JPS62216936A - Production of porous base material for optical fiber - Google Patents
Production of porous base material for optical fiberInfo
- Publication number
- JPS62216936A JPS62216936A JP5657486A JP5657486A JPS62216936A JP S62216936 A JPS62216936 A JP S62216936A JP 5657486 A JP5657486 A JP 5657486A JP 5657486 A JP5657486 A JP 5657486A JP S62216936 A JPS62216936 A JP S62216936A
- Authority
- JP
- Japan
- Prior art keywords
- glass
- cladding
- temp
- base material
- 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
- 239000000463 material Substances 0.000 title claims abstract description 35
- 239000013307 optical fiber Substances 0.000 title claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000011521 glass Substances 0.000 claims abstract description 76
- 238000005253 cladding Methods 0.000 claims abstract description 32
- 238000000151 deposition Methods 0.000 claims abstract description 27
- 230000008021 deposition Effects 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 24
- 239000010419 fine particle Substances 0.000 claims abstract description 9
- 230000015572 biosynthetic process Effects 0.000 claims description 22
- 238000003786 synthesis reaction Methods 0.000 claims description 22
- 230000002194 synthesizing effect Effects 0.000 abstract description 4
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 230000000717 retained effect Effects 0.000 abstract 1
- 238000009826 distribution Methods 0.000 description 11
- 238000004017 vitrification Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002737 fuel gas Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
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]
- C03B37/01413—Reactant delivery systems
- C03B37/0142—Reactant deposition burners
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/50—Multiple burner arrangements
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/60—Relationship between burner and deposit, e.g. position
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/70—Control measures
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geochemistry & Mineralogy (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
「産業上の利用分野ｊ
本発明はコア合成用バーナと複数本のクラッド合成用バ
ーナとを用いたＶＡＤ法により、光ファイバ用の多孔質
母材を製造する方法に関する。Detailed Description of the Invention: Industrial Field of Application The present invention relates to a method for manufacturing a porous preform for optical fibers by a VAD method using a core synthesis burner and a plurality of clad synthesis burners. .
「従来の技術Ｊ
光ファイバ用の多孔質ｌｌ材を製造する手段の一つにＶ
ＡＤ法があり、かかるＶＡＤ法によりシングルモード型
光ファイバの多孔質母材を製造する場合、−木のコア合
成用バーナと複数本のクラッド合成用バーナとを用いる
のが一般である。"Conventional technology J: One of the means of manufacturing porous materials for optical fibers is V
There is an AD method, and when a porous base material for a single-mode optical fiber is manufactured by the VAD method, a burner for synthesizing the wood core and a plurality of burners for synthesizing the cladding are generally used.
その理由は、シングルモード型光ファイバにおけるコア
径／クラツド径が約ｌ／１３にもなるため。The reason for this is that the core diameter/cladding diameter in a single mode optical fiber is approximately 1/13.
多孔質母材の作製段階においてクラッド用ガラス層の外
径を大きくし、所定の外径比を確保しようとするからで
ある。This is because the outer diameter of the cladding glass layer is increased in the step of producing the porous base material to ensure a predetermined outer diameter ratio.
周知の通り、上記ＶＡＤ法ではコア合成用へ−すを介し
て生成されたガラス微粒子をターゲットの下端に堆積さ
せてコア用ガラス層を形成すると同時に、複数本のクラ
ッド合成用／ヘーナをして生成されたガラス微粒子をコ
ア用ガラス層の外周に堆積させてクラッド用ガラス層を
形成する。As is well known, in the above-mentioned VAD method, the glass particles generated through the core synthesis heath are deposited on the lower end of the target to form a core glass layer, and at the same time, multiple cladding synthesis/heena layers are deposited on the lower end of the target. The generated glass particles are deposited on the outer periphery of the core glass layer to form a cladding glass layer.
この際、クラッド合成用の各バーナは、これらの火炎が
相互に干渉してガラス堆積面における温度分布を形成す
る。At this time, the flames of the burners for cladding synthesis interfere with each other to form a temperature distribution on the glass deposition surface.
第１図は上記ＶＡＤ法における多孔質母材の作製状況を
その多孔質ｉｆＪ材の温度の！１１とともに示したもの
であり、第２図は多孔！ｌ！ｔｍ材の嵩密度を示したも
のである。Figure 1 shows the preparation status of the porous base material using the above VAD method and the temperature of the porous ifJ material. 11, and Figure 2 is porous! l! This figure shows the bulk density of tm material.
