法拉第旋转镜对旋转光纤磁光性能测量的影响  

Influence of Faraday Rotator Mirror on Measurement of Magneto-Optical Properties of Spun Fibers

作　　者：曾嘉伟 文建湘[1] 时昊 吴妍 陈伟[1] 张小贝[1] 庞拂飞[1] 王廷云[1] Zeng Jiawei;Wen Jianxiang;Shi Hao;Wu Yan;Chen Wei;Zhang Xiaobei;Pang Fufei;Wang Tingyun(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学特种光纤与光接入网省部共建国家重点实验室培育基地,特种光纤与先进通信国际合作联合实验室,上海200444

出　　处：《光学学报》2023年第3期86-94,共9页Acta Optica Sinica

基　　金：国家自然科学基金(61975113,61935002);国家重点研发计划(2020YFB1805800);111项目(D20031)。

摘　　要：为了解决随机线性双折射对光纤磁光特性测量的影响,采用旋转光纤(SF)结合法拉第旋转镜(FRM)的测量方法,研究了FRM对旋转光纤磁光特性测量的影响。首先,从理论方面研究旋转光纤与FRM的引入如何减小光纤中的随机线性双折射对磁光特性测量的影响,并搭建基于FRM的旋转光纤磁光特性测试系统。当光源波长为1310 nm时,FRM作用前的旋转光纤费尔德常数都比未旋转光纤的大,且旋转光纤的节距越短,费尔德常数越大。特别是旋转光纤的节距为1.0 mm时,其费尔德常数为0.8304 rad/(T·m),比未旋转光纤的费尔德常数[0.8029 rad/(T·m)]增大了约3.43%。当测试系统加入FRM后,不同光纤的费尔德常数测量值相较于未使用FRM的光纤费尔德常数测量值都有一定幅度的增大,尤其相比于节距为1.0 mm时的旋转光纤更进一步提高了7.50%,并且在FRM作用前后不同光纤费尔德常数测量值的均方差分别为0.99%和0.61%,说明FRM的引入提高了掺杂光纤费尔德常数的测量精度与稳定性。Objective Due to the advantages of high sensitivity and electromagnetic interference resistance,the fiberoptic current sensor based on the Faraday effect has received extensive attention and is one of the research focuses in current measurement.However,there is high random linear birefringence inside the sensing coil,which seriously affects the sensitivity of the sensor.The spun fiber is widely used in the field of current sensing to overcome the influence of random linear birefringence on sensitivity.Moreover,the method of adding a Faraday rotator mirror(FRM)to the end of the sensor's induction coil can also be used to analyze the effect of random linear birefringence.An FRM induces light reflection and polarization rotation of 90°so that the outgoing light is orthogonally polarized to the incoming light.Polarization modulation can be eliminated when orthogonally polarized light undergoes reciprocal birefringence.To remove the influence of random linear birefringence on the measurement of fibers'magnetooptical properties,we prepare spun fibers with four helical pitches and unspun fibers and build an FRMbased testing system for magnetooptical properties of fibers.Methods The optical fiber samples used are homemade lowbirefringence spun fibers.During the fiber drawing process,the fiber preforms are rotated at 1000 r·min−1,667 r·min−1,500 r·min−1,and 333 r·min−1,and spun fibers with a pitch of 1.0 mm,1.5 mm,2.0 mm,and 3.0 mm are obtained,respectively.The wavelength of the light source used in the experiment is 1310 nm.A magnetooptical property testing system based on FRM is built to accurately measure the extinction ratio and Verdet constant of fiber samples.Specifically,the extinction ratio characteristics of spun fibers with different helical pitches and unspun fibers without and with the FRM are measured.Afterward,the Faraday rotation angles and Verdet constants of spun fibers with different helical pitches and unspun fibers without and with the FRM are Results and Discussions In the case of no FRM,

关 键 词：测量 法拉第效应 磁光特性 法拉第旋转镜 费尔德常数 双折射 

分 类 号：O436.4[机械工程—光学工程]