Fantastic Photonic Computing Systems and How to Use Them for AI
Guest Speaker: Dr. Ajay Joshi, Professor, Department of ECE, BU
Moderated by Dr. Avinash Mohan, Assistant Prof of CS
Friday, 28th March, 2025
Abstract: Artificial Intelligence (AI)-based computing is commonly used today in a variety of domains including finance, healthcare, supply chain, and education. To support the ever-growing demands of AI-based computing workloads, there is a recent resurgence in using photonics for computing. However, photonics is not a panacea and should be used only where appropriate. In this talk, I’ll present three different electro-photonic AI accelerator designs – ADEPT, MIRAGE, and PhotoHDC, that we have developed in our group. ADEPT focuses on efficient DNN inference. It leverages a photonic computing core for efficiently performing GEMM operations, a vectorized digital electronic ASIC for performing non-GEMM operations, and SRAM arrays for storing DNN parameters and activations. MIRAGE builds on ADEPT and accelerates DNN training. By combining Residue Number System (RNS) and photonics, MIRAGE provides high energy efficiency without compromising precision and can successfully train state-of-the-art DNNs achieving accuracy comparable to FP32 training. PhotoHDC uses a combination of hyperdimensional computing (HDC) and photonics, two technologies that complement each other very well. PhotoHDC achieves multiple orders of magnitude energy-efficient HDC training and inference as compared to prior art.
Bio: Ajay Joshi received his Ph.D. degree from Georgia Tech in 2006 and then worked as a postdoctoral researcher at MIT. In 2009, he joined the ECE department at Boston University, where he is currently a Professor. He was a Visiting Researcher at Google in 2017-18 and an Architect at Lightmatter Inc. He recently co-founded a company, CipherSonic Labs, which is focused on data privacy. His research is in the areas of computer architecture and digital VLSI with focus on data security and privacy, machine learning and photonic computing. He received the NSF CAREER Award in 2012, Boston University ECE Department’s Award for Excellence in Teaching in 2014, Best Paper Award at ASIACCS 2018 and HOST 2023, and Google Faculty Research Award in 2018 and 2019. He currently serves as the Associate Editor for IEEE Transactions on VLSI Systems.