强电场极化氮化硅的二阶光学非线性及相关光子器件的研究

For future high speed all-optical communication and signal processing, integrated photonic devices owning different nonlinear functions are of great importance, and the research about this field become quite active recently. In this proposal, a normal semiconductor material, namely, silicon nitride, will be made used of. The target of this proposal is to study the second order nonlinear optical properties of silicon nitride itself or that of the multiple dieletric layers comprised of silicon nitride and silicon oxide, and investigate the methodology of inducing and strenthing such nonlineality. Based on the optimal strenthing conditions, the dispersive characteristics of waveguides with different structures, as well as the phase matching condition between the fundamental and second harmonic optical wave at different orders, will be further researched. Through reasonable designing and optimised fabricating technique, it is expected to obtain planar integrated photonic devices with strong second order nonlinear function. These devices would be of low transmission loss, high stability and high conversion efficiency. The work would lay the foundation for further research of the core optical components constructing the next generation high speed all-optical communication and signal processing system.

具有各类非线性效应的集成光子器件，对未来新型高速全光通信和信号处理具有非常重要的理论和现实意义，因而其研究成为目前光电子学器件领域最活跃的前沿方向之一。本项目基于一种常规的半导体材料——氮化硅，将主要研究氮化硅材料自身及其与氧化硅材料组成的多层界面结构的二阶非线性光学特性，并探索通过高温下强电场极化的方式来诱导激发以增强此二阶非线性的方法和手段，获得最佳的诱导激发条件。在此基础上，研究不同结构波导的色散特性，以及基频光与倍频光在不同偏振条件下不同阶次模式之间的相位匹配条件。通过合理的设计及优化的微纳加工工艺，获得传输损耗低，稳定性高、转换效率高的平面集成型二阶非线性光子器件原型。为今后进一步研发构成下一代光通信和高速全光信号处理系统硬件基础的核心光子学功能器件，提供理论基础和技术平台。

氮化硅材料作为一种常规的半导体材料，由于具有折射率高、通光范围宽、禁带宽度大、CMOS工艺兼容等优点，近年来成为集成非线性光子器件较为理想的材料选择。本项目紧紧围绕基于氮化硅材料的非线性集成光子器件研究展开，对氮化硅光学薄膜的生长、氮化硅-氧化硅膜系及氮化硅光波导的高温退火行为、薄膜的二阶光学非线性测量、氮化硅集成光波导的工艺制备、波导线性光损耗以及波导的非线性系数与折射率测量等内容进行了全面深入的研究。创新性的提出并从实验上验证了利用等离子体增强化学气相沉积法、接触式光学光刻以及高温退火工艺获得大面积、具有极低损耗和较大非线性系数并且波导截面高度可调的氮化硅集成光波导的可行性，克服了利用低压化学气相沉积法对波导横截面高度的限制，极大的增加了波导色散调控的灵活性。项目的研究成果为今后进一步开展氮化硅集成非线性光子器件在信号处理、波长转换、光频梳、超连续谱等方面的应用提供了坚实的实验基础。