JP4495838B2 - Manufacturing method of glass preform for optical fiber - Google Patents
Manufacturing method of glass preform for optical fiber Download PDFInfo
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- JP4495838B2 JP4495838B2 JP2000238515A JP2000238515A JP4495838B2 JP 4495838 B2 JP4495838 B2 JP 4495838B2 JP 2000238515 A JP2000238515 A JP 2000238515A JP 2000238515 A JP2000238515 A JP 2000238515A JP 4495838 B2 JP4495838 B2 JP 4495838B2
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- Prior art keywords
- core
- preform
- optical fiber
- base material
- glass
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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
- C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
- C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
- C03B37/01228—Removal of preform material
-
- 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]
- C03B37/01466—Means for changing or stabilising the diameter or form of tubes or rods
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/02—Pure silica glass, e.g. pure fused quartz
- C03B2201/03—Impurity concentration specified
-
- 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
- C03B2201/07—Impurity concentration specified
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/10—Internal structure or shape details
- C03B2203/22—Radial profile of refractive index, composition or softening point
- C03B2203/24—Single mode [SM or monomode]
Description
【０００１】
【発明の属する技術分野】
本発明は、伝送損失の小さい光ファイバの製造に好適な光ファイバ用ガラス母材（以下、単に光ファイバ母材と称する）の製造方法に関する。
【０００２】
【従来の技術】
光ファイバ中に金属不純物が存在すると、伝送損失が増すことは過去の文献等で報告されている。このため、金属不純物を除去するために数々の工夫がなされている。特に、光の信号伝送が光ファイバのコア部分で行なわれるため、光ファイバ母材の製造時には、特にコア部分に金属不純物が含まれないように注意がはらわれている。
【０００３】
光ファイバ母材の製造は、ＳｉＣｌ4の様な液体原料の蒸気を酸水素火炎中に導入し、火炎反応によって生成したＳｉＯ2のガラス微粒子（スート）を堆積して多孔質ガラス母材とし、これを焼成ガラス化することによって行なわれている。この液体原料の蒸気を使用する方法は、蒸留過程で液体原料中の不純物を除去し易く、さらに、酸水素火炎中に導入するために蒸発させる際にも蒸留作用が働いて、原料ガス中の金属不純物量が極めて少なくなる。
【０００４】
さらに、得られた多孔質ガラスをハロゲンガス中で加熱処理することで、残留金属不純物はハロゲン化物に変換され、蒸気化してガラス外部に排出される。引き続き、これを焼結し透明ガラス化することによって、金属不純物の極めて少ない光ファイバ母材が得られる。
大型の光ファイバ母材を製造する場合は、このようにして、先ず、光ファイバ母材のコア部分となるコア母材を製造し、次いで、このコア母材の外側にクラッド部を外付けで形成している。
【０００５】
通常のステップ型のシングルモードファイバの場合、ファイバ径１２５μｍに対してコア径は１０μｍ程度と小さく、伝送される光信号がコアからその一部が浸みだして伝搬するため、コア母材を製造するとき、コアにクラッドの一部を付けた状態で製造するとよい。
コア母材の周囲にクラッド部を形成する方法としては、外付け法の他に、酸水素火炎中にガラス原料を導入し、生成する石英ガラススートをコア母材上に堆積するスート法、あるいは、別途用意した石英ガラス管にコア母材を挿入し、これらを溶着して一体化するジャケット法などが挙げられる。
【０００６】
【発明が解決しようとする課題】
