Phase-coherent microwave-to-optical link with a self-referenced microcomb


Precise measurements of the frequencies of light waves have become common with mode-locked laser frequency combs1. Despite their huge success, optical frequency combs currently remain bulky and expensive laboratory devices. Integrated photonic microresonators are promising candidates for comb generators in out-of-the-lab applications, with the potential for reductions in cost, power consumption and size2. Such advances will significantly impact fields ranging from spectroscopy and trace gas sensing3 to astronomy4, communications5 and atomic time-keeping6,7. Yet, in spite of the remarkable progress shown over recent years8,9,10, microresonator frequency combs (‘microcombs’) have been without the key function of direct f–2f self-referencing1, which enables precise determination of the absolute frequency of each comb line. Here, we realize this missing element using a 16.4 GHz microcomb that is coherently broadened to an octave-spanning spectrum and subsequently fully phase-stabilized to an atomic clock. We show phase-coherent control of the comb and demonstrate its low-noise operation.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Experimental set-up for f–2f self-referencing of a microcomb.
Figure 2: Carrier envelope offset frequency measurement.
Figure 3: Absolute optical frequency measurement and out-of-loop validation.
Figure 4: Carrier envelope offset frequency stabilization.
Figure 5: Stabilizing a self-referenced microcomb to a hydrogen maser frequency reference.


  1. 1

    Udem, T., Holzwarth, R. & Hänsch, T. W. Optical frequency metrology. Nature 416, 233–237 (2002).

  2. 2

    Del'Haye, P. et al. Optical frequency comb generation from a monolithic microresonator. Nature 450, 1214–1217 (2007).

  3. 3

    Diddams, S. A., Hollberg, L. & Mbele, V. Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb. Nature 445, 627–630 (2007).

  4. 4

    Steinmetz, T. et al. Laser frequency combs for astronomical observations. Science 321, 1335–1337 (2008).

  5. 5

    Pfeifle, J. et al. Optimally coherent Kerr combs generated with crystalline whispering gallery mode resonators for ultrahigh capacity fiber communications. Phys. Rev. Lett. 114, 093902 (2015).

  6. 6

    Savchenkov, A. A. et al. Stabilization of a Kerr frequency comb oscillator. Opt. Lett. 38, 2636–2639 (2013).

  7. 7

    Papp, S. B. et al. Microresonator frequency comb optical clock. Optica 1, 10–14 (2014).

  8. 8

    Coen, S., Randle, H. G., Sylvestre, T. & Erkintalo, M. Modeling of octave-spanning Kerr frequency combs using a generalized mean-field Lugiato–Lefever model. Opt. Lett. 38, 37–39 (2013).

  9. 9

    Herr, T. et al. Temporal solitons in optical microresonators. Nature Photon. 8, 145–152 (2013).

  10. 10

    Jost, J. D. et al. Counting the cycles of light using a self-referenced optical microresonator. Optica 2, 706–711 (2015).

  11. 11

    Savchenkov, A. A. et al. Tunable optical frequency comb with a crystalline whispering gallery mode resonator. Phys. Rev. Lett. 101, 093902 (2008).

  12. 12

    Levy, J. S. et al. CMOS-compatible multiple-wavelength oscillator for on-chip optical interconnects. Nature Photon. 4, 37–40 (2010).

  13. 13

    Razzari, L. et al. CMOS-compatible integrated optical hyper-parametric oscillator. Nature Photon. 4, 41–45 (2010).

  14. 14

    Ferdous, F. et al. Spectral line-by-line pulse shaping of on-chip microresonator frequency combs. Nature Photon. 5, 770–776 (2011).

  15. 15

    Grudinin, I. S. & Yu, N. Dispersion engineering of crystalline resonators via microstructuring. Optica 2, 221–224 (2015).

  16. 16

    Jung, H., Xiong, C., Fong, K. Y., Zhang, X. F. & Tang, H. X. Optical frequency comb generation from aluminum nitride microring resonator. Opt. Lett. 38, 2810–2813 (2013).

