基于填充式多孔光纤的太赫兹偏振分离器  

Terahertz Polarization Splitter Based on Filled Porous Fiber

作　　者：李珊珊[1] 常胜江[1] 张昊[1] 刘伟伟[1] 

机构地区：[1]南开大学现代光学研究所,天津300071

出　　处：《光学学报》2014年第7期218-222,共5页Acta Optica Sinica

基　　金：国家973计划(2014CB339800);国家863计划(2011AA010205;2013AA014201);国家自然科学基金(61171027;11274182;11004110);天津市科技计划项目(13RCGFGX01127);天津市高等学校科技发展基金计划项目(20120706)

摘　　要：提出了一种基于填充式多孔光纤的宽带太赫兹偏振分离器。结构设计采用折射率反转匹配耦合法,数值模拟采用有限元法,光纤基底选择聚合物材料TOPAS。研究了普通三角晶格多孔光纤填充前和填充后的色散和双折射特性,发现通过隔行填充匹配材料,多孔光纤的模式双折射提高了一个数量级,由10-3提高至10-2。利用两根纤芯微结构具有正交关系的填充式多孔光纤实现偏振分离功能。模拟结果表明,该偏振分离器在0.8~2.5THz频率范围内都能够实现偏振分离。在1THz,分离长度为0.77cm;x,y两偏振奇模和偶模的实际吸收损耗均小于0.2dB;消光比分别为-12.73dB和-13.70dB。与以往双芯光子晶体光纤偏振分离器设计相比,该设计具有结构简单、易于实现、可调谐、宽带和低损耗等优点。A broadband terahertz polarization splitter based on filled porous fiber is proposed. The fiber structure is designed by using index converse matching coupling method. The numerical simulation is completed by employing full vector finite element method. The background material is TOPAS. The properties of dispersion and birefringence for before and after filling a common porous fiber are analyzed in detail. It can be found that after interlacing filling to the porous fiber, the mode birefringence of the fiber improves an order of magnitude that changes from 10-3 to 10 2. Then we analyze the properties of terahertz polarization splitter based on filled porous fibers. The numerical simulation shows that the splitting operation can be realized in a broad frequency ranging from 0.8 THz to 2.5 THz. At 1 THz, the splitting length is only 0.77 cm, and the practical material absorption losses for x- and y- polarization are less than 0.20 dg, respectively. The extinction ratios for x- and y- polarization are -- lg. 73 dB and -- 13.70 dB, respectively. Compared with other designs of dual-core-PCF based polarization splitter, porous fiber is simpler in design, easier in fabrication, and more feasible in experiment. Moreover, this structure has advantages of tunable, low loss and broadband.

关 键 词：光纤光学 偏振分离器 太赫兹 填充 多孔光纤 

分 类 号：O439[机械工程—光学工程]