第１図、第２図において、 １０は多孔質母材、１１は
コア用ガラス層、１２．１３．１４はクラッド用ガラス
層であり、２１はコア合成用バーナ、２２．２３．２４
はクラッド合成用バーナである。1 and 2, 10 is a porous base material, 11 is a core glass layer, 12.13.14 is a cladding glass layer, 21 is a core synthesis burner, 22.23.24
is a burner for cladding synthesis.
第１図の温度分布は多孔質母材１０の軸心線ａ−ａ’上
における望ましい状態であり、この温度分布の場合、各
部の温度差が小さいが、従来のＶＡＤ法では、多孔質母
材１０におけるガラス堆積面の温度分布につき、技術的
配慮がなされていないため、そのガラス堆積面での温度
差が太きものとなっている。The temperature distribution shown in FIG. 1 is a desirable state on the axis a-a' of the porous base material 10. In this temperature distribution, the temperature difference in each part is small, but in the conventional VAD method, the porous base material 10 Since no technical consideration has been given to the temperature distribution on the glass deposition surface of the material 10, the temperature difference on the glass deposition surface is large.
自明の通り、ガラス層の焼結度が温度に比例するため、
ガラス堆積面の温度が高いときはガラス層が硬くなり、
逆にその温度が低ときはガラス層が軟らかくなり、した
がって、多孔質母材のガラス堆積面に温度差がある場合
、第２図のごとく、各ガラス層に粗密が生じる。As is obvious, since the degree of sintering of the glass layer is proportional to the temperature,
When the temperature of the glass deposition surface is high, the glass layer becomes hard,
On the other hand, when the temperature is low, the glass layer becomes soft, and therefore, if there is a temperature difference between the glass deposition surfaces of the porous base material, each glass layer becomes dense and dense, as shown in FIG.
ｒ発明が解決しようとする問題点」
上述した従来法の場合、多孔質ｆす材のガラス堆積面に
温度差があり、各ガラス層に粗密が生じるため、これに
起因した下記の問題が生じる。``Problems to be Solved by the Invention'' In the conventional method described above, there is a temperature difference on the glass deposition surface of the porous fusing material, and each glass layer is uneven, resulting in the following problems. .
その一つは多孔質母材に割れ（クラック）が発生しやす
くなる。One of them is that cracks are more likely to occur in the porous base material.
これは、多孔質は材の合成後に温度が下がり、母材自身
が収縮する際、各ガラス層の粗密により応力が均一に加
わらなくなるため１割れが生じると考えられる。This is thought to be due to the fact that when the temperature of the porous material decreases after synthesis and the base material itself contracts, stress is no longer applied uniformly due to the density of each glass layer, resulting in single cracks.
他の一つは多孔質母材を透明ガラス化した際に気泡が発
生する。Another problem is that bubbles are generated when a porous base material is made into transparent glass.
これは、透明ガラス化速度が各ガラス層の粗密により異
なり、密なる部分の透明ガラス化が進行するのに対し、
粗なる部分の透明ガラス化がとり残されるため、気泡が
発生すると考えられる。This is because the rate of transparent vitrification differs depending on the density of each glass layer, and transparent vitrification progresses in denser areas.
It is thought that bubbles are generated because the transparent vitrification of the rough parts is left behind.
一方、クラッド合成用バーナとして、−木の大型バーナ
を用いる場合、広い範囲で均一な温度のｔ１ｉを得るこ
とはむずかしく、かかる手段も、結果的に、Ｌ記と同様
の問題が生じる。On the other hand, when a large -wood burner is used as a burner for cladding synthesis, it is difficult to obtain a uniform temperature t1i over a wide range, and such a method also results in the same problem as in Section L.
本発明は上記の問題点に鑑み、ガラス微粒子堆積時にお
ける各クラッド用ガラス層の温度分布を適切にして、ク
ラックの発生が阻止できる。しかも透明ガラス化時の気
泡の少ない多孔質母材が製造できる方法を提供しようと
するものである。In view of the above-mentioned problems, the present invention makes it possible to prevent the occurrence of cracks by appropriately controlling the temperature distribution of each cladding glass layer during the deposition of glass fine particles. Furthermore, the present invention aims to provide a method for producing a porous base material with fewer bubbles during transparent vitrification.
