Tang Gangchao, Huang Yuhao, Chen Jianfeng, Li Zhi-Yuan, Liang Wenyao
Opt Express. 2022 Aug 1;30(16):28762-28773. doi: 10.1364/OE.460271.
We have proposed a controllable topological add-drop filter (ADF) by utilizing the one-way transmission property and resonant coupling effect of topological photonic states in magneto-optical photonic crystal (MOPC) system. The ADF is symmetrically constructed by a central ring resonator (RR) with each side a MO microcavity and a topological waveguide formed by MOPC/AlO PCs. The topological waveguide supports one-way transmission and the microcavity is used to adjust resonant frequency and improve filtering performance. Based on the symmetry of structure and the adjustability of magnetic field, the input and output ports can be reconfigured conveniently to realize the dropping and adding functions of the ADF. Such an ADF possesses merits of nearly perfect filtering performance, convenient adjustability of resonance mode, and strong robustness against various defects. Moreover, we further design an optical demultiplexer consisting of two PCRRs which is able to separate two different resonant modes independently and efficiently. These results hold promise in many fields such as optical communications and wavelength-division multiplexing.
我们利用磁光光子晶体（MOPC）系统中拓扑光子态的单向传输特性和共振耦合效应，提出了一种可控拓扑分插复用滤波器（ADF）。该ADF由一个中心环形谐振器（RR）对称构建而成，其每一侧各有一个MO微腔以及一个由MOPC/AlO光子晶体形成的拓扑波导。拓扑波导支持单向传输，微腔则用于调节共振频率并改善滤波性能。基于结构的对称性和磁场的可调节性，输入和输出端口可方便地重新配置，以实现ADF的分插功能。这种ADF具有近乎完美的滤波性能、共振模式调节方便以及对各种缺陷具有强大鲁棒性等优点。此外，我们还进一步设计了一种由两个平行耦合环形谐振器（PCRRs）组成的光解复用器，它能够独立且高效地分离两种不同的共振模式。这些结果在光通信和波分复用等许多领域都具有广阔前景。
