JPS60180928A - Production of quartz base material for optical fiber - Google Patents
Production of quartz base material for optical fiberInfo
- Publication number
- JPS60180928A JPS60180928A JP3682784A JP3682784A JPS60180928A JP S60180928 A JPS60180928 A JP S60180928A JP 3682784 A JP3682784 A JP 3682784A JP 3682784 A JP3682784 A JP 3682784A JP S60180928 A JPS60180928 A JP S60180928A
- Authority
- JP
- Japan
- Prior art keywords
- base material
- glass
- quartz
- optical fiber
- glass layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
- C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/08—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
- C03B2201/12—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with fluorine
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Thermal Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明はフッ素がドープされた石英系光フアイバ母材の
製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing a fluorine-doped quartz-based optical fiber base material.
（従来技術）
通信用としてすでに実用化されている光ファイバは、一
般にそのコアが酸化ゲルマニウムを含む石英系ガラス（
高屈折率）からなり、クラッドが高純度石英ガラス（低
屈折率）からなるが、この光ファイバは放射線環境下に
おいて既知の失透が起こるので、耐放射線光ファイバと
してクラッドにフッ素をドープしたものが提案されてい
る。(Prior art) Optical fibers that have already been put into practical use for communication purposes generally have a core made of silica glass containing germanium oxide (
The cladding is made of high-purity silica glass (low refractive index), but since this optical fiber suffers from known devitrification in a radiation environment, the cladding is doped with fluorine as a radiation-resistant optical fiber. is proposed.
光フアイバ母材の製造に際してフッ素ドープト石英ガラ
ス（クラッド用ガラス）を合成するとき、例えば火炎分
解法における火炎中に直接フツ素化合物を混入してその
合成ガラス中にフッ素をドープする方法が試みられてい
る。When synthesizing fluorine-doped quartz glass (glass for cladding) in the production of optical fiber base materials, attempts have been made, for example, to dope fluorine into the synthetic glass by directly mixing a fluorine compound into the flame of the flame decomposition method. ing.
この方法の場合、フッ素がガラス中のケイ素と反応して
気体状のＳ ｓ Ｆ ａを生成する傾向が強く、そのた
めガラス中にドープできるフッ素の量に限界があった。In this method, fluorine has a strong tendency to react with silicon in the glass to produce gaseous S s Fa, and therefore there is a limit to the amount of fluorine that can be doped into the glass.
一方、多孔質ガラスからなる棒状母材をフッ素化剤の雰
囲気中で焼結する方法も試みられているが、この方法に
しても上記と同様の理由によりフッ素ドープ量の限界が
あった。On the other hand, a method has also been attempted in which a rod-shaped base material made of porous glass is sintered in an atmosphere of a fluorinating agent, but even with this method, there is a limit to the amount of fluorine doped for the same reason as above.
その他、石英ガラスの屈折率を低下させる成分としてホ
ウ素が知られており、ＣＶＤ法や火炎分解法などにおけ
る気相原料中にフッ素とホウ素とを送りこみ、こうして
生成される石英ガラス中にフッ素とホウ素とを同時に含
有させる試みもあるが、かかる方法でもフッ素とホウ素
との親和力が非常に大きいため優先的に気体状のＢＦ３
が生成されてしまい、ガラス中にドープされるドーパン
トの量がわずかなものとなっていた。In addition, boron is known as a component that lowers the refractive index of silica glass, and fluorine and boron are introduced into the gas phase raw materials in CVD methods, flame decomposition methods, etc., and fluorine and boron are added to the quartz glass produced in this way. Some attempts have been made to contain boron at the same time, but even with such methods, since the affinity between fluorine and boron is very large, gaseous BF3 is preferentially added.
was produced, and the amount of dopant doped into the glass was small.
このように、従来の試みでは石英ガラス中にフッ素を十
分含有させることができず、その結果°、例えばコア用
ガラスが高純度石英ガラス製、クラッド用ガラスがフッ
素ドープト石英ガラス製である光フアイバ母材により耐
放射線光ファイバをつくるとき、クラッド中における屈
折率低下用のフッ素量が少ないためコア、クラッド相互
の十分な屈折率差が確保できなかった。As described above, in the conventional attempts, it was not possible to sufficiently incorporate fluorine into quartz glass, and as a result, for example, optical fibers in which the core glass is made of high-purity quartz glass and the cladding glass is made of fluorine-doped quartz glass. When making a radiation-resistant optical fiber using a base material, it was not possible to ensure a sufficient refractive index difference between the core and the cladding because the amount of fluorine in the cladding was small to lower the refractive index.
