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Universal linear optics

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)711-716
Number of pages6
Issue number6249
Early online date9 Jul 2015
DateE-pub ahead of print - 9 Jul 2015
DatePublished (current) - 13 Aug 2015


Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons, and their measurement with a 12-single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with an average fidelity of 0.999 ± 0.001. Our system can be rapidly reprogrammed to implement these and any other linear optical protocol, pointing the way to applications across fundamental science and quantum technologies.

Additional information

The authors acknowledge support from the Engineering and Physical Sciences Research Council (EPSRC), the European Research Council (ERC), including BBOI, QUCHIP (H2020-FETPROACT-3-2014: Quantum simulation), PIQUE (FP7-PEOPLE-2013-ITN), the Centre for Nanoscience and Quantum Information (NSQI), the U.S. Army Research Office (ARO) grant W911NF-14-1-0133, and the U.S. Air Force Office of Scientific Research (AFOSR). J.C.F.M. was supported by a Leverhulme Trust Early Career Fellowship. J.L.O’B. acknowledges a Royal Society Wolfson Merit Award and a Royal Academy of Engineering Chair in Emerging Technologies.

    Research areas

  • Reprogrammable Optical Chip, Linear Optics, QUANTUM CIRCUITS

    Structured keywords

  • Bristol Quantum Information Institute
  • QETLabs



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