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 spectrum1,2. 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.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the plots within this Letter and other findings of this study are available from the corresponding author(s) upon reasonable request.
Nagatsuma, T., Ducournau, G. & Renaud, C. C. Advances in terahertz communications accelerated by photonics. Nat. Photon. 10, 371–379 (2016).
Kürner, T. & Priebe, S. Towards THz communications—status in research, standardization and regulation. J. Infrared Millim. Terahertz Waves 35, 53–62 (2014).
Seeds, A. J., Shams, H., Fice, M. J. & Renaud, C. C. Terahertz photonics for wireless communications. J. Lightwave Technol. 33, 579–587 (2015).
Cisco Visual Networking Index: Forecast and Methodology, 2016–2021, White Paper 22 (Cisco, 2017); http://www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/complete-white-paper-c11-481360.pdf
Chow, C. W. et al. 100 GHz ultra-wideband (UWB) fiber-to-the-antenna (FTTA) system for in-building and in-home networks. Opt. Express 18, 11–15 (2010).
Koenig, S. et al. Wireless sub-THz communication system with high data rate. Nat. Photon. 7, 977–981 (2013).
Yu, X. et al. 160 Gbit/s photonics wireless transmission in the 300–500 GHz band. APL Photon. 1, 081301 (2016).
Pang, X. et al. 260 Gbit/s photonic–wireless link in the THz band. In Proceedings of 2016 IEEE Photonics Conference (IPC) 9–10 (IEEE, 2016).
Beling, A. & Campbell, J. C. InP-based high-speed photodetectors. J. Lightwave Technol. 27, 343–355 (2009).
Kanno, A. et al. Coherent terahertz wireless signal transmission using advanced optical fiber communication technology. J. Infrared Millim. Terahertz Waves 36, 180–197 (2015).
Nagatsuma, T. et al. Terahertz wireless communications based on photonics technologies. Opt. Express 21, 23736 (2013).
Wang, C. et al. 0.34-THz wireless link based on high-order area network applications. IEEE Trans. Terahertz Sci. Technol. 4, 75–85 (2014).
Crowe, T. W. GaAs Schottky barrier mixer diodes for the frequency range 1–10 THz. Int. J. Infrared Millim. Waves 10, 765–777 (1989).
Harter, T. et al. 110-m THz wireless transmission at 100 Gbit/s using a Kramers–Kronig Schottky barrier diode receiver. In Proceedings of 44th European Conference on Optical Communication (ECOC’18) Th3F.7 (postdeadline paper) (IEEE, 2018).
Ummethala, S. et al. Terahertz-to-optical conversion using a plasmonic modulator. In Proceedings of Conference on Lasers and Electro-Optics STu3D.4 (Optical Society of America, 2018).
Ummethala, S. et al. Wireless transmission at 0.3 THz using direct THz-to-optical conversion at the receiver. In Proceedings of 44th European Conference on Optical Communication (ECOC’18) We4H.3 (Optical Society of America, 2018).
Melikyan, A. et al. High-speed plasmonic phase modulators. Nat. Photon. 8, 229–233 (2014).
Haffner, C. et al. All-plasmonic Mach–Zehnder modulator enabling optical high-speed communication at the microscale. Nat. Photon. 9, 525–528 (2015).
Salamin, Y. et al. Direct conversion of free space millimeter waves to optical domain by plasmonic modulator antenna. Nano Lett. 15, 8342–8346 (2015).
Melikyan, A. et al. Plasmonic–organic hybrid (POH) modulators for OOK and BPSK signaling at 40 Gbit/s. Opt. Express 23, 9938–9946 (2015).
Ayata, M. et al. High-speed plasmonic modulator in a single metal layer. Science 358, 630–632 (2017).
Haffner, C. et al. Low-loss plasmon-assisted electro-optic modulator. Nature 556, 483–486 (2018).
Hoessbacher, C. et al. Plasmonic modulator with >170 GHz bandwidth demonstrated at 100 GBd NRZ. Opt. Express 25, 1762–1768 (2017).
