Microwave plasmonic mixer in a transparent fibre–wireless link


To cope with the high bandwidth requirements of wireless applications1, carrier frequencies are shifting towards the millimetre-wave and terahertz bands2,3,4,5. Conversely, data is normally transported to remote wireless antennas by optical fibres. Therefore, full transparency and flexibility to switch between optical and wireless domains would be desirable6,7. Here, we demonstrate a direct wireless-to-optical receiver in a transparent optical link. We successfully transmit 20 and 10 Gbit s−1 over wireless distances of 1 and 5 m, respectively, at a carrier frequency of 60 GHz. Key to the breakthrough is a plasmonic mixer directly mapping the wireless information onto optical signals. The plasmonic scheme with its subwavelength feature and pronounced field confinement provides a built-in field enhancement of up to 90,000 over the incident field in an ultra-compact and complementary metal-oxide–semiconductor compatible structure. The plasmonic mixer is not limited by electronic speed and thus compatible with future terahertz technologies.

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Fig. 1: Prospective application scenario for a point-to-point high-capacity fibre–wireless link.
Fig. 2: Device structure and performance.
Fig. 3: Fibre-to-wireless and wireless-to-fibre link experiment.
Fig. 4: Experimental results.

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

  • 07 November 2018

    In the version of this Letter originally published online, the ORCID number, 0000-0002-8900-3237, of the author A. Josten was missing; and in Fig. 2b, in the y axis label, ‘×105’should have been ‘×103’. These errors have now been corrected in all versions.


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This work was carried out partially at the Binnig and Rohrer Nanotechnology Center (BRNC) and in the FIRST lab cleanroom facility at ETH Zurich. We are grateful to H. R. Benedickter and U. Drechsler for the help in the measurement and fabrication, respectively. The European Union project ERC PLASILOR (670478) and PLASMOfab (688166) are acknowledged for partial funding of the work. The US National Science Foundation (DMR-1303080) and the Air Force Office of Scientific Research (FA9550-15-1-0319). The ETH Postdoctoral Fellowship (16-2-FEL-51). M.B. acknowledges the SNSF Ambizione grant (173996).

Author information




Y.S conceived the concept, designed and fabricated the device, designed and performed the experiments and analysed the data. B.B., F.C.A. and A.J. performed the data experiment and data analysis. W.H. fabricated the device, developed the poling process and contributed to the measurements. Y.F. fabricated the device. C.H. contributed to the design of the device and experiment. R.B. and M.B. contributed to the design of the experiment. T.W contributed to the design of the device. D.L.E. and L.R.D. developed and synthesized the HD-BB-OH/YLD124 nonlinear material. J.L. conceived the concept and supervised the project. All authors have contributed to the writing of the manuscript.

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Correspondence to Y. Salamin or J. Leuthold.

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Supplementary information

Supplementary Information

Discussion of the plasmonic phase modulator, field enhancement and experimental set-up

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Salamin, Y., Baeuerle, B., Heni, W. et al. Microwave plasmonic mixer in a transparent fibre–wireless link. Nature Photon 12, 749–753 (2018). https://doi.org/10.1038/s41566-018-0281-6

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