传统光调制器基本是通过调控介质光学特性来实现的。由于介质光致响应小，很难有效实现弱光调控弱光。与等离激元结合，表面局域光场增强使得介质的光致响应与调制效率显著提高。作为光子和电子集体振荡的强耦合模式，同时调控金属的材料性质还可进一步提高调制效率。. 我们提出在表面等离激元混合波导中直接调控金属表面电子浓度分布来实现光调制。它提供了一种不依赖于介质材料的新型光学调制方法。本项目拟在制备双臂混合波导M-Z干涉结构与单臂混合波导光栅耦合结构并研究其电光调制特性的基础上，分析金属表面整体电子浓度变化与电子浓度空间分布对等离激元传输特性的影响，建立金属表面电子浓度存在波长尺度的空间分布时修正的金属自由电子气模型；利用光场激发局域表面等离激元共振来调控混合波导中金属电子浓度分布，设计全光调制结构，研究其相位敏感等特性；最后结合电子浓度分布与介质光学特性的双重调控，探索弱光控制弱光的全光调制方案。

Traditional optical modulators are usually achieved by controlling dielectric properties of optical media. Due to the relatively low photoresponse, it’s difficult to realize all optical modulation in weak light. By combining traditional optical modulators with surface plasma polaritons (SPPs), field enhancement localized on metal surface results in significant increase of photoresponse and modulation efficiency. As strong coupling mode of photon and electron collective oscillation, modulation efficiency can be further improved by controlling the metal property at the same time. . We propose to achieve optical modulation in metal-insulator hybrid waveguide by directly controlling electron concentration distribution on metal surface. It provides a new method of optical modulation without relying on optical media. This project firstly plans to analyze the effect of whole electron concentration change and electron concentration distribution on the SPPs propagation and build the revised Drude model in the presence of wavelength scale electron distribution, based upon the fabrication of two-arm hybrid waveguide M-Z interference modulator and one-arm hybrid waveguide grating-coupled modulator and the study on their electro-optic modulation characteristics. Secondly, we will design all optical modulation structure by utilizing optically excited localized surface plasma oscillation to control electron distribution in hybrid waveguide, and study on the phase dependence of incident light and transmission SPPs. Finally, we will explore the solution of all optical modulation in weak light by combining electron concentration distribution and photoresponse of optical media.