Macario, J. et al. Full spectrum millimeter-wave modulation. Opt. Express 20, 810–815 (2012).
Wang, C. et al. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages. Nature 562, 101–106 (2018).
Andrew, J. M. et al. Thin film lithium niobate electro-optic modulator with terahertz operating bandwidth. Opt. Express 26, 14810–14816 (2018).
Veronis, G. & Fan, S. Modes of subwavelength plasmonic slot waveguides. J. Lightwave Technol. 25, 2511–2521 (2007).
Veronis, G. & Fan, S. Guided subwavelength plasmonic mode supported by a slot in a thin metal film. Opt. Lett. 30, 3359–3361 (2005).
Pile, D. F. P., Gramotnev, D. K., Oulton, R. F. & Zhang, X. On long-range plasmonic modes in metallic gaps. Opt. Express 15, 13669 (2007).
Urbas, A. M. et al. Roadmap on silicon photonics. J. Opt. 18, 073003 (2016).
Atabaki, A. H. et al. Integrating photonics with silicon nanoelectronics for the next generation of systems on a chip. Nature 556, 349–354 (2018).
Pile, D. F. P. & Gramotnev, D. K. Adiabatic and nonadiabatic nanofocusing of plasmons by tapered gap plasmon waveguides. Appl. Phys. Lett. 89, 041111 (2006).
Enami, Y., Luo, J. & Jen, A. K. Y. Short hybrid polymer/sol-gel silica waveguide switches with high in-device electro-optic coefficient based on photostable chromophore. AIP Adv. 1, 042137 (2011).
Koos, C. et al. Silicon–organic hybrid (SOH) and plasmonic–organic hybrid (POH) integration. J. Lightwave Technol. 34, 256–268 (2016).
Shi, Y., Yan, L. & Willner, A. E. High-speed electrooptic modulator characterization using optical spectrum analysis. J. Lightwave Technol. 21, 2358–2367 (2003).
Naik, G. V., Shalaev, V. M. & Boltasseva, A. Alternative plasmonic materials: beyond gold and silver. Adv. Mater. 25, 3264–3294 (2013).
Haffner, C. et al. Harnessing nonlinearities near material absorption resonances for reducing losses in plasmonic modulators. Opt. Mater. Express 7, 2168–2181 (2017).
Kieninger, C. et al. Ultra-high electro-optic activity demonstrated in a silicon–organic hybrid (SOH) modulator. Optica 5, 739–748 (2018).
Chang, F., Onohara, K. & Mizuochi, T. Forward error correction for 100 G transport networks. IEEE Commun. Mag. 48, 48–55 (2010).
This work was supported by the European Research Council (ERC Consolidator Grant ‘TeraSHAPE’, no. 773248), the DFG project PACE (no. 403188360) within the Priority Programme ‘Electronic–Photonic Integrated Systems for Ultrafast Signal Processing’ (SPP 2111), the BMBF project SPIDER (no. 01DR18014A), the Alfried Krupp von Bohlen und Halbach Foundation, the Helmholtz International Research School of Teratronics (HIRST) and the Karlsruhe Nano Micro Facility (KNMF). We also thank J. Luo and A.K.-Y. Jen from Soluxra for providing the organic EO material.
The authors declare no competing interests.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Ummethala, S., Harter, T., Koehnle, K. et al. THz-to-optical conversion in wireless communications using an ultra-broadband plasmonic modulator. Nat. Photonics 13, 519–524 (2019). https://doi.org/10.1038/s41566-019-0475-6
Nature Photonics (2021)
Systematic study of the structure-property relationship of a series of near-infrared absorbing push-pull heptamethine chromophores for electro-optics
Science China Chemistry (2021)
La Rivista del Nuovo Cimento (2021)
High-temperature-resistant silicon-polymer hybrid modulator operating at up to 200 Gbit s−1 for energy-efficient datacentres and harsh-environment applications
Nature Communications (2020)
Communications Physics (2020)