Letter | Published:

All-optical high-speed signal processing with silicon–organic hybrid slot waveguides

Nature Photonics volume 3, pages 216219 (2009) | Download Citation



Integrated optical circuits based on silicon-on-insulator technology are likely to become the mainstay of the photonics industry. Over recent years an impressive range of silicon-on-insulator devices has been realized, including waveguides1,2, filters3,4 and photonic-crystal devices5. However, silicon-based all-optical switching is still challenging owing to the slow dynamics of two-photon generated free carriers. Here we show that silicon–organic hybrid integration overcomes such intrinsic limitations by combining the best of two worlds, using mature CMOS processing to fabricate the waveguide, and molecular beam deposition to cover it with organic molecules that efficiently mediate all-optical interaction without introducing significant absorption. We fabricate a 4-mm-long silicon–organic hybrid waveguide with a record nonlinearity coefficient of γ ≈ 1 × 105 W−1 km−1 and perform all-optical demultiplexing of 170.8 Gb s−1 to 42.7 Gb s−1. This is—to the best of our knowledge—the fastest silicon photonic optical signal processing demonstrated.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    et al. Microphotonics devices based on silicon microfabrication technology. IEEE J. Sel. Top. Quantum Electron. 11, 232–240 (2005).

  2. 2.

    Guiding, modulating, and emitting light on silicon—challenges and opportunities. J. Lightwave Technol. 23, 4222–4238 (2005).

  3. 3.

    et al. Hitless-reconfigurable and bandwidth-scalable silicon photonic circuits for telecom and interconnect applications. Optical Fiber Communincation Conference (OFC'08), paper OTuF4 (OSA, 2008).

  4. 4.

    et al. Compact wavelength-selective functions in silicon-on-insulator photonic wires. IEEE J. Sel. Top. Quantum Electron. 12, 1394–1401 (2006).

  5. 5.

    , , & Active control of slow light on a chip with photonic crystal waveguides. Nature 438, 65–69 (2005).

  6. 6.

    et al. Low-threshold continuous-wave Raman silicon laser. Nature Photon. 1, 232–237 (2007).

  7. 7.

    et al. Raman amplification in ultrasmall silicon-on-insulator wire waveguides. Opt. Express 12, 3713–3718 (2004).

  8. 8.

    et al. A hybrid AlGaInAs–silicon evanescent amplifier. IEEE Photon. Technol. Lett. 19, 230–232 (2007).

  9. 9.

    et al. Electrically pumped hybrid AlGaInAs–silicon evanescent laser. Opt. Express 14, 9203–9210 (2006).

  10. 10.

    et al. A photonic interconnect layer on CMOS. European Conference on Optical Communications (ECOC'07), paper 6.3.1 (2007).

  11. 11.

    , , & Mode-locked silicon evanescent lasers. Opt. Express 15, 11225–11233 (2007).

  12. 12.

    et al. A hybrid AlGaInAs–silicon evanescent waveguide photodetector. Opt. Express 15, 6044–6052 (2007).

  13. 13.

    et al. 40 Gbit/s silicon optical modulator for high-speed applications. Electron. Lett. 43, 1196–1197 (2007).

  14. 14.

    et al. Signal regeneration using low-power four-wave mixing on silicon chip. Nature Photon. 2, 35–38 (2008).

  15. 15.

    et al. Demonstration of wavelength conversion at 40 Gb/s data rate in silicon waveguides. Opt. Express 14, 11721–11726 (2006).

  16. 16.

    et al. Terahertz all-optical modulation in a silicon-polymer hybrid system. Nature Mater. 5, 703–709 (2006).

  17. 17.

    , , , & Nonlinear silicon-on-insulator waveguides for all-optical signal processing. Opt. Express 15, 5976–5990 (2007).

  18. 18.

    et al. Optical modulation and detection in slotted silicon waveguides. Opt. Express 13, 5216–5226 (2005).

  19. 19.

    et al. Towards a millivolt optical modulator with nano-slot waveguides. Opt. Express, 15, 8401–8410 (2007).

  20. 20.

    et al. High-speed low-voltage electro-optic modulator with a polymer-infiltrated silicon photonic crystal waveguide. Opt. Express 16, 4177–4191 (2008).

