Abstract-On-chip quantum interference between silicon photon-pair sources

                                                          Mode of operation, mechanism of photon-pair              generation and physical structure of the device.

• J. W. Silverstone,
• D. Bonneau,
• K. Ohira,
• N. Suzuki,
• H. Yoshida,
• N. Iizuka,
• M. Ezaki,
• C. M. Natarajan,
• M. G. Tanner,
• R. H. Hadfield,
• V. Zwiller,
• G. D. Marshall,
• J. G. Rarity,
• J. L. O'Brien
• & M. G. Thompson

http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2013.339.html
Large-scale integrated quantum photonic technologies^1, 2 will require on-chip integration of identical photon sources with reconfigurable waveguide circuits. Relatively complex quantum circuits have been demonstrated already^{1, 2, 3, 4, 5, 6, 7}, but few studies acknowledge the pressing need to integrate photon sources and waveguide circuits together on-chip^8, 9. A key step towards such large-scale quantum technologies is the integration of just two individual photon sources within a waveguide circuit, and the demonstration of high-visibility quantum interference between them. Here, we report a silicon-on-insulator device that combines two four-wave mixing sources in an interferometer with a reconfigurable phase shifter. We configured the device to create and manipulate two-colour (non-degenerate) or same-colour (degenerate) path-entangled or path-unentangled photon pairs. We observed up to 100.0 ± 0.4% visibility quantum interference on-chip, and up to 95 ± 4% off-chip. Our device removes the need for external photon sources, provides a path to increasing the complexity of quantum photonic circuits and is a first step towards fully integrated quantum technologies.