  17. 17

    Hausmann, B., Bulu, I., Venkataraman, V., Deotare, P. & Loncar, M. Diamond nonlinear photonics. Nature Photon. 8, 369–374 (2014).

  18. 18

    Yang, K. et al. Broadband dispersion-engineered microresonator on a chip. Nature Photon. 10, 316–320 (2016).

  19. 19

    Del'Haye, P., Arcizet, O., Schliesser, A., Holzwarth, R. & Kippenberg, T. J. Full stabilization of a microresonator-based optical frequency comb. Phys. Rev. Lett. 101, 053903 (2008).

  20. 20

    Papp, S. B., Del'Haye, P. & Diddams, S. A. Mechanical control of a microrod-resonator optical frequency comb. Phys. Rev. X 3, 031003 (2013).

  21. 21

    Del'Haye, P., Papp, S. B. & Diddams, S. A. Hybrid electro-optically modulated microcombs. Phys. Rev. Lett. 109, 263901 (2012).

  22. 22

    Jost, J. et al. All-optical stabilization of a soliton frequency comb in a crystalline microresonator. Opt. Lett. 40, 4723–4726 (2015).

  23. 23

    Lee, H. et al. Chemically etched ultrahigh-Q wedge-resonator on a silicon chip. Nature Photon. 6, 369–373 (2012).

  24. 24

    Del'Haye, P., Beha, K., Papp, S. B. & Diddams, S. A. Self-injection locking and phase-locked states in microresonator-based optical frequency combs. Phys. Rev. Lett. 112, 043905 (2014).

  25. 25

    Del'Haye, P. et al. Phase steps and resonator detuning measurements in microresonator frequency combs. Nature Commun. 6, 5668 (2015).

  26. 26

    Brasch, V. et al. Photonic chip-based optical frequency comb using soliton Cherenkov radiation. Science 351, 357–360 (2016).

  27. 27

    Beha, K. et al. Self-referencing a continuous-wave laser with electro-optic modulation. Preprint at (2015).

  28. 28

    Kuyken, B. et al. An octave-spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide. Nature Commun. 6, 6310 (2015).

  29. 29

    Mayer, A. S. et al. Frequency comb offset detection using supercontinuum generation in silicon nitride waveguides. Opt. Express 23, 15440–15451 (2015).

  30. 30

    Del'Haye, P. Optical Frequency Comb Generation in Monolithic Microresonators. PhD thesis, Ludwig Maximilian Univ. Munich (2011).

  31. 31

    Del'Haye, P., Arcizet, O., Gorodetsky, M. L., Holzwarth, R. & Kippenberg, T. J. Frequency comb assisted diode laser spectroscopy for measurement of microcavity dispersion. Nature Photon. 3, 529–533 (2009).

Download references


This work is supported by the National Institute of Standards and Technology, the National Physical Laboratory, the California Institute of Technology, the Defense Advanced Research Projects Agency Quantum—Assisted Sensing and Readout programme, the Air Force Office of Scientific Research and the National Aeronautics and Space Administration. P.D. acknowledges support from the Humboldt Foundation. D.C.C. acknowledges support from the National Science Foundation Graduate Research Fellowship Program under grant no. DGE 1144083.

Author information




P.D., S.B.P. and S.A.D. conceived the experiments. P.D. and A.C. designed and performed the experiments. T.F. contributed to the fceo stabilization. K.B. and D.C.C. contributed to the nonlinear spectral broadening. K.Y.Y., H.L. and K.J.V. provided the microresonator. P.D. and S.A.D. prepared the manuscript, with input from all co-authors.

Corresponding authors

Correspondence to Pascal Del'Haye or Scott A. Diddams.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Del'Haye, P., Coillet, A., Fortier, T. et al. Phase-coherent microwave-to-optical link with a self-referenced microcomb. Nature Photon 10, 516–520 (2016).

Download citation

Further reading