Effective electro-optical modulation with high extinction ratio by a graphene-silicon microring resonator

Yunhong Ding, Xiaolong Zhu, Sanshui Xiao, Hao Hu, Lars Hagedorn Frandsen, N. Asger Mortensen, Kresten Yvind

Research output: Contribution to journalJournal articleResearchpeer-review


Graphene opens up for novel optoelectronic applications thanks to its high carrier mobility, ultra-large 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.
Original languageEnglish
JournalNano Letters
Issue number7
Pages (from-to)4393-4400
Publication statusPublished - 2015


  • Graphene photonics
  • Silicon microring resonator
  • Electro-optical modulation
  • High modulation depth

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