Abstract: Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Abstract: Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Abstract: The present invention relates to a method of making an optical fiber product. In particular, this manufacturing method is characterized in that, between a drawing step in which a coated optical fiber comprising a glass fiber and a primary coating layer disposed around the outer periphery of the glass fiber is wound around a reel and a processing step in which the coated optical fiber wound around the reel is rewound around a bobbin, a control step is provided for holding the coated optical fiber wound around the reel in a place with a mean atmospheric temperature T (>0° C.) for at least 30,000/T2 (hr) and, in the case where a coloring layer or the like is disposed around the outer periphery of the coated optical fiber, for at least 30,000/T2 (hr) but not longer than 210,000/T2 (hr).

Abstract: The invention provides a production method for a PMF. Two or more bores at regular intervals are formed in a glass rod including a core and a clad so that the bores may be located on a concentric circle around a center axis of the glass rod. A stress applying member is inserted into the bore. The glass rod and the stress applying member may be heated before or after inserting. The glass rod with the stress applying is drawn without exposure to the atmosphere after heating in order to form an optical fiber.

Abstract: In a fabrication method of coated optical fiber 21, the coated optical fiber 21 is fabricated by heating to soften an end of an optical fiber preform 11 to draw a glass fiber 13 out therefrom, laying coatings 16, 19 on the glass fiber 13 to make the coated optical fiber 21, and guiding the coated optical fiber 21 via a swing guide roller 23 periodically swinging, to twist the coated optical fiber 21, thereby imparting twists about the axis to the glass fiber 13 inside the coated optical fiber 21.