（発明の目的）
本発明は上記の問題点に鑑み、クラッド用カラス中に必
要かつ十分な量のフッ素がドープできる石英系光フアイ
バ母材の製造方法を提供しようとするものである。(Object of the Invention) In view of the above-mentioned problems, the present invention seeks to provide a method for manufacturing a silica-based optical fiber base material in which a necessary and sufficient amount of fluorine can be doped into the glass for cladding.
（発明の構成）
本発明は高純度石英系の多孔質ガラスまたは非多孔質ガ
ラスからなる棒状母材の外周に、酸化ホウ素含有の高純
度石英からなる多孔質ガラス層を形成した後、その多孔
質ガラス層を、フッ素化剤を含む雰囲気中にて焼結する
ことを特徴としている。(Structure of the Invention) The present invention involves forming a porous glass layer made of high-purity quartz containing boron oxide on the outer periphery of a rod-shaped base material made of high-purity quartz-based porous glass or non-porous glass, and then forming a porous glass layer made of high-purity quartz containing boron oxide. The method is characterized in that the glass layer is sintered in an atmosphere containing a fluorinating agent.
（実施例）
以下、本発明の実施例につき、図面を参照して −説明
する。(Example) Examples of the present invention will be described below with reference to the drawings.
第１図において、ｌは高純度石英系の多孔質ガラスから
なる棒状母材であり、この棒状母材は、火炎分解法の一
種である既知のＶＡＤ法を介してつくられる。In FIG. 1, l is a rod-shaped base material made of high-purity quartz-based porous glass, and this rod-shaped base material is produced through the known VAD method, which is a type of flame decomposition method.
ＶＡＤ法を介して棒状母材ｌをつくるとき、気相原料と
してはＳ ｉＣｌ ａが用いられ、火炎としては酸水素
炎、−酸化炭素火炎などが用いられる。When the rod-shaped base material 1 is produced by the VAD method, SiCl a is used as the gas phase raw material, and an oxyhydrogen flame, a -carbon oxide flame, etc. are used as the flame.
上記棒状母材ｌの外周には、酸化ホウ素を含有せる高純
度石英系の多孔質ガラス層２が形成される。A high-purity quartz-based porous glass layer 2 containing boron oxide is formed on the outer periphery of the rod-shaped base material 1.
この多孔質ガラス層２もＶＡＤ法を介してつくられるの
であり、例えば二つの反応バーナを介してＶＡＤ法を実
施するとき、棒状母材１、多孔質ガラス層２は同時に合
成することができる。This porous glass layer 2 is also produced through the VAD method. For example, when implementing the VAD method through two reaction burners, the rod-shaped base material 1 and the porous glass layer 2 can be synthesized at the same time.
棒状母材ｌ外周に多孔質ガラス層２を形成した後は、こ
れらを焼結して透明ガラス化する。After forming the porous glass layer 2 on the outer periphery of the rod-shaped base material 1, the porous glass layer 2 is sintered to form transparent glass.
この際の焼結はフッ素化剤を含む雰囲気中で行なわれる
が、当該焼結時、多孔質ガラス層２中の酸化ホウ素とフ
ッ素化剤中のフッ素とに親和性があってこれら酸化ホウ
素とフッ素とが強力に結合しようとする傾向を示すから
、その多孔質ガラス層２中には多量のフッ素が含有され
、かかる状態にて棒状母材ｌ、多孔質ガラス層２が透明
ガラス化される。This sintering is performed in an atmosphere containing a fluorinating agent, but at the time of sintering, boron oxide in the porous glass layer 2 has an affinity with fluorine in the fluorinating agent, and these boron oxides have an affinity for each other. Since fluorine shows a tendency to strongly bond, a large amount of fluorine is contained in the porous glass layer 2, and in this state, the rod-shaped base material 1 and the porous glass layer 2 are made into transparent glass. .
透明ガラス化後の棒状母材１．ガラス層２はそれぞれコ
ア用ガラス、クラッド用ガラスなるのであり、これらの
ガラスを備なえた光フアイバ母材を常法（加熱延伸）に
て紡糸することにｉり所望の光ファイバが得られる。Rod-shaped base material after transparent vitrification 1. The glass layer 2 is a glass for the core and a glass for the cladding, respectively, and a desired optical fiber can be obtained by spinning an optical fiber base material provided with these glasses by a conventional method (heat drawing).
