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A chip-scale polarization-spatial-momentum quantum SWAP gate in silicon nanophotonics

Nature Photonics volume 17, pages 656–665 (2023)Cite this article

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Abstract

Recent progress in quantum computing and networking has enabled high-performance, large-scale quantum processors by connecting different quantum modules. Optical quantum systems show advantages in both computing and communications, and integrated quantum photonics further increases the level of scaling and complexity. Here we demonstrate an efficient SWAP gate that deterministically swaps a photon’s polarization qubit with its spatial-momentum qubit on a nanofabricated two-level silicon photonics chip containing three cascaded gates. The on-chip SWAP gate is comprehensively characterized by tomographic measurements with high fidelity for both single-qubit and two-qubit operation. The coherence preservation of the SWAP gate process is verified by single-photon and two-photon quantum interference. The coherent reversible conversion of our SWAP gate facilitates examinations of a quantum interconnect between two chip-scale photonic subsystems with different degrees of freedom, now demonstrated by distributing four Bell states between the two chips. We also elucidate the source of decoherence in the SWAP operation in pursuit of near-unity fidelity. Our deterministic SWAP gate in the silicon platform provides a pathway towards integrated quantum information processing for interconnected modular systems.

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Fig. 1: A chip-scale polarization–spatial single-photon two-qubit SWAP gate.
Fig. 2: Experimental configuration for characterization of the single-photon two-qubit SWAP gate and truth-table measurements.
Fig. 3: Quantum state and process tomographies for one-qubit and two-qubit SWAP operation.
Fig. 4: Coherence preservation of the SWAP gate and quantum state distribution between dual SWAP gate chips.

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Data availability

All the data and methods are presented in the main text and the Supplementary Information. The figures are also available on Figshare at https://doi.org/10.6084/m9.figshare.22590367. The raw datasets generated and/or analysed during the current study are available from the corresponding author upon request. Source data are provided with this paper.

References

  1. Harrow, A. W. & Montanaro, A. Quantum computational supremacy. Nature 549, 203–209 (2017).

    ADS  Google Scholar 

  2. Preskill, J. Quantum computing in the NISQ era and beyond. Quantum 2, 79 (2018).

    Google Scholar 

  3. Arute, F. et al. Quantum supremacy using a programmable superconducting processor. Nature 574, 505–510 (2019).

    ADS  Google Scholar 

  4. Zhong, H.-S. et al. Quantum computational advantage using photons. Science 370, 1460–1463 (2020).

    ADS  Google Scholar 

  5. O’Brien, J. L. Optical quantum computing. Science 318, 1567–1570 (2007).

    ADS  Google Scholar 

  6. Knill, E., Laflamme, R. & Milburn, G. J. A scheme for efficient quantum computation with linear optics. Nature 409, 46–52 (2001).

    ADS  Google Scholar 

  7. Wang, X.-L. et al. 18-Qubit entanglement with six photons’ three degrees of freedom. Phys. Rev. Lett. 120, 260502 (2018).

    ADS  Google Scholar 

  8. Kok, P. et al. Linear optical quantum computing with photonic qubits. Rev. Mod. Phys. 79, 135–174 (2007).

    ADS  Google Scholar 

  9. Raussendorf, R. & Briegel, H. J. A one-way quantum computer. Phys. Rev. Lett. 86, 5188–5191 (2001).

    ADS  MATH  Google Scholar 

  10. Walther, P. et al. Experimental one-way quantum computing. Nature 434, 169–176 (2005).

    ADS  Google Scholar 

  11. O’Brien, J., Furusawa, A. & Vučković, J. Photonic quantum technologies. Nat. Photon. 3, 687–695 (2009).

    ADS  Google Scholar 

  12. Fiorentino, M. & Wong, F. N. C. Deterministic controlled-NOT gate for single-photon two-qubit quantum logic. Phys. Rev. Lett. 93, 070502 (2004).

    ADS  Google Scholar 

  13. Carolan, J. et al. Universal linear optics. Science 349, 711–716 (2015).

    MathSciNet  MATH  Google Scholar 

  14. Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008).

    ADS  Google Scholar 

  15. Wehner, S., Elkouss, D. & Hanson, R. Quantum internet: a vision for the road ahead. Science 362, eaam9288 (2018).

    ADS  MathSciNet  MATH  Google Scholar 

  16. Cacciapuoti, A. S. et al. Quantum internet: networking challenges in distributed quantum computing. IEEE Netw. 34, 137–143 (2020).

    Google Scholar 

  17. Awschalom, D. et al. Development of quantum interconnects for next-generation information technologies. PRX Quantum 2, 017002 (2021).