このようにして製造した光ファイバ母材を線引して光ファイバとしたときに、金属不純物によるものと見られる伝送損失増が認められることがあり、問題となっていた。
そこで本発明は、金属不純物による伝送損失のない光ファイバ母材の製造方法を提供することを目的としている。
【０００７】
【課題を解決するための手段】
本発明の光ファイバ母材の製造方法は、ガラス微粒子を堆積させてコアとなるスート体を形成し、これを加熱焼成しガラス化してコア母材とし、この上に外付けでクラッド部を形成してコアとクラッドからなる光ファイバ用ガラス母材を製造する方法であって、該コア母材を得るに際し、ガラス微粒子を堆積させてコアとこの外周にクラッドの一部を形成し、これを加熱焼成しガラス化してコア母材とし、該コア母材の外周を０．１ｍｍ以上削ってこの表面近傍に含まれる金属不純物を除去した後、この上にクラッド部を形成し、該コア母材とこの上に形成されたクラッド部との界面が、中心から半径方向に約２０〜４０％の位置にコアと同心のリング状に位置するように形成し、該界面近傍での金属不純物濃度を１０ｐｐｂ以下とすることを特徴としている。
【０００８】
なお、コア母材の外周を削りとる量は０．１ｍｍ以上、好ましくは０．２ｍｍ以上とされる。外周を削りとる手段は、フッ化水素酸を用いて、あるいは酸水素火炎で行なう方法とするのが好ましい。
コア母材の加熱手段は電気抵抗加熱とするのが好ましい。また、コア母材上へのクラッド部の外付けは、スート法、ジャケット法のいずれで行なってもよい。シングルモード光ファイバは、上記光ファイバ母材を線引して得られる。
【０００９】
【発明の実施の形態】
本発明の光ファイバ母材の製造方法は、先ず、コアとこの外周にクラッドの一部を有するコア母材を形成し、この外周を削ってこの表面近傍に含まれる金属不純物を除去した後、この上にクラッド部を形成することにある。
光伝送部への不純物の混入を避けるためには、コア母材のクラッドの厚さを十分とった方がよいが、このクラッドが厚すぎるとコア母材の作製が困難になったり長時間を要し、外付けするクラッド部の厚さが相対的に小さくなり、製造コストが増すという問題が生じる。
【００１０】
このためコア母材のクラッド厚をコア径の４倍程度以下にすることで、光ファイバ母材の半径方向に占めるコア母材の割合が４０％以下（ガラス化前の堆積割合では１６％以下）になり、コア母材の作製が容易となる上、コスト的に有利な外付けで作製されるクラッド部の割合が十分とれ、光ファイバ母材を安価に提供できる。従って、光ファイバ母材の半径方向に占めるコア母材の割合は、これらを考慮して約２０〜４０％とされる。
【００１１】
スートを堆積させて作製した直後のコア母材には、ミリ単位の微少な外径変動が存在し、この母材を線引して光ファイバとすると、長手方向のモードフィールド径やカットオフ波長などの光学特性が母材の長手方向で変動する。
このため、クラッド部の外付け工程に入る前に、コア母材の外径変動を修正しておかねばならない。コア母材の外径変動を修正するには、コア母材を酸水素火炎や電気抵抗加熱炉などで軟化点付近まで加熱し、張力を加えて延伸しつつ外径を調整する。このとき、加熱雰囲気中に存在する金属不純物が、軟化状態にあるコア母材表面に取り込まれる。そして、この上に外付けでクラッド部が形成されると、光ファイバ母材中に金属不純物が残留することとなり、この母材を線引して光ファイバ化する際に、金属不純物が光伝搬部に拡散して伝送損失が増大するものと考えられる。
【００１２】
本発明の製造方法は、スートを堆積させてコアとこの外周にクラッドの一部を形成し、これを加熱焼成しガラス化した後、軟化点付近まで加熱・延伸し外径変動を修正してコア母材とし、その後、この外周をフッ化水素酸を用いて、あるいは酸水素火炎で半径方向に０．１ｍｍ以上削って所定の径に調整するとともに、ガラス化時及び外径修正時にコア母材の表面に付着した金属不純物を除去するものであり、このようにして、コアとこの外周にクラッドの一部を有するコア母材を作製し、さらにこの上にクラッド部を形成して光ファイバ母材が製造される。これによってコア母材とクラッド部との界面が中心から半径方向に約２０〜４０％の位置にコアと同心のリング状に形成され、界面近傍での金属不純物濃度は１０ｐｐｂ以下となり、伝送損失が極めて小さくなる。
【００１３】
【実施例】
（実験１）
先ず、コア／クラッド比の異なる３種類のコア母材（1，2，3）を作製し、電気抵抗加熱炉で軟化点付近にまで加熱・延伸して、外径をφ２０ｍｍ±１ｍｍに調整した。なお、コア径が約９μｍとなるようにコア母材を作製した。
作製したこれらのコア母材の一部を切り出し、外周表面を少量のフッ化水素酸で表面から約０．１ｍｍ溶解した。次に、この溶液中の金属不純物の含有量を分析して求めた。
【００１４】
分析は、先ず、溶液の一部を硝酸溶液に希釈してＩＣＰ−ＡＥＳ（原子発光分光分析）でＳｉ濃度を求めた。次いで溶液の残りに過酸化水素を加えて脱ケイ素を行い乾固し、再び少量の硝酸と過酸化水素を加えて溶解、濃縮し、その後水を加えてできた溶液をＩＣＰ−ＡＥＳで各種金属量を求めた。この金属量を前記Ｓｉから換算して得た溶解ＳｉＯ2量で除算して、コア母材表面ガラス中の金属濃度を求めた（分析１）。
上記フッ化水素で外周を溶解した試料（コア母材）に対して、フッ化水素酸でさらに表面から約０．１ｍｍ溶解し同様の分析を行った（分析２）。
この後、さらに表面を約０．１ｍｍ溶解して分析した（分析３）。
これらの結果をまとめて表１に示した。なお、分析３の結果は、表中の全ての元素が検出限界以下であったので表中への記載を省略した。
【００１５】
【表１】
