Manipulation of multiphoton entanglement in waveguide quantum circuits

Jonathan C.F. Matthews, Alberto Politi, André Stefanov, Jeremy L. O'Brien

Research output: Contribution to journalArticlepeer-review

343 Citations (Scopus)


On-chip integrated photonic circuits are crucial to further progress towards quantum technologies and in the science of quantum optics. Here we report precise control of single photon states and multiphoton entanglement directly on-chip. We manipulate the state of path-encoded qubits using integrated optical phase control based on resistive elements, observing an interference contrast of 98.20.3%. We demonstrate integrated quantum metrology by observing interference fringes with two- and four-photon entangled states generated in a waveguide circuit, with respective interference contrasts of 97.20.4% and 924%, sufficient to beat the standard quantum limit. Finally, we demonstrate a reconfigurable circuit that continuously and accurately tunes the degree of quantum interference, yielding a maximum visibility of 98.20.9%. These results open up adaptive and fully reconfigurable photonic quantum circuits not just for single photons, but for all quantum states of light.

Original languageEnglish
Pages (from-to)346-350
Number of pages5
JournalNature Photonics
Issue number6
Publication statusPublished - 1 Jun 2009
Externally publishedYes


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