Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

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

Abstract

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.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Seamless integration of THz wireless links into fibre-optic infrastructures by direct O/T and T/O conversion.
Fig. 2: Bandwidth measurement of POH modulator.
Fig. 3: Demonstration of THz wireless data transmission using direct O/T and T/O conversion.

Data availability

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.

References

  1. 1.

    Nagatsuma, T., Ducournau, G. & Renaud, C. C. Advances in terahertz communications accelerated by photonics. Nat. Photon. 10, 371–379 (2016).

    ADS  Article  Google Scholar 

  2. 2.

    Kürner, T. & Priebe, S. Towards THz communications—status in research, standardization and regulation. J. Infrared Millim. Terahertz Waves 35, 53–62 (2014).

    Article  Google Scholar 

  3. 3.

    Seeds, A. J., Shams, H., Fice, M. J. & Renaud, C. C. Terahertz photonics for wireless communications. J. Lightwave Technol. 33, 579–587 (2015).

    ADS  Article  Google Scholar 

  4. 4.

    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

  5. 5.

    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).

    Google Scholar 

  6. 6.

    Koenig, S. et al. Wireless sub-THz communication system with high data rate. Nat. Photon. 7, 977–981 (2013).

    ADS  Article  Google Scholar 

  7. 7.

    Yu, X. et al. 160 Gbit/s photonics wireless transmission in the 300–500 GHz band. APL Photon. 1, 081301 (2016).

    ADS  Article  Google Scholar 

  8. 8.

    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).

  9. 9.

    Beling, A. & Campbell, J. C. InP-based high-speed photodetectors. J. Lightwave Technol. 27, 343–355 (2009).

    ADS  Article  Google Scholar 

  10. 10.

    Kanno, A. et al. Coherent terahertz wireless signal transmission using advanced optical fiber communication technology. J. Infrared Millim. Terahertz Waves 36, 180–197 (2015).

    Article  Google Scholar 

  11. 11.

    Nagatsuma, T. et al. Terahertz wireless communications based on photonics technologies. Opt. Express 21, 23736 (2013).

    ADS  Article  Google Scholar 

  12. 12.

    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).

    ADS  Article  Google Scholar 

  13. 13.

    Crowe, T. W. GaAs Schottky barrier mixer diodes for the frequency range 1–10 THz. Int. J. Infrared Millim. Waves 10, 765–777 (1989).

    ADS  Article  Google Scholar 

  14. 14.

    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).

  15. 15.

    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).

  16. 16.

    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).

  17. 17.

    Melikyan, A. et al. High-speed plasmonic phase modulators. Nat. Photon. 8, 229–233 (2014).

    ADS  Article  Google Scholar 

  18. 18.

    Haffner, C. et al. All-plasmonic Mach–Zehnder modulator enabling optical high-speed communication at the microscale. Nat. Photon. 9, 525–528 (2015).

    ADS  Article  Google Scholar 

  19. 19.

    Salamin, Y. et al. Direct conversion of free space millimeter waves to optical domain by plasmonic modulator antenna. Nano Lett. 15, 8342–8346 (2015).

    ADS  Article  Google Scholar 

  20. 20.

    Melikyan, A. et al. Plasmonic–organic hybrid (POH) modulators for OOK and BPSK signaling at 40 Gbit/s. Opt. Express 23, 9938–9946 (2015).

    ADS  Article  Google Scholar 

  21. 21.

    Ayata, M. et al. High-speed plasmonic modulator in a single metal layer. Science 358, 630–632 (2017).

    ADS  Article  Google Scholar 

  22. 22.

    Haffner, C. et al. Low-loss plasmon-assisted electro-optic modulator. Nature 556, 483–486 (2018).

    ADS  Article  Google Scholar 

  23. 23.

    Hoessbacher, C. et al. Plasmonic modulator with >170 GHz bandwidth demonstrated at 100 GBd NRZ. Opt. Express 25, 1762–1768 (2017).

