光学学报, 2010, 30 (7): 1950, 网络出版: 2010-07-13
矩形晶格双折射多孔光纤宽带稳定拍长的优化设计
Optimized Design for Rectangular Lattice Holey Birefringent Fiber with Wideband Stable Beat length
光纤光学 多孔光纤 模式双折射 拍长 矩形晶格 波长敏感性 fiber optics holey fiber modal birefringence beat length rectangular lattice wavelength sensitivity
摘要
在矩形晶格多孔光纤的基础上,通过加入一对大直径圆孔,并进一步优化结构参数可以得到宽带稳定的双折射拍长。采用有限差分波束传播法计算了多孔光纤的模式双折射特性,分析了不同参数变化对模式双折射的影响。计算表明,这两种非对称结构分别具有正值和负值双折射,两者相互作用能够控制模式双折射随波长的变化斜率,在一定的波长范围内使模式双折射与波长呈现等比例的线性变化关系,从而得到基本不随波长变化的双折射拍长。通过优化结构参数,分别在1310 nm和1550 nm波长窗口获得了中心拍长为10 mm的平坦拍长曲线,相对带宽达到12%以上,这种光纤非常适合制作集成于全光纤大电流传感器之中的宽带光纤波片。
Abstract
A design scheme of holey fiber with the combination of rectangular lattice and a pair of large-diameter holes in the cross section is proposed,and wideband stable birefringence beat length can be obtained via optimization of the structural parameters. Finite-difference beam propagation method is used to calculate the modal birefringent characteristics of the holey fiber. The influence of different structural parameters on the modal birefringence is analyzed. The calculation suggests these two asymmetric structures can provide positive and negative birefringence respectively. And their interaction can control the variation slope of birefringence over wavelength. Then linear relation of proportional variation between the birefringence with wavelength can be achieved in some given bandwidth,so that wideband stable beat length can be obtained. By optimizing the lattice pitch and the diameter of air holes,stable beat length with the value of 10 mm at 1310 nm and 1550 nm is designed with relative bandwidth more than 12%. This optimal fiber is very suitable for make wideband fiber-optic wave-plate integrated in all-fiber large current sensor.
李铭佳, 石志东, 林建强, 葛泉. 矩形晶格双折射多孔光纤宽带稳定拍长的优化设计[J]. 光学学报, 2010, 30(7): 1950. Li Mingjia, Shi Zhidong, Lin Jianqiang, Ge Quan. Optimized Design for Rectangular Lattice Holey Birefringent Fiber with Wideband Stable Beat length[J]. Acta Optica Sinica, 2010, 30(7): 1950.