设计并优化了一种基于外反射原理的狭缝波导结构,可以实现将光限制在低折射率材料中传播且能量更为集中。这种狭缝波导由两块对称的高折射率板、中间一层低折射率狭缝和外围的包层构成。利用有限元分析方法,在入射波长为1550 nm的情况下,仿真研究了包层大小、狭缝高度、狭缝宽度和板宽度这4个关键参数对二维波导结构光场传播的影响,并对这些结构参数进行优化调整,使得能量更加集中在低折射率的狭缝中。利用优化后的参数建立三维波导模型,研究三维空间中电场的分布情况,证明了利用所设计的波导结构,可以将光限制在低折射率材料中传播。

In this study, a slot waveguide structure is designed based on the principle of external reflection. Further, this structure is optimized to limit the propagation of light in low-refractive-index materials and concentrate energy. The slot waveguide structure comprises two symmetrical high-refractive-index slabs, a middle low-refractive-index slot, and a peripheral cladding. The effects of the cladding size, the height and width of the middle low-refractive-index slot, and the width of the slab are simulated under two-dimensional conditions with an incident wavelength of 1550 nm based on the finite element analysis method. The aforementioned parameters are optimized to ensure that energy is more concentrated in the middle low-refractive-index slot. In addition, the distribution of the electric field in a three-dimensional space is studied when the optimized parameters are used to establish a three-dimensional model, proving that light can propagate in low-refractive-index materials when the proposed structure is used.