提出一种基于SOI材料的超紧凑型3×3 MMI波导光开关,开关仅有一个多模波导,且多模波导采用更为紧凑的双曲结构。用FD-BPM方法对其各个状态进行了模拟和分析,并对器件的结构参数进行了优化设计。结果表明,这种光开关可以成功实现任意两输入和输出通道间的开关功能,优化后的开关呈现优良的综合性能,且整个器件的尺寸小于4 mm。 An ultracompact 3 × 3 MMI waveguide optical switch based on SOI material is proposed. The switch has only one multimode waveguide, and the multimode waveguide adopts a more compact hyperbolic structure. The FD-BPM method was used to simulate and analyze the various states of the device, and the structural parameters of the device were optimized. The results show that this optical switch can successfully switch between any two input and output channels. The optimized switch exhibits excellent overall performance with an overall device size of less than 4 mm.