This study aims at optimising the graphene coverage in a microresonator for the design of an efficient modulator by using a combination of graphene induced losses and phase shift. The graphene integration in the ring can provide tunability by means of altering the loss and coupling coefficient by changing the graphene coverage or its chemical potential. The fundamental parameters of graphene integrated all-pass ring resonator are extracted based on the transmission characteristics using finite-difference time-domain method. As compared to conventional graphene-oxide-semiconductor straight waveguide, graphene integrated on an all-pass ring resonator shows enhanced optical absorption and phase shift due to field enhancement factor. A modulator based on graphene tunable loss and phase shift is investigated taking into account the field enhancement factor. For 1.55 μm radiation and ring radius of 3.75 μm with 22% graphene coverage, a maximum modulation depth of 12.6 dB is demonstrated based on electrostatic control of graphene chemical potential. The proposed modulator can feature operational speed in the range of 10 GHz that is useful in a variety of electro-optic applications.

中文翻译：

---

场增强辅助基于石墨烯的微环调制器，可实现高调制深度

这项研究旨在通过结合使用石墨烯引起的损耗和相移来优化微谐振器中的石墨烯覆盖率，以设计高效的调制器。环中的石墨烯集成可以通过改变石墨烯的覆盖率或其化学势来改变损耗和耦合系数，从而提供可调性。利用有限差分时域方法，根据传输特性，提取出石墨烯集成全通环形谐振器的基本参数。与常规的氧化石墨烯半导体直波导相比，集成在全通环形谐振器中的石墨烯由于场增强因子而显示出增强的光吸收和相移。考虑到场增强因子，研究了基于石墨烯可调损耗和相移的调制器。对于1.55μm的辐射和3.75μm的环半径，石墨烯覆盖率为22％，基于对石墨烯化学势的静电控制，最大调制深度为12.6 dB。所提出的调制器的工作速度可以在10 GHz范围内，可用于各种电光应用。