JP3044087B2 - Transparent vitrification method of porous glass base material - Google Patents
Transparent vitrification method of porous glass base materialInfo
- Publication number
- JP3044087B2 JP3044087B2 JP11223891A JP11223891A JP3044087B2 JP 3044087 B2 JP3044087 B2 JP 3044087B2 JP 11223891 A JP11223891 A JP 11223891A JP 11223891 A JP11223891 A JP 11223891A JP 3044087 B2 JP3044087 B2 JP 3044087B2
- Authority
- JP
- Japan
- Prior art keywords
- base material
- transparent
- porous glass
- glass base
- temperature
- 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.)
- Expired - Fee Related
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
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)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、多孔質ガラス母材、
特に光ファイバ用多孔質ガラス母材の透明ガラス化方法
に関するものである。The present invention relates to a porous glass base material,
In particular, the present invention relates to a method for making a porous glass base material for optical fibers transparent.
【０００２】[0002]
【従来の技術】例えば、ＶＡＤ法や外付け法によって得
られた光ファイバ用多孔質ガラス母材の透明ガラス化に
際しては、この母材を垂直に吊るし、所定の速度で加熱
炉内に導入して、その一端から傾斜焼結させて透明ガラ
ス化している。この方法における炉内の温度コントロー
ルは、ヒータの表面温度を測定することで行っており、
一般的には常に一定の温度となるように制御している。2. Description of the Related Art For example, when a porous glass preform for an optical fiber obtained by a VAD method or an external method is formed into a transparent glass, the preform is suspended vertically and introduced into a heating furnace at a predetermined speed. Then, it is tilted and sintered from one end to form a transparent glass. In this method, the temperature inside the furnace is controlled by measuring the surface temperature of the heater.
Generally, the temperature is controlled to be always constant.
【０００３】ところが、この方法では、多孔質ガラス母
材の透明ガラス化が次第に進行すると、それにつれて母
材の下端部の透明ガラス化済みの部分の重量が次第に増
加する。このため、ヒータ温度、ひいては炉内温度が一
定であると、透明ガラス化される部分の粘度は一定であ
るから、それより下の透明ガラス化済みの部分の重量の
増加につれて透明ガラス化部の伸びが増すことになり、
これが母材径の変動の要因をなしていた。However, in this method, as the vitrification of the porous glass base material gradually progresses, the weight of the transparent vitrified portion at the lower end of the base material gradually increases. For this reason, when the heater temperature, and thus the furnace temperature, is constant, the viscosity of the portion to be vitrified is constant, and therefore, as the weight of the transparent vitrified portion below that increases, the transparent vitrified portion becomes Growth will increase,
This was the cause of the variation of the base metal diameter.
【０００４】この母材径の変動は、線引張力の変動要因
をなすが、通常の石英系ファイバの場合はさほど影響が
少なく多少の変動（平均値×０．２）／ｍは許容範囲と
されていた。[0004] This variation in the base material diameter causes a variation in the drawing tension. However, in the case of a normal quartz fiber, the variation is not so large and a slight variation (average value x 0.2) / m is considered as an allowable range. It had been.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、フッ素
ドープファイバのように線引張力の許容範囲の小さいフ
ァイバが現われるに至り、線引張力の変動の主な原因で
ある母材外径の変動幅の許容範囲が従来より厳しいもの
となってきた。中でも、純粋石英コア−フッ素ドープク
ラッド単一モードファイバ母材の製造では、クラッドの
製造を複数回に分けて行っているため、前工程で形成さ
れ、既にフッ素がドープされたクラッドの一部を有する
中間母材はフツ素がドープされていることで、純粋石英
ガラスロッドと比較して粘度が１／２〜１／１０と低
く、透明ガラス化温度を一定になるように制御するだけ
の従来法はもはや通用しないものとなってしまった。However, the emergence of a fiber having a small allowable range of the drawing tension, such as a fluorine-doped fiber, and the fluctuation of the outer diameter of the base material which is a main cause of the fluctuation of the drawing tension. The allowable range has become stricter than before. Above all, in the production of a pure quartz core-fluorine-doped clad single-mode fiber preform, since the production of the clad is performed in a plurality of times, a part of the clad formed in the previous step and already doped with fluorine is produced. Since the intermediate base material is doped with fluorine, its viscosity is 1/2 to 1/10 lower than that of pure quartz glass rods, and the conventional method only controls the transparent vitrification temperature to be constant. The law is no longer valid.
【０００６】[0006]
【課題を解決するための手段】この発明は、以上の観点
から多孔質ガラス母材、特に光ファイバ用多孔質ガラス
母材の透明ガラス化に際して、その長手方向に径変動の
ない一定の外径の透明ガラス母材を提供しようとするも
ので、垂直に支承された多孔質ガラス母材を加熱炉内に
導入して、その先端から傾斜焼結させて透明ガラス化す
るに際して、透明ガラス化部分の温度を漸次低減するこ
とで解決を図ったものである。SUMMARY OF THE INVENTION The present invention has been made in view of the above points of view and has been made in view of the above. In order to provide a transparent glass preform, a vertically supported porous glass preform is introduced into a heating furnace, and from the tip thereof, when it is tilted and sintered to form a transparent glass, a transparent vitrified portion is formed. The problem was solved by gradually lowering the temperature of.
