title: Effective Electro-Optical Modulation with High Extinction Ratio by a Graphene-Silicon Microring Resonator.
abstract: Graphene opens up for novel optoelectronic applications thanks to its high carrier mobility, ultralarge absorption bandwidth, and extremely fast material response. In particular, the opportunity to control optoelectronic properties through tuning of the Fermi level enables electro-optical modulation, optical-optical switching, and other optoelectronics applications. However, achieving a high modulation depth remains a challenge because of the modest graphene-light interaction in the graphene-silicon devices, typically, utilizing only a monolayer or few layers of graphene. Here, we comprehensively study the interaction between graphene and a microring resonator, and its influence on the optical modulation depth. We demonstrate graphene-silicon microring devices showing a high modulation depth of 12.5 dB with a relatively low bias voltage of 8.8 V. On-off electro-optical switching with an extinction ratio of 3.8 dB is successfully demonstrated by applying a square-waveform with a 4 V peak-to-peak voltage.
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Yunhong
authors.initials: Y
authors.lastname: Ding
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Zhu
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Sanshui
authors.initials: S
authors.lastname: Xiao
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Hao
authors.initials: H
authors.lastname: Hu
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Lars Hagedorn
authors.initials: LH
authors.lastname: Frandsen
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: N Asger
authors.initials: NA
authors.lastname: Mortensen
authors.affiliation: †Department of Photonics Engineering and ‡Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Kresten
authors.initials: K
authors.lastname: Yvind
keywords: Graphene photonics; electro-optical modulation; high modulation depth; silicon microring resonator