PURPOSE: To obtain a good image optical fiber without generating foam or the like even if the fiber is heated at high density and is reduced in diameter in the stage of bundling by applying the tension of the own weight to the part of the vertically suspended optical fiber irradiated with a CO2 laser beam from the diametral direction thereby cutting the fiber.
CONSTITUTION: An optical fiber 3 having 300μm outside diameter is suspended with capstans 4 and is fed while heating with a heater 2 from a base material 1 of quartz for optical fiber. The fiber 3 is subjected to irradiation of a beam L with a CO2 gas laser oscillator 5. The irradiated part is heated by the heat of the beam and begins to melt. The fiber 3 is slightly elongated by receiving the tension by its own weight until it is melt cut. The forward end part of the fiber 3 is kept irradiated with the beam even after the melt cutting; therefore, the molten part on the top end side 7a of a strand 7 is rounded by surface tension. The forward end on the bottom end side 7b is also rounded by the surface tension. The increase in the size of the forward end is thus prevented and the generation of flash is obviated.
SATOU TSUGIO
KOMATSU WATARU
TAGUCHI EIICHI
