大模场掺镱双包层光子晶体光纤内包层新型结构研究

制备了掺镱多组分硅酸盐光子晶体光纤纤芯材料。其折射率为1.586，有效荧光半高宽为85.3 nm，荧光寿命为1.30 ms。分析了光纤结构参数对光子晶体光纤的归一化频率（单模截止条件）、数值孔径、有效模面积、非线性效应和限制损耗等参数的影响。设计了以该材料为纤芯，内包层为八边形、五层空气孔的新型结构光子晶体光纤。用有限元法对该光子晶体光纤性能进行了数值模拟。结果表明，该光纤有效模场面积为1 150 μm²；当空气孔直径为21.6 μm、孔间距为60 μm时，内包层数值孔径达到0.45。

Preparation of Yb3+ Doped Core Material and Study on The Inner Clad Structure of Large Mode Area Double Clad Photonic Crystal Fiber

Yb³⁺ doped multicomponent silicate used as photonic crystal fiber core material was prepared. Its refractive index is 1.586, efficient half width of the fluorescent spectrum band is 85.3 nm, and fluorescence lifetime is 1.30 ms. The influences of structural parameter on the normalized frequency (single mode cutoff condition), numerical aperture, effective mode area, nonlinear effect, and limit loss of the photonic crystal fiber were investigated. Using Yb³⁺ doped silicate as fiber core material, an octagonal and five layer air hole structure based photonic crystal fiber was designed. The performances of the photonic crystal fiber were digitally simulated using the limited element method. The calculated results indicate that the effective mode field area is 1 150 μm² and the numerical aperture of the inner clad is 0.45 when the aperture of the air hole is 21.6 μm and the space between the air holes is 60 μm.