Article | Published:

Silicon–plasmonic integrated circuits for terahertz signal generation and coherent detection

Nature Photonicsvolume 12pages625633 (2018) | Download Citation


Optoelectronic signal processing offers great potential for generation and detection of ultra-broadband waveforms in the terahertz range (so-called T-waves). However, fabrication of the underlying devices still relies on complex processes using dedicated III–V semiconductor substrates. This severely restricts the application potential of current T-wave transmitters and receivers and impedes co-integration of these devices with advanced photonic signal processing circuits. Here, we demonstrate that these limitations can be overcome by plasmonic internal-photoemission detectors (PIPEDs). PIPEDs can be realized on the silicon photonic platform, which allows exploiting the enormous opportunities of the associated device portfolio. In our experiments, we demonstrate both T-wave signal generation and coherent detection at frequencies up to 1 THz. To prove the viability of our concept, we monolithically integrate PIPED transmitters and receivers on a common silicon chip and use them to measure the complex transfer impedance of an integrated T-wave device.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Additional information

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


  1. 1.

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

  2. 2.

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

  3. 3.

    Ma, J., Karl, N. J., Bretin, S., Ducournau, G. & Mittleman, D. M. Frequency-division multiplexer and demultiplexer for terahertz wireless links. Nat. Commun. 8, 729 (2017).

  4. 4.

    Capmany, J. & Novak, D. Microwave photonics combines two worlds. Nat. Photon. 1, 319–330 (2007).

  5. 5.

    Krügener, K. et al. Terahertz meets sculptural and architectural art: evaluation and conservation of stone objects with T-ray technology. Sci. Rep. 5, 14842 (2015).

  6. 6.

    Shalit, A., Ahmed, S., Savolainen, J. & Hamm, P. Terahertz echoes reveal the inhomogeneity of aqueous salt solutions. Nat. Chem. 9, 273–278 (2016).

  7. 7.

    Tonouchi, M. Cutting-edge terahertz technology. Nat. Photon. 1, 97–105 (2007).

  8. 8.

    Fan, S., He, Y., Ung, B. S. & Pickwell-MacPherson, E. The growth of biomedical terahertz research. J. Phys. D 47, 374009 (2014).

  9. 9.

    Stantchev, R. I. et al. Noninvasive, near-field terahertz imaging of hidden objects using a single-pixel detector. Sci. Adv. 2, e1600190 (2016).

  10. 10.

    Naftaly, M., Clarke, R. G., Humphreys, D. A. & Ridler, N. M. Metrology state-of-the-art and challenges in broadband phase-sensitive terahertz measurements. Proc. IEEE 105, 1151–1165 (2017).

  11. 11.

    Brown, E. R., McIntosh, K. A., Nichols, K. B. & Dennis, C. L. Photomixing up to 3.8 THz in low‐temperature‐grown GaAs. Appl. Phys. Lett. 66, 285–287 (1995).

  12. 12.

    Preu, S., Döhler, G. H., Malzer, S., Wang, L. J. & Gossard, A. C. Tunable, continuous-wave terahertz photomixer sources and applications. J. Appl. Phys. 109, 061301 (2011).

  13. 13.

    Göbel, T. et al. Telecom technology based continuous wave terahertz photomixing system with 105 decibel signal-to-noise ratio and 3.5 terahertz bandwidth. Opt. Lett. 38, 4197–4199 (2013).

  14. 14.

    Sartorius, B., Stanze, D., Göbel, T., Schmidt, D., & Schell, M. Continuous wave terahertz systems based on 1.5 μm telecom technologies. J. Infrared Millim. Terahertz Waves 33, 405–417 (2011).

  15. 15.

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

  16. 16.

    Puerta, R. et al. Single-carrier dual-polarization 328-Gb/s wireless transmission in a D-band millimeter wave 2×2 MU-MIMO radio-over-fiber system. J. Lightwave Technol. 36, 587–593 (2018).

  17. 17.

    Hsieh, Y.-D. et al. Terahertz frequency-domain spectroscopy of low-pressure acetonitrile gas by a photomixing terahertz synthesizer referenced to dual optical frequency combs. J. Infrared Millim. Terahertz Waves 37, 903–915 (2016).

  18. 18.

