设计了一种带有增益介质包层的两个平行圆柱形纳米金属棒构成的表面等离子体光波导，基于频域有限差分法，对这种波导所支持的基模的能流密度分布、有效折射率、传播长度和模式面积随几何结构参数和电磁参数的依赖关系进行了分析。结果表明，沿纵向的能流主要分布在两个圆柱形金属棒所形成的中间区域。通过调节这种波导的几何参数及电磁参数，可以调节模式的传播特性。在增益介质的辅助下，传播距离明显增大。这种表面等离子体光波导可以用于光子器件集成领域和传感器领域。

A kind of surface plasmonic waveguide with double parallel columniform metallic nanorods coated with the gain medium is introduced. The dependence of distribution of longitudinal energy flux density, effective index, propagation length and mode area of the fundamental mode with longer propagation length supported by this waveguide on geometrical parameters and electromagnetic parameters are analyzed using the finite-difference frequency-domain (FDFD) method. Results show that the longitudinal energy flux density distributes mainly in the middle area which is formed by the two columniform metallic rods. The propagation properties can be adjusted by changing the geometrical parameters and electromagnetic parameters. The propagation length can be extended obviously with the help of the gain medium. This kind of surface plasmonic waveguide can be applied in the field of photonic device integration and sensors.