庞加莱球的光纤应力测量

推导用斯托克斯参数表示的光纤应力计算公式．指出在一个无损耗单元内，从一个偏振态到另一个偏振态的任何变化，都对应着庞加莱球相对于直径的一个旋转．如果令球的半径为R=k(相位应力系数)，则压应力F可用球与S2OS3平面相交圆上的一段大圆弧表示．当入射光为线偏振光时，若单模光纤无固有双折射，则F=ktg^-1(S3/S2)]；若单模光纤存在固有双折射，可将固有双折射看成-初始附加压力Fo的作用结果．给出斯托克斯参数测量值和光纤应力计算值．并比较实际外加应力．结果与实际情况相符。

Fiber Stress Measarement Based on Poincare Sphere

A formula is derived for calculating fiber stress showing by stokes parameter. In a lossless unit, any change from a polarization state to another polarization state is pointed out to be corresponded to a rotation of Poincare sphere relative to the diameter. Let the radius of sphere be egual to phase stress factor k , then, the pressure stress F can be shown by a section of orthodrome on the circle where the sphere and the S 2OS 3 plane intersect. When the incident light is linearly polarized light and there is no inherent birefringence in single mode fibre optical, then, F=k tg -1 ( S 3/S 2 )]; when there is inherent birefringence in single mode fibre optical, the inherent birefringence can be seen as result from the action of an initially additional pressure F 0. The measured value of stokes parameter and calculated value of fiber stress are compared with actually applied stress. The results conform to actual state.