ｒ問題点を解決するための手段Ｊ
本発明は所期の目的を達成するため、コア合成用バーナ
と、複数本のクラッド合成用バーナとを用いたＶＡＤ法
により、ガラス微粒子を堆積成長させて、コア用ガラス
層と、その外周のクランド用ガラス層とならなる光ファ
イバ用の多孔質母材を製造する方法において、クラッド
用ガラス層のガラス堆積面における最低温度部、最高温
度部のうち、その最低温度部を５５０℃以上に保持し、
これら最低温度部、最高温度部の温度差が２００℃以内
となるようにして、ガラス微粒子を堆積させることを特
徴とする。Means for Solving Problems J In order to achieve the intended purpose of the present invention, glass fine particles are deposited and grown by a VAD method using a core synthesis burner and a plurality of clad synthesis burners. , in a method for manufacturing a porous preform for an optical fiber that becomes a core glass layer and a crund glass layer on the outer periphery, the lowest temperature part and the highest temperature part on the glass deposition surface of the cladding glass layer, The lowest temperature part is maintained at 550℃ or higher,
The glass particles are deposited such that the temperature difference between the lowest temperature part and the highest temperature part is within 200°C.
「作用１
本発明のＶＡＤ法により多孔質母材を製造するとき、ク
ラッド用ガラス層のガラス堆積面での最低温度部を５５
０℃以上に保持し、その堆積面における最低温度部、最
高温度部の温度差が２００℃以内となるようにして、ガ
ラス微粒子を堆積させるから、各ガラス層の適切な嵩密
度（硬さ）が得られるとともに、各ガラス層の温度分布
がほぼ均一化し、良質の多孔質母材が得られる。"Effect 1 When manufacturing a porous base material by the VAD method of the present invention, the lowest temperature part on the glass deposition surface of the glass layer for cladding is set to 55%.
Glass particles are deposited by maintaining the temperature at 0°C or higher and keeping the temperature difference between the lowest temperature part and the highest temperature part within 200°C on the deposition surface, so each glass layer has an appropriate bulk density (hardness). At the same time, the temperature distribution of each glass layer becomes almost uniform, and a porous base material of good quality is obtained.
すなわち、上記最低温度部が５５０℃未満の場合は、焼
結不足によるクラッド用ガラス層のクラックが発生し、
Ｅ記最低温度部、最高温度部の温度差が２００℃を越え
る場合は、各クラッド用ガラス層相互の粗密によりクラ
ックばかりか、透明ガラス化後のけ材に気泡をも多発す
るが、これら最低温度部、最高温度部につき、所定の条
件を満足させた場合、このような問題が発生しがたい。That is, if the lowest temperature part is less than 550°C, cracks will occur in the cladding glass layer due to insufficient sintering.
If the temperature difference between the lowest temperature part and the highest temperature part exceeds 200°C, not only will cracks occur due to the relative density of each cladding glass layer, but also bubbles will occur frequently in the glazing material after transparent vitrification. If predetermined conditions are satisfied for the temperature section and the maximum temperature section, such problems are unlikely to occur.
ｒ実 施 例Ｊ
以下、本発明方法の実施例につき、図面を参照して説明
する。rExample J Examples of the method of the present invention will be described below with reference to the drawings.
本発明方法は第１図で述べたＶＡＤ法ものと基本的に同
じである。The method of the present invention is basically the same as the VAD method described in FIG.
すなわち第１図のごとく、コア合成用バーナ２１を介し
て生成されたガラス微粒子を、回転しながら引き上げら
れるターゲット（図示せず）の下端に堆積させてコア用
ガラスＦ！：１１を形成すると同時に、複数本のクラッ
ド合成用バーナ２２．２３．２４をして生成されたガラ
ス微粒子をコア用ガラス層１１の外周に堆積させてクラ
ッド用ガラス層１２．１３．１４を形成し、かくて多孔
質母材１０を製造する。That is, as shown in FIG. 1, glass fine particles generated through the core synthesis burner 21 are deposited on the lower end of a target (not shown) that is pulled up while rotating to form the core glass F! : At the same time as forming the core glass layer 11, glass fine particles generated by using a plurality of cladding synthesis burners 22, 23, 24 are deposited on the outer periphery of the core glass layer 11 to form a cladding glass layer 12, 13, 14. In this way, the porous base material 10 is manufactured.
