, which struggle to achieve high-speed graph learning. By leveraging diffraction-based optical propagation and phase modulation, the architecture performs graph message passing at the speed of light and introduces an innovative optical skip connection to establish a domain-specific, fully optical end-to-end message-passing mechanism. This design breaks through the speed and energy-efficiency bottlenecks inherent in conventional digital graph neural networks. Experimental results on the Cora-ML and Citeseer datasets demonstrate classification performance comparable to or even surpassing that of digital GNNs, thereby validating the feasibility and superiority of all-optical graph learning.
📝 Abstract
As a representative of next-generation device/circuit technology beyond CMOS, physics-based neural networks such as Diffractive Optical Neural Networks (DONNs) have demonstrated promising advantages in computational speed and energy efficiency. However, existing DONNs and other physics-based neural networks have mostly focused on exploring their machine intelligence, with limited studies in handling graph-structured tasks. Thus, we introduce HoloGraph, the first monolithic free-space all-optical graph neural network system. It proposes a novel, domain-specific message-passing mechanism with optical skip channels integrated into light propagation for the all-optical graph learning. HoloGraph enables light-speed optical message passing over graph structures with diffractive propagation and phase modulations. Our experimental results with HoloGraph, conducted using standard graph learning datasets Cora-ML and Citeseer, show competitive or even superior classification performance compared to conventional digital graph neural networks. Comprehensive ablation studies demonstrate the effectiveness of the proposed novel architecture and algorithmic methods.