单偏振空芯微结构光纤及在高精度小型化谐振式光纤陀螺的应用研究

As the most promising high precision miniaturized fiber optic gyroscope, resonant fiber optic gyroscope (R-FOG) plays a significant role in the development of high level inertial navigation technology. Using the properties of single polarization and hollow core, this project focus on investigating the fabrication process of single-polarization hollow core microstructure fiber (HC-MSF) and its application in R-FOG. Our goal is to break throuth the bottleneck of various effects from scattering, nonlinearity and polarization coupling, which has a negative influence on the long-term stability of R-FOG. Based on the structure innovation and fabrication technology breakthrough, an online real-time monitoring system based on lateral optical tomography will be established to solve the structural maintenance problem during the fabrication process. A feedback theoretical model system in the closed loop, including the analyze model, fabrication model and online real-time monitoring model, will be established to investigate the structural innovation and improve the efficiency of fabrication technology. A single-polarization hollow core microstructure fiber which has an extinction ratio higher than 30 dB at the wavelength of 1550 nm with a low loss less than 5 dB/km and a crucial bend radius less than 2cm will be realized successfully. Based on the fabricated fiber, the winding technology of optical resonator and the generation and suppression mechanism of the weak noise will be studied in detail to make the resolution of resonant ring up to 100. We will try our best to catch up with the advanced level of the fabrication process of HC-MSF and the application of FOG. The research results have scientific significances and application values in developing high precision fiber optic gyroscope and break through the block in China.

谐振式光纤陀螺是高精度小型化光纤陀螺的发展方向，对推进高端惯性导航技术发展意义重大。本项目将单偏振与空芯特性相结合，进行单偏振空芯微结构光纤及在谐振式光纤陀螺的应用研究。以突破散射、非线性及偏振串扰等对陀螺长期稳定性的制约瓶颈为目标，紧抓空芯微结构光纤发展契机，以结构创新及制备技术攻关为突破口，创新性提出侧向光层析成像在线实时监控方法，建立集设计、制备及实时特性监控分析为一体的闭环反馈控制模型，提高结构创新和制备工艺改进时效性，解决横纵向均匀性保持难题；研制出1550nm波段消光比大于30dB、弯曲半径小于2厘米、损耗低于5dB/km的单偏振空芯微结构光纤；研究绕环工艺、微弱噪声产生及抑制机理，研制出清晰度高达100的谐振腔。在空芯微结构光纤研制及在光纤陀螺应用方面实现弯道超车。研究成果，对突破封锁，提升我国光纤陀螺研究水平，占领空芯微结构光纤及应用学术前沿，具有非常重要的意义和科学价值。

本项目以高精度小型化谐振式光纤陀螺发展为牵引，以结构创新和制备技术攻关为抓手，进行新型单偏振空芯光纤及其敏感环应用攻关。以空芯光纤分析、制备及单偏振单模实现机制等理论研究为支撑，在系列新型空芯光纤结构设计及制备方法等方面取得了突破，部分研究成果达到国际先进水平，按期圆满完成课题任务。项目研究了不同导光机制下空芯光纤单偏振单模特性实现机制，提出差异壁厚单偏振单模空芯光纤新结构，在1550nm波长处偏振消光比高达17662，单偏振单模带宽达8nm；为突破单一导光机制的空芯光纤难以兼顾单模、高双折射、低弯曲损耗特性的瓶颈，提出基于光子带隙和反谐振效应的混合导光型空芯光纤新结构，在200 nm带宽内，双折射高达10^-3量级，高阶模消光比高于100；利用空芯光纤中多孔为材料修饰提供的天然通道，提出了应用镀硅层包层管实现单偏振单模空芯光纤的结构设计方案，并结合已报道多种空芯光纤结构，证明了方案的有效性；利用金属的表面等离子体共振效应，提出基于金属修饰的新型单偏振单模空芯光纤。在制备理论与技术研究方面，项目针对多路气压协同控制的问题，建立融多气压参数影响的空芯光纤制备理论模型，以指导制备参数的优化；经过多年攻关，成功地研制出空芯保偏光纤，在波长1500 nm, 光纤损耗为9.2 dB/km，双折射可达1.67E-3量级，弯曲半径小于2 mm；首次研制出一种偏芯结构的单模低弯曲损耗空芯光纤，制备的光纤性能指标达到国际先进水平。此外，基于研制光纤开展了敏感环绕制实验，完成耐辐照及环境稳定性测试实验，实验结果有力地证明了空芯光纤环的优异性能。总结凝练项目研究成果，出版学术专著一部，发表SCI论文42篇，顶级国际会议发表论文3篇，应邀在国际会议做特邀报告4次，获授权国家发明专利3项，培养毕业博士生5人，硕士生9人。研究成果对推进空芯光纤及谐振式光纤陀螺应用发展具有重要的意义和实用价值。