提出一种基于长程表面等离子体的介质-金属纳米线阵列-非线性介质复合全光调制器.考虑克尔效应对折射率变化的影响, 采用时域有限差分法分析了金属纳米线直径、介质层厚度和泵浦光强度对反射谱的影响, 通过合理配置金属纳米线和介质层的参数提高调制器的耦合性能, 并在此基础上分析不同强度泵浦光的反射特性.结果表明: 当金属纳米线直径为40 nm, 介质层厚度为1 800 nm时, 全光调制器的模式耦合能力达到最强.反射谱的反射率与泵浦光强度的变化呈线性关系, 相关系数为0.998 1, 且只需要0.5 GW/cm2功率的泵浦光就能使入射光的反射率从0.015提高到0.82, 较好地实现光信号对光的全光调制.

An all-optical modulator based on long-range surface plasmon resonance with metal nano-wires array is proposed. It respected for the Kerr effect to induce refractive index changes and numerically investigated respected for using the finite-difference time-domain simulation. The all-optical modulator is realized with low intensity of pump light. The diameter of metal nano-wire, the thickness of buffer dielectric layer and the intensity of pump light have a significant influence on the reflectance spectra of all-optical modulator. The coupling performance of the all-optical modulator is improved by allocating the parameters of metal nano-wire and buffer dielectric layer reasonably. The results show that the mode coupling ability of the all-optical modulator is optimal when the diameter of metal nano-wire and the thickness of buffer dielectric layer are 40 nm and 1 800 nm, respectively. There is a linear relationship between the change of reflectivity spectrum and pump intensity, which the correlation coefficient is 0.998 1. The reflectance of incident light reaches 0.82 by applying the intensity of pump light as low as 0.5 GW/cm2, which can realize all-optical modulation of optical signal to light very well.