END SURFACE PROCESSING METHOD FOR COATED OPTICAL FIBER

PROBLEM TO BE SOLVED: To maintain the optical transmission performance of an optical fiber without the need for excessive heating by making the optical fiber sufficiently large up to the corners of a taper in a ferrule, and increasing the holding force (tensile force) of the optical fiber which is fixed to the ferrule. SOLUTION: A coating material 2 at the end part of an optical fiber cord is removed and an internal coated optical fiber 1 is inserted into the ferrule 3; and a side face heating body 7 is brought into contact with the outermost circumferential surface of the ferrule nearby the tip and the tip opening of the ferrule 3 and a mirror surface plate 5 are brought into contact with each other. Then the mirror surface body 5 is pressed and heated by an end surface heating body 6 to soften and fuse the coated optical fiber tip part facing the tip opening, thereby forming an expanded part 1a. A cooling body 8 protects the part which need not be heated and expanded. While the mirror surface body 5 is made to abut, the end surface heating body 6 and the side face heating body 7 are separated to carry out cooling and the end surface of the coated optical fiber is thus hardened and put away from the mirror surface plate 5 to transfer the mirror surface to the end surface of the coated optical fiber.