Patent ID: 6519404
Filing Date: 2003-02-11
Classification: C03B,C03C

Abstract:
A method of fabricating a coated optical fiber by heating to soften an end of an optical fiber preform to draw a glass fiber out therefrom, laying a coating on the glass fiber to make a coated optical fiber, and guiding the coated optical fiber via a swing guide roller periodically swinging, to twist the coated optical fiber, thereby imparting twists about the axis to the glass fiber inside the coated optical fiber, said method comprising a step of passing the coated optical fiber having passed said swing guide roller, through a free zone in which the coated optical fiber is allowed to freely rotate about the axis of the optical fiber, and thereby longitudinally canceling out elastic torsion stored in the coated optical fiber because of longitudinally alternate inversion of twist directions thereof, wherein a zone length L (m) of said free zone is not less than Lo (m) defined as follows:Lo (m)=[a maximum drawing speed of the coated optical fiber (m/min)]/[the number of clockwise and counterclockwise swing motions per unit time of the swing guide roller (motions/min)].