    Google Scholar 

  18. Erhard, M., Krenn, M. & Zeilinger, A. Advances in high-dimensional quantum entanglement. Nat. Rev. Phys. 2, 365–381 (2020).

    Google Scholar 

  19. Wang, J., Sciarrino, F., Laing, A. & Thompson, M. G. Integrated photonic quantum technologies. Nat. Photon. 14, 273–284 (2020).

    ADS  Google Scholar 

  20. Wang, J. et al. Multidimensional quantum entanglement with large-scale integrated optics. Science 360, 285–291 (2018).

    ADS  MathSciNet  MATH  Google Scholar 

  21. Qiang, X. et al. Large-scale silicon quantum photonics implementing arbitrary two-qubit processing. Nat. Photon. 12, 534–539 (2018).

    ADS  Google Scholar 

  22. Barz, S. et al. Demonstration of blind quantum computing. Science 335, 303–308 (2012).

    ADS  MathSciNet  MATH  Google Scholar 

  23. Cirac, J. I., Ekert, A. K., Huelga, S. F. & Macchiavello, C. Distributed quantum computation over noisy channels. Phys. Rev. A 59, 4249–4254 (1999).

    ADS  MathSciNet  Google Scholar 

  24. Sheng, Y.-B. & Zhou, L. Distributed secure quantum machine learning. Sci. Bull. 62, 1025–1029 (2017).

    Google Scholar 

  25. Fiorentino, M., Kim, T. & Wong, F. N. C. Single-photon two-qubit SWAP gate for entanglement manipulation. Phys. Rev. A 72, 012318 (2005).

    ADS  Google Scholar 

  26. Kagalwala, K. H., Di Giuseppe, G., Abouraddy, A. F. & Saleh, B. E. A. Single-photon three-qubit quantum logic using spatial light modulators. Nat. Commun. 8, 739 (2017).

    ADS  Google Scholar 

  27. Lu, H.-H. et al. Quantum phase estimation with time-frequency qudits in a single photon. Adv. Quantum Tech. 3, 1900074 (2020).

    Google Scholar 

  28. Zhang, M. et al. Supercompact photonic quantum logic gate on a silicon chip. Phys. Rev. Lett. 126, 130501 (2021).

    ADS  Google Scholar 

  29. Li, J.-P. et al. Heralded nondestructive quantum entangling gate with single-photon sources. Phys. Rev. Lett. 126, 140501 (2021).

    ADS  Google Scholar 

  30. Nielsen, M. A. & Chuang, I. L. Quantum Computation and Quantum Information (Cambridge Univ. Press, 2000).

  31. Barwicz, T. et al. Polarization-transparent microphotonic devices in the strong confinement limit. Nat. Photon. 1, 57–60 (2007).

    ADS  Google Scholar 

  32. Su, Y., Zhang, Y., Qiu, C., Guo, X. & Sun, L. Silicon photonic platform for passive waveguide devices: materials, fabrication and applications. Adv. Mater. Technol. 5, 1901153 (2020).

    Google Scholar 

  33. Goi, K. et al. Low-loss partial rib polarization rotator consisting only of silicon core and silica cladding. Opt. Lett. 40, 1410–1413 (2015).

    ADS  Google Scholar 

  34. Horikawa, T. et al. A 300-mm silicon photonics platform for large-scale device integration. IEEE J. Sel. Top. Quantum Electron. 24, 8200415 (2018).

    Google Scholar 

  35. Chang, K.-C. et al. 648 Hilbert space dimensionality in a biphoton frequency comb: entanglement of formation and Schmidt mode decomposition. NPJ Quantum Inf. 7, 48 (2021).

    ADS  Google Scholar 

  36. Xie, Z. et al. Harnessing high-dimensional hyperentanglement through a biphoton frequency comb. Nat. Photon. 9, 536–542 (2015).

    ADS  Google Scholar 

  37. O’Brien, J. L. et al. Quantum process tomography of a controlled-NOT gate. Phys. Rev. Lett. 93, 080502 (2004).

    ADS  Google Scholar 

  38. White, A. G. et al. Measuring two-qubit gates. J. Opt. Soc. Am. B 24, 172–183 (2007).

    ADS  Google Scholar 

  39. Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between two photons by interference. Phys. Rev. Lett. 59, 2044–2046 (1987).

    ADS  Google Scholar 

  40. Feng, L.-T. et al. On-chip coherent conversion of photonic quantum entanglement between different degrees of freedom. Nat. Commun. 7, 11985 (2016).

    ADS  Google Scholar 

  41. Silverstone, J. W. et al. On-chip quantum interference between silicon photon-pair sources. Nat. Photon. 8, 104–108 (2014).

