High-performance hybrid silicon and lithium niobate Mach–Zehnder modulators for 100 Gbit s−1 and beyond

Article metrics


Optical modulators are at the heart of optical communication links. Ideally, they should feature low loss, low drive voltage, large bandwidth, high linearity, compact footprint and low manufacturing cost. Unfortunately, these criteria have been achieved only on separate occasions. Based on a silicon and lithium niobate hybrid integration platform, we demonstrate Mach–Zehnder modulators that simultaneously fulfil these criteria. The presented device exhibits an insertion loss of 2.5 dB, voltage–length product of 2.2 V cm in single-drive push–pull operation, high linearity, electro-optic bandwidth of at least 70 GHz and modulation rates up to 112 Gbit s−1. The high-performance modulator is realized by seamless integration of a high-contrast waveguide based on lithium niobate—a popular modulator material—with compact, low-loss silicon circuitry. The hybrid platform demonstrated here allows for the combination of ‘best-in-breed’ active and passive components, opening up new avenues for future high-speed, energy-efficient and cost-effective optical communication networks.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Structure of the hybrid Si/LN MZM.
Fig. 2: Static EO performance.
Fig. 3: EO bandwidth and linearity.
Fig. 4: Data transmission testing.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. 1.

    Cisco Cisco Visual Networking Index: Forecast and Methodology 2015–2020 (Cisco, 2016).

  2. 2.

    Tkach, R. W. Scaling optical communications for the next decade and beyond. Bell Labs Tech. J. 14, 3–10 (2010).

  3. 3.

    Kilper, D. C. & Rastegarfar, H. Energy challenges in optical access and aggregation networks. Phil. Trans. R. Soc. A. 374, 20140435 (2016).

  4. 4.

    Miller, D. Device requirements for optical interconnects to CMOS silicon chips. In Photonics in Switching PMB3 (OSA, 2010).

  5. 5.

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

  6. 6.

    Heck, M. J. et al. Hybrid silicon photonics for optical interconnects. IEEE J. Sel. Top. Quantum Electron. 17, 333–346 (2011).

  7. 7.

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

  8. 8.

    Sun, C. et al. Single-chip microprocessor that communicates directly using light. Nature 528, 534–538 (2015).

  9. 9.

    Xu, Q., Schmidt, B., Pradhan, S. & Lipson, M. J. Micrometre-scale silicon electro-optic modulator. Nature 435, 325–327 (2005).

  10. 10.

    Li, M. et al. Silicon intensity Mach–Zehnder modulator for single lane 100 Gb/s applications. Photon. Res. 6, 109–116 (2018).

  11. 11.

    Ding, R. et al. High-speed silicon modulator with slow-wave electrodes and fully independent differential drive. J. Lightwave Technol. 32, 2240–2247 (2014).

  12. 12.

    Dong, P. et al. Monolithic silicon photonic integrated circuits for compact 100+ Gb/s coherent optical receivers and transmitters. IEEE J. Sel. Top. Quantum Electron. 20, 150–157 (2014).

  13. 13.

    Samani, A. et al. Experimental parametric study of 128 Gb/s PAM-4 transmission system using a multi-electrode silicon photonic Mach Zehnder modulator. Opt. Express 25, 13252–13262 (2017).

  14. 14.

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

  15. 15.

    Xiong, C. et al. Aluminum nitride as a new material for chip-scale optomechanics and nonlinear optics. New J. Phys. 14, 20 (2012).

  16. 16.

    Zhang, C. et al. Ultralinear heterogeneously integrated ring-assisted Mach–Zehnder interferometer modulator on silicon. Optica 3, 1483–1488 (2016).

  17. 17.

    Tang, Y. et al. 50 Gb/s hybrid silicon traveling-wave electroabsorption modulator. Opt. Express 19, 5811–5816 (2011).

  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).

  19. 19.

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

  20. 20.

    Alloatti, L. et al. 100 GHz silicon–organic hybrid modulator. Light Sci. Appl. 3, e173 (2014).

  21. 21.

    Lee, M. et al. Broadband modulation of light by using an electro-optic polymer. Science 298, 1401–1403 (2002).

  22. 22.

    Han, J.-H. et al. Efficient low-loss InGaAsP/Si hybrid MOS optical modulator. Nat. Photon. 11, 486–490 (2017).

  23. 23.

    Kikuchi, N., Yamada, E., Shibata, Y. & Ishii, H. High-speed InP-based Mach–Zehnder modulator for advanced modulation formats. In Compound Semiconductor Integrated Circuit Symposium (CSICS) 1–4 (IEEE, 2012).

  24. 24.

    Phare, C. T., Lee, Y. H. D., Cardenas, J. & Lipson, M. Graphene electro-optic modulator with 30 GHz bandwidth. Nat. Photon. 9, 511–514 (2015).

  25. 25.

    Liu, M. et al. A graphene-based broadband optical modulator. Nature 474, 64–67 (2011).

  26. 26.

    Sorianello, V. et al. Graphene–silicon phase modulators with gigahertz bandwidth. Nat. Photon. 12, 40–44 (2018).

  27. 27.

    Chen, A. Broadband Optical Modulators: Science, Technology, and Applications (CRC Press, 2011).

  28. 28.

