光纤折射率调制由受限的纤芯区域向广阔的包层空间拓展，调制结构由一维向二维及三维的转变，不仅为设计和研制新型光纤光栅提供了创新空间，也使优化和提升光纤光栅调控光场功能成为可能。为此，本项目开展基于折射率多维调制结构的空间光纤光栅理论与应用研究，系统地对空间光纤光栅进行理论建模、光谱特性模拟、机理探索表征、模式调控分析、光栅写制技术、器件设计研制、实验测量分析等应用基础研究，重点研究基于折射率多维调制结构的空间倾斜光纤光栅和空间交错光纤光栅，以及由此级联衍生的特种空间光纤光栅。本项目是一个在理论、实验、技术及应用多方面具有创新意义的研究课题，其中的新思想、新方法、新结构及新技术，对于研制具有特殊光学性质的新型光纤光栅、集多种优异功能于一体的集成光纤光子器件，以及由此对光纤通信、光纤传感发展和物联网的推动，均具有重要的参考价值和基础科学意义。

Optical fiber refractive index modulation expands from limited core region to broad cladding spaces, and modulated structures transform from one-dimension to two- and three-dimensions. These changes not only provide innovation spaces for design and development of new fiber gratings, but also make it possible to optimize and upgrade the regulation of light by fiber gratings. Therefore, this project will carry out theoretical and practical research on spatial fiber gratings based on refractive index multi-dimensional modulation which include many systematical basic application studies on theoretical modeling, spectral characteristics simulation, mechanism exploration, mode regulation analysis, fabrication technology of fiber gratings, design and manufacture of related devices, and experimental measurement analysis, etc. The project detailed studies spatial fiber gratings based on refractive index tilted modulation and interlaced modulation as well as particular spatial fiber gratings derived from cascading. This project is a new research topic which has innovative significance in many respects of theory, experiment, technology, and application. The fresh ideas, new methods, novel structures, and innovative technologies have great reference value and basic scientific meanings on developing particular fiber gratings which possess special optical properties, integrated optical fiber photonic devices which have many excellent functions, and promoting fiber communications, fiber sensing, and internet of things.