单模光纤折射率分布对偏振模色散的影响

Effect on Polarization Mode Dispersion Due to Eccentricity of Refractive Index Distribution in a Single-Mode Fiber

利用将任意非圆性等效为椭圆的方法分析和计算了单模光纤中包层和芯层折射率分布不同心导致的偏振模色散 ,得到了两个偏振模式的传输常数差Δβ和偏振模色散Δτ与偏心比、入射光的波长、芯层半径、相对折射率差的关系曲线 ,为实践中尽量减小单模光纤的偏振模色散提供理论上的指导。与椭圆度引起的偏振模色散相比 ,不同心引起的偏振模色散具有相同的数量级。

The polarization mode dispersion (PMD) in a single-mode fiber caused by eccentricity of refractive index distribution of core and clad is analyzes and calculates considering that arbitrary uncircularity is equivalent to the ellipse. The relative curves of the difference of propagation constants Δβ and PMD versus the ratio of eccentricity, wavelength, radius of core and difference of refractive index are obtained. It can offer a theoretic guidance for decreasing the PMD in a single-mode fiber. The PMD caused by eccentricity has the same magnitude with that caused by ellipticity.