Ultracompact, Reflection-Free and High-Efficiency Channel Drop Filters Based on Photonic Crystal Nanobeam Cavities
YU Ping1, HU Ting1, QIU Chen1, SHEN Ao1, QIU Hui-Ye1, WANG Fan2, JIANG Xiao-Qing1, WANG Ming-Hua1, YANG Jian-Yi1,3**
1Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027 2Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163 3Cyrus Tang Center for Sensor Materials and Applicatons, Zhejiang University, Hangzhou 310027
Abstract：We propose an ultracompact channel drop filter (CDF) based on photonic crystal nanobeam cavities. The conditions for implementing such an ideal CDF are derived from the temporal coupled-mode equations governing the operation of the CDF. By considering the intercoupling of the two involved nanobeam cavities, some ambiguities of the previous equivalent circuit model analysis are cleared up. Practical configurations on silicon-on-insulator (SOI) for the proposed CDF are suggested with a typical length less than 15 μm . Finite difference time domain (FDTD) method calculations show that the proposed filter can achieve drop efficiency higher than 99% without any reflection. Compared to the λ/4-shifted Bragg grating resonators based CDF, the proposed CDF is more compact, high-efficient and reflection-free. It is also easy to implement a low-power tunable filter due to the ultrahigh quality factor Q and ultrasmall modal volume V of the involved photonic crystal nanobeam cavities.
2013, Vol. 30 
