Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators

Feng Qiu, Hiromu Sato, Andrew M. Spring, Daisuke Maeda, Masa Aki Ozawa, Keisuke Odoi, Isao Aoki, Akira Otomo, Shiyoshi Yokoyama

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32 Citations (Scopus)


Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed and fabricated. The waveguide consists of a silicon core with a thickness of 30 nm and a width of 2 μm. The cladding is an EO polymer. Optical mode calculation reveals that 55% of the optical field around the silicon extends into the EO polymer in the TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. The measured half-wave voltage of the MZI with 7 μm spacing and 1.3 cm long electrodes is 4.6 V at 1550 nm. The evaluated EO coefficient is 70 pm/V, which is comparable to that of the bulk EO polymer film. Using ultra-thin silicon is beneficial in order to reduce the side-wall scattering loss, yielding a propagation loss of 4.0 dB/cm. We also investigated a mode converter which couples light from the hybrid EO waveguide into a strip silicon waveguide. The calculation indicates that the coupling loss between these two devices is small enough to exploit the potential fusion of a hybrid EO polymer modulator together with a silicon micro-photonics device.

Original languageEnglish
Article number123302
JournalApplied Physics Letters
Issue number12
Publication statusPublished - Sep 21 2015

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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    Qiu, F., Sato, H., Spring, A. M., Maeda, D., Ozawa, M. A., Odoi, K., Aoki, I., Otomo, A., & Yokoyama, S. (2015). Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators. Applied Physics Letters, 107(12), [123302]. https://doi.org/10.1063/1.4931490