| 摘要 |
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, includes (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<SUB>f</SUB>) 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 equations <maths id="MATH-US-00001" num="00001"> <MATH OVERFLOW="SCROLL"> <MROW> <MROW> <MI>Exp</MI> <MO></MO> <MROW> <MO>(</MO> <MROW> <MROW> <MN>24</MN> <MO></MO> <MI>t</MI> </MROW> <MO>-</MO> <MN>12</MN> </MROW> <MO>)</MO> </MROW> </MROW> <MO><=</MO> <MI>y</MI> <MO><=</MO> <MROW> <MROW> <MROW> <MO>-</MO> <MN>20</MN> </MROW> <MO>x</MO> <MROW> <MI>log</MI> <MO>(</MO> <MFRAC> <MSUB> <MI>V</MI> <MI>f</MI> </MSUB> <MN>500</MN> </MFRAC> <MO>)</MO> </MROW> </MROW> <MO>+</MO> <MN>25</MN> </MROW> </MROW> </MATH> </MATHS> and t=(0.21xCladOval)+(0.04xCoreOval)+(0.17xECC), where y is a maximum spatial frequency of spin [turns/m], V<SUB>f </SUB>is a drawing velocity [mpm], CladOval is a clad ovality [%], CoreOval is a core ovality [%], and ECC is an eccentricity [mum].
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