| 摘要 |
PURPOSE:To make it possible to obtain an optical fiber without increasing transmission loss even in the use under low-temperature environment by applying a resin reduced in dissolved air amount to the surface of a glass fiber drawn by a drawing furnace. CONSTITUTION:When a resin is applied to the surface of a glass fiber drawn by a drawing furnace and cured to provide the coated glass fiber, a resin for primary layer before coating is subjected to heat treatment or defoaming treatment by reduced pressure and after removing foam by seeing by one's eyes, the resin is further sufficiently defoamed and thereafter, dissolved air amount is measured with a gas chromatography, etc. After it is confirmed that the measured value is an amount which is not left as ultrafine foam during coating when the resin is cured, coating and curing operation is carried out. |
