Article comprising optical fiber having low polarization mode dispersion, and method of making the fiber

Abstract From the Canadian patent

The presence of (typically unintended) birefringence in single mode optical fiber can severely limit the usefulness of the fiber for e.g. high bit rate or, analog optical fiber communication systems due to the resulting polarization mode dispersion (PMD). It has now been discovered that PMD can be substantially reduced if, during drawing of the fiber (13) a torque is applied to the fiber such that a "spin" is impressed on the fiber. Desirably the torque is applied such that the spin impressed on the fiber does not have constant spatial frequency e.g. has alternately, clockwise and counterclockwise helicity. At least a portion of optical fiber according to the invention has a spin whose …