    Hisatake, S., Koda, Y., Nakamura, R., Hamada, N. & Nagatsuma, T. Terahertz balanced self-heterodyne spectrometer with SNR-limited phase-measurement sensitivity. Opt. Express 23, 26689–26695 (2015).

  19. 19.

    Harter, T. et al. Wireless multi-subcarrier THz communications using mixing in a photoconductor for coherent reception. In 2017 IEEE Photonics Conference (IPC) 147–148 (IEEE, 2017).

  20. 20.

    Ishibashi, T., Muramoto, Y., Yoshimatsu, T. & Ito, H. Unitraveling-carrier photodiodes for terahertz applications. IEEE J. Sel. Top. Quantum Electron. 20, 79–88 (2014).

  21. 21.

    Song, H.-J. et al. Uni-travelling-carrier photodiode module generating 300 GHz power greater than 1 mW. IEEE Microw. Wireless Compon. Lett. 22, 363–365 (2012).

  22. 22.

    Beling, A., Xie, X. & Campbell, J. C. High-power, high-linearity photodiodes. Optica 3, 328–338 (2016).

  23. 23.

    Berry, C. W. et al. High power terahertz generation using 1550 nm plasmonic photomixers. Appl. Phys. Lett. 105, 011121 (2014).

  24. 24.

    Olvera, A. D. J. F., Lu, H., Gossard, A. C. & Preu, S. Continuous-wave 1550 nm operated terahertz system using ErAs:In(Al)GaAs photo-conductors with 52 dB dynamic range at 1 THz. Opt. Express 25, 29492–29500 (2017).

  25. 25.

    Thomson, D. et al. Roadmap on silicon photonics. J. Opt. 18, 073003 (2016).

  26. 26.

    Vivien, L. & Pavesi, L. (eds) Handbook of Silicon Photonics (CRC Press, Boca Raton, FL, 2013).

  27. 27.

    Bogaerts, W. et al. Nanophotonic waveguides in silicon-on-insulator fabricated with CMOS technology. J. Lightwave Technol. 23, 401–412 (2005).

  28. 28.

    Muehlbrandt, S. et al. Silicon–plasmonic internal-photoemission detector for 40 Gbit/s data reception. Optica 3, 741–747 (2016).

  29. 29.

    Harter, T. et al. Silicon-plasmonic photomixer for generation and homodyne reception of continuous-wave THz radiation. In Conference on Lasers and Electro-Optics SM4E.5 (OSA, 2016).

  30. 30.

    Pfeifle, J., Alloatti, L., Freude, W., Leuthold, J. & Koos, C. Silicon–organic hybrid phase shifter based on a slot waveguide with a liquid-crystal cladding. Opt. Express 20, 15359–15376 (2012).

  31. 31.

    Harris, N. C. et al. Efficient, compact and low loss thermo-optic phase shifter in silicon. Opt. Express 22, 10487–10493 (2014).

  32. 32.

    Kim, J.-Y. et al. Compact and stable THz vector spectroscopy using silicon photonics technology. Opt. Express 22, 7178–7185 (2014).

  33. 33.

    Reed, G. T., Mashanovich, G., Gardes, F. Y. & Thomson, D. J. Silicon optical modulators. Nat. Photon. 4, 518–526 (2010).

  34. 34.

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

  35. 35.

    Hiraki, T. et al. Heterogeneously integrated III–V/Si MOS capacitor Mach–Zehnder modulator. Nat. Photon. 11, 482–485 (2017).

  36. 36.

    Timurdogan, E. et al. An ultralow power athermal silicon modulator. Nat. Commun. 5, 4008 (2014).

  37. 37.

    Billah, M. R. et al. Hybrid integration of silicon photonics circuits and InP lasers by photonic wire bonding. Optica 5, 876–883 (2018).

  38. 38.

    Quay, R. et al. High-power microwaveGaN/AlGaN HEMTs and MMICs on SiC and silicon substrates for modern radio communication. Phys. Status Solidi 215, 1700655 (2018).

  39. 39.

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

  40. 40.

    Canali, C., Majni, G., Minder, R. & Ottaviani, G. Electron and hole drift velocity measurements in silicon and their empirical relation to electric field and temperature. IEEE Trans. Electron. Devices 22, 1045–1047 (1975).

  41. 41.