この際、使用されるバーナ２１．２２．２３．２４はそ
れぞれ多重管構造を有し、これらバーナ２１〜２４の各
流路には、気相のガラス原料（ＳｉＣ１４） 、気相の
ドープ原料（Ｇｅ系、Ｐ系、Ｂ系など）、燃料ガス（Ｈ
２） 、助燃ガス（０２） 、シールガス（Ａｒなどの
不活性ガス）が供給され、これら各ガスの火炎加水分解
反応によりスート状のガラス微粒子が生成さ 未発明で
は、かかるＶＡＤ法により多孔質母材を製造するとき、
クラッド用ガラス層１２．１３．１４のガラス堆積面で
の最低温度部を５５０℃以上に保持し、その堆積面にお
ける最低温度部、最高温度部の湿度差が２００℃以内と
なるようにするが、その具体的方法として、丁記に例示
する手段が単一または複合して用いられる。At this time, the burners 21, 22, 23, and 24 used each have a multi-tube structure, and each flow path of these burners 21 to 24 contains a vapor phase glass raw material (SiC14), a vapor phase dope material ( Ge-based, P-based, B-based, etc.), fuel gas (H
2) A combustion assisting gas (02) and a sealing gas (inert gas such as Ar) are supplied, and soot-like glass particles are generated by a flame hydrolysis reaction of each of these gases. When manufacturing the base material,
The lowest temperature part on the glass deposition surface of the cladding glass layer 12.13.14 should be maintained at 550°C or higher, and the humidity difference between the lowest temperature part and the highest temperature part on the deposition surface should be within 200°C. As a specific method, the means listed below may be used singly or in combination.
■ ガラス堆積面に対する各クラッド合成用バーナの間
隔を調整する。■ Adjust the spacing of each cladding synthesis burner relative to the glass deposition surface.
■ 各クラッド合成用バーナへの燃料ガス州。■ Fuel gas supply to each cladding synthesis burner.
助燃カス量、シールカス賃をコントロールする。Controls the amount of auxiliary combustion scum and the amount of seal scum.
■ 各クラッド合成用バーナへの気相原料のチャージ量
をコントロールする。■ Control the amount of gas phase raw material charged to each cladding synthesis burner.
■ 各クラッド合成用へ−すにおけるバーナフードの深
さを変えて火炎の広がりをコントロールする。■ Control flame spread by varying the depth of the burner hood in each cladding cell.
上記いずれの手段を採用してもガラス堆積面の温度分布
は変化する。No matter which of the above methods is employed, the temperature distribution on the glass deposition surface changes.
所定の条件が満足できるならば、いずれのパラメータを
動かしてもよい。Any parameter may be changed as long as the predetermined conditions are satisfied.
第３図はガラス堆積面に対するクラッド合成用／ヘーナ
の間隔（ガラス堆積面とバーナ先端との間隔）を５０ｍ
ｍに設定した場合のガラス堆積面の温度分布である。Figure 3 shows the distance between the cladding synthesis/hener and the glass deposition surface (the distance between the glass deposition surface and the burner tip) of 50 m.
This is the temperature distribution on the glass deposition surface when the temperature is set to m.
第３図の場合、火炎相互の干渉がなく、そのため同図２
１、Ｐ２の箇所には、火炎相互の間隙による低温部があ
られれている。In the case of Figure 3, there is no mutual interference between the flames, so
1. At the location P2, there is a low temperature area due to the gap between the flames.
このような現象があられれたＶＡＤ法では、その低温部
の嵩密度が低いため、多孔質母材の割れが多発した。In the VAD method where such a phenomenon occurred, cracks in the porous base material occurred frequently because the bulk density of the low temperature part was low.
前記第１図はガラス堆積面に対するクラッド合成用バー
ナの間隔を３０ｍｍに設定した場合のガラス堆積面の温
度分布である。FIG. 1 shows the temperature distribution on the glass deposition surface when the distance between the cladding synthesis burner and the glass deposition surface is set to 30 mm.
この場合は、火炎相互が干渉し、ガラス堆積面における
最低温度も上昇したため、多孔質母材の割れは発生しな
かった。In this case, the flames interfered with each other and the lowest temperature on the glass deposition surface also increased, so no cracking of the porous base material occurred.
その後、当該多孔′Ａ母材を透明ガラス化したところ、
気泡の発生が前者に比べて格段に少なく、良好な透明ガ
ラス母材が得られた。After that, when the porous 'A base material was made into transparent glass,
The generation of bubbles was much less than in the former case, and a good transparent glass base material was obtained.