上記分析から、次のことが明らかとなった。
（１）加熱直後のコア母材表面には金属不純物が数十ｐｐｂオーダーで存在する。このため、これを除去せずにこの上にクラッド部を外付けすると、光ファイバ母材のコア母材／クラッド界面に金属不純物が残留する。
（２）金属不純物の殆どは、コア母材の表面から約０．１ｍｍ以内に局在している。
（３）従って、コア母材の表面を約０．１ｍｍ削れば表面の金属不純物は７０％以上除去でき、さらに約０．１ｍｍすなわち合計約０．２ｍｍ削ると金属不純物をほぼ完全に除去できる。
【００１７】
金属不純物の発生源は、抵抗加熱体や電極の銅が微量蒸着したり、加熱炉の構造物のステンレス材料が蒸着したものと考えられる。
金属不純物をコア母材の表面から除去する方法には、フッ化水素酸による溶解など化学的な除去方法の他、酸水素火炎で強熱して表面ガラス層を蒸発させたり、ダイヤモンド切削工具等で機械的な切削を行った後、表面に付着した金属を硝酸などで溶解除去する方法などが挙げられる。
【００１８】
（実験２）
実験１で作製したコア母材1，2，3の分析しなかった残りを２等分し、それぞれの一方をフッ化水素酸で表面から０．２ｍｍ溶解し、それぞれ順にコア母材11，12，13とした。これらのコア母材にクラッド部を外付けし、光ファイバ母材１０１，１０２，１０３，１１１，１１２，１１３とした。さらに、これらの光ファイバ母材を線引してシンルグルモード光ファイバ２０１，２０２，２０３，２１１，２１２，２１３を得た。
これらのコア母材中のコア率（コア径／コア母材径）、光ファイバ母材中のコア母材の割合（コア母材径／光ファイバ母材径 ×１００（％））を測定した。このコア母材の割合が示す位置（中心から半径方向に向けての位置）は、コア母材とクラッド部との界面の位置に対応している。
さらに、光ファイバの伝送損失特性をカットバック法を用いて波長１,３００ｎｍ、１,５５０ｎｍで測定した。測定結果をまとめて表２に示した。
【００１９】
【表２】
表２から明らかなように、表面から０．２ｍｍ削って金属不純物をほぼ完全に除去したコア母材11，12，13にクラッド部を外付けして光ファイバ母材とし、これを線引して得た光ファイバの伝送損失は、除去していないコア母材1，2，3を用いたものに比べて、波長１,３００ｎｍ、１,５５０ｎｍのいずれにおいても極めて改善されている。
【００２１】
【発明の効果】
本発明によって光ファイバ母材中の金属不純物が、コア母材とクラッド部との界面に集中的に存在していることが明らかとなり、コア母材を表面から０．１ｍｍ以上削りとり、クラッド部を外付けして光ファイバ母材とし、これを線引することによって、極めて伝送損失の小さい光ファイバが得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an optical fiber glass base material (hereinafter simply referred to as an optical fiber base material) suitable for manufacturing an optical fiber having a small transmission loss .
[0002]
[Prior art]
It has been reported in past literatures and the like that transmission loss increases when metal impurities are present in an optical fiber. For this reason, many ideas have been made to remove metal impurities. In particular, since optical signal transmission is performed in the core portion of the optical fiber, care is taken especially when the optical fiber preform is manufactured so that the core portion does not contain metal impurities.
[0003]
The optical fiber preform is manufactured by introducing a liquid raw material vapor such as SiCl 4 into an oxyhydrogen flame, and depositing SiO 2 glass particles (soot) generated by the flame reaction to form a porous glass preform. This is done by calcination. This method of using the vapor of the liquid raw material is easy to remove impurities in the liquid raw material during the distillation process, and further, the distillation action also works when evaporating for introduction into the oxyhydrogen flame. The amount of metal impurities is extremely reduced.
