Wang Tao, Guo Hengquan, Chen Haoxiang, Yang Jianhong, Jia Hao
Appl Opt. 2020 Mar 20;59(9):2754-2758. doi: 10.1364/AO.388787.
Mode converters play an essential role in mode-division multiplexing systems. A reflective mode converter (RMC), which is utilized to accomplish the mode conversion in the contra-propagation process, can fold the optical path and realize the mode exchange in an optical network. In this paper, we propose and experimentally demonstrate an RMC based on a silicon subwavelength structure. It can convert the input fundamental mode (${\text{TE}_0}$TE) into the first-order mode (${\text{TE}_1}$TE) in a ${2.0};\unicode{x00B5} \text{m} \times {2.0};\unicode{x00B5} \text{m}$2.0µm×2.0µm footprint. The simulated insertion loss and cross talk are lower than 0.6 dB and $ - {20.3};\text{dB}$-20.3dB in 1525-1565 nm. Experimental results verify the functionality of the device. The measured insertion loss and cross talk are lower than 2.2 dB and $ - {16.2};\text{dB}$-16.2dB. To further prove the generality of the methodology, we design another two RMCs realizing the mode conversion functions of ${\text{TE}_0}$TE to ${\text{TE}_2}$TE and ${\text{TE}_0}$TE to ${\text{TE}_3}$TE modes. The simulated insertion losses are lower than 1.1 dB and 1.8 dB.
模式转换器在模分复用系统中起着至关重要的作用。反射式模式转换器（RMC）用于在反向传播过程中完成模式转换，它可以折叠光路并在光网络中实现模式交换。在本文中，我们提出并通过实验证明了一种基于硅亚波长结构的RMC。它可以在2.0微米×2.0微米的占地面积内将输入的基模（TE₀）转换为一阶模（TE₁）。在1525 - 1565纳米范围内，模拟的插入损耗和串扰分别低于0.6分贝和-20.3分贝。实验结果验证了该器件的功能。测量得到的插入损耗和串扰分别低于2.2分贝和-16.2分贝。为了进一步证明该方法的通用性，我们设计了另外两个RMC，实现了TE₀到TE₂以及TE₀到TE₃模式的模式转换功能。模拟的插入损耗分别低于1.1分贝和1.8分贝。
