Microwave plasmonic mixer in a transparent fibre–wireless link

• Published in: Nature photonics Vol. 12; no. 12; pp. 749 - 753
• Main Authors: Salamin, Y., Baeuerle, B., Heni, W., Abrecht, F. C., Josten, A., Fedoryshyn, Y., Haffner, C., Bonjour, R., Watanabe, T., Burla, M., Elder, D. L., Dalton, L. R., Leuthold, J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2018; Nature Publishing Group
• Subjects: 142/126; 639/624/1075/1081; 639/624/1075/187; 639/624/1075/401; 639/624/399/1099; 639/925/927/1021; Applied and Technical Physics; Bandwidths; Carrier frequencies; Domains; Letter; Metal oxides; Millimeter waves; Optical communication; Optical fibers; Optical receivers; Physics; Physics and Astronomy; Quantum Physics; nonlinear optics; modulator; terahertz; field enhancement; microwave photonics; optical communications; Plasmonics
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-018-0281-6

To cope with the high bandwidth requirements of wireless applications 1 , carrier frequencies are shifting towards the millimetre-wave and terahertz bands 2 – 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 desirable 6 , 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. A direct wireless-to-optical receiver in a transparent optical link is achieved, thanks to a subwavelength two-dimensionally localized gap-plasmon mixer encoding wireless information directly onto optical signals.