Samsung Electronics Co., Ltd.

Young-sik Yoon

Young-Min Baik

Seung-Hun Oh

Sun-Uk Kim

Myung-Chul Jun

Young-min Baik

A silica glass composition and a method for manufacturing silica glass using the silica glass composition are provided. The silica glass composition includes: pyrogenetic silica having an average particle diameter of 5.times.10.sup.-3 to 1.times.10.sup.-1 .mu.m and a specific surface area of 50 to 400 m.sup.2 /g; and heat-treated silica, as an agglomerate of the pyrogenetic silica, having an average diameter of 2 to 15 .mu.m and a specific surface area less than that of the pyrogenetic silica. A high purity silica glass tube, in which cracking after drying rarely occurs and the shrinking ratio is remarkably decreased, can be obtained by using the silica glass composition according to the present invention. Also, a large silica glass tube can be manufactured by using the composition.

Silica glass composition and method for manufacturing silica glass using

A silica glass monolith fabricating method using a sol-gel process. In the method, a first sol is formed by mixing 100 parts by weight of high-density silica containing powder with 100-300 parts by weight of water, and rapidly dried, while the pH of the first sol is being controlled in the range between 9 and 11. The dried first sol is powdered and then thermally treated at or above 600.degree. C., and a second sol is formed by mixing the thermally-treated powdered first sol with 100-200 parts by weight of deionized water and a aqueous organic binder. The second sol is gelled in a mold, dried, thermally treated, and sintered. Thus, a high-purity silica glass monolith is obtained.

Silica glass monolith fabricating method using sol-gel process

A method of fabricating a dispersion shifted optical fiber with a smooth annular ring refractive index profile has the steps of heating a quartz tube with an external oxygen or hydrogen burner and supplying the quartz tube with raw materials including SiCl.sub.4, GeCl.sub.4, POCl.sub.3 and CF.sub.4. O.sub.2 is later supplied. Then, the quartz tube is heated in nine passes of decreasing temperature from 1920.degree. C. to 1890.degree. C., so as to deposit a core section. In the nine passes, the quantity of SiCl.sub.4 feed flow decreases from 380 milligrams per minute to 260 milligrams per minute, the quantity of GeCl.sub.4 feed flow increases from 20 milligrams per minute to 195 milligrams per minute, and the quantity of O.sub.2 feed flow is kept constant at 1500 cubic centimeters per minute.

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Gumi, South Korea

Young-sik Yoon