磁场中双折射光纤的琼斯矩阵等效模型

采用延迟器与旋光器的串联模型, 研究磁场中双折射光纤的偏振传输特性, 将它们的琼斯矩阵按照两种不同的顺序级联相乘, 导出了两种等效模型中等效相位延迟量、等效快轴方向和等效旋光角的解析表达式。研究发现, 当光纤同时具有线双折射和圆双折射时, 单位长度的等效相位延迟量并不等于其固有的线双折射, 等效旋光角也不等于其法拉第旋转角, 它们同时都与光纤的固有线双折射和磁场引起的圆双折射相关联。且在不同级联顺序的两种等效模型中, 等效相位延迟器的快轴方向都不与光纤的双折射主轴重合, 而是分别向两个相反的方向偏移一定的角度, 偏移角为等效旋光角的一半。

Jones Matrix Model of Birefringent Fibre in Magnetic Field

Through the model of cascading retarder and rotator, the polarization transmission characteristics of birefringent fiber in magnetic field have been studied. By multiplying their Jones Matrixes in different cascading order, we have deduced the analytic expressions for the phase shift and fast axis orientation of the equivalent retarder as well as the angular rotation of the equivalent rotator. When linear birefringence and circular birefringence occur in the same fiber, it is found that the equivalent phase retardation in unit length is not equal to its inherent birefringence, nor the equivalent angular rotation is equal to its Faraday rotation. They are relevant meanwhile both to the inherent linear birefringence of fiber and to the circular birefringence caused by the magnetic field. What’s more, in the equivalent models with different cascading order, the fast axis of the equivalent retarder does not coincide with the linear birefringent axis of fiber, but has an offset angle respectively with opposite spin-wise, and the offset is just equal to the half of the equivalent angular rotation.