Zhang Jingjing, Shi Xiaodong, Zhang Zhaojian, Ma Chao, Chen Xuefeng, Liu Liping, Song Xiaoxian, Zhang Haiting, Yu Yu, Ou Haiyan, Guo Kai, Yang Junbo
Opt Lett. 2021 Oct 1;46(19):5027-5030. doi: 10.1364/OL.436223.
Waveguide taper, a key component in the photonic integrated circuit (PIC), enables on-chip mode conversion, but large-footprint tapers are detrimental to the PIC, which desires compact and efficient devices. Polarization sensitivity also limits the tapers in the applications involving orthogonal modes. In this work, we design an efficient polarization-insensitive ultra-short MMI-based waveguide taper, through the mode spreading principle and the self-image principle. The proposed taper is 26.3 µm long, one order of magnitude shorter than the standard linear taper. We fabricate the taper, and experimentally demonstrate that it exhibits a high transmission efficiency of ∼70 and a wide 1 dB bandwidth of >54, for both TE and TM polarizations.
波导渐变器是光子集成电路（PIC）中的关键组件，可实现片上模式转换，但大尺寸的渐变器对PIC不利，因为PIC需要紧凑高效的器件。偏振敏感性也限制了渐变器在涉及正交模式的应用中的使用。在这项工作中，我们通过模式扩展原理和自镜像原理设计了一种高效的偏振不敏感超短基于多模干涉（MMI）的波导渐变器。所提出的渐变器长度为26.3 µm，比标准线性渐变器短一个数量级。我们制作了该渐变器，并通过实验证明，对于TE和TM偏振，它都具有约70的高传输效率和大于54的宽1 dB带宽。