[0004]
Further, by subjecting the obtained porous glass to heat treatment in a halogen gas, residual metal impurities are converted into halides, vaporized, and discharged outside the glass. Subsequently, an optical fiber preform with a very small amount of metal impurities can be obtained by sintering it into a transparent glass.
In the case of manufacturing a large-sized optical fiber preform, first, a core preform that is a core portion of the optical fiber preform is manufactured, and then a cladding portion is externally attached to the outside of the core preform. Forming.
[0005]
In the case of a normal step type single mode fiber, the core diameter is as small as about 10 μm with respect to the fiber diameter of 125 μm, and the transmitted optical signal penetrates part of the core and propagates. Sometimes, the core may be manufactured with a part of the cladding.
As a method of forming the clad portion around the core base material, in addition to the external method, a soot method in which a glass raw material is introduced into an oxyhydrogen flame and the generated quartz glass soot is deposited on the core base material, or For example, a jacket method may be used in which a core base material is inserted into a separately prepared quartz glass tube and these are fused and integrated.
[0006]
[Problems to be solved by the invention]
When the optical fiber preform manufactured in this way is drawn into an optical fiber, an increase in transmission loss that may be caused by metal impurities may be recognized, which has been a problem.
Accordingly, an object of the present invention is to provide a method of manufacturing an optical fiber preform that is free from transmission loss due to metal impurities.
[0007]
[Means for Solving the Problems]
The optical fiber preform manufacturing method of the present invention forms a soot body as a core by depositing glass fine particles, and heat-fires and vitrifies it to form a core preform, on which an external cladding is formed. A method for producing a glass base material for an optical fiber comprising a core and a clad, wherein when obtaining the core base material, glass fine particles are deposited to form a part of the clad on the core and the outer periphery. After heating and firing to vitrify to make a core base material, the outer periphery of the core base material is shaved by 0.1 mm or more to remove metal impurities contained in the vicinity of the surface, and then a clad portion is formed on the core base material. And the clad portion formed thereon are positioned so as to be located in a ring shape concentric with the core at a position of about 20 to 40% in the radial direction from the center, and the metal impurity concentration in the vicinity of the interface is 10ppb or less It is characterized.
[0008]
Note that the amount of scraping the outer periphery of the core base material is 0.1 mm or more, preferably 0.2 mm or more. The means for scraping the outer periphery is preferably a method using hydrofluoric acid or an oxyhydrogen flame.
The heating means for the core base material is preferably electric resistance heating. Further, the cladding part may be externally attached onto the core base material by either the soot method or the jacket method. The single mode optical fiber is obtained by drawing the optical fiber preform.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The optical fiber preform manufacturing method of the present invention first forms a core preform having a core and a part of the cladding on the outer periphery, and after removing the metal impurities contained in the vicinity of the surface by cutting the outer periphery, A clad portion is formed on this.
In order to avoid contamination of impurities in the optical transmission part, it is better to have a sufficient thickness of the cladding of the core base material. However, if this cladding is too thick, it will be difficult to manufacture the core base material or take a long time. In other words, the thickness of the cladding portion to be externally attached becomes relatively small, which causes a problem that the manufacturing cost increases.
[0010]
For this reason, by making the cladding thickness of the core preform about 4 times the core diameter or less, the ratio of the core preform in the radial direction of the optical fiber preform is 40% or less (the deposition ratio before vitrification is 16% or less). Therefore, the core base material can be easily manufactured, and the ratio of the clad portion manufactured by external attachment that is advantageous in terms of cost is sufficient, so that the optical fiber base material can be provided at low cost. Therefore, the ratio of the core base material in the radial direction of the optical fiber base material is about 20 to 40% in consideration of these.
[0011]
The core preform just after soot is deposited has a slight fluctuation in the outer diameter in millimeters. When this preform is drawn into an optical fiber, the longitudinal mode field diameter and cutoff wavelength Such optical characteristics vary in the longitudinal direction of the base material.
For this reason, it is necessary to correct the outer diameter variation of the core base material before entering the cladding step. In order to correct the outer diameter fluctuation of the core base material, the core base material is heated to the vicinity of the softening point with an oxyhydrogen flame or an electric resistance heating furnace, and the outer diameter is adjusted while stretching by applying tension. At this time, metal impurities existing in the heating atmosphere are taken into the surface of the core base material in a softened state. If an external cladding is formed on this, metal impurities remain in the optical fiber preform, and when the preform is drawn into an optical fiber, the metal impurities propagate light. It is considered that the transmission loss increases due to spreading to the part.