    Wooten, E. L. et al. A review of lithium niobate modulators for fiber-optic communications systems. IEEE J. Sel. Top. Quantum Electron 6, 69–82 (2000).

  29. 29.

    Raybon, G. et al. Single carrier high symbol rate transmitter for data rates up to 1.0 Tb/s. In Optical Fiber Communication Conference Th3A.2 (OSA, 2016).

  30. 30.

    Janner, D., Tulli, D., García-Granda, M., Belmonte, M. & Pruneri, V. Micro-structured integrated electro-optic LiNbO3 modulators. Laser Photon. Rev. 3, 301–313 (2009).

  31. 31.

    Poberaj, G., Hu, H., Sohler, W. & Günter, P. Lithium niobate on insulator (LNOI) for micro-photonic devices. Laser Photon. Rev. 6, 488–503 (2012).

  32. 32.

    Guarino, A., Poberaj, G., Rezzonico, D., Degl’Innocenti, R. & Günter, P. Electro–optically tunable microring resonators in lithium niobate. Nat. Photon. 1, 407–410 (2007).

  33. 33.

    Jin, S., Xu, L., Zhang, H. & Li, Y. LiNbO3 thin-film modulators using silicon nitride surface ridge waveguides. IEEE Photon. Technol. Lett. 28, 736–739 (2016).

  34. 34.

    Rao, A. et al. High-performance and linear thin-film lithium niobate Mach–Zehnder modulators on silicon up to 50 GHz. Opt. Lett. 41, 5700–5703 (2016).

  35. 35.

    Wang, J. et al. High-Q lithium niobate microdisk resonators on a chip for efficient electro-optic modulation. Opt. Exp. 23, 23072–23078 (2015).

  36. 36.

    Cai, L., Kang, Y. & Hu, H. Electric-optical property of the proton exchanged phase modulator in single-crystal lithium niobate thin film. Opt. Exp. 24, 4640–4647 (2016).

  37. 37.

    Chang, L. et al. Thin film wavelength converters for photonic integrated circuits. Optica 3, 531–535 (2016).

  38. 38.

    Chang, L. et al. Heterogeneous integration of lithium niobate and silicon nitride waveguides for wafer-scale photonic integrated circuits on silicon. Opt. Lett. 42, 803–806 (2017).

  39. 39.

    Wang, C. et al. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages. Nature 562, 101–104 (2018).

  40. 40.

    Boes, A., Corcoran, B., Chang, L., Bowers, J. & Mitchell, A. Status and potential of lithium niobate on insulator (LNOI) for photonic integrated circuits. Laser Photon. Rev. 12, 1700256 (2018).

  41. 41.

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

  42. 42.

    Rao, A. & Fathpour, S. Compact lithium niobate electrooptic modulators. IEEE J. Sel. Top. Quantum Electron. 24, 1–14 (2018).

  43. 43.

    Chen, L., Xu, Q., Wood, M. G. & Reano, R. M. Hybrid silicon and lithium niobate electro-optical ring modulator. Optica 1, 112–118 (2014).

  44. 44.

    Weigel, P. O. et al. Bonded thin film lithium niobate modulator on a silicon photonics platform exceeding 100 GHz 3-dB electrical modulation bandwidth. Opt. Exp. 26, 23728–23739 (2018).

  45. 45.

    QSFP-DD Hardware Specification for QSFP Double Density 8X Pluggable Transceiver Rev. 4.0 (QSFP-DD MSA, 2018); http://www.qsfp-dd.com/wp-content/uploads/2018/09/QSFP-DD-Hardware-rev4p0-9-12-18-clean.

  46. 46.

    Kok, P. et al. Linear optical quantum computing with photonic qubits. Rev. Mod. Phys. 79, 135–174 (2007).

  47. 47.

    Wolf, S. et al. Silicon-organic hybrid (SOH) Mach–Zehnder modulators for 100 Gbit/s on–off keying. Sci. Rep. 8, 2598 (2018).

  48. 48.

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

  49. 49.

    Messner, A. et al. Integrated ferroelectric BaTiO3/Si plasmonic modulator for 100 Gbit/s and beyond. In Optical Fiber Communication Conference M2I.6 (OSA, 2018).

  50. 50.

    Xiong, C. et al. Active silicon integrated nanophotonics: ferroelectric BaTiO3 devices. Nano Lett. 14, 1419–1425 (2014).

Download references


This work was supported by the National Natural Science Foundation of China (NSFC) (11690031, 61675069, 61575224, 61622510); Guangzhou Science and Technology Program (201707010444, 201701010096). X.C. would like to acknowledge helpful discussions with P. Jiang.

Author information

X.C. developed the idea. X.C. and L.L. conceived device design. M.H. and J.J. carried out the LN fabrication. M.H., S.G., H.C., L.Z., L.L. and S.S. carried out the silicon fabrication. M.H. and Y.R. carried out the bonding process. M.X., Z.R., Y.X., X.W. and C.G., carried out the measurement. L.L. and X.C. carried out the data analysis. All authors contributed to the writing. X.C. finalized the paper. S.Y., L.L. and X.C. supervised the project.

Correspondence to Liu Liu or Xinlun Cai.

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

Waveguide and electrode design.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Further reading