Multiphoton quantum interference in a multiport integrated photonic device

Benjamin J. Metcalf*, Nicholas Thomas-Peter, Justin B. Spring, Dmytro Kundys, Matthew A. Broome, Peter C. Humphreys, Xian-Min Jin, Marco Barbieri, W. Steven Kolthammer, James C. Gates, Brian J. Smith, Nathan K. Langford, Peter G. R. Smith, Ian A. Walmsley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

130 Citations (Scopus)


Increasing the complexity of quantum photonic devices is essential for many optical information processing applications to reach a regime beyond what can be classically simulated, and integrated photonics has emerged as a leading platform for achieving this. Here we demonstrate three-photon quantum operation of an integrated device containing three coupled interferometers, eight spatial modes and many classical and nonclassical interferences. This represents a critical advance over previous complexities and the first on-chip nonclassical interference with more than two photonic inputs. We introduce a new scheme to verify quantum behaviour, using classically characterised device elements and hierarchies of photon correlation functions. We accurately predict the device's quantum behaviour and show operation inconsistent with both classical and bi-separable quantum models. Such methods for verifying multiphoton quantum behaviour are vital for achieving increased circuit complexity. Our experiment paves the way for the next generation of integrated photonic quantum simulation and computing devices.

Original languageEnglish
Article number1356
JournalNature Communications
Publication statusPublished - 15 Jan 2013

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Chemistry
  • General Physics and Astronomy


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