小孔缺陷光子晶体光纤双折射增强机理及单偏振色散平坦化研究

Polarization-maintaining fibers occupy an important position in modern optical systems, and have wide market prospect. Polarization-maintaining photonic crystal fibers with small-hole defects can deliver ultra-high birefringence and broad single-polarization properties, and they have now attracted widespread attentions from research members domestic and abroad. As for a single-polarization photonic crystal fiber with small-hole defects proposed by our research group, this program plans to use the coupled-mode theory to further study the fundamental reason of the birefringence enhancement caused by small holes in the core of such kind of fibers. Then this program proposed a developed dispersion-normalized method and a systematic design idea, so as to achieve flattened dispersion in single-polarization photonic crystal fibers. Finally, according to structural parameters given by theoretical calculations, this program will use the “Stack and draw” method to fabricate the fiber sample, and proposed a combination method of broadband light source interference and special frequency domain analysis to precisely measure the birefringence and single polarization. The research results can help to optimize the operation characteristic for polarization-maintaining photonic crystal fibers, thus providing transmission mediums with high performance in modern optical systems.

保偏光纤在现代光学系统中占据着非常重要的地位，具有广阔的市场前景。小孔缺陷保偏光子晶体光纤能够实现超高双折射和宽带单偏振特性，目前引起了国内外研究人员的广泛关注。针对课题组前期研究成果中提出的一种小孔缺陷单偏振光子晶体光纤，本项目拟采用耦合模理论进一步研究这类光纤的芯区小孔致使双折射增强的根本原因；然后提出一种改进的色散归一化方法和一种系统的设计思路以实现单偏振光子晶体光纤的色散平坦化；最后根据理论计算所得结构参数采用堆积拉丝工艺制备出光纤样品，并提出一种宽带光源干涉结合空间频域分析的测量方法来实现对光纤样品双折射和单偏振的精确测量。本项目的研究成果将有助于优化保偏光子晶体光纤的工作特性，从而为现代光学系统提供高性能的传输媒介。

按照研究计划，项目采用耦合模理论成功解释了小孔缺陷致使光子晶体光纤双折射增强的根本原因，并揭示了小孔缺陷光子晶体光纤双折射随小孔尺寸变化的基本规律。在小孔缺陷结构的基础上，提出了一种系统的单偏振单模光子晶体光纤色散平坦化方法，并实现了约400nm带宽的工作范围。利用空间频域分析技术实现对小孔缺陷光子晶体光纤双折射的精确测量，并利用色散分析仪验证了单偏振单模光子晶体光纤的平坦色散特性。该项目研究成果能够在基于波分复用的光通信系统、光纤传感及超连续谱光源等领域得到广泛应用。项目资助发表学术论文5篇，网络见刊1篇。培养硕士生3名，均已经取得硕士学位。项目资助经费24万元，支出经费12.5964万元，剩余经费2.3142万元，剩余经费计划用于本项目研究后续支出。