🤖 AI Summary
To address the energy-efficiency and computational throughput bottlenecks arising from digital AI accelerators approaching physical limits, this work proposes a multidimensional photonic neural network (PNN) architecture. It introduces, for the first time, time–wavelength–space-division multiplexing (T-WSDM) encoding, implemented on a Si₃N₄ microcomb laser integrated with a 16×16 arrayed-waveguide grating router (AWGR) photonic chip. The resulting high-parallel photonic AI accelerator achieves 262 TOPS of optical computational throughput—24× higher than state-of-the-art waveguide-based accelerators—and supports in-flight photonic tensor multiply-accumulate operations and on-chip multi-wavelength interferometric detection. Evaluated on DDoS attack detection, it attains a Cohen’s kappa of 0.867; on MNIST classification, it achieves 92.14% accuracy—both nearing software-level performance—while operating at a measured symbol rate of 32 Gbaud. The core innovations are the T-WSDM three-dimensional coordinated encoding scheme and the integrated microcomb-driven multidimensional photonic computing paradigm.
📝 Abstract
The ever-increasing volume of data has necessitated a new computing paradigm, embodied through Artificial Intelligence (AI) and Large Language Models (LLMs). Digital electronic AI computing systems, however, are gradually reaching their physical plateaus, stimulating extensive research towards next-generation AI accelerators. Photonic Neural Networks (PNNs), with their unique ability to capitalize on the interplay of multiple physical dimensions including time, wavelength, and space, have been brought forward with a credible promise for boosting computational power and energy efficiency in AI processors. In this article, we experimentally demonstrate a novel multidimensional arrayed waveguide grating router (AWGR)-based photonic AI accelerator that can execute tensor multiplications at a record-high total computational power of 262 TOPS, offering a ~24x improvement over the existing waveguide-based optical accelerators. It consists of a 16x16 AWGR that exploits the time-, wavelength- and space- division multiplexing (T-WSDM) for weight and input encoding together with an integrated Si3N4-based frequency comb for multi-wavelength generation. The photonic AI accelerator has been experimentally validated in both Fully-Connected (FC) and Convolutional NN (NNs) models, with the FC and CNN being trained for DDoS attack identification and MNIST classification, respectively. The experimental inference at 32 Gbaud achieved a Cohen's kappa score of 0.867 for DDoS detection and an accuracy of 92.14% for MNIST classification, respectively, closely matching the software performance.