螺旋形微结构光纤圆双折射特性优化及其传感应用研究

In the past few years, more and more attention has been attracted by helically-twisted microstructured optical fibers due to their unique properties such as circular-polarized eigenmodes and circular birefringence, which have very high potentials in orbital angular momentum related applications as well as circular-polarization fiber devices. Thanks to the new dimensional modulation, helically-twisted microstructured optical fibers own higher flexibility in the investigations on light-matter interaction and the interactions between light and other physical quantities. However, the research works on helically-twisted microstructured optical fibers are currently very limited. An avalanche of new properties, mechanisms, applications of this new type of fiber are keen for investigating theoretically and experimentally, such as the underlying mechanisms of the generation of high-purity circular birefringence, the optimization of circular birefringence, the filters and sensors based on circular birefringence, and so on. In this project, we will focus on the high-quality fabrication of helically-twisted microstructured optical fibers, optimization of highly circular birefringence, and related applications for high-sensitivity sensing. Moreover, we propose to develop two novel fiber-based circular-polarization interferometers and the corresponding application in highly sensitive electric or magnetic field detection. Also, a series of functional devices based on helically-twisted microstructured optical fibers for multi-parameter measurements of strain, torsion, optofluid, will be investigated theoretically and experimentally.

螺旋形微结构光纤是截面折射率分布沿光纤轴向呈螺旋线形变化的一种新型微结构光纤，具有传统正规波导微结构光纤所不具备的圆偏振本征模式和圆双折射特性，为研究光纤中轨道角动量模式的激发和传输、圆双折射光纤器件等方面提供新的契机；同时由于轴向折射率调制的引入，为研究光纤中光与物质或其它物理量相互作用以及相应光纤功能器件提供了更高的自由度和灵活度。然而，目前关于螺旋形微结构光纤圆双折射特性及其应用的研究还处于起步阶段，无论是圆双折射产生机理和优化研究，还是光纤制备和功能器件研究，都存在巨大的空间和潜力。本项目中，我们将以螺旋形微结构光纤的圆双折射机理、制备工艺以及传感应用为研究主线，有机结合微结构光纤结构优势与螺旋波导特性，重点研究螺旋形微结构光纤的圆双折射特性优化、高质量制备、圆偏振/圆双折射干涉仪，及其在电/磁场、机械量的高灵敏度传感和手性分子光学活性检测的应用等一系列关键性科学与技术问题。

近年来，关于螺旋形微结构光纤及其功能器件受到越来越多科研工作者的关注。由于轴向折射率调制的引入，螺旋形微结构光纤为研究光纤中光与物质或其他物理量相互作用以及相应的光纤光子器件提供更高的自由度和灵活度，具有重要的科学意义和工程应用价值。本项目围绕螺旋形微结构光纤及其功能器件优化设计、制备、表征及其传感应用等方面展开了一系列的理论和实验研究，主要工作如下：首先，基于有限单元法建立了针对螺旋形微结构光纤的理论研究方法并应用于不同扭转率的螺旋形微结构光纤的双折射特性设计；第二，利用后处理方法实现了螺旋形微结构光纤的快速制备，并设计研制了一批新型的特殊微结构光纤，为后续工作的开展积累了基础和资源；第三，利用制成的螺旋形微结构光纤和特殊微结构光纤制成了多种特性新颖的传感器件；第四，探索了基于飞秒激光微加工技术制备螺旋结构光纤器件的先进工艺，并在新型螺旋形光纤光栅方面取得重要进展；此外，本项目还设计了多种基于长程表面等离子谐振的新型微结构光纤传感器件。..本项目共发表SCI期刊论文8篇（一区1篇、二区4篇）、学术会议论文8篇、申请国家发明专利1项、培养硕士研究生5名、合作培养博士生1名。