    Bowers, J. & Burrus, C. Ultrawide-band long-wavelength p–i–n photodetectors. J. Lightwave Technol. 5, 1339–1350 (1987).

  42. 42.

    Renaud, C. C. et al. Antenna integrated THz uni-traveling carrier photodiodes. IEEE J. Sel. Top. Quantum Electron. 24, 8500111 (2018).

  43. 43.

    Latzel, P. et al. Generation of mW Level in the 300-GHz band using resonant-cavity-enhanced unitraveling carrier photodiodes. IEEE Trans. Terahertz Sci. Technol. 7, 800–807 (2017).

  44. 44.

    Rouvalis, E., Fice, M. J., Renaud, C. C. & Seeds, A. J. Millimeter-wave optoelectronic mixers based on uni-traveling carrier photodiodes. IEEE Trans. Microw. Theory Tech. 60, 686–691 (2012).

  45. 45.

    Hisatake, S., Kim, J.-Y., Ajito, K. & Nagatsuma, T. Self-heterodyne spectrometer using uni-traveling-carrier photodiodes for terahertz-wave generators and optoelectronic mixers. J. Lightwave Technol. 32, 3683–3689 (2014).

  46. 46.

    Berry, C. W., Wang, N., Hashemi, M. R., Unlu, M. & Jarrahi, M. Significant performance enhancement in photoconductive terahertz optoelectronics by incorporating plasmonic contact electrodes. Nat. Commun. 4, 1622 (2013).

  47. 47.

    Dietz, R. J. B. et al. Influence and adjustment of carrier lifetimes in InGaAs/InAlAs photoconductive pulsed terahertz detectors: 6 THz bandwidth and 90 dB dynamic range. Opt. Express 22, 19411–19422 (2014).

  48. 48.

    van Dijk, F. et al. Integrated InP heterodyne millimeter wave transmitter. IEEE Photon. Technol. Lett. 26, 965–968 (2014).

  49. 49.

    Ponnampalam, L. et al. Monolithically integrated photonic heterodyne system. J. Lightwave Technol. 29, 2229–2234 (2011).

  50. 50.

    Vallaitis, T. et al. Optical properties of highly nonlinear silicon–organic hybrid (SOH) waveguide geometries. Opt. Express 17, 17357–17368 (2009).

  51. 51.

    Roggenbuck, A. et al. Coherent broadband continuous-wave terahertz spectroscopy on solid-state samples. New J. Phys. 12, 043017 (2010).

Download references


This work was supported by the European Research Council (ERC Starting Grant ‘EnTeraPIC’, no. 280145; ERC Consolidator Grant ‘TeraSHAPE’, no. 773248), by the Alfried Krupp von Bohlen und Halbach Foundation, by the Helmholtz International Research School of Teratronics (HIRST), by the Karlsruhe School of Optics and Photonics (KSOP) and by the Karlsruhe Nano Micro Facility (KNMF).

Author information


  1. Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

    • T. Harter
    • , S. Muehlbrandt
    • , S. Ummethala
    • , A. Schmid
    • , W. Freude
    •  & C. Koos
  2. Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany

    • T. Harter
    • , S. Muehlbrandt
    • , S. Ummethala
    • , L. Hahn
    •  & C. Koos
  3. Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute (HHI), Berlin, Germany

    • S. Nellen


  1. Search for T. Harter in:

  2. Search for S. Muehlbrandt in:

  3. Search for S. Ummethala in:

  4. Search for A. Schmid in:

  5. Search for S. Nellen in:

  6. Search for L. Hahn in:

  7. Search for W. Freude in:

  8. Search for C. Koos in:


T.H., S.M., W.F. and C.K. developed the idea. T.H., S.M., S.U. and L.H. contributed to the fabrication of the devices. T.H., S.M., W.F. and C.K. developed the mathematical formulation. T.H., S.M. and A.S. conducted the measurements. T.H. and S.N. performed experiments to calibrate the reference Tx and Rx. T.H. performed electromagnetic simulations. W.F. and C.K. supervised the project. T.H., W.F. and C.K. wrote the paper. All authors revised the paper.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to T. Harter or C. Koos.

Supplementary information

  1. Supplementary Information

    Supplementary notes and figures.

About this article

Publication history





Further reading