つぎに本発明の他の実施例を第２図により説明すると、
この実施例では棒状母材ｌを高純度石英系の非多孔質ガ
ラス、すなわち透明ガラス製としたものである。Next, another embodiment of the present invention will be explained with reference to FIG.
In this embodiment, the rod-shaped base material l is made of high-purity quartz-based non-porous glass, that is, transparent glass.
この実施例の棒状母材１としては、例えばＭＣＶＤ法、
ＯＶＤ法、ＶＡＤ法などを介してつくられた透明ガラス
棒が採用される。As the rod-shaped base material 1 of this embodiment, for example, MCVD method,
Transparent glass rods made using the OVD method, VAD method, etc. are used.
上記棒状母材ｌの外周には前記と同じく酸化ホウ素を含
有せる高純度石英系の多孔質ガラス層２が形成されるの
であり、当該多孔質ガラス層２を形成する手段としては
ＶＡＤ法、ＯＶＤ法などが採用される。A high purity quartz-based porous glass layer 2 containing boron oxide is formed on the outer periphery of the rod-shaped base material 1 as described above, and methods for forming the porous glass layer 2 include the VAD method and the OV method. Laws etc. will be adopted.
このようにして棒状母材ｌの外周に形成された多孔質ガ
ラス層２は、これも前記と同じくフッ素化剤を含む雰囲
気中で焼結され、透明ガラス化される。The porous glass layer 2 thus formed on the outer periphery of the rod-shaped base material 1 is sintered in an atmosphere containing a fluorinating agent as described above, and is made into transparent glass.
この場合も酸化ホウ素とフッ素との親和性により、上記
ガラス層２中には多量のフッ素が含有される。In this case as well, a large amount of fluorine is contained in the glass layer 2 due to the affinity between boron oxide and fluorine.
以下は前記と同様に光フアイバ母材が紡糸されて所定の
光ファイバが得られる。Thereafter, the optical fiber preform is spun to obtain a predetermined optical fiber in the same manner as described above.
なお、上記において多孔質ガラス層２に含有させるホウ
素の量は０．１モル％以上であることが望ましく、その
上限は通常２５モル％以′下マあ〜る・
フッ素化剤としてはＳ Ｆ ｅ 、 ＣＦ ａ 、 Ｃ
２Ｆ ｅおよびＣＣｌ２Ｆ２など、気体状フッ素化合物
が使用できる。In the above, the amount of boron contained in the porous glass layer 2 is preferably 0.1 mol% or more, and the upper limit is usually 25 mol% or less.The fluorinating agent is SF. e, CFa, C
Gaseous fluorine compounds can be used, such as 2Fe and CCl2F2.
上記多孔質ガラス層２を焼結する際の雰囲気中にはフッ
素化剤とともにヘリウムガスが含まれていることが望ま
しい。It is desirable that the atmosphere in which the porous glass layer 2 is sintered contains helium gas together with a fluorinating agent.
当該焼結は多孔質ガラス層２の最低焼結温度よりも高い
温度で行なうのであり、その焼結温度は通常、１１００
〜１５００℃とする。The sintering is performed at a temperature higher than the minimum sintering temperature of the porous glass layer 2, and the sintering temperature is usually 1100°C.
~1500°C.
コア用ガラスとなる棒状母材ｌは低レイリー散乱性や耐
放射線性などを高めるとで高純度石英系とするのがよい
。The rod-shaped base material 1 serving as the core glass is preferably made of high-purity quartz to improve low Rayleigh scattering properties and radiation resistance.
つぎに本発明の具体例につき説明する。Next, specific examples of the present invention will be explained.
具体例１
水酸基８００ｐｐｍを含む高純度石英系（合成）ガラス
棒を棒状母材ｌとし、これを回転させながらその母材外
周にはＯＶＤ法により酸化ホウ素５モル％含有せる高純
度石英系の多孔質ガラス層２を形成した。Specific Example 1 A high-purity quartz-based (synthetic) glass rod containing 800 ppm of hydroxyl groups is used as a rod-shaped base material l, and while rotating this base material, high-purity quartz-based porous material containing 5 mol% of boron oxide is formed by OVD method. A glass layer 2 was formed.
