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.

中文翻译：

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石墨烯-硅微环谐振器对高消光比的有效电光调制

石墨烯因其高的载流子迁移率，超大的吸收带宽和极快的材料响应性而为新型光电应用打开了大门。特别是，通过调节费米能级来控制光电特性的机会使电光调制，光光开关和其他光电子应用成为可能。但是，由于石墨烯-硅器件中的石墨烯-光相互作用适度，通常仅利用单层或几层石墨烯，实现高调制深度仍然是一个挑战。在这里，我们全面研究了石墨烯与微环谐振器之间的相互作用及其对光调制深度的影响。我们演示了石墨烯-硅微环器件，该器件显示了12.5 dB的高调制深度和8.8 V的相对较低的偏置电压。