Abstract

Artificial neural networks are computational network models inspired by signal processing in the brain. These models have dramatically improved performance for many machine-learning tasks, including speech and image recognition. However, today's computing hardware is inefficient at implementing neural networks, in large part because much of it was designed for von Neumann computing schemes. Significant effort has been made towards developing electronic architectures tuned to implement artificial neural networks that exhibit improved computational speed and accuracy. Here, we propose a new architecture for a fully optical neural network that, in principle, could offer an enhancement in computational speed and power efficiency over state-of-the-art electronics for conventional inference tasks. We experimentally demonstrate the essential part of the concept using a programmable nanophotonic processor featuring a cascaded array of 56 programmable Mach–Zehnder interferometers in a silicon photonic integrated circuit and show its utility for vowel recognition.

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Acknowledgements

The authors thank Y. LeCun, M. Tegmark, G. Pratt, I. Chuang and V. Sze for discussions. This work was supported in part by the Army Research Office through the Institute for Soldier Nanotechnologies under contract no. W911NF-13-D0001 and in part by the National Science Foundation under grant no. CCF-1640012 and in part by the Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (FA9550-14-1-0052) and the Air Force Research Laboratory RITA programme (FA8750-14-2-0120). M.H. acknowledges support from AFOSR STTR grants, numbers FA9550-12-C-0079 and FA9550-12-C-0038 and G. Pomrenke, of AFOSR, for his support of the OpSIS effort, through both a PECASE award (FA9550-13-1-0027) and funding for OpSIS (FA9550-10-1-0439). N.H. acknowledges support from National Science Foundation Graduate Research Fellowship grant no. 1122374.

Author information

Author notes

    • Yichen Shen
    •  & Nicholas C. Harris

    These authors contributed equally to this work.

Affiliations

  1. Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Yichen Shen
    • , Nicholas C. Harris
    • , Scott Skirlo
    • , Mihika Prabhu
    • , Dirk Englund
    •  & Marin Soljačić
  2. Elenion, 171 Madison Avenue, Suite 1100, New York, New York 10016, USA

    • Tom Baehr-Jones
    •  & Michael Hochberg
  3. Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Xin Sun
  4. Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Shijie Zhao
  5. Université de Sherbrooke, Administration, 2500 Boulevard de l'Université, Sherbrooke, Quebec J1K 2R1, Canada

    • Hugo Larochelle

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Contributions

Y.S., N.C.H., S.S., X.S., S.Z., D.E. and M.S. developed the theoretical model for the optical neural network. N.H. designed the photonic chip and built the experimental set-up. N.H., Y.S. and M.P. performed the experiment. Y.S., S.S. and X.S. prepared the data and developed the code for training MZI parameters. T.B.-J. and M.H. fabricated the photonic integrated circuit. All authors contributed to writing the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Yichen Shen or Nicholas C. Harris.

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https://doi.org/10.1038/nphoton.2017.93

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