[0012]
In the manufacturing method of the present invention, soot is deposited to form a part of the core and the outer periphery of the core, and this is heated and fired to vitrify, and then heated and stretched to near the softening point to correct the outer diameter fluctuation. Then, the outer periphery of the core is adjusted to a predetermined diameter by using a hydrofluoric acid or by an oxyhydrogen flame by cutting 0.1 mm or more in the radial direction, and at the time of vitrification and correction of the outer diameter. In this way, a core base material having a core and a part of a clad on the outer periphery thereof is produced, and a clad portion is further formed thereon to form an optical fiber. A base material is manufactured. As a result, the interface between the core base material and the cladding is formed in a ring shape concentric with the core at a position of about 20 to 40% in the radial direction from the center, the metal impurity concentration in the vicinity of the interface is 10 ppb or less, and transmission loss is reduced. Extremely small.
[0013]
【Example】
(Experiment 1)
First, three types of core base materials (1, 2, 3) with different core / cladding ratios were prepared, heated and stretched to near the softening point in an electric resistance heating furnace, and the outer diameter was adjusted to φ20 mm ± 1 mm. . A core base material was prepared so that the core diameter was about 9 μm.
A part of the produced core base material was cut out, and the outer peripheral surface was dissolved by a small amount of hydrofluoric acid from the surface by about 0.1 mm. Next, it analyzed and calculated | required content of the metal impurity in this solution.
[0014]
In the analysis, first, a part of the solution was diluted in a nitric acid solution, and the Si concentration was determined by ICP-AES (atomic emission spectroscopy). Next, hydrogen peroxide is added to the rest of the solution, the silicon is removed by drying, and a small amount of nitric acid and hydrogen peroxide are added again to dissolve and concentrate, and then water is added to the resulting solution with various metals using ICP-AES. The amount was determined. This metal amount was divided by the dissolved SiO 2 amount obtained by conversion from the Si to determine the metal concentration in the core base material surface glass (Analysis 1).
About the sample (core base material) which melt | dissolved the outer periphery with the said hydrogen fluoride, about 0.1 mm was further melt | dissolved from the surface with hydrofluoric acid, and the same analysis was performed (analysis 2).
Thereafter, the surface was further dissolved by about 0.1 mm and analyzed (Analysis 3).
These results are summarized in Table 1. In addition, as for the result of the analysis 3, since all the elements in a table | surface were below the detection limit, description to the table | surface was abbreviate | omitted.
[0015]
[Table 1]
From the above analysis, the following became clear.
(1) Metal impurities are present on the core base material surface immediately after heating in the order of several tens of ppb. For this reason, if a clad portion is externally attached on this without removing it, metal impurities remain at the core preform / cladding interface of the optical fiber preform.
(2) Most of the metal impurities are localized within about 0.1 mm from the surface of the core base material.
(3) Accordingly, if the surface of the core base material is cut by about 0.1 mm, the metal impurities on the surface can be removed by 70% or more, and if further cut by about 0.1 mm, that is, about 0.2 mm in total, the metal impurities can be removed almost completely.
[0017]
It is considered that the source of the metal impurity is that a small amount of resistance heating body or copper of the electrode is vapor-deposited, or a stainless material of the structure of the heating furnace is vapor-deposited.
In addition to chemical removal methods such as dissolution with hydrofluoric acid, metal impurities can be removed from the surface of the core base material by heating with an oxyhydrogen flame to evaporate the surface glass layer or using a diamond cutting tool, etc. For example, a method of dissolving and removing the metal adhering to the surface with nitric acid after performing mechanical cutting may be used.
[0018]
(Experiment 2)
The remainder of the core base materials 1, 2, and 3 prepared in Experiment 1 was divided into two equal parts, and one of each was dissolved with hydrofluoric acid by 0.2 mm from the surface. , 13. A clad portion was externally attached to these core preforms to obtain optical fiber preforms 101, 102, 103, 111, 112, 113. Further, these optical fiber preforms were drawn to obtain single-mode optical fibers 201, 202, 203, 211, 212, and 213.
The core ratio in these core preforms (core diameter / core preform diameter) and the ratio of the core preform in the optical fiber preform (core preform diameter / optical fiber preform diameter × 100 (%)) were measured. . The position indicated by the ratio of the core base material (position from the center toward the radial direction) corresponds to the position of the interface between the core base material and the clad portion.
