Patent ID: 8613209

Claim:
An optical fiber drawing device that produces an optical fiber from a preform, comprising: a drawing furnace that heats, melts, and draws the preform; a preform feeding unit that holds said preform and feeds said preform into said drawing furnace; a cooling unit that cools a bare optical fiber drawn by said drawing furnace; a coating unit that applies a coating resin to said bare optical fiber; a capstan that takes up a coated bare optical fiber; a winding unit that winds up an optical fiber strand taken up by the capstan; a real drawing speed detection unit that detects a real drawing speed of said optical fiber strand being taken up; arithmetic and control means for generating a speed command signal of a preform feeding speed on the basis of a signal of the real drawing speed detected by said real drawing speed detection unit by adopting, as a preform feeding speed, a base preform feeding speed and a feed-back correction determined on the basis of a deviation between a target variation of a drawing speed and a variation of the real drawing speed, wherein at least one of said base preform feeding speed and the target variation of the drawing speed is a function of the real drawing speed; and a preform feeding speed adjusting unit that adjusts a preform feeding speed by the preform feeding unit, on the basis of the speed command signal; further comprising a stepwise storage means that stores stepwise, as a function of said real drawing speed, values of one of said base preform feeding speed and the target variation of the drawing speed, which is set as a function of the real drawing speed, wherein said values stored in the stepwise storage means are extracted as a function of the real drawing speed, and the values extracted are applied.