Quantum photonics on a silicon chip
Final Report Abstract
In this project key components for integrated quantum photonic circuits on monolithic silicon chips were developed. Advanced nanofabrication techniques allowed for realizing sources of quantum light, linear optic circuit components and efficient single photon detectors embedded into a network of nanophotonic waveguides. Such integrated sources, circuits and detectors are the building blocks of a photonic quantum information processor that holds great promise for implementing efficient algorithmic solutions to complex computational problems. The benefit of developing nanoscale devices on a silicon photonic platform for controlling individual quantum system, as demonstrated here, lies in straightforward replication of each building block by exploiting state-of-the-art nanofabrication techniques, hence rendering the approach scalable. We demonstrated the first fully integrated spontaneous parametric down conversion source in an aluminum nitride micro-ring resonator yielding quantum-correlated photon pairs at MHz-rates with high signal to noise ratio. A measurement of the second order correlation function of heralded signal photons clearly revealed that our source produces single-photons in pure quantum states, as required for quantum information processing applications. We realize several nanophotonic circuit components that are essential to linear optic implementations of quantum computing. In particular, directional waveguide couplers were employed to demonstrate high-visibility two-photon interference, which is a quantum effect that enables critical gate operations in complex quantum circuits. Integration of directional couplers, low-loss waveguides, electrostatically actuated phase shifters and efficient fiber-chip interfaces further allowed the implementation of a nanophotonic circuit that realizes the controlled-NOT gate operation, which plays a pivotal role in many quantum algorithms. We implemented a novel waveguide-integrated superconducting nanowire single-photon detector employing niobium titanium nitride thin-film technology. This material system yielded extremely low noise detector performance setting record low dark count rates while simultaneously achieving high detection efficiency, high speed and high timing accuracy. We routinely fabricate several hundred of such detectors on a silicon chip and demonstrated their seamless integration with nanophotonic circuits in the measurement of quantum interference directly on-chip. With the successful development of nanophotonic quantum sources, circuits and detectors in this project the way is paved for fabricating large numbers of these components on silicon chips for applications in quantum technologies. We have taken first steps in this direction by integrating single-photon detectors with nanophotonic circuit components - as recognized in several US media outlets - and anticipate that future work will be concerned with incorporating singlephoton sources on such circuit-detector-chips leading to scalable quantum information processing.
Publications
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Waveguide integrated low noise NbTiN nanowire singlephoton detectors with milli-Hz dark count rate, Scientific Reports 3, 1893 (2013)
C. Schuck, W. H. P. Pernice, H. X. Tang
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Integrated On-Chip interaction-free measurement via the quantum Zeno effect, Physical Review A 90, 042109 (2014)
X. Ma, X. Guo, C. Schuck, K. Y. Fong, L. Jiang, H. X. Tang
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Design and characterization of integrated components for SiN photonic quantum circuits, Optics Express 24, 6843 (2016)
M. Poot, C. Schuck, X.-S. Ma, X. Guo, H. X. Tang
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Quantum Interference in heterogeneously integrated superconducting-photonic circuits on a silicon chip, Nature Communications 7, 10352 (2016)
C. Schuck, X. Guo, L. Fan, X. Ma, H. X. Tang
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Superconducting Single Photon Detector, US9500519 B2, granted 22. Nov. 2016
H. X. Tang, W. H. P. Pernice, C. Schuck
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Waveguide integrated superconducting nanowire singlephoton detectors on silicon, Superconducting devices in quantum optics, Springer, Ed. R. Hadfield (2016)
W. H. P. Pernice, C. Schuck, H. X. Tang
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Parametric-down-conversion photon-pair source on a nanophotonic chip. Light: Science & Applications 6, e16249 (2017)
X. Guo, C.L. Zou, C. Schuck, H. Jung, H. X. Tang
