《有限包层半径光纤Bragg光栅的理论研究张霞》由会员分享，可在线阅读，更多相关《有限包层半径光纤Bragg光栅的理论研究张霞（3页珍藏版）》请在金锄头文库上搜索。
1、K;8Bragg;E张霞夏月辉黄永清任晓敏(v;Y,100876)K1采用光纤波导三层模型,对有限包层半径光纤Bragg光栅导模有效折射率的改变进行了理论分析, 结果表明:当包层直径小于16 m时,单模光纤Bragg光栅(纤芯直径为8.3 m)的导模有效折射率才开始发生明显变化.在包层外添加外包层,通过改变外包层的折射率可以实现对光栅Bragg反射波长的调谐,同时对不同芯子直径的光栅Bragg波长移动进行了数值计算.在保证光纤归一化频率不变的前提下,芯径越小Bragg 波长调谐范围越大,当包层厚度为1 m时,芯径为 a =2.2 m的光栅Bragg波长调谐范围约为3.9 m.1oM;8;E;B
2、raggQoms|TN252DSMA国家863高科技基金资助项目(2001AA122041)通信联系人Tel:010-62284004收稿日期:2002 05 200;8;E(Fiber Bragg Grating)o/ 1,2 ,M;8o|qPs7.M|qP;E+o;Q,7oV1YV;E,Qo(Bragg)o.os(WDM)b(1)y;8;E,In_LP0m,|l =0 .In|qsVF(r)=AJ0(ur/a)BI0(wr/b)+CK0(wr/b)DK0(vr/b)(rb)(3)T, u =a n12k02 -2 ,w =b 2 -n22k02 , v =b 2 -n32k02 , q,
3、r_, J、I 、KsYBBesself,BMBesself#=MBesself,/SVUBessel3222003M2;0ACTA PHOTONICA SINICA Vol.32 No.2February 2003f.n3 n2H,.ln2k0 n3.9Hn3Sn2 n30W,n3 n2f,Tnm3.n39FH,neffKvHr|qn09F;l,MA,2b=9.3 mH,M1.410-3.图3n3 n2 时,不同包层半径基模有效折射率随外包层折射率的变化Fig.3 Changes in effective refractive index as a function of outerclad
4、ding refractive index for n3n22.2;8;EBraggon3M;8;EBraggQo 6B =2neff (5)T;E.9H|/:;E=0.53 m,n1 =1.46810, V=3 .59261,;8BBqV=ak n12 -n22M,O0b -a=1 m,0=4.15 m,3.1 m, 2.2 mf/,9oHr|q,isT(5)BraggQo, n3 n2n3 n2HBraggQoBMKvHBraggQoB0MB -B0|qM1nm4、m5.图4n3n2时,不同芯径的光栅Bragg波长随 n3的变化Fig.4 Bragg wavelength shift as
5、 a function of outer claddingrefractive index for n3n2Vm4m5V:|qn3 n2H,n3hlBraggQo_oZ_M;n3 n2H,n39F, BraggQo_oZ_M;OMdL.0l;8;E,?A9vS,0a =2.2 m;E,:1 mHSVr3.9 m.3f),.K;8Bragg;E223 图5n3n2时,不同芯径的光栅Bragg波长随的变化Fig.5 Bragg wavelength shift as a function of outer claddingrefractive index for n3 n23K;8;E,|qM7o
6、Ms,Y;8,r|q|qMKl16 17 m;.-4/,l;8;ESv,OMwL,e.ID1Hill K O, Fuji Y, Johnson D C, et al.Photosensitivity inoptical fiber waveguides: application to reflection filterfabrication.ApplPhysLett, 1978, 32(6):647 6492MeltzG ., Morey M M, Glenn W H.Formation of Bragggratings in optical fibers by a transverse ho
7、lographic method.OptLett, 1989, 14(15):823 8253R,:,b,.T/;8;EBraggo+.;0;, 2000, 11(1):23 25Guo W, Liu K, Huang Y Q, et al.Journal of optoelectroniceslaser,2000, 11(1):23 254Cruz J L, Diez A, AndresM V.Improved thermalsensitivity of fiber Bragg gratings using a polymer overlay.ElectronLett , 1996, 32(
8、4):385 3875 Kumazaki H, Yamada Y, Nakamura H, et al.Tunablewavelength filter using a Bragg grating fiber thinned by plasmaetching.IEEE PhotoTechLett , 2001, 13(4):1206 12086Erdogan T.Fiber grating spectra.J LightwaveTechnol, 1997,15(8):1277 1294Analysis of Shift in Bragg Wavelength of Fiber Bragg Gr
9、atingsWith Finite Cladding RadiusZhang Xia,Xia Yuehui,Huang Yongqing, Ren XiaominOptical CommunicationCenter, BeijingUniversity ofPostsandTelecommunications, Beijing 100876, ChinaReceived date:2002 05 20AbstractThe effective refractive index of the fundamental mode is calculated using three-layer mo
10、del for single modefiber Bragg grating (FBG).The changes of effective refractive index for FBG with finite cladding radius aredemonstrated .The result shows that appreciable change of effective refractive index for FBG (4.15 m -core radius)happen below cladding diameter of 16 m.The Bragg reflection
11、wavelength for single-mode FBG with thin claddingradius can be tuned by changing the refractive index of the surrounding material called as outer cladding.The numericalanalysis of Bragg wavelength shift of FBG with different core radius a=4.15 m,3.1 m and 2.2m are also presentedrespectively.On condi
12、tion that normalized frequency keeps constant, the tunable range of Bragg reflection wavelengthincreases as the core radius decreases.For the 2.2 m-core radius FBG with absolute cladding radius of 1 m, a tunablerange of about 1.7 nm can be obtained for the FBG surrounded by outer cladding, of which refractive index changes from1.33 to n2 .When the refractive index of the outer cladding ch
