一种低损耗混合模等离激元光波导的模式、耦合特性及其集成问题的研究

Low-loss plasmonic waveguide is potentially important for realization of high-density integrated photonic circuits, but there are still serious problems. To overcome them, we provide some suggestions on design of the plasmonic waveguides and their applications in integrated photonics. Previously, we proposed and initially studied a type of hybrid plasmon waveguide that was considered to have the lowest loss as experimentally reported. In this proposal, we plan to perform a further and general study on the mode and coupling properties of the waveguide both theoretically and experimentally, so as to facilitate solving some fundamental problems that we met in its device design and applications. These problems includes hybrid mode design, maintaining and restoring of the propagation mode, loss reduction, and coupling between waveguides and modes, etc.. Based on the above study, we plan to further study some basic passive waveguide devices of this type, and some special active devices, based on the properties of plasmons in the waveguide, that have enhanced performance or new functions. Additionally, we plan to study some practical issues on hybrid integration of this waveguide with those conventional ones in silicon-based integrated photonic circuits. We expect this study will provide some new ideas, fundamentals, and proof experiments that are valuable to solve some bottle-neck problems in the field of integrated photonics.

低损耗等离激元光波导对实现高密度集成光路具有一定的潜力和重要意义，但目前仍存在一些问题。基于此，我们对等离激元光波导的设计和在集成光路中的应用提出了一些新的思路。此前，申请者提出并初步研究了一种被认为目前实验上实现最低损耗的混合模等离激元光波导。本项目拟就该类型波导的模式和耦合特性进一步进行深入、全面的理论和实验研究，以便解决我们在其器件设计和应用研究中的所面临的若干基础问题，如波导混合模式的设计、传播模式的保持和修复、传播损耗的减小、波导及其模式间的耦合等。在此基础上，研究基于该波导结构的无源基本波导器件，以及基于其中等离激元波特性、具有增强性能或新功能的特色有源器件。此外，我们将就该类型波导与硅基集成光路中传统光波导之间实现混合集成的有关实际问题进行研究。通过该项目，期望为目前集成光学中若干关键瓶颈问题的解决提供新的思路、理论基础和实践验证。

本项目研究一种新型混合模等离激元光波导以实现其低传播损耗；并基于这种波导模式与金属微纳结构中其它模式的相互耦合特性，研究其所涉及的等离激元新效应、及可用于集成微光学系统的新型功能器件。具体包括：（1）对这种混合模等离激元光波导模式特性的分析，及其在硅基底上的加工制备和波导特性研究。（2）通过分析这种波导的TE偏振分量波导模式，提出TE偏振准表面波的概念，并以此研究了这种TE表面波模式在金属微纳结构中的作用和一系列新效应。（3）等离激元波导中不同模式间的耦合效应的研究。（4）增益纳米材料的制备、及其与等离激元模式间光相互作用的研究。（5）基于混合模等离激元波导谐振模式的窄带透射效应的研究。（6）非对称等离激元谐振模式间的相互耦合特性及其相关效应。相关工作为这种等离激元光波导的研究及其波导模式在不同结构和器件中的应用提供了重要的理论和实验基础。我们以相关成果在本领域核心期刊上发表论文18篇，申请发明专利1项；同时培养博士生3名，硕士生6名。