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Parallel convolutional processing using an integrated photonic tensor core

A Publisher Correction to this article was published on 23 February 2021

This article has been updated


With the proliferation of ultrahigh-speed mobile networks and internet-connected devices, along with the rise of artificial intelligence (AI)1, the world is generating exponentially increasing amounts of data that need to be processed in a fast and efficient way. Highly parallelized, fast and scalable hardware is therefore becoming progressively more important2. Here we demonstrate a computationally specific integrated photonic hardware accelerator (tensor core) that is capable of operating at speeds of trillions of multiply-accumulate operations per second (1012 MAC operations per second or tera-MACs per second). The tensor core can be considered as the optical analogue of an application-specific integrated circuit (ASIC). It achieves parallelized photonic in-memory computing using phase-change-material memory arrays and photonic chip-based optical frequency combs (soliton microcombs3). The computation is reduced to measuring the optical transmission of reconfigurable and non-resonant passive components and can operate at a bandwidth exceeding 14 gigahertz, limited only by the speed of the modulators and photodetectors. Given recent advances in hybrid integration of soliton microcombs at microwave line rates3,4,5, ultralow-loss silicon nitride waveguides6,7, and high-speed on-chip detectors and modulators, our approach provides a path towards full complementary metal–oxide–semiconductor (CMOS) wafer-scale integration of the photonic tensor core. Although we focus on convolutional processing, more generally our results indicate the potential of integrated photonics for parallel, fast, and efficient computational hardware in data-heavy AI applications such as autonomous driving, live video processing, and next-generation cloud computing services.

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Fig. 1: Photonic in-memory computing using a photonic-chip-based microcomb and PCMs.
Fig. 2: Concept of photonic tensor cores for convolution operations.
Fig. 3: Convolution using sequential MVM operations.
Fig. 4: Convolution using parallel MVM operations.
Fig. 5: Digit recognition with a CNN and scalability.

Data availability

All data used in this study are available from the corresponding author upon reasonable request.

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This research was supported by EPSRC via grants EP/J018694/1, EP/M015173/1 and EP/M015130/1 in the UK and Deutsche Forschungsgemeinschaft (DFG) grant PE 1832/5-1 in Germany. This material is based upon work supported by the Air Force Office of Scientific Research under award number FA9550-19-1-0250. W.H.P.P. gratefully acknowledges support by the European Research Council through grant 724707. We further acknowledge funding for this work from the European Union’s Horizon 2020 Research and Innovation Programme (Fun-COMP project number 780848). A.S. acknowledges support by the European Research Council though grant 682675. H.G. thanks the Studienstiftung des deutschen Volkes for financial support. We thank F. Brückerhoff-Plückelmann, S. Agarwal and W. Zhou for help with sample fabrication and discussions of the experimental results.

Author information




W.H.P.P., H.B., A.S., T.J.K. and C.D.W. conceived the experiment. J.F. fabricated the devices with assistance from N.Y., H.G. and X.L. N.Y. performed the deposition of the Ge2Sb2Te5 material, together with X.L. J.F. implemented the measurement setup and carried out the measurements with help from N.Y., M.K., M.S. and H.G. M.K., X.F., A.L., A.S.R. and J.L. implemented the frequency comb source. All authors discussed the data and wrote the manuscript together.

Corresponding authors

Correspondence to A. Sebastian, T. J. Kippenberg, W. H. P. Pernice or H. Bhaskaran.

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Peer review information Nature thanks Huaqiang Wu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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Supplementary Information

Supplementary methods and notes. The file contains Supplementary Tables 1–2, Supplementary Figures 1–22 and Supplementary References. It gives further methodological information on the experimental setups and provides additional data to validate and illustrate the main results of the manuscript.

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Feldmann, J., Youngblood, N., Karpov, M. et al. Parallel convolutional processing using an integrated photonic tensor core. Nature 589, 52–58 (2021).

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