Method for manufacturing optical fiber

A method for manufacturing an optical fiber including a glass fiber and a primary resin layer coating an outer periphery of the glass fiber, the method comprising:

• applying an ultraviolet curable resin composition to be the primary resin layer, the resin composition including a photoinitiator;
• and
• forming the primary resin layer by curing the resin composition by ultraviolet irradiation reactor(s),
• wherein a number N of the ultraviolet irradiation reactor(s), a ratio of normalized output φ for each of the ultraviolet irradiation reactor(s), and an irradiation time t (sec) of each of the ultraviolet irradiation reactor(s) in the forming of the primary resin layer satisfy
• 6.00×10−5≤N*φ*t≤2.88×10−1
• wherein a concentration C [mass %] of the photoinitiator in the forming of the primary resin layer is in accordance with formula (1) represented by an initial concentration C0 [mass %] of the photoinitiator, a linear velocity v [m/s] of the glass fiber, an irradiation length l [in] for each of the ultraviolet irradiation reactor(s), a non-irradiation length L [m] between the ultraviolet irradiation reactor(s), an initiation reaction rate constant k [1/(mass %·sec)], a dark reaction rate constant kD [1/(mass %·sec)], and a reverse reaction rate constant kR [1/(mass %·sec)]:
• C
• =
• C
• ⁢
• 0
• *
• exp
• (
• -
• N
• *
• φ
• *
• l
• ν
• *
• k
• )
• *
• exp
• (
• -
• N
• *
• φ
• *
• L
• v
• *
• kD
• )
• +
• C
• ⁢
• 0
• *
• (
• 1
• -
• exp
• (
• -
• φ
• *
• lk
• +
• LkD
• v
• )
• )
• *
• (
• 1
• -
• (
• 1
• +
• N
• *
• l
• v
• *
• 4
• ⁢
• kR
• *
• C
• ⁢
• 0
• *
• (
• 1
• -
• exp
• (
• -
• φ
• *
• lk
• +
• LkD
• v
• )
• )
• )
• -
• 1
• )
• (
• 1
• )
• wherein the initiation reaction rate constant k is from 20 to 100,
• wherein the dark reaction rate constant kD is 0≤kD≤30, and
• wherein the reverse reaction rate constant kR is 0≤kR≤10.