    ADS  Article  Google Scholar 

  24. 24.

    Macario, J. et al. Full spectrum millimeter-wave modulation. Opt. Express 20, 810–815 (2012).

    Article  Google Scholar 

  25. 25.

    Wang, C. et al. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages. Nature 562, 101–106 (2018).

    ADS  Article  Google Scholar 

  26. 26.

    Andrew, J. M. et al. Thin film lithium niobate electro-optic modulator with terahertz operating bandwidth. Opt. Express 26, 14810–14816 (2018).

    Article  Google Scholar 

  27. 27.

    Veronis, G. & Fan, S. Modes of subwavelength plasmonic slot waveguides. J. Lightwave Technol. 25, 2511–2521 (2007).

    ADS  Article  Google Scholar 

  28. 28.

    Veronis, G. & Fan, S. Guided subwavelength plasmonic mode supported by a slot in a thin metal film. Opt. Lett. 30, 3359–3361 (2005).

    ADS  Article  Google Scholar 

  29. 29.

    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).

    ADS  Article  Google Scholar 

  30. 30.

    Urbas, A. M. et al. Roadmap on silicon photonics. J. Opt. 18, 073003 (2016).

    Article  Google Scholar 

  31. 31.

    Atabaki, A. H. et al. Integrating photonics with silicon nanoelectronics for the next generation of systems on a chip. Nature 556, 349–354 (2018).

    ADS  Article  Google Scholar 

  32. 32.

    Pile, D. F. P. & Gramotnev, D. K. Adiabatic and nonadiabatic nanofocusing of plasmons by tapered gap plasmon waveguides. Appl. Phys. Lett. 89, 041111 (2006).

    ADS  Article  Google Scholar 

  33. 33.

    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).

    ADS  Article  Google Scholar 

  34. 34.

    Koos, C. et al. Silicon–organic hybrid (SOH) and plasmonic–organic hybrid (POH) integration. J. Lightwave Technol. 34, 256–268 (2016).

    ADS  Article  Google Scholar 

  35. 35.

    Shi, Y., Yan, L. & Willner, A. E. High-speed electrooptic modulator characterization using optical spectrum analysis. J. Lightwave Technol. 21, 2358–2367 (2003).

    ADS  Article  Google Scholar 

  36. 36.

    Naik, G. V., Shalaev, V. M. & Boltasseva, A. Alternative plasmonic materials: beyond gold and silver. Adv. Mater. 25, 3264–3294 (2013).

    Article  Google Scholar 

  37. 37.

    Haffner, C. et al. Harnessing nonlinearities near material absorption resonances for reducing losses in plasmonic modulators. Opt. Mater. Express 7, 2168–2181 (2017).

    ADS  Article  Google Scholar 

  38. 38.

    Kieninger, C. et al. Ultra-high electro-optic activity demonstrated in a silicon–organic hybrid (SOH) modulator. Optica 5, 739–748 (2018).

    Article  Google Scholar 

  39. 39.

    Chang, F., Onohara, K. & Mizuochi, T. Forward error correction for 100 G transport networks. IEEE Commun. Mag. 48, 48–55 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

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.

Author information

Affiliations

Authors

Contributions

S.U., T.H., W.F. and C.K. developed the concept and designed the experiment. S.U. and Z.L. designed the modulators and fabricated them with support from K.K., S.M., S.K.G., A.B. and L.H. S.U. and J.S. characterized the devices. S.U. and T.H. performed the transmission experiments and analysed the data together with J.K. and P.M.-P. Y.K. developed the poling procedure for the POH modulators and formulated the organic EO material. A.T. and M.W. developed and provided the THz MMIC amplifiers. The work was supervised jointly by T.Z., S.R., W.F. and C.K. S.U., W.F. and C.K. wrote the paper. All authors revised the paper.

Corresponding authors

Correspondence to S. Ummethala or C. Koos.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary data, analysis and discussion, Supplementary Figs. 1–8 and Supplementary references 1–25.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

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

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing