Synchronization of coupled optical microresonators


The phenomenon of synchronization occurs universally across the natural sciences and provides critical insight into the behaviour of coupled nonlinear dynamical systems. It also offers a powerful approach to robust frequency or temporal locking in diverse applications including communications, superconductors and photonics. Here, we report the experimental synchronization of two coupled soliton mode-locked chip-based frequency combs separated over distances of 20 m. We show that such a system obeys the universal Kuramoto model for synchronization and that the cavity solitons from the microresonators can be coherently combined, which overcomes the fundamental power limit of microresonator-based combs. This study could significantly expand the applications of microresonator combs, and with its capability for massive integration it offers a chip-based photonic platform for exploring complex nonlinear systems.

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Fig. 1: Illustration of the synchronization of microresonator combs.
Fig. 2: Dynamics of synchronization.
Fig. 3: Characterization of synchronization behaviour.
Fig. 4: Demonstration of coherent comb combining.

Data availability

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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This work was supported by the Air Force Office of Scientific Research (AFOSR) (grant no. FA9550-15-1-0303), the National Science Foundation (NSF) (grant no. CCF-1640108) and the Semiconductor Research Corporation (SRC) (grant no. SRS 2016-EP-2693-A). The authors also thank K. Bergman and R. Polster for lending the high-resolution optical spectrum analyser and autocorrelator.

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J.K.J. and A.K. performed experiment. J.K.J carried out theoretical analysis and numerical simulation, and wrote the manuscript with inputs from all authors. J.K.J., A.K., Y.O. and A.L.G. contributed to the interpretation of data. X.J. fabricated the devices under the supervision of M.L. A.L.G. supervised the overall project.

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Correspondence to Alexander L. Gaeta.

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Jang, J.K., Klenner, A., Ji, X. et al. Synchronization of coupled optical microresonators. Nature Photon 12, 688–693 (2018).

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