つぎに上記ガラス層材の棒状母材ｌを、濃度１モル％の
六フッ化イオウ（ＳＦ６）を含むヘリウムガス雰囲気中
に入れ、１２５０℃の温度で加熱することにより多孔質
ガラス層２を焼結し、透明ガラス化した。Next, the rod-shaped base material l of the glass layer material is placed in a helium gas atmosphere containing sulfur hexafluoride (SF6) at a concentration of 1 mol%, and heated at a temperature of 1250°C to sinter the porous glass layer 2. It was cured and turned into transparent vitrification.
これによりコア、クラッド相互間の屈折率差が１．５％
となる光フアイバ母材が得られた。This results in a refractive index difference of 1.5% between the core and cladding.
An optical fiber base material was obtained.
この屈折率差１．５％は従来例における屈折率差０．６
％をかなり上回っており、実用的開口数をもつ光ファイ
バを得るのに十分な値であった。This refractive index difference of 1.5% is 0.6% in the conventional example.
%, which was sufficient to obtain an optical fiber with a practical numerical aperture.
具体例２
ｖＡＤ法により高純度石英系の多孔質ガラスからなる棒
状母材ｌをつくりながら、該棒状母材ｌに酸化ホウ素８
モル％含有の高純度石英系多孔質ガラス層２を形成した
。Specific example 2 While making a rod-shaped base material l made of high-purity quartz-based porous glass by the vAD method, boron oxide 8 was added to the rod-shaped base material l.
A high-purity quartz-based porous glass layer 2 containing mol % was formed.
つぎに上記多孔質棒状母材を、０．８モル％の０２Ｆ８
を含むヘリウムガス雰囲気中で加熱焼結し、透明ガラス
化した。Next, the porous rod-shaped base material was mixed with 0.8 mol% of 02F8.
The material was heated and sintered in a helium gas atmosphere containing transparent glass.
これにより得られた光フアイバ母材の前記屈折率差は１
．２％であり、この場合も従来例の値を上回ることとな
った。The refractive index difference of the optical fiber base material thus obtained is 1
．． 2%, which in this case also exceeded the value of the conventional example.
（発明の効果）
以上説明した通り、本発明によるときは棒状母材外周に
多孔質ガラス層を形成するとき、これにあらかじめ酸化
ホウ素を含有させておき、その掻除多孔質ガラス層をフ
ッ素化側含有雰囲気中で焼結するといった二段階の工程
をとるから、不本意な生成物を生ずることなく酸化ホウ
素とフッ素との親和力により、多孔質ガラス層中に多量
のフッ素をドープすることができ、しかも酸化ホウ素は
石英ガラス中に比較的均一に分布するので、これを介在
としてフッ素も該ガラス中に分布するようになり、した
がってフッ素が多量かつ均一にドープされた石英系光フ
アイバ母材が製造できる。(Effects of the Invention) As explained above, according to the present invention, when a porous glass layer is formed on the outer periphery of a rod-shaped base material, boron oxide is contained in the porous glass layer in advance, and the porous glass layer is fluorinated. Because it takes a two-step process of sintering in a side-containing atmosphere, it is possible to dope a large amount of fluorine into the porous glass layer due to the affinity between boron oxide and fluorine without producing any unwanted products. Furthermore, since boron oxide is distributed relatively uniformly in quartz glass, fluorine is also distributed in the glass through the intervening presence of boron oxide, so that a silica-based optical fiber base material doped with a large amount and uniformly of fluorine is obtained. Can be manufactured.
