超薄金属膜V-型槽等离子波导的定向耦合研究

分析了在 1 550 nm 波长下超薄金属膜(金膜厚t=10 nm)V-型槽等离子波导间长程沟道等离激元导模的定向耦合。通过计算不同波导间距下的模式分布,得出了定向耦合器中奇、偶模有效折射率实部和传播长度随波导间距的变化情况,并进一步计算了相邻波导间的耦合长度、最大串扰与波导间距的关系曲线。计算结果表明:在波导间距较小时,耦合长度小于各模式的传播长度,随着波导间距的增加,耦合长度随之增加,最大串扰随之减小。对超薄金属膜V-型槽等离子波导的定向耦研究在集成光路的实际应用中具有重要的价值。

Directional coupling in V-groove plasmonic waveguides with ultra thin metal film

The directional coupling of long-ranging channel plasmon polariton in the V-groove plasmonic waveguides covered with ultra thin metal film was studied. By calculating the modes' distributions, confinement factors and propagation lengths of the odd and even modes in different waveguide distances were acquired. The relationship between coupling length and maximum crosstalk with different waveguide distances were calculated. It is found that the coupling length is smaller than the propagation lengths of any mode in small waveguide distance, and the coupling length becomes larger and the maximum crosstalk becomes smaller as the waveguide distance increases. The investigation of the directional coupling in the V-groove plasmonic waveguides with ultra thin metal film is important to its applications in the photonic integrated circuits.