  21. 21.

    and Polymer silicon hybrid systems: A platform for practical nonlinear optics. J. Phys. Chem. C 112, 8085–8090 (2008).

  22. 22.

    , , & Guiding and confining light in void nanostructure. Opt. Lett. 29, 1209–1211 (2004).

  23. 23.

    et al. A high optical quality supramolecular assembly for third-order integrated nonlinear optics. Adv. Mater. 20, 4584–4587 (2008).

  24. 24.

    et al. A new class of organic donor–acceptor molecules with large third-order optical nonlinearities. Chem. Commun. 737–739 (2005).

  25. 25.

    , , & Extended conjugation and donor–acceptor substitution to improve the third-order optical nonlinearity of small molecules. Appl. Phys. Lett. 90, 251106 (2007).

  26. 26.

    et al. Highly-nonlinear silicon photonics slot waveguide. Optical Fiber Communications Conference (OFC'08), postdeadline paper PDP25 (2008).

  27. 27.

    et al. A lead silicate holey fiber with γ = 1860 W−1 km−1 at 1550 nm. Optical Fiber Communications Conference (OFC'05), postdeadline paper PDP22 (2005).

  28. 28.

    et al. Enhanced Kerr nonlinearity in sub-wavelength diameter As2Se3 chalcogenide fiber tapers. Opt. Express 15, 10324–10329 (2007).

  29. 29.

    et al. Slow and fast dynamics of gain and phase in a quantum dot semiconductor optical amplifier. Opt. Express 16, 170–178 (2008).

  30. 30.

    et al. Highly nonlinear silicon photonic slot waveguides without free carrier absorption related speed-limitations. Proc. 34rd European Conference on Optical Communication (ECOC'08), paper Th.2.D.6 (2008).

Download references


This work was supported in part by the DFG (German Research Foundation) Center for Functional Nanostructures (CFN), by the Initiative of Excellence of the University of Karlsruhe within a Feasibility Study of Young Scientists (FYS), the Karlsruhe School of Optics, and by the European project TRIUMPH (Transparent Ring Interconnection Using Multi-wavelength PHotonic switches, grant IST-027638 STP). We acknowledge support by the European Network of Excellence ePIXnet, including fabrication by ePIXfab (www.epixfab.eu), and by ASML Netherlands B.V., and we acknowledge equipment loan from Siemens Portugal and from Optoelectronics Research Centre (ORC) in Southampton, UK. I.B. and B.E. acknowledge partial support from the Commonwealth of Pennsylvania, Ben Franklin Technology Development Authority. F.D. and T.M. acknowledge support from the ETH research council.

Author information

Author notes

    • C. Koos

    Present address: Carl Zeiss AG, Corporate Research and Technology, 73447 Oberkochen, Germany


  1. Institute of Photonics and Quantum Electronics, University of Karlsruhe, 76131 Karlsruhe, Germany

    • C. Koos
    • , P. Vorreau
    • , T. Vallaitis
    • , W. Freude
    •  & J. Leuthold
  2. Photonics Research Group, Ghent University – IMEC, B-9000 Gent, Belgium

    • P. Dumon
    • , W. Bogaerts
    •  & R. Baets
  3. Department of Physics and Center for Optical Technologies, Lehigh University, Bethlehem, Pennsylvania 18015, USA

    • B. Esembeson
    •  & I. Biaggio
  4. Laboratorium für Organische Chemie, ETH Zürich, Hönggerberg, HCI, CH-8093 Zürich, Switzerland

    • T. Michinobu
    •  & F. Diederich


  1. Search for C. Koos in:

  2. Search for P. Vorreau in:

  3. Search for T. Vallaitis in:

  4. Search for P. Dumon in:

  5. Search for W. Bogaerts in:

  6. Search for R. Baets in:

  7. Search for B. Esembeson in:

  8. Search for I. Biaggio in:

  9. Search for T. Michinobu in:

  10. Search for F. Diederich in:

  11. Search for W. Freude in:

  12. Search for J. Leuthold in:

Corresponding authors

Correspondence to W. Freude or J. Leuthold.

About this article

Publication history






Further reading