Furthermore, the transmission loss characteristics of the optical fiber were measured at wavelengths of 1,300 nm and 1,550 nm using the cutback method. The measurement results are summarized in Table 2.
[0019]
[Table 2]
As is clear from Table 2, an optical fiber preform is obtained by externally attaching a cladding portion to core preforms 11, 12, 13 from which metal impurities are almost completely removed by cutting 0.2 mm from the surface. The transmission loss of the optical fiber obtained in this way is significantly improved at any of the wavelengths of 1,300 nm and 1,550 nm compared to those using the core base materials 1, 2, and 3 that are not removed.
[0021]
【The invention's effect】
According to the present invention, it becomes clear that metal impurities in the optical fiber preform are concentrated on the interface between the core preform and the cladding, and the core preform is scraped by 0.1 mm or more from the surface, and the cladding Is used as an optical fiber preform, and an optical fiber with extremely small transmission loss can be obtained by drawing this.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000238515A JP4495838B2 (en) | 2000-08-07 | 2000-08-07 | Manufacturing method of glass preform for optical fiber |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000238515A JP4495838B2 (en) | 2000-08-07 | 2000-08-07 | Manufacturing method of glass preform for optical fiber |
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| Publication Number | Publication Date |
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| JP2002053335A JP2002053335A (en) | 2002-02-19 |
| JP4495838B2 true JP4495838B2 (en) | 2010-07-07 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP2000238515A Expired - Lifetime JP4495838B2 (en) | 2000-08-07 | 2000-08-07 | Manufacturing method of glass preform for optical fiber |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2005162512A (en) * | 2003-12-01 | 2005-06-23 | Shin Etsu Chem Co Ltd | Method for manufacturing glass preform |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5348536A (en) * | 1976-10-14 | 1978-05-02 | Nippon Telegr & Teleph Corp <Ntt> | Production of optical fibers |
| JPS60141634A (en) * | 1983-12-28 | 1985-07-26 | Shin Etsu Chem Co Ltd | Parent material for optical fiber and its preparation |
| JPS6136129A (en) * | 1984-07-30 | 1986-02-20 | Sumitomo Electric Ind Ltd | Manufacture of glass preform for optical fiber |
| JPH02201403A (en) * | 1989-01-31 | 1990-08-09 | Hitachi Cable Ltd | Optical fiber and production of base material thereof as well as production of optical fiber |
| JPH02263724A (en) * | 1989-04-04 | 1990-10-26 | Sumitomo Electric Ind Ltd | Production of optical fiber preform |
| JPH06144861A (en) * | 1992-11-05 | 1994-05-24 | Fujikura Ltd | Method for processing preform for optical fiber |
| JPH08310823A (en) * | 1995-05-15 | 1996-11-26 | Sumitomo Electric Ind Ltd | Flame polishing method for glass preform |
| JPH09241030A (en) * | 1996-03-07 | 1997-09-16 | Shinetsu Quartz Prod Co Ltd | High purity silica glass for far ultraviolet and its production |
-
2000
- 2000-08-07 JP JP2000238515A patent/JP4495838B2/en not_active Expired - Lifetime
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5348536A (en) * | 1976-10-14 | 1978-05-02 | Nippon Telegr & Teleph Corp <Ntt> | Production of optical fibers |
| JPS60141634A (en) * | 1983-12-28 | 1985-07-26 | Shin Etsu Chem Co Ltd | Parent material for optical fiber and its preparation |
| JPS6136129A (en) * | 1984-07-30 | 1986-02-20 | Sumitomo Electric Ind Ltd | Manufacture of glass preform for optical fiber |
| JPH02201403A (en) * | 1989-01-31 | 1990-08-09 | Hitachi Cable Ltd | Optical fiber and production of base material thereof as well as production of optical fiber |
| JPH02263724A (en) * | 1989-04-04 | 1990-10-26 | Sumitomo Electric Ind Ltd | Production of optical fiber preform |
| JPH06144861A (en) * | 1992-11-05 | 1994-05-24 | Fujikura Ltd | Method for processing preform for optical fiber |
| JPH08310823A (en) * | 1995-05-15 | 1996-11-26 | Sumitomo Electric Ind Ltd | Flame polishing method for glass preform |
| JPH09241030A (en) * | 1996-03-07 | 1997-09-16 | Shinetsu Quartz Prod Co Ltd | High purity silica glass for far ultraviolet and its production |
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| JP2002053335A (en) | 2002-02-19 |
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