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The growing computational demands of deep learning have driven interest in analog neural networks using resistive memory and silicon photonics. However, these technologies face inherent limitations in computing parallelism when used independently. Photonic phase-change memory (PCM), which integrates photonics with PCM, overcomes these constraints by enabling simultaneous processing of multiple inputs encoded on different wavelengths, significantly enhancing parallel computation for deep neural network (DNN) inference and training. This paper presents MERIT, a sustainable DNN accelerator that capitalizes on the non-volatility of resistive memory and the high operating speed of photonic devices. MERIT enables seamless inference and training by loading weight kernels into photonic PCM arrays and selectively supplying light encoded with input features for the forward pass and loss gradients for the backward pass. We compare MERIT with state-of-the-art digital and analog DNN accelerators including TPU, DEAP, and PTC. Simulation results demonstrate that MERIT reduces execution time by 68% and energy consumption by 64% for inference, and reduces execution time by 79% and energy consumption by 84% for training. 

Generative adversarial networks (GANs) have emerged as a powerful solution for generating synthetic data when the availability of large, labeled training datasets is limited or costly in large-scale machine learning systems. Recent advancements in GAN models have extended their applications across diverse domains, including medicine, robotics, and content synthesis. These advanced GAN models have gained recognition for their excellent accuracy by scaling the model. However, existing accelerators face scalability challenges when dealing with large-scale GAN models. As the size of GAN models increases, the demand for computation and communication resources during inference continues to grow. To address this scalability issue, this article proposes Chiplet-GAN, a chiplet-based accelerator design for GAN inference. Chiplet-GAN enables scalability by adding more chiplets to the system, thereby supporting the scaling of computation capabilities. To handle the increasing communication demand as the system and model scale, a novel interconnection network with adaptive topology and passive/active network links is developed to provide adequate communication support for Chiplet-GAN. Coupled with workload partition and allocation algorithms, Chiplet-GAN reduces execution time and energy consumption for GAN inference workloads as both model and chiplet-system scales. Evaluation results using various GAN models show the effectiveness of Chiplet-GAN. On average, compared to GANAX, SpAtten, and Simba, the Chiplet-GAN reduces execution time and energy consumption by 34% and 21%, respectively. Furthermore, as the system scales for large-scale GAN model inference, Chiplet-GAN achieves reductions in execution time of up to 63% compared to the Simba, a chiplet-based accelerator. 

The convergence of edge computing and artificial intelligence requires that inference is performed on-device to provide rapid response with low latency and high accuracy without transferring large amounts of data to the cloud. However, power and size limitations make it challenging for electrical accelerators to support both inference and training for large neural network models. To this end, we propose Trident, a low-power photonic accelerator that combines the benefits of phase change material (PCM) and photonics to implement both inference and training in one unified architecture. Emerging silicon photonics has the potential to exploit the parallelism of neural network models, reduce power consumption and provide high bandwidth density via wavelength division multiplexing, making photonics an ideal candidate for on-device training and inference. As PCM is reconfigurable and non-volatile, we utilize it for two distinct purposes: (i) to maintain resonant wavelength without expensive electrical or thermal heaters, and (ii) to implement non-linear activation function, which eliminates the need to move data between memory and compute units. This multi-purpose use of PCM is shown to lead to significant reduction in energy consumption and execution time. Compared to photonic accelerators DEAP-CNN, CrossLight, and PIXEL, Trident improves energy efficiency by up to 43% and latency by up to 150% on average. Compared to electronic edge AI accelerators Google Coral which utilizes the Google Edge TPU and Bearkey TB96-AI, Trident improves energy efficiency by 11% and 93% respectively. While NVIDIA AGX Xavier is more energy efficient, the reduced data movement and GST activation of Trident reduce latency by 107% on average compared to the NVIDIA accelerator. When compared to the Google Coral and the Bearkey TB96-AI, Trident reduces latency by 1413% and 595% on average.