Ultra-compact graphene plasmonic filter integrated in a waveguide<xref rid="cpb_27_9_094101fn1" ref-type="fn">*</xref><fn id="cpb_27_9_094101fn1"><label>*</label><p>Project supported by the National Basic Key Research Program of China (Grant No. 2015CB932400), the National Key Research and Development Program of China (Grant No. 2016YFA0201600), the National Natural Science Foundation of China (Grant Nos. 51372045, 11504063, and 11674073), the Key Program of the Bureau of Frontier Sciences and Education, Chinese Academy of Sciences (Grant No. QYZDBSSW- SLH021), and the Science and Technology Projects of Beijing City, China (Grant No. Z161100002116016).</p></fn>

Ultra-compact graphene plasmonic filter integrated in a waveguide**

Project supported by the National Basic Key Research Program of China (Grant No. 2015CB932400), the National Key Research and Development Program of China (Grant No. 2016YFA0201600), the National Natural Science Foundation of China (Grant Nos. 51372045, 11504063, and 11674073), the Key Program of the Bureau of Frontier Sciences and Education, Chinese Academy of Sciences (Grant No. QYZDBSSW- SLH021), and the Science and Technology Projects of Beijing City, China (Grant No. Z161100002116016).

Liao Baoxin^{1, 2}, Guo Xiangdong^{1, 2}, Hu Hai^{1, 2}, Liu Ning^{1, 2}, Chen Ke^{1, 2}, Yang Xiaoxia^{1, 2, ‡}, Dai Qing^{1, 2, †}

(color online) (a), (c) Transmission spectra of GPs filters with different cavity lengths (l) and widths (d), respectively. (b), (d) The resonant frequencies of peaks 1 and 2 extracted from panel (a) and (c) plotted as a function of the equivalent radius (R_i + R_o)/2.