Provided is an optical fiber manufacturing method where an optical fiber preform is drawn while being heated in a drawing furnace to form an optical fiber, the method including acquiring a captured image obtained by simultaneously photographing the optical fiber preform and an opening of the drawing furnace before drawing the optical fiber preform, and adjusting a position of the optical fiber preform so that a center of the optical fiber preform and a center of the opening match based on the captured image.

There is provided a method for producing a multicore optical fiber while reducing the mass of a glass block to be connected to a common cladding tube. A production method for a multicore optical fiber includes in order, a preform forming step of forming a common cladding tube having a plurality of holes extending between a first end and a second end, an insertion step of inserting core rods in the holes in a state in which end portions of the core rods are recessed from the first end, a heat shrinkage step of reducing a diameter of the first end by heating, a sealing step of sealing the holes by connecting a glass block to the first end, and a drawing step of depressurizing insides of the holes from the second end and performing spinning from the first end while combining the common cladding tube and the core rods.

The present disclosure relates to a method and apparatus for constraining an optical fiber (104) in the draw tower (100, 101). The method (700) includes steps of trapping (714) the optical fiber (104) in a central position along a vertical axis (Y-Y) by one or more acoustic waves generated by an acoustic centering apparatus (112). In particular, the vertical axis (Y-Y) is parallel to a draw tower axis (Y-Y) and/or coincides with the draw tower axis (Y-Y). The movement of the optical fiber (104) is constrained within 1 milli-meter from the vertical axis (Y-Y) with a coating ovality of a coated optical fiber (105) is less than 4%.

There is provided a method for producing a multicore optical fiber while reducing the mass of a glass block to be connected to a common cladding tube. A production method for a multicore optical fiber includes in order, a preform forming step of forming a common cladding tube having a plurality of holes extending between a first end and a second end, an insertion step of inserting core rods in the holes in a state in which end portions of the core rods are recessed from the first end, a heat shrinkage step of reducing a diameter of the first end by heating, a sealing step of sealing the holes by connecting a glass block to the first end, and a drawing step of depressurizing insides of the holes from the second end and performing spinning from the first end while combining the common cladding tube and the core rods.