Ultra-fine metal gate operated graphene optical intensity modulator

Rai Kou, Yosuke Hori, Tai Tsuchizawa, Kaori Warabi, Yuzuki Kobayashi, Yuichi Harada, Hiroki Hibino, Tsuyoshi Yamamoto, Hirochika Nakajima, Koji Yamada

    Research output: Contribution to journalArticlepeer-review

    9 Citations (Scopus)


    A graphene based top-gate optical modulator on a standard silicon photonic platform is proposed for the future optical telecommunication networks. On the basis of the device simulation, we proposed that an electro-absorption light modulation can be realized by an ultra-narrow metal top-gate electrode (width less than 400 nm) directly located on the top of a silicon wire waveguide. The designed structure also provides excellent features such as carrier doping and waveguide-planarization free fabrication processes. In terms of the fabrication, we established transferring of a CVD-grown mono-layer graphene sheet onto a CMOS compatible silicon photonic sample followed by a 25-nm thick ALD-grown Al2O3 deposition and Source-Gate-Drain electrodes formation. In addition, a pair of low-loss spot-size converter for the input and output area is integrated for the efficient light source coupling. The maximum modulation depth of over 30% (1.2 dB) is observed at a device length of 50 μm, and a metal width of 300 nm. The influence of the initial Fermi energy obtained by experiment on the modulation performance is discussed with simulation results.

    Original languageEnglish
    Article number251101
    JournalApplied Physics Letters
    Issue number25
    Publication statusPublished - Dec 19 2016

    All Science Journal Classification (ASJC) codes

    • Physics and Astronomy (miscellaneous)


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