Patent ID: 7529452

Claim:
A method for manufacturing a single mode optical fiber with a reduced PMD (Polarization Mode Dispersion), by drawing an optical fiber preform composed of a core and a clad surrounding the core, the method comprising: (a) heating the optical fiber preform to a high temperature using a furnace, and drawing an optical fiber from an outlet of the furnace at a linear velocity (V f ) of 500 mpm or above by means of neck-down drawing; and (b) impressing a spin on the optical fiber by means of a spin impressing device provided on a drawing path of the optical fiber, wherein a maximum spatial frequency of spin (y) impressed on the optical fiber satisfies the following equation: Exp ⁡ ( 24 ⁢ t - 12 ) ≤ y ≤ - 20 × log ( V f 500 ) + 25 and t = ( 0.21 × CladOval ) + ( 0.04 × CoreOval ) + ( 0.17 × ECC ) where y is a maximum spatial frequency of spin expressed in turns per meter, V f is a drawing velocity expressed in meters per minute, CladOval is a clad ovality expressed in a percentage, CoreOval is a core ovality expressed in a percentage, and ECC is an eccentricity expressed in μm.