１発明の効果１
以上説明した通り、本発明方法によるときは、所定のＶ
ＡＤ法において、クラッド用ガラス層のガラス堆積面に
おける最低温度部、最高温度部のうち、その最低温度部
を５５０℃以上に保持し、これら最低温度部、最高温度
部の温度差が２００℃以内となるようにして、ガラス微
粒子を堆積させるから、クラックの生じがたい、かつ、
爾後の透明ガラス化に際しても気泡が多発することのな
い多孔質母材が製造できる。1 Effect of the invention 1 As explained above, when using the method of the present invention, the predetermined V
In the AD method, the lowest temperature part of the lowest temperature part and the highest temperature part on the glass deposition surface of the cladding glass layer is maintained at 550°C or higher, and the temperature difference between the lowest temperature part and the highest temperature part is within 200°C. Since the glass fine particles are deposited in such a manner, cracks are difficult to occur, and
It is possible to produce a porous base material that does not generate many bubbles even during subsequent transparent vitrification.
第１図は本発明方法の一実施例を多孔￥１母材の温度分
布とともに略示した説明図、第２図は多孔質母材の嵩密
度を示した説明図、第３図は従来法おける多孔質母材の
温度分布を示した説明図である。
１０・拳・・・多孔質母材
１１・・・・拳コア用ガラス層
１２〜１４・の−クラッド用ガラス層
２１１１・・・・コア合成用バーナ
２２〜２４・１１や合成用へ−す
代理人 弁理士 斎 藤 義 雄
第１図
１ｏＬ
第 ２ 図Fig. 1 is an explanatory diagram schematically showing an example of the method of the present invention together with the temperature distribution of the porous base material, Fig. 2 is an explanatory diagram showing the bulk density of the porous base material, and Fig. 3 is an explanatory diagram showing the conventional method. FIG. 2 is an explanatory diagram showing the temperature distribution of a porous base material at 10. Fist... Porous base material 11... Glass layer for fist core 12-14. Glass layer for cladding 2111... Burner for core synthesis 22-24. 11 and heath for synthesis. Agent Patent Attorney Yoshio Saito Figure 1 1oL Figure 2
Claims (1)
を用いたＶＡＤ法により、ガラス微粒子を堆積成長させ
て、コア用ガラス層と、その外周のクラッド用ガラス層
とからなる光ファイバ用の多孔質母材を製造する方法に
おいて、クラッド用ガラス層のガラス堆積面における最
低温度部、最高温度部のうち、その最低温度部を５５０
℃以上に保持し、これら最低温度部、最高温度部の温度
差が２００℃以内となるようにして、ガラス微粒子を堆
積させることを特徴とする光ファイバ用多孔質母材の製
造方法。Glass fine particles are deposited and grown using a VAD method using a core synthesis burner and a plurality of cladding synthesis burners to form a porous optical fiber consisting of a core glass layer and a cladding glass layer on its outer periphery. In the method for manufacturing a quality base material, the lowest temperature part of the glass deposition surface of the cladding glass layer is set to 550.
A method for producing a porous preform for an optical fiber, which comprises depositing glass fine particles while maintaining the temperature at or above .degree. C. so that the temperature difference between the lowest and highest temperature portions is within 200.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61056574A JP2583217B2 (en) | 1986-03-14 | 1986-03-14 | Method for producing porous base material for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61056574A JP2583217B2 (en) | 1986-03-14 | 1986-03-14 | Method for producing porous base material for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62216936A true JPS62216936A (en) | 1987-09-24 |
| JP2583217B2 JP2583217B2 (en) | 1997-02-19 |
Family
ID=13030919
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61056574A Expired - Fee Related JP2583217B2 (en) | 1986-03-14 | 1986-03-14 | Method for producing porous base material for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2583217B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56109834A (en) * | 1980-02-05 | 1981-08-31 | Nippon Telegr & Teleph Corp <Ntt> | Manufacture of base material for optical fiber |
| JPS6046942A (en) * | 1983-08-26 | 1985-03-14 | Sumitomo Electric Ind Ltd | Preparation of parent material for optical fiber |
-
1986
- 1986-03-14 JP JP61056574A patent/JP2583217B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56109834A (en) * | 1980-02-05 | 1981-08-31 | Nippon Telegr & Teleph Corp <Ntt> | Manufacture of base material for optical fiber |
| JPS6046942A (en) * | 1983-08-26 | 1985-03-14 | Sumitomo Electric Ind Ltd | Preparation of parent material for optical fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2583217B2 (en) | 1997-02-19 |
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