【０００７】一般的に、母材の伸び量は以下の式に見ら
れる関係にある。 （ｄｌ／ｄｔ）＝Ａ×Ｍ／η ｄｌ／ｄｔ 伸び量 Ａ 定数 Ｍ ヒータを通過した透明ガラス化済みの部分
の重量 η 透明ガラス化部の粘度Generally, the amount of elongation of a base material has a relationship as shown in the following equation. (Dl / dt) = A × M / η dl / dt Elongation A constant M Weight of the portion of the vitrified glass that passed through the heater η Viscosity of the transparent vitrified portion
【０００８】したがって、母材の伸び量を一定に、すな
わち母材の径を一定にするためにはヒータを通過した透
明ガラス化済みの部分の重量Ｍが増すにつれて透明ガラ
ス化部の粘度ηを大に、ひいては透明ガラス化温度を低
く設定するようにする。Accordingly, in order to keep the amount of elongation of the base material constant, that is, to keep the diameter of the base material constant, the viscosity η of the transparent vitrified portion is increased as the weight M of the transparent vitrified portion passing through the heater increases. In general, the transparent vitrification temperature is set to be low.
【０００９】[0009]
【作用】母材の透明ガラス化が進行するにつれて、透明
ガラス化済みの部分の重量が増加するが、それにともな
ってヒータの温度が漸次低下するので、透明ガラス化部
の粘度は低下し、その伸びは常に一定に維持され、径変
動のない母材が得られる。As the vitrification of the base material progresses, the weight of the transparent vitrified portion increases, but the temperature of the heater gradually decreases accordingly, so that the viscosity of the transparent vitrified portion decreases. The elongation is always kept constant, and a base material having no diameter variation can be obtained.
【００１０】[0010]
【実施例】図１は、母材の伸び量を一定に、すなわち母
材の径を一定にするための、ヒータを通過した透明ガラ
ス化済みの部分の重量Ｍと透明ガラス化温度との関係を
示すグラフである。なお、透明ガラス化済みの部分の重
量Ｍは、炉内への母材の降下速度から知ることができ
る。FIG. 1 is a graph showing the relationship between the weight M of a transparent vitrified portion that has passed through a heater and the transparent vitrification temperature in order to keep the elongation of the base material constant, that is, to keep the diameter of the base material constant. FIG. The weight M of the transparent vitrified portion can be known from the descending speed of the base material into the furnace.
【００１１】この図１のグラフに基づいて、ヒータ温度
を漸減させつつ母材の透明ガラス化を図った。図２は、
その結果を示している。図から明らかなように、得られ
た母材の有効部３００ｍｍの長さの両端の径差は０．７
１ｍｍであった。Based on the graph of FIG. 1, the vitrification of the base material was attempted while gradually reducing the heater temperature. FIG.
The results are shown. As is clear from the figure, the diameter difference between both ends of the effective portion 300 mm length of the obtained base material is 0.7.
1 mm.
【００１２】因みに、ヒータ温度一定で透明ガラス化さ
れた母材の長さ方向の径差は、１．４３ｍｍであつた。Incidentally, the diameter difference in the longitudinal direction of the base material which was made vitrified at a constant heater temperature was 1.43 mm.
【００１３】[0013]
【発明の効果】この発明方法は、以上のように透明ガラ
ス化済みの部分の重量が増すにつれてヒータの温度を漸
減して、常に母材の伸び量が一定になるようにしたの
で、得られる母材の径変動が抑制され、以て線引張力の
変動が抑制される。As described above, the method of the present invention is obtained because the heater temperature is gradually decreased as the weight of the transparent vitrified portion increases, so that the elongation of the base material is always constant. Fluctuations in the diameter of the base material are suppressed, and thus fluctuations in the drawing tension are suppressed.
【図１】この発明方法により得られた母材の両端の径差
を示すグラフである。FIG. 1 is a graph showing a diameter difference between both ends of a base material obtained by the method of the present invention.
【図２】母材の伸び量を一定にするための透明ガラス化
済みの部分の重量と透明ガラス化温度との関係を示すグ
ラフである。FIG. 2 is a graph showing a relationship between the weight of a transparent vitrified portion and a transparent vitrification temperature for keeping the amount of elongation of a base material constant.
Claims (2)
熱炉内に導入して、その先端から傾斜焼結させて透明ガ
ラス化するに際して、透明ガラス化部分の温度を漸次低
減することを特徴とする多孔質ガラス母材の透明ガラス
化方法。1. When a vertically supported porous glass base material is introduced into a heating furnace and is inclinedly sintered from its tip to form a transparent glass, the temperature of the transparent vitrified portion is gradually reduced. A transparent vitrification method for a porous glass base material.
あることを特徴とする請求項１記載の多孔質ガラス母材
の透明ガラス化方法。2. The method according to claim 1, wherein the porous glass base material is a base material for an optical fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11223891A JP3044087B2 (en) | 1991-04-18 | 1991-04-18 | Transparent vitrification method of porous glass base material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11223891A JP3044087B2 (en) | 1991-04-18 | 1991-04-18 | Transparent vitrification method of porous glass base material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04321529A JPH04321529A (en) | 1992-11-11 |
| JP3044087B2 true JP3044087B2 (en) | 2000-05-22 |
Family
ID=14581704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11223891A Expired - Fee Related JP3044087B2 (en) | 1991-04-18 | 1991-04-18 | Transparent vitrification method of porous glass base material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3044087B2 (en) |
-
1991
- 1991-04-18 JP JP11223891A patent/JP3044087B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04321529A (en) | 1992-11-11 |
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