Ls Cable Ltd.

Lg Cable Ltd.

Chan-Joo Lee

Ki-Wan Jang

Lae-Hyuk Park

Young-beom Seo

Soon-Il Son

Jae-Sun Kim

Disclosed is a low-attenuation single-mode optical fiber having a photoconductive core and a clad, which shows very low OH concentration in MFD (Mode Field Diameter) region. The optical fiber includes a core positioned at its center for photoconduction, and a dehydrated clad and a base clad which are coated on the clad in order. The dehydrated clad has a substantially identical refractive index to the base clad. A refractive index of the core is greater than those of the dehydrated clad and the base clad. The dehydrated clad has a relatively lower OH concentration than the base clad. The region composed of the core and the dehydrated clad has an MFD region at which OH concentration is less than 0.8 ppb.

Low attenuation optical fiber and its producing method in MCVD

Disclosed is a method of manufacturing an optical fiber perform using MCVD including dehydration and dechlorination, which executes the following process repeatedly with changing the composition of soot generation gas according to the refractive index profile, the process including the steps of: forming a soot layer having pores on an inner wall of a deposition tube at a temperature lower than the soot sintering temperature with putting soot generation gas and oxygen gas into the rotating deposition tube; removing hydroxyl groups with keeping the pores by putting dehydration gas into the deposition tube; removing chlorine impurities existing in the soot layer with keeping the pores by putting dehydration gas into the deposition tube; and sintering the soot layer by heating the deposition tube at a temperature over the soot sintering temperature.

Method of manufacturing optical fiber preform using modified chemical vapor deposition including dehydration and dechlorination process and optical fiber manufactured by the method

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Seoul, South Korea

Chan-Joo Lee