Abstract: A method for manufacturing an optical fiber includes: exposing a glass fiber by stripping a fiber coating layer at an end portion, on a splicing side, of each of a pair of optical fibers; fusion-splicing the glass fibers; and recoating a protective resin on a periphery of exposed portions of the glass fibers. The fiber coating layer includes a primary resin layer on an inner peripheral side and having a Young's modulus of 0.5 MPa or less and a secondary resin layer on an outer peripheral side and having a Young's modulus of 800 MPa or greater, the exposing includes forming a shape of a coating edge of the fiber coating layer which includes the primary resin layer and the secondary resin layer into a tapered shape which becomes narrower toward the end portion side, and the recoating includes coating the protective resin to include the coating edge.

Abstract: A method for manufacturing a glass fine particle deposit includes: emitting a siloxane gas, a carrier gas, and a combustion gas from a burner; setting volume concentration of a supply volume amount of the siloxane gas per unit time with respect to the sum of the supply volume amount of the siloxane gas per unit time and a supply volume amount of the carrier gas per unit time (C1) to 10.6 volume %<C1<20.0 volume %; and setting volume concentration of the supply volume amount of the siloxane gas per unit time with respect to the sum of the supply volume amount of the siloxane gas per unit time, the supply volume amount of the carrier gas per unit time, and a supply volume amount of the seal gas per unit time (C2) to 5.8 volume %<C2<10.0 volume %.

Abstract: A method for manufacturing an optical fiber includes: exposing a glass fiber by stripping a fiber coating layer at an end portion, on a splicing side, of each of a pair of optical fibers; fusion-splicing the glass fibers; and recoating a protective resin on a periphery of exposed portions of the glass fibers. The fiber coating layer includes a primary resin layer on an inner peripheral side and having a Young's modulus of 0.5 MPa or less and a secondary resin layer on an outer peripheral side and having a Young's modulus of 800 MPa or greater, the exposing includes forming a shape of a coating edge of the fiber coating layer which includes the primary resin layer and the secondary resin layer into a tapered shape which becomes narrower toward the end portion side, and the recoating includes coating the protective resin to include the coating edge.

Abstract: The disclosure provides a method of manufacturing a multicore optical fiber comprising a plurality of cores and a common cladding covering each of the plurality of cores and having a non-circular cross-sectional shape capable of passive alignment. The method includes providing an optical fiber preform having a cross-sectional shape delimited by a line obtained by replacing a part of a circumference with one chord or two chords parallel to each other, and applying a drawing tension to one end of the optical fiber preform to draw a multicore optical fiber. An aspect ratio x of the cladding defined by a ratio of a radius of a circle defining the circumference to a distance from the center of the circle to the chord and a drawing tension y are set so that the common cladding has a depression at the center of a plane corresponding to the one or each of the two chords.

Abstract: A method for manufacturing an optical fiber is disclosed. The method for manufacturing an optical fiber includes: drawing an optical fiber by heating an optical fiber preform inside a drawing furnace into which a first gas is introduced; and annealing the optical fiber by causing the optical fiber to pass through an annealing furnace disposed downstream of the drawing furnace and adjusted to a temperature lower than a temperature at which the optical fiber preform is heated. In the annealing, a second gas having a lower heat conductivity than the first gas is introduced into the annealing furnace through one or more gas introduction ports such that a total flow rate becomes 3 slm or higher, and a flow rate of the second gas per gas introduction port is adjusted to 30 slm or lower.