Frequency-domain Hong–Ou–Mandel interference

Journal name:
Nature Photonics
Year published:
Published online

Hong–Ou–Mandel (HOM) interference is one of the most prominent features of quantum indistinguishable particles, and has been used as the core of many quantum information protocols1. Since its first observation in 19872, it has been understood as a phenomenon that occurs when two identical bosons are fed to two input ports of a beam splitter. Here, we report the observation of HOM interference exhibited by two photons with different colours3. We developed a frequency-domain beam splitter via a second-order nonlinear medium driven by strong coherent light4, 5. A photon passing through the device changes its colour probabilistically. When a single pulse containing two photons with different colours was fed to the beam splitter, the pair of output photons showed a tendency to assume the same colour, with a visibility exceeding the classical limit. Combined with wavelength-division multiplexing, our results will pave the way towards the miniaturization of highly integrated optical circuits for quantum information processing.

At a glance


  1. Frequency-domain HOM interferometer.
    Figure 1: Frequency-domain HOM interferometer.

    a, The frequency converter based on the second-order nonlinear optical effect. It partially converts the wavelengths of the photons in a single spatial mode from/to 780 nm to/from 1,522 nm via difference/sum frequency generation. b, Principle of the frequency-domain HOM effect. When a single photon in the upper mode and another photon in the lower mode are mixed by the frequency converter, the single photon occupation events in the output disappear due to the destructive interference. c, The experimental set-up for frequency-domain HOM interference. In the experiment, the heralded single photon source (HSPS) at 780 nm and the weak coherent pulse (WCP) at 1,522 nm are prepared to serve as two input photons to the frequency HOM interferometer. The two photons are combined by DM2 into a single spatial mode and then enter the PPLN waveguide used as the frequency-domain BS. The output light pulses are separated into two spatial modes by DM4 for photon detection of the two frequency modes. BBO, β-barium borate; HPF, high-pass filter; PBS, polarizing beam splitter; QWP, quarter-wave plate; TDC, time-to-digital converter.

  2. The count rate versus the pump power.
    Figure 2: The count rate versus the pump power.

    a, The count rate of the transition/staying events per pulse pU,t/s (circle/triangle) for the heralded single photon at 780 nm when the heralding signal is detected at DV1. b, The count rate of the transition/staying events per pulse pL,t/s (triangle/circle) for the coherent light pulse at 1,522 nm. The dashed curves are obtained from our theoretical model with the observed values of pU,t/s and pL,t/s (see Supplementary Information).

  3. The peak value of the internal transition probability.
    Figure 3: The peak value of the internal transition probability.

    The curve is obtained by the best fit to with , where the fitting parameters A and η are 0.99 and 0.0036 per mW, respectively.

  4. Observed frequency-domain HOM interference.
    Figure 4: Observed frequency-domain HOM interference.

    a, The observed HOM dip at 140 mW pump power. The circles represent the experimental threefold coincidence counts. The solid curve is the Gaussian fit to the experimental counts. The dashed curve is obtained from our theoretical model under the experimental parameters. The dashed horizontal line describes the half value of the maximum of the fitting result. b, The dependence of the visibility on pump power. The circles represent the experimental results. The dashed curve is obtained from our theoretical model under the experimental parameters. The error bars indicate the standard deviations estimated by Monte Carlo method under the assumption of the Poisson statistics of the photon counts.


