Abstract: Disclosed is an optical fiber coating apparatus for preventing generation of bubble in a coating layer of an optical fiber when the optical fiber is coated, which includes a coating unit for allowing an optical fiber to pass through and forming a coating layer on the optical fiber; a base coupled with a lower portion of the coating unit to draw the optical fiber; a cover installed to an upper portion of the coating unit to isolate the coating unit from an external air and having an optical fiber introduction hole; a gas supply line for supplying gas, having smaller kinetic viscosity than the air, into an inner space formed by the cover; and a coating agent discharge line for discharging a coating agent remained in the inner space of the cover. The inner space forms positive pressure circumstance by using the gas having smaller kinetic viscosity than the air.

Abstract: A furnace for drawing an optical fiber includes a body having an upper and lower openings for supplying a preform and discharging a drawn optical fiber, a heating unit installed in the body for receiving and melting the preform, an atmosphere blocking tube installed to the lower opening for discharging the drawn optical fiber and blocking the optical fiber from the atmosphere, an upper introduction port formed at an upper portion of the body for introducing an inert gas toward the preform and partially discharged outside through a gap between the preform and the upper opening, a central and lower introduction ports formed at central and lower portions for introducing an inert gas into the body, a first flow guiding means for guiding the inert gas introduced through the central introduction port upward and then flowed down along a surface of the preform, and a second flow guiding means for guiding the inert gas introduced through the lower introduction port upward and then discharged outside through the atmosp

Abstract: A furnace for drawing an optical fiber includes a body having an upper and lower openings for supplying a preform and discharging a drawn optical fiber, a heating unit installed in the body for receiving and melting the preform, an atmosphere blocking tube installed to the lower opening for discharging the drawn optical fiber and blocking the optical fiber from the atmosphere, an upper introduction port formed at an upper portion of the body for introducing an inert gas toward the preform and partially discharged outside through a gap between the preform and the upper opening, a central and lower introduction ports formed at central and lower portions for introducing an inert gas into the body, a first flow guiding means for guiding the inert gas introduced through the central introduction port upward and then flowed down along a surface of the preform, and a second flow guiding means for guiding the inert gas introduced through the lower introduction port upward and then discharged outside through the atmosp

Abstract: An outer and inner diameter measuring method for a transparent tube in a non-contact manner includes the steps of irradiating a light having a linear sectional shape, inclined at a pre-determined angle with respect to a plane perpendicular to a length direction of a transparent tube, to the transparent tube; obtaining a light beam pattern formed since the light having a linear sectional shape is intercepted and refracted by the tube; obtaining an inner diameter of the tube by extracting inner diameter information of the tube from the obtained light beam pattern; and obtaining an outer diameter from a light beam pattern refracted by the tube, thereby calculating the outer and inner diameters together.

Abstract: Disclosed is an optical fiber coating apparatus for preventing generation of bubble in a coating layer of an optical fiber when the optical fiber is coated, which includes a coating unit for allowing an optical fiber to pass through and forming a coating layer on the optical fiber; a base coupled with a lower portion of the coating unit to draw the optical fiber; a cover installed to an upper portion of the coating unit to isolate the coating unit from an external air and having an optical fiber introduction hole; a gas supply line for supplying gas, having smaller kinetic viscosity than the air, into an inner space formed by the cover; and a coating agent discharge line for discharging a coating agent remained in the inner space of the cover. The inner space forms positive pressure circumstance by using the gas having smaller kinetic viscosity than the air.

Abstract: An apparatus for producing an optical fiber preform to perform the deposition process by modified chemical vapor deposition. The Apparatus comprises a main heat source location sensor (800) for detecting the location of a main heat source for heating a substrate tube 100, an additional supporting device control part (1000) wiredly or wirelessly connected to the main heat source location sensor (800), and an additional supporting device (1100) wiredly or wirelessly connected to the additional supporting device control part (1000) for supporting the substrate tube (100). The present invention reduces the effective length of the substrate tube (100) by additionally supporting the substrate tube (100), thereby minimizing the deflection of the substrate tube (100). Particularly, it is possible to considerably reduce the deflection of the substrate tube at its initial part and thus to achieve a high deposition efficiency. Accordingly, it is possible to mass-produce an optical fiber preform of high quality.

Abstract: A method for monitoring a spin imparted on an optical fiber in order to reduce Polarization Mode Dispersion (PMD) includes the steps of imparting a spin on a high-temperature optical fiber which is drawn from a preform, photographing a dispersion pattern peculiar to the spun optical fiber with a camera from scattered light naturally generated by the spin imparted on the optical fiber, and displaying the photographed dispersion pattern. The method enables monitoring of rate and period of the spin imparted on the optical fiber on the basis of the displayed dispersion pattern.

Abstract: Disclosed is a method for measuring a pitch of a stranded cable which includes the steps of (A) manufacturing a stranded cable by stranding at least two wires; (B) irradiating a parallel ray on one side of the stranded cable moving at a regular velocity, and receiving the parallel ray at the opposed side of the stranded cable; and (C) determining a stranded cycle of the cable on the basis of a light-receiving quantity pattern on the opposed side corresponding to a stranded pattern of the cable, and then measuring a stranded pitch of the cable by calculating a moved distance of the cable during the stranded cycle. This method enables to measure a pitch of a spirally stranded cable in real time at a low cost.

Abstract: A method of applying spin to a coated optical fiber to be rotated on its longitudinal axis so that the optical fiber has an ultra-low PMD (Polarization Mode Dispersion) includes the steps of: guiding the coated optical fiber so as not to be deviated from a certain range off a drawing axis at a lower end of an optical fiber coating point; giving torque to the optical fiber by contacting the coated optical fiber with a driving roller which vibrates on the center of an axis substantially parallel to a drawing direction at a lower end of the guiding point; and adjusting an amplitude (A) of the driving roller and a distance (l) between the guiding point and the vibrating point so as to control an angle (?) between the vibrating optical and the drawing axis. This makes it possible to control a spin rate (spins/m) of the optical fiber generated by rotation.

Abstract: Disclosed is a method for measuring a pitch of a stranded cable which includes the steps of (A) manufacturing a stranded cable by stranding at least two wires; (B) irradiating a parallel ray on one side of the stranded cable moving at a regular velocity, and receiving the parallel ray at the opposed side of the stranded cable; and (C) determining a stranded cycle of the cable on the basis of a light-receiving quantity pattern on the opposed side corresponding to a stranded pattern of the cable, and then measuring a stranded pitch of the cable by calculating a moved distance of the cable during the stranded cycle. This method enables to measure a pitch of a spirally stranded cable in real time at a low cost.

Abstract: A furnace for drawing an optical fiber includes a body having an upper and lower openings for supplying a preform and discharging a drawn optical fiber, a heating unit installed in the body for receiving and melting the preform, an atmosphere blocking tube installed to the lower opening for discharging the drawn optical fiber and blocking the optical fiber from the atmosphere, an upper introduction port formed at an upper portion of the body for introducing an inert gas toward the preform and partially discharged outside through a gap between the preform and the upper opening, a central and lower introduction ports formed at central and lower portions for introducing an inert gas into the body, a first flow guiding means for guiding the inert gas introduced through the central introduction port upward and then flowed down along a surface of the preform, and a second flow guiding means for guiding the inert gas introduced through the lower introduction port upward and then discharged outside through the atmosp

Abstract: Disclosed is a method for monitoring a spin imparted on an optical fiber in order to reduce Polarization Mode Dispersion(PMD).