    ADS  Google Scholar 

  42. Llewellyn, D. et al. Chip-to-chip quantum teleportation and multi-photon entanglement in silicon. Nat. Phys. 16, 148–153 (2020).

    Google Scholar 

  43. Kwiat, P. G. et al. New high-intensity source of polarization-entangled photon pairs. Phys. Rev. Lett. 75, 4337–4341 (1995).

    ADS  Google Scholar 

  44. Zhang, Z. & Zhuang, Q. Distributed quantum sensing. Quantum Sci. Technol. 6, 043001 (2021).

    ADS  Google Scholar 

  45. Harris, N. C. et al. Quantum transport simulations in a programmable nanophotonic processor. Nat. Photon. 11, 447–452 (2017).

    ADS  Google Scholar 

  46. Wang, J. et al. Chip-to-chip quantum photonic interconnect by path-polarization interconversion. Optica 3, 407–413 (2016).

    ADS  Google Scholar 

  47. Xiong, C. et al. Compact and reconfigurable silicon nitride time-bin entanglement circuit. Optica 2, 724–727 (2015).

    ADS  Google Scholar 

  48. Gao, X., Erhard, M., Zeilinger, A. & Krenn, M. Computer-inspired concept for high-dimensional multipartite quantum gates. Phys. Rev. Lett. 125, 050501 (2020).

    ADS  MathSciNet  Google Scholar 

  49. Imany, P. et al. High-dimensional optical quantum logic in large operational spaces. NPJ Quantum Inf. 5, 59 (2019).

    ADS  Google Scholar 

  50. Najafi, F. et al. On-chip detection of non-classical light by scalable integration of single-photon detectors. Nat. Commun. 6, 5873 (2015).

    ADS  Google Scholar 

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Acknowledgements

We acknowledge discussions with H. Liu, K. Yu, Y. Cho, A. Veitia, T. Zhong and F. Sun and SEM assistance from J. F. McMillan. This work is supported by the National Science Foundation (EFRI-ACQUIRE 1741707, QII-TAQS 1936375, 1919355 and 2008728) and the University of California National Laboratory research programme (LFRP-17-477237).

Author information

Author notes

  1. These authors contributed equally: Xiang Cheng, Kai-Chi Chang, Zhenda Xie.

Authors and Affiliations

  1. Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, CA, USA

    Xiang Cheng, Kai-Chi Chang, Zhenda Xie, Murat Can Sarihan, Yoo Seung Lee, Yongnan Li, Abhinav Kumar Vinod & Chee Wei Wong

  2. Optical Nanostructures Laboratory, Columbia University, New York, NY, USA

    Zhenda Xie, XinAn Xu, Serdar Kocaman & Chee Wei Wong

  3. National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing, China

    Zhenda Xie

  4. Department of Electrical Engineering, Middle East Technical University, Ankara, Turkey

    Serdar Kocaman

  5. Institute of Microelectronics, Singapore, Singapore

    Mingbin Yu, Patrick Guo-Qiang Lo & Dim-Lee Kwong

  6. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, and Shanghai Industrial Technology Research Institute, Shanghai, China

    Mingbin Yu

  7. Advanced Micro Foundry, Singapore, Singapore

    Patrick Guo-Qiang Lo

  8. Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA

    Jeffrey H. Shapiro & Franco N. C. Wong

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Contributions

X.C., K.C.C., Z.X. and Y.S.L. performed the measurements. Y.L., S.K. and X.X. performed the design layout. M.Y., P.G.Q.L. and D.L.K. performed the device nanofabrication. X.C., M.C.S., X.X., A.K.V., J.H.S. and F.N.C.W. contributed to the theory and numerical modelling. X.C., Z.X., X.X., J.H.S., F.N.C.W. and C.W.W. wrote the manuscript, with contributions from all authors.

Corresponding authors

Correspondence to Xiang Cheng, Kai-Chi Chang or Chee Wei Wong.

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Nature Photonics thanks Marco Fiorentino and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–20 and discussion.

Source data

Source Data Fig. 2

Data for SPDC photons’ wavelength tenability and truth table for PC-NOT, MC-NOT and SWAP gate.

Source Data Fig. 3

Data for Bloch spheres, single-qubit process tomography and two-qubit process tomography.

Source Data Fig. 4

Data for single-photon self-interferences, HOM interferences, and density matrices of the four polarization Bell states.

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Cheng, X., Chang, KC., Xie, Z. et al. A chip-scale polarization-spatial-momentum quantum SWAP gate in silicon nanophotonics. Nat. Photon. 17, 656–665 (2023). https://doi.org/10.1038/s41566-023-01224-x

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