包层空气孔孔径的不均匀性对微结构光纤非线性系数的影响

在基于微结构光纤(MOFs)的非线性装置中,光纤的非线性系数是一个很重要的参数,它受包层空气孔不均匀性的影响。用全矢量有限元法和误差理论分析了包层空气孔孔径的不均匀性对六角形高非线性微结构光纤非线性系数的影响。通过计算,得到了这种光纤HE1x1和HEy11模的非线性系数与每个空气孔孔径之间的关系,从而进一步得到了非线性系数的标准差与包层空气孔孔径标准差之间的关系。这样,在已知孔径的标准差时,很容易得到非线性系数的标准差。当孔径标准差与孔径设计值的比为5%时,HE1x1和HE1y1模非线性系数标准差与均匀孔径情况下非线性系数值的比分别为2.55%和3.06%。

Effect of Hetero-Diameters of Cladding Air Holes on Nonlinearity Coefficient of Microstructured Optical Fibers

The nonlinearity coefficient of microstructured optical fibers(MOFs) is a quantity of great importance in devices based on the nonlinearity of the fibers.The distribution asymmetry of the cladding air holes can make an impact on it.The effect of hetero-diameters of the cladding air holes on the nonlinearity coefficient of a highly nonlinear MOFs with a hexagonal lattice is analyzed by the full-vector finite element method and the error theory.The dependence of the nonlinearity coefficients of the HE~x_(11) and HE~y_(11) modes of the fiber on the diameter of cladding air hole is computed.Subsequently,the dependence of the standard error of the nonlinearity coefficients on the standard error of the diameters of the air holes is obtained.As a result,if the standard error of the diameters of the air holes is given,it is easy to obtain the standard error of the nonlinearity coefficients.When the ratio of the air hole diameter standard error to the designed diameter is 5%,the ratios of the nonlinearity coefficient standard errors of the HE~x_(11) and HE~y_(11) modes to the nonlinearity coefficient of the fiber with uniform cladding air holes are(2.55%) and 3.06%,respectively.