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Inverse-designed non-reciprocal pulse router for chip-based LiDAR

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Non-reciprocal devices such as isolators and circulators are key enabling technologies for communication systems, both at microwave and optical frequencies. Although non-reciprocal devices based on magnetic effects are available for free-space and fibre-optic communication systems, their on-chip integration has been challenging, primarily due to the concomitant high insertion loss, weak magneto-optical effects and material incompatibility. We show that χ(3) nonlinear resonators can be used to achieve all-passive, low-loss, bias-free non-reciprocal transmission for applications in photonic systems such as chip-scale LiDAR. A multi-port nonlinear Fano resonator is used as an on-chip, non-reciprocal pulse router for frequency comb-based optical ranging. Because time-reversal symmetry imposes stringent limitations on the operating power range and transmission of a single nonlinear resonator, we implement a cascaded Fano–Lorentzian resonator system that overcomes these limitations and substantially improves the insertion loss and operating power range of current state-of-the-art devices. This work provides a platform-independent design for non-reciprocal transmission and routing that is ideally suited for photonic integration.

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Fig. 1: All-passive non-reciprocal transmission using a silicon photonic resonator.
Fig. 2: Non-reciprocal pulse routing and optical distance measurement.
Fig. 3: Non-reciprocal transmission in broad operating power range using cascaded nonlinear resonators.

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.

Change history

  • 30 March 2020

    In the PDF version of this Article originally published online, Figs. 2 and 3 appeared in reverse order; this has now been amended. The HTML version was unaffected.


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We acknowledge insightful discussions with D. Sounas, W. Bogaerts, D. A. B. Miller, P. Del’Haye, M. Soltani, L. Chang and J. E. Bowers, and are also grateful for technical advice from C. Langrock, B. Buscaino, N. V. Sapra, L. Su and J. M. Kahn. The silicon devices were fabricated in the Stanford Nanofabrication Facility and the Stanford Nano Shared Facilities. K.Y.Y. acknowledges support from a Quantum and Nano Science and Engineering postdoctoral fellowship, J.S. acknowledges support from the National Science Foundation Graduate Research Fellowship (grant no. DGE-1656518) and M.C. is supported by a Rubicon postdoctoral fellowship by The Netherlands Organization for Scientific Research (NWO). This work is funded by the Air Force Office of Scientific Research under the AFOSR MURI programme (award no. FA9550-17-1-0002) and the Gordon and Betty Moore Foundation (GBMF4744 and GBMF4743). We thank G. Pomrenke and the AFOSR MURI programme management team for discussions throughout the project.

Author information




K.Y.Y., J.S., M.C., A.Alù and J.V. conceived the experiments. K.Y.Y., J.S. and M.C. designed the device. K.Y.Y. and J.S. fabricated and tested the devices with assistance from M.C., A.D., G.H.A., M.S. and D.V. M.C. and K.Y.Y. conducted numerical simulations. K.Y.Y. and A.D. conducted optical ranging measurement with assistance from J.S., M.C. and D.V. All authors analysed the data and contributed to writing the manuscript. J.V. and A.Alù supervised the project.

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Correspondence to Jelena Vučković.

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Supplementary Information

Supplementary Figs. 1–12, Table 1 and discussion (eight sections).

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Yang, K.Y., Skarda, J., Cotrufo, M. et al. Inverse-designed non-reciprocal pulse router for chip-based LiDAR. Nat. Photonics 14, 369–374 (2020).

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