Letter | Published:

Efficient low-loss InGaAsP/Si hybrid MOS optical modulator

Nature Photonics volume 11, pages 486490 (2017) | Download Citation

Abstract

An optical modulator integrated on silicon is a key enabler for high-performance optical interconnects1,2,3,4,5,6. However, Si-based optical modulators suffer from low phase-modulation efficiency owing to the weak plasma dispersion effect in Si, which also results in large optical loss. Therefore, it is essential to find a novel modulation scheme for Si photonics. Here, we demonstrate an InGaAsP/Si hybrid metal-oxide–semiconductor (MOS) optical modulator formed by direct wafer bonding7,8. Electron accumulation at the InGaAsP MOS interface enables the utilization of the electron-induced refractive index change in InGaAsP, which is significantly greater than that in Si (refs 9,10). The presented modulator exhibits a phase-modulation efficiency of 0.047 Vcm and low optical attenuation of 0.23 dB at π phase shift at 1.55 μm wavelength, which are approximately 5 times higher and 10 times lower than Si MOS optical modulators11,12,13,14,15,16,17, respectively. This approach provides a new, high-performance phase-modulation scheme for Si photonics.

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Acknowledgements

This work was supported in part by the New Energy and Industrial Technology Development Organization (NEDO) and the Japan Society for the Promotion of Science (JSPS) KAKENHI grant number JP26709022. The authors would like to thank O. Ichikawa, M. Yokoyama, T. Yamamoto and H. Yamada in Sumitomo Chemical Corporation for their collaboration. J.-H.H. and F.B. would also like to thank JSPS for a research fellowship.

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Author notes

    • Jae-Hoon Han

    Present address: Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.

Affiliations

  1. The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

    • Jae-Hoon Han
    • , Frederic Boeuf
    • , Shinichi Takagi
    •  & Mitsuru Takenaka
  2. Photonics Electronics Technology Research Association (PETRA), Tsukuba, Ibaraki 305-8569, Japan

    • Junichi Fujikata
    •  & Shigeki Takahashi

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Contributions

J.-H.H. contributed to the idea, simulation, fabrication, measurement and manuscript preparation. F.B. contributed to the simulation and manuscript preparation. J.F. and S. Takahashi contributed to the measurement of the dynamic characteristics. S.Takagi contributed to the discussion and provided high-level project supervision. M.T. contributed to the idea, discussion, manuscript revision, and provided high-level project supervision.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Jae-Hoon Han or Mitsuru Takenaka.

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DOI

https://doi.org/10.1038/nphoton.2017.122