基于多芯光纤束和定位单元平移技术的LAMOST系统光纤定位检测研究

“Large Sky Area Multi-Objective Fiber Spectroscopic Telescope” (LAMOST), designed and established by our country, employs 4000 astrology transmission optical fibers as the key device of detecting and transmitting star light. The LAMOST has the highest spectrum acquisition efficiency in the world. In this project, we are going to develop a multi-core optical fiber bundle with positioning function and realize the measurement of the fiber positioning accuracy of the LAMOST based on the multi-core optical fiber bundle and fiber positioning unit translation technologies. We will detailedly investigate preparation technology of multi-core optical fiber bundle probe, packaging technology of pigtal arrays in multi-core optical fiber bundle probe and the positioning accuracy measurement and feedback technology based on multi-core optical fiber bundle and fiber positioning unit translation technologies. A special optical fiber bundle probe with functionalities of positioning guiding and spectra transmitting will be constructed. On this basis, a new measurement technology will be developed based on the multi-core optical fiber bundle for optical fiber positioning accuracy measuring. The optical fiber positioning accuracy of the LAMOST can be improved, and the key problem of realizing closed-loop control of optical fiber positioning unit of the LAMOST will be addressed. The proposed scheme can realize the positioning measurement and feedback when the offset is in the range of 0 ~ 3.54 arc sec. The project can further improve the spectrum acquiring efficiency of the LAMOST, provide key devices and technology supports and pave the way to design and constructed the next generation of Multi-Objective Fiber Spectroscopic Telescope.

我国自行设计并建造的“大天区多目标光纤光谱望远镜”（LAMOST），采用4000根光纤作为星光接收和传输关键器件，是国际上光谱获取效率最高的多目标光纤光谱望远镜。本项目拟发展一种具有位置引导功能的多芯光纤束，利用该光纤束和附加光纤定位单元平移技术实现LAMOST系统星像引导光纤位置的精确检测。拟开展多芯光纤束位置引导探头研制、探头尾纤阵列封装、光纤定位单元平移放大偏移量实现光纤单元定位精度快速检测及反馈技术的研究。构建集位置引导和光谱传输于一体的多芯光纤束，研发基于该探头的光纤定位精确检测技术，用以提高LAMOST系统光纤定位的检测精度，并解决光纤定位单元无法实现闭环反馈的关键问题，理论上可实现偏移量在0~3.54 arc sec范围内的位置检测及反馈。该项目的研究将有望进一步提高LAMOST系统的观测效率，为我国下一代大天区多目标光纤光谱望远镜的设计与建造提供关键器件及技术支撑。

实现光纤定位精度的精确检测，对实现光纤定位单元闭环控制，提高大天区面积多目标光纤光谱天文望远镜观测效率具有重要意义。本项目提出基于多芯光纤束探头和光纤定位单元平移技术实现光纤定位精度检测。项目设计了一种集光谱传输与位置引导功能于一体的13芯光纤束探头，并基于光纤堆栈技术和高精度3D打印技术分别对探头进行了制备。同时，利用高精度3D打印技术实现了13芯光纤束探头位置引导光纤阵列封装。在此基础上，设计了基于13芯光纤束探头和光纤定位单元平移技术的光纤定位精度检测方法，并开展了实验测试研究。该方法可对模拟星斑与探头中心间存在的约100 μm左右的偏移量有效检出，检测误差小于20%。