基于多模干涉器的三维模式转换分束器的设计

Design of Three-dimensional Beam Splitter with Mode Conversion based on Multimode Interferometer

采用三维结构光子器件可以实现多维度的空分复用,即并行处理多路信号,从而增加传输容量,提高集成密度。文章根据三维多模干涉耦合器的自成像原理,设计了一种易于集成的三维模式转换分束器。该分束器可以将输入的基模光场转换为3个基模光场和3个一阶模光场输出。用聚合物材料设计并优化得到多模波导的长、宽和高分别为3 398.17、50.00和29.37μm。模拟结果显示,在1 550nm波长时的总传输效率为85.5%,其中基模输出光场的传输效率为28.9%,最大不均衡性为0.010dB;一阶模输出光场的转换效率为56.6%,最大不均衡性为0.004dB。

Three-dimensional photonic devices can process multiple signals simultaneously in terms of multi-dimensional space division multiplexing,which increase the transmission capacity and improve the integrated density.In this paper,based on selfimage principle of 3D Multimode Interference（MMI）coupler,a 3D Beam Splitter（BS）with mode conversion is designed,which can be easily integrated.The 3D-BS with mode conversion can convert the input beam at the fundamental mode into three output beams at the fundamental mode and three output beams at the first-order mode.The length,width and height of the MMI are designed with polymer materials and optimized to be 3 398.17,50.00 and 29.37μm respectively.The simulation results show that the total transmission efficiency of the BS is 85.5%,and the transmission efficiency of the output fundamental mode is 28.9% with the maximum imbalance of 0.010 dB.The conversion efficiency of the output first-order mode is 56.6% and its maximum imbalance is 0.004 dB.