基于分层微结构纤芯的太赫兹高双折射光子晶体光纤  

Terahertz Ultra-high Birefringent Photonic Crystal Fiber with Hierarchical Microstructured Core

作　　者：李珊珊[1] 张昊[1] 常胜江[1] 范飞[1] Li Shanshan;Zhang Hao;Chang Shengjiang;Fan Fei(Institute of Moderm Optics,Nankai University,Tianjin 300350,China)

机构地区：[1]南开大学现代光学研究所,天津300071

出　　处：《南开大学学报（自然科学版）》2022年第6期62-68,共7页Acta Scientiarum Naturalium Universitatis Nankaiensis

基　　金：National Key Research and Development Program of China(2017YFA0701000);National Natural Science Foundation of China(61831012,61671491,61505088,61971242,11774181);the Young Elite Scientiscts Sponsorship Program by Tianjin(TJSQNTJ-2017-12);Natural Science Foundation of Tianjin City(19JCYBJC16600,19JCYBJC16700)。

摘　　要：基于"功能基元"+"序构"的设计思想,提出了一种在纤芯引入等差分层微结构的太赫兹超高双折射光子晶体光纤.光纤包层由三角晶格排列的圆形空气孔组成;纤芯由三角晶格排列,尺寸满足等差分层条件的椭圆空气孔组成.数值模拟结果显示,当入射光频率为0.5-1.5 THz时,光纤能够实现超高模式双折射;在0.9 THz,模式双折射达到最大值4.07×10-2,此时基模x,y偏振模式的有效材料损耗(EML)分别为0.075 cm-1和0.062cm-1.与6种不同尺寸的均匀微结构纤芯光子晶体光纤的模式双折射特性进行对比研究.结果显示,提出的分层微结构纤芯光子晶体光纤,能够在很宽的工作频段,实现更稳定的超高模式双折射,且具有较低的材料吸收损耗.对于通信、传感、测量等领域的有限长度光纤器件应用,能够起到优化设计,显著提高器件性能的作用.In light of the idea of’functional unit’in combination with’sequential structure’,a THz ultra-high birefringent photonic crystal fiber is proposed by introducing the hierarchical microstructures into the fiber core region.The fiber cladding is composed of wavelength-scale circular air holes arranged in triangular array and the fiber core region consists of subwavelength-scale elliptical air holes that satisfy the equal-differential condition for adjacent layers.Numerical simulation results indicate ultra-high birefringence and low effective material loss is supported in the proposed THz fiber for an operation frequency range of0.5-1.5 THz.And the highest modal birefringence reaches 4.07×10-2 at 0.9 THz,corresponding to effective material losses of x-and y-polarization modes are 0.075 cm-1and 0.062 cm-1,respectively.Moreover,the modal birefringence properties of the proposed THz fiber is investigated in comparison with those of the uniform microstructured fibers of six different sizes.The results show that the proposed hierarchical structure would help to achieve flattened modal birefringence within wide THz operation frequency range,which would be of particular significance for the optimization of communication devices and sensors that could be applied in the field of THz sciences.

关 键 词：光子晶体光纤 太赫兹 等差分层 高双折射 微结构纤芯 

分 类 号：O43[机械工程—光学工程]