Abstract-THz-to-optical conversion in wireless communications using an ultra-broadband plasmonic modulator

S. Ummethala, T. Harter, K. Koehnle, Z. Li, S. Muehlbrandt, Y. Kutuvantavida, J. Kemal, P. Marin-Palomo, J. Schaefer, A. Tessmann, S. K. Garlapati, A. Bacher, L. Hahn, M. Walther, T. Zwick, S. Randel, W. Freude. C. Koos,

Fig. 1: Seamless integration of THz wireless links into fibre-optic infrastructures by direct O/T and T/O conversion.

https://www.nature.com/articles/s41566-019-0475-6

Future wireless communication networks will need to handle data rates of tens or even hundreds of Gbit s−1 per link, requiring carrier frequencies in the unallocated THz spectrum. In this context, seamless integration of THz links into existing fibre-optic infrastructures3 is of great importance to complement the inherent portability and flexibility advantages of wireless networks and the reliable and virtually unlimited capacity of optical transmission systems. On the technological level, this requires novel device and signal processing concepts for direct conversion of data streams between the THz and optical domains. Here, we demonstrate a THz link that is seamlessly integrated into a fibre-optic network using direct THz-to-optical (T/O) conversion at the wireless receiver. We exploit an ultra-broadband silicon-plasmonic modulator having a 3 dB bandwidth in excess of 0.36 THz for T/O conversion of a 50 Gbit s−1 data stream that is transmitted on a 0.2885 THz carrier over a 16-m-long wireless link. Optical-to-THz (O/T) conversion at the wireless transmitter relies on photomixing in a uni-travelling-carrier photodiode.

Abstract-Controlling intensity and phase of terahertz radiation with an optically thin liquid crystal-loaded metamaterial

O. Buchnev¹, J. Wallauer², M. Walther², M. Kaczmarek³, N. I. Zheludev^1,4, and V. A. Fedotov¹

http://apl.aip.org/resource/1/applab/v103/i14/p141904_s1?isAuthorized=no

We experimentally demonstrate intensity and phase modulation of terahertz radiation using an actively controlled large-area planar metamaterial (metafilm) hybridized with a 12 μm thick layer of a liquid crystal. Active control was introduced through in-plane electrical switching of the liquid crystal, which enabled to achieve a reversible single-pass absolute transmission change of 20% and a phase change of 40° at only 20 V.

© 2013 AIP Publishing LLC

Article-Plasmonics: Terahertz Localized Surface Plasmon Resonances in Coaxial Microcavities

http://onlinelibrary.wiley.com/doi/10.1002/adom.201370038/abstract
Withayachumnankul, W., Shah, C. M., Fumeaux, C., Kaltenecker, K., Walther, M., Fischer, B. M., Abbott, D., Bhaskaran, M. and Sriram, S.
Coaxial microcavities etched into the surface of a heavily-doped silicon substrate by W. Withayachumnankul, S. Sriram, and co-workers are shown on page 443 to support localized surface plasmon resonances at terahertz frequencies through the interplay between the cylindrical surface plasmon polaritons and the cavity modes. The coaxial geometry partly determines the resonance frequency, as illustrated by the absorption map.