提出一种新颖的对称混合长程表面等离子激元波导结构并对其进行了数值分析。结果表明在传播长度与模式限制两个特性之间实现了很好的平衡。在通信波长1550 nm处，利用有限元数值仿真方法分析了该结构在不同介质尺寸下基模的有效折射率、模式宽度、传播长度和品质因数。计算结果表明：对称混合长程表面等离子激元波导的传播长度及传播长度最大值点的品质因数都有明显的提高。鉴于这些优点，该对称混合长程表面等离子激元波导在实现高性能、高密度的光子集成电路方面具有一定的潜在用途。

A novel symmetric hybrid long-range surface plasmon polariton waveguide structure is proposed and numerically analyzed. The results show that the proposed structure provides a better trade-off between the propagation length and mode confinement. The characteristics of the mode effective index, mode width, propagation length and figures of merit of the fundamental mode supported by this waveguide structure are calculated at the telecom wavelength 1550 nm for different dimensions of the polymer ridge and relatively low index dielectric regions (RLIDRs) under the metal. It is shown that the symmetric structure exhibits an increase in the propagation length, as well as a substantial increase in the figures of merit at the maximum point of the propagation length. For these advantages, the symmetric hybrid long-range surface plasmon polariton waveguide is a good candidate for realizing highly functional density photonic integration circuits.