Patent ID: 8196435

Claim:
A method of manufacturing a holey fiber including a core region and a cladding region surrounding the core region and having air holes arranged around the core region in layers, the method comprising: forming a preform by arranging a core rod at a center of a jacket tube and arranging capillary tubes having hollows around the core rod inside the jacket tube; drawing the preform by heat melting the preform in a heating furnace; determining, during the step of drawing the preform, whether an average of inner diameters of air holes in a first layer from the core region among a plurality of layers of air holes has reached a target value; and controlling, during the step of drawing the preform, at least one of a gas pressure to be applied to insides of the hollows of the capillary tubes, a temperature of the heating furnace, and a drawing speed, based only on a structure of only the air holes in the first layer from the core region among the plurality of layers of air holes and on the determination of whether the average of the inner diameters of the air holes in the first layer from the core region has reached the target value, wherein the number of layers of the air holes are three or more, diameters of the air holes are substantially uniform, and intervals between the air holes are substantially uniform.