School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology, 50, UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
Nanoscale. 2017 Nov 16;9(44):17429-17438. doi: 10.1039/c7nr07045d.
This work reports a mid-infrared modulator based on a hybrid plasmonic waveguide with graphene on a grating in its slot region. The modulator utilizes a graphene plasmon for electro-optic tuning in a more practical and effective way than graphene-plasmon-based waveguide devices studied up to now. The hybrid plasmonic waveguide can be easily and efficiently integrated with input and output photonic waveguides. It supports a hybrid plasmonic waveguide mode and a graphene-plasmon-based waveguide mode. Grating-assisted coupling of the former to the latter in it is demonstrated to work successfully even though the two modes have significantly different propagation constants and losses. Theoretical investigation of the modulator shows that the coupling via the grating of length 5.92 μm generates a deep rejection band at a wavelength of 8.014 μm in the transmission spectrum of the output photonic waveguide of the modulator. With the graphene chemical potential tuned between 0.6 eV and 0.65 eV, the transmission at the wavelength is modulated between -27 dB and -1.8 dB. The subwavelength modulator, which may have a large bandwidth and small energy consumption, is expected to play a key role in free-space communications and sensing requiring mid-infrared integrated photonics.
这项工作报道了一种基于混合等离子体波导的中红外调制器，该波导在其槽区具有石墨烯光栅。与迄今为止研究的基于石墨烯等离子体波导器件相比，该调制器利用石墨烯等离子体以更实际和有效的方式实现电光调谐。混合等离子体波导可以很容易且有效地与输入和输出光子波导集成。它支持混合等离子体波导模式和基于石墨烯等离子体的波导模式。即使这两种模式具有明显不同的传播常数和损耗，也成功地证明了在其中通过光栅对前者到后者的光栅辅助耦合。对调制器的理论研究表明，长度为 5.92μm 的光栅的耦合在调制器的输出光子波导的传输光谱中在波长为 8.014μm 处产生了一个深的抑制带。当石墨烯化学势在 0.6eV 和 0.65eV 之间调谐时，在该波长处的传输在-27dB 到-1.8dB 之间调制。该亚波长调制器有望在需要中红外集成光子学的自由空间通信和传感中发挥关键作用，因为其具有大带宽和小能耗的特点。