  1. Pan, J.-W. et al. Multiphoton entanglement and interferometry. Rev. Mod. Phys. 84, 777838 (2012).
  2. Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between two photons by interference. Phys. Rev. Lett. 59, 20442046 (1987).
  3. Raymer, M., van Enk, S., McKinstrie, C. & McGuinness, H. Interference of two photons of different color. Opt. Commun. 283, 747752 (2010).
  4. Giorgi, G., Mataloni, P. & De Martini, F. Frequency hopping in quantum interferometry: efficient up-down conversion for qubits and ebits. Phys. Rev. Lett. 90, 027902 (2003).
  5. Ikuta, R. et al. Observation of two output light pulses from a partial wavelength converter preserving phase of an input light at a single-photon level. Opt. Express 21, 2786527872 (2013).
  6. Kok, P. et al. Linear optical quantum computing with photonic qubits. Rev. Mod. Phys. 79, 135174 (2007).
  7. Barz, S. et al. Demonstration of blind quantum computing. Science 335, 303308 (2012).
  8. Spagnolo, N. et al. Experimental validation of photonic boson sampling. Nature Photon. 8, 615620 (2014).
  9. Carolan, J. et al. Universal linear optics. Science 349, 711716 (2015).
  10. Tang, Y.-L. et al. Measurement-device-independent quantum key distribution over 200 km. Phys. Rev. Lett. 113, 190501 (2014).
  11. Guan, J.-Y. et al. Experimental passive round-robin differential phase-shift quantum key distribution. Phys. Rev. Lett. 114, 180502 (2015).
  12. Sangouard, N., Simon, C., de Riedmatten, H. & Gisin, N. Quantum repeaters based on atomic ensembles and linear optics. Rev. Mod. Phys. 83, 3380 (2011).
  13. Hofmann, J. et al. Heralded entanglement between widely separated atoms. Science 337, 7275 (2012).
  14. Bao, X.-H. et al. Quantum teleportation between remote atomic-ensemble quantum memories. Proc Natl Acad. Sci. USA 109, 2034720351 (2012).
  15. Teich, M., Saleh, B., Wong, F. & Shapiro, J. Variations on the theme of quantum optical coherence tomography: a review. Quantum Inf. Process. 11, 903923 (2012).
  16. Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S. & Yamamoto, Y. Indistinguishable photons from a single-photon device. Nature 419, 594597 (2002).
  17. Patel, R. B. et al. Two-photon interference of the emission from electrically tunable remote quantum dots. Nature Photon. 4, 632635 (2010).
  18. Beugnon, J. et al. Quantum interference between two single photons emitted by independently trapped atoms. Nature 440, 779782 (2006).
  19. Maunz, P. et al. Quantum interference of photon pairs from two remote trapped atomic ions. Nature Phys. 3, 538541 (2007).
  20. Sipahigil, A. et al. Quantum interference of single photons from remote nitrogen-vacancy centers in diamond. Phys. Rev. Lett. 108, 143601 (2012).
  21. Sipahigil, A. et al. Indistinguishable photons from separated silicon-vacancy centers in diamond. Phys. Rev. Lett. 113, 113602 (2014).
  22. Di Martino, G. et al.Observation of quantum interference in the plasmonic Hong–Ou–Mandel effect. Phys. Rev. Appl. 1, 034004 (2014).
  23. Fakonas, J. S., Lee, H., Kelaita, Y. A. & Atwater, H. A. Two-plasmon quantum interference. Nature Photon. 8, 317320 (2014).
  24. Lopes, R. et al. Atomic Hong–Ou–Mandel experiment. Nature 520, 6668 (2015).
  25. Toyoda, K., Hiji, R., Noguchi, A. & Urabe, S. Hong–Ou–Mandel interference of two phonons in trapped ions. Nature 527, 7477 (2015).
  26. Shih, Y. H. & Sergienko,, A. V. Observation of quantum beating in a simple beam-splitting experiment: Two-particle entanglement in spin and space-time. Phys. Rev. A 50, 2564 (1994).
  27. Ramelow, S. Ratschbacher, L. Fedrizzi, A. Langford, N. K. & Zeilinger, A. Discrete tunable color entanglement. Phys. Rev. Lett. 103, 253601 (2009).
  28. Tanzilli, S. et al. A photonic quantum information interface. Nature 437, 116120 (2005).
  29. Ikuta, R. et al. Wide-band quantum interface for visible-to-telecommunication wavelength conversion. Nature Commun. 2, 537 (2011).
  30. Ikuta, R. et al. High-fidelity conversion of photonic quantum information to telecommunication wavelength with superconducting single-photon detectors. Phys. Rev. A 87, 010301(R) (2013).
  31. Kumar, P. Quantum frequency conversion. Opt. Lett. 15, 14761478 (1990).
  32. Rarity, J. G., Tapster, P. R. & Loudon, R. Non-classical interference between independent sources. J. Opt. B 7, S171 (2005).
  33. Ikuta, R. et al. Nonclassical two-photon interference between independent telecommunication light pulses converted by difference-frequency generation. Phys. Rev. A 88, 042317 (2013).
  34. Miki, S., Yamashita, T., Terai, H. & Wang, Z. High performance fiber-coupled NbTiN superconducting nanowire single photon detectors with Gifford-McMahon cryocooler. Opt. Express 21, 1020810214 (2013).

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Author information


  1. Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan

    • Toshiki Kobayashi,
    • Rikizo Ikuta,
    • Shuto Yasui,
    • Takashi Yamamoto &
    • Nobuyuki Imoto
  2. Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), Kobe 651-2492, Japan

    • Shigehito Miki,
    • Taro Yamashita &
    • Hirotaka Terai
  3. Photon Science Center, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan

    • Masato Koashi


T.K., R.I and T.Y. designed the experiment. T.K., R.I and S.Y. carried out the experiments under supervision of T.Y., M.K. and N.I. S.M., T.Y. and H.T. developed the system of the superconducting single-photon detectors. All authors analysed the experimental results and contributed to the discussions and interpretations. T.K. wrote the manuscript, with input from all authors.

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