硫系薄膜热光稳定性及其亚微米光波导的热压印研究

The advantage of hot embossing is that its processing accuracy is only sensitive to the linewidth in the stamps rather than optical diffraction in a traditional lithography processing. This enables it to be the best technique to fabricate sub-micrometer-scale chalcogenide optical waveguide with low cost and high efficiency. Currently the application of the hot-embossing is limited by the issues:(1)the inadequate knowledgement of the structure-property relation in chalcogenide glasses; (2)adhesion between the chalcogenide and stamp during the hot embossing, and the defects in the waveguide structure induced by the volatility of chalcogenides. This project will explore the correlation between the thermal/optical stability and mean coordination number in order to screen the best glasses with high optical nonlinearity for hot embossing. We will further deposit a thin Al2O3 film on the surface of chalcogenide to solve the issues like the adhesion and volatility, and fabricate high quality dispersion engineered chalcogenide waveguide. The success of the project will lead to our own intelligent property on the hot embossing of chalogenide waveguide with zero (or negative) dispersion and high optical nonlinearity, as well as a better understanding of the mechanism of the structural stability. This potentially opens an attractive route to make hot embossing of chalcogenide glass for the fabrication of waveguide used for the ultrafast Tbit/s all-optical signal processing in an integrated platform.

热压印技术不受光学衍射的限制，压印精度只取决于模具线宽的特点，有望取代光刻技术成为亚波长结构硫系光波导的主流制备技术。但现阶段热压印硫系光波导存在着以下科学和技术问题：①硫系玻璃热/光稳定性与结构的关系研究缺乏；②压印过程中硫系玻璃与模具之间的粘连和材料的挥发引起波导结构的缺陷问题。本项目以研究三元Ge-Sb-Se玻璃系统的热/光稳定性与平均配位数MCN之间关系为契机，优化获得非线性应用并适合热压印的硫系玻璃组分，设计光波导结构实现其色散裁剪，通过硫系材料表面沉积高熔点Al2O3薄膜解决与模具粘连和材料挥发问题，旨在掌握具有自主知识产权的亚微米尺度硫系光波导热压印制备技术，实现该尺度下硫系光波导的零(负)色散特性和高非线性特性，并且完善硫系材料结构稳定性机理。研究工作为推动硫系光波导热压印技术的发展以及今后在超快Tbit/s全光信号处理集成光器件的应用提供理论依据和科学的实验数据。

热压印技术不受光学衍射的限制，压印精度只取决于模具线宽的特点，有望取代光刻技术成为亚波长结构硫系光波导的主流制备技术。但现阶段热压印硫系光波导存在着以下科学和技术问题：①硫系玻璃热/光稳定性与结构的关系研究缺乏；②压印过程中硫系玻璃与模具之间的粘连和材料的挥发引起波导结构的缺陷问题。本项目系统研究三元Ge-Sb-Se玻璃系统的热/光稳定性与平均配位数MCN 之间关系，发现了Ge含量在30%以下时GexSe1-x薄膜也具有光漂白的特性。在Ge-Sb-Se薄膜系统中同时存在着光漂白和光暗化现象，而在MCN约为2.7时接近光稳。优化获得非线性应用并适合热压印的硫系玻璃组分，设计的硫系光波导脊宽在500～900 nm或脊高H在400～1000 nm范围内，能实现波导的零色散和反常色散。优化了热压印的温度、压印时间和压印压强等工艺参数，掌握了具有自主知识产权的Ge15Sb20Se65和Ge12.5Sb10Se77.5硫系光波导热压印制备技术，压印了相应的光波导，并测试了其光传输损耗，结果显示其具有较低的传输损耗（约为0.7dB/cm）。研究工作为推动硫系光波导热压印技术的发展以及今后在超快Tbit/s 全光信号处理集成光器件的应用提供理论依据和科学的实验数据。