Apparatuses and methods for imparting mechanical twist in optical fibers

摘要

Methods and apparatuses introduce mechanical twist to an optical fiber having relatively large polarization mode dispersion (PMD), such as unspun fiber or fiber spun with constant spatial frequency, which mechanical twist reduces the fiber's PMD. A spool of optical fiber having relatively large PMD is mounted and fiber is pulled from the end of the spool to impart a specified mechanical twist. Additionally, the spool may be controllably rotated by a control system while optical fiber is pulled therefrom, allowing the system to generate a precise amount of mechanical twist to the fiber. Also, it is possible to measure the amount of mechanical twist in an optical fiber and the amount of mechanical twist in an optical fiber as a function of fiber length.