第１図、ＭＳ２図は本発明方法の各実施例により製造さ
れる光フアイバ母材の略示説明図である。
ｌ・・・棒状母材
２・・・多孔質ガラス層
代理人 弁理士 斎藤 義雄
第１図
第２図FIGS. 1 and 2 are schematic illustrations of optical fiber preforms manufactured by each embodiment of the method of the present invention. l... Rod-shaped base material 2... Porous glass layer agent Yoshio Saito, patent attorney Figure 1 Figure 2
Claims (1)
なる棒状母材の外周に、酸化ホウ素含有の高純度石英か
らなる多孔質ガラス層を形成した後、その多孔質ガラス
層を、フッ素化剤を含む雰囲気中にて焼結することを特
徴とする石英系光フアイバ母材の製造方法。After forming a porous glass layer made of high-purity quartz containing boron oxide on the outer periphery of a rod-shaped base material made of high-purity quartz-based porous glass or non-porous glass, the porous glass layer is treated with a fluorinating agent. 1. A method for producing a quartz-based optical fiber base material, which comprises sintering in an atmosphere containing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3682784A JPS60180928A (en) | 1984-02-28 | 1984-02-28 | Production of quartz base material for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3682784A JPS60180928A (en) | 1984-02-28 | 1984-02-28 | Production of quartz base material for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60180928A true JPS60180928A (en) | 1985-09-14 |
| JPS6251215B2 JPS6251215B2 (en) | 1987-10-29 |
Family
ID=12480573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3682784A Granted JPS60180928A (en) | 1984-02-28 | 1984-02-28 | Production of quartz base material for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60180928A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0547335A2 (en) * | 1991-12-16 | 1993-06-23 | Corning Incorporated | Method of making fluorine/boron doped silica tubes |
| EP0738691A2 (en) * | 1990-11-09 | 1996-10-23 | Corning Incorporated | Method of forming an elongated glass article |
| EP2712848A1 (en) * | 2012-09-27 | 2014-04-02 | Heraeus Quarzglas GmbH & Co. KG | Hydrogen-assisted fluorination of soot bodies |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS642106U (en) * | 1987-06-24 | 1989-01-09 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5567533A (en) * | 1978-11-07 | 1980-05-21 | Nippon Telegr & Teleph Corp <Ntt> | Production of glass base material for light transmission |
-
1984
- 1984-02-28 JP JP3682784A patent/JPS60180928A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5567533A (en) * | 1978-11-07 | 1980-05-21 | Nippon Telegr & Teleph Corp <Ntt> | Production of glass base material for light transmission |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0738691A2 (en) * | 1990-11-09 | 1996-10-23 | Corning Incorporated | Method of forming an elongated glass article |
| EP0738691A3 (en) * | 1990-11-09 | 1997-03-19 | Corning Inc | Method of forming an elongated glass article |
| EP0547335A2 (en) * | 1991-12-16 | 1993-06-23 | Corning Incorporated | Method of making fluorine/boron doped silica tubes |
| EP2712848A1 (en) * | 2012-09-27 | 2014-04-02 | Heraeus Quarzglas GmbH & Co. KG | Hydrogen-assisted fluorination of soot bodies |
| WO2014048694A1 (en) * | 2012-09-27 | 2014-04-03 | Heraeus Quarzglas Gmbh & Co. Kg | Hydrogen-supported fluorination of soot bodies |
| CN104661972A (en) * | 2012-09-27 | 2015-05-27 | 赫罗伊斯石英玻璃股份有限两合公司 | Hydrogen-supported fluorination of soot bodies |
| US9416044B2 (en) | 2012-09-27 | 2016-08-16 | Heraeus Quarzglas Gmbh & Co. Kg | Hydrogen-supported fluorination of soot bodies |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6251215B2 (en) | 1987-10-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0249230B1 (en) | Glass preform for dispersion shifted single mode optical fiber and method for the production of the same | |
| Schultz | Fabrication of optical waveguides by the outside vapor deposition process | |
| US4690504A (en) | Quartz glass-made optical fibers and a method for the preparation thereof | |
| Blankenship et al. | The outside vapor deposition method of fabricating optical waveguide fibers | |
| US4812153A (en) | Method of making a glass body having a graded refractive index profile | |
| JPS62275035A (en) | Production of base material for optical fiber | |
| JPS60180928A (en) | Production of quartz base material for optical fiber | |
| JP4079204B2 (en) | Quartz glass tube for optical fiber preform and manufacturing method thereof | |
| EP0164127B1 (en) | Method for producing glass preform for optical fibers | |
| JP3106564B2 (en) | Manufacturing method of optical fiber and silica-based optical fiber | |
| JPS61191544A (en) | Quartz base optical fiber | |
| JPS62108744A (en) | Transparent vitrification method of porous glass base material | |
| JPS6131324A (en) | Production of base material for optical fiber | |
| JPH0463365B2 (en) | ||
| US5641333A (en) | Increasing the retention of Ge02 during production of glass articles | |
| JPH038743A (en) | Optical fiber preform and preparation thereof | |
| JP4565221B2 (en) | Optical fiber preform | |
| JPS6289B2 (en) | ||
| CA2458680A1 (en) | Reconstructed glasses for fibre optic applications | |
| JPH0551542B2 (en) | ||
| JPH0327491B2 (en) | ||
| JPS6221725A (en) | Production of base material for optical fiber | |
| AU698054B2 (en) | Increasing the retention of GeO2 during production of glass articles | |
| JPS60231432A (en) | Manufacture of quartz series optical fiber base material | |
| JPS60145927A (en) | Production of base material for optical fiber |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |