Microcavity-based frequency combs, or ‘microcombs’1,2, have enabled many fundamental breakthroughs3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21 through the discovery of temporal cavity-solitons. These self-localized waves, described by the Lugiato–Lefever equation22, are sustained by a background of radiation usually containing 95% of the total power23. Simple methods for their efficient generation and control are currently being investigated to finally establish microcombs as out-of-the-lab tools24. Here, we demonstrate microcomb laser cavity-solitons. Laser cavity-solitons are intrinsically background-free and have underpinned key breakthroughs in semiconductor lasers22,25,26,27,28. By merging their properties with the physics of multimode systems29, we provide a new paradigm for soliton generation and control in microcavities. We demonstrate 50-nm-wide bright soliton combs induced at average powers more than one order of magnitude lower than the Lugiato–Lefever soliton power threshold22, measuring a mode efficiency of 75% versus the theoretical limit of 5% for bright Lugiato–Lefever solitons23. Finally, we can tune the repetition rate by well over a megahertz without any active feedback.

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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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The authors acknowledge support from the UK Quantum Technology Hub for Sensors and Metrology, EPSRC, under grant no. EP/M013294/1 and from INNOVATE UK, project ‘IOTA’ grant agreement no. EP/R043566/1. This project received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant no. 725046). A.P. acknowledges support from the People Programme (Marie Curie Actions) of the European Union’s FP7 Programme under REA grant agreement CHRONOS (327627). B.W. acknowledges support from the People Programme (Marie Curie Actions) of the European Union’s FP7 Programme under REA grant agreement INCIPIT (PIOF-GA-2013-625466). S.T.C. acknowledges support from the Research Grant Council of Hong Kong (GRF# 9042663). B.E.L. acknowledges support from the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB24030300). R.M. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Strategic, Discovery and Acceleration Grants Schemes, by the MESI PSR-SIIRI Initiative in Quebec, by the Canada Research Chair Program, as well as additional support by the Government of the Russian Federation through the ITMO Fellowship and Professorship Program (grant no. 074-U 01) and by the 1000 Talents Sichuan Program.

Author information


  1. Emergent Photonics (Epic) Laboratory, Department of Physics and Astronomy, University of Sussex, Brighton, UK

    • Hualong Bao
    • , Andrew Cooper
    • , Maxwell Rowley
    • , Luigi Di Lauro
    • , Juan Sebastian Totero Gongora
    • , Benjamin Wetzel
    • , Marco Peccianti
    •  & Alessia Pasquazi
  2. Department of Physics, City University of Hong Kong, Hong Kong, China

    • Sai T. Chu
  3. State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Xi’an, China

    • Brent E. Little
  4. SUPA, Department of Physics, University of Strathclyde, Glasgow, UK

    • Gian-Luca Oppo
  5. INRS-EMT, Varennes, Québec, Canada

    • Roberto Morandotti
  6. Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, China

    • Roberto Morandotti
  7. ITMO University, St Petersburg, Russia

    • Roberto Morandotti
  8. Centre for Microphotonics, Swinburne University of Technology, Hawthorn, Victoria, Australia

    • David J. Moss


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A.P., H.B. and M.P. developed the original concept. B.E.L. and S.T.C. designed and fabricated the integrated devices. H.B performed the experiments. A.P. developed the theoretical model. A.C., M.R., L.D.L., J.S.T.G., G.-L.O., D.J.M., R.M. and B.W. contributed to the development of the experiment, the numerical model and the data analysis. A.P., B.W., G.-L.O., D.J.M., R.M., H.B. and M.P. contributed to the writing of the manuscript. B.W., M.P. and A.P. supervised the research.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Alessia Pasquazi.

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    This file contains more information about the work, Supplementary Figures 1–8 and Supplementary Tables 1–2.

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