隔行分层填充的太赫兹超高双折射多孔光纤∗
Ultrahigh birefringence terahertz p orous fib ers based on interlacing layered infiltration metho d
摘要
Abstract
In this paper, an interlacing layered infiltration method is proposed, using some liquid material as the common porous fiber with triangular air-hole array in the core region, which can achieve the characteristic of ultrahigh modal birefringence in this circumstance. Firstly, the basic properties of the porous fiber with a porosity of 43.08% are thoroughly analyzed by using a full-vector finite element method, as wellas the dispersion curves of the fiber, modal birefringence, fraction of the fundamental modal power for x and y polarizations, loss characteristics, etc. Secondly, to enhance the asymmetry of the proposed structure, some liquid material with a refractive index of 1.4 is infiltrated into the air holes in the fiber core region, by using interlacing filling method. It is found that the modal birefringence of the fiber dramatically increases. At an operation frequency of 1.1 THz, the peak value of modal birefringence rises from 1.05 × 10−3 to 1.36 × 10−2 after the infiltration operation. The fundamental model effective material absorption loss coefficients for x and y polarization modes increase from 0.16 dB/cm to 0.25 dB/cm and 0.28 dB/cm, respectively. And the operation frequency band increases from 1.1 to 1.9 THz. Simulation results indicate that the modal birefringence of the fiber can be remarkably improved by increasing the refractive index of the infiltrated liquid material. With an operation frequency of 2.2 THz and a refractive index of 2, this fiber can realize an ultrahigh modal birefringence of 8.03 × 10−2. Moreover, to achieve the gradient distribution of the refractive index, an interlacing layered infiltration method to infiltrate the liquid material with different refractive indices in different layers is employed. Results show that the confinement capability to the guided modes has been greatly enhanced. Results also show that the peak value of the modal birefringence for the fundamental modes does not exist in the operation band. It represents a monotonically increasing trend. At an operation frequency of 2.2 THz, the fiber modal birefringence can reach as high as 7.19 × 10−2. This scheme presents an ultrahigh modal birefringence, and it presents the tunable characteristic as well. This study may be of significance in the practical applications in the field of THz functional devices.关键词
高双折射/多孔光纤/填充/隔行分层Key words
highly birefringent fiber/porous fiber/infiltration/interlacing layered引用本文复制引用
李珊珊,张昊,白晋军,刘伟伟,常胜江..隔行分层填充的太赫兹超高双折射多孔光纤∗[J].物理学报,2015,(15):1-9,9.基金项目
国家重点基础研究发展计划(973项目)(批准号:2014CB339800),国家高技术研究发展计划(863)(批准号:2013AA014201)、国家自然科学基金(批准号:61171027 （973项目）
11274182 （）
11004110)、教育部博士点基金(批准号:20090031110033)、天津市科技计划项目(批准号:13RCGFGX01127)和天津市高等学校科技发展基金计划项目(批准号:20120706)资助的课题.@@@@* Project supported by the National Basic Research Program of China (Grant NO.2014CB339800), the National High Technology Research and Development Program of China (Grant No.2013AA014201), the National Natural Science Foundation of China (Grant Nos.61171027,11274182,11004110), the Doctoral Fund of Ministry of Education of China (Grant No.20090031110033), the Science and Technology Program of Tianjin, china (Grant No.13RCGFGX01127), and the Tianjin City High School Science & Technology Fund Planning Project (Grant No.20120706) （批准号:20090031110033）
