BY modifying phase mask UV exposure system and inserting a circumvolved device which making optical fiber rotation in back of the phase mask, the PMD in fiber Bragg gratings is compensated.

改变光纤光栅紫外曝光系统，在相位掩模板后插入一个旋转装置，使得光纤在制作过程中可以进行某种旋转。