JP3141545B2 - Drawing method of preform for optical fiber - Google Patents
Drawing method of preform for optical fiberInfo
- Publication number
- JP3141545B2 JP3141545B2 JP19388692A JP19388692A JP3141545B2 JP 3141545 B2 JP3141545 B2 JP 3141545B2 JP 19388692 A JP19388692 A JP 19388692A JP 19388692 A JP19388692 A JP 19388692A JP 3141545 B2 JP3141545 B2 JP 3141545B2
- Authority
- JP
- Japan
- Prior art keywords
- fitting member
- optical fiber
- dummy
- preform
- dummy rod
- 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
Landscapes
- Glass Melting And Manufacturing (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は光ファイバ用母材の延伸
方法に関するもので、特に大型の光ファイバ用母材も容
易に延伸できる方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing a preform for an optical fiber, and more particularly to a method for easily drawing a preform for a large optical fiber.
【０００２】[0002]
【従来の技術】光ファイバの従来の製造方法を、例えば
気相軸付け法（Vapour-phase axial deposition metho
d, ＶＡＤ法と略す）で説明する。ＶＡＤ法は同心円状
多重管バーナにより酸水素火炎を形成し、この火炎中に
ガラス原料ガス、例えばＳｉＣｌ 4 ，ＳｉＨＣｌ3 等お
よび場合によってドーパント原料ガス例えばＧｅＣ
ｌ4 ，ＰＯＣｌ3 ，ＢＣｌ3 などを投入し、火炎加水分
解反応あるいは酸化反応によりガラス微粒子を生成し、
このガラス微粒子を出発ロッドの先端あるいは外周にス
ス付けし、、ガラス微粒子堆積体を合成し、その後これ
を加熱炉にて透明化することにより、透明ガラスプリフ
ォームを得る方法である。次にこの方法を用いて光ファ
イバを具体的に作る方法を述べると、まず、上記方法を
用い、出発ロッド先端にドーパントを含むコアまたはコ
アとその外周にクラッドの一部を有するコア母材を合成
し、ハロゲン系ガスで脱水した後、透明ガラス化する。
その後、この透明ガラスロッドの外周に更にクラッド用
ガラス微粒子堆積体を合成する。こうして得られたガラ
スロッドとガラス微粒子堆積体を再び、焼結炉で透明ガ
ラス化し、光ファイバ用母材（光ファイバ用プリフォー
ム）を得る。この後、光ファイバ用プリフォームのガラ
ス表面を火炎研磨した後、電気炉あるいは酸水素バーナ
を用いて延伸し、所定の太さのプリフォームロッドを作
製する。このプリフォームロッドを線引炉で紡糸するこ
とにより光ファイバが得られる。ガラス微粒子堆積体を
透明ガラス化して得たプリフォームは、続く火炎研磨や
延伸工程に付すために、図３に示すように当該プリフォ
ーム（光ファイバ用母材）１の先端にダミー棒１９が溶
着等により一体的に設けられた形状とし、該ダミー棒部
分を把持して電気炉等の加熱炉にて溶融延伸している。2. Description of the Related Art Conventional methods for manufacturing optical fibers are described, for example, by
Vapor-phase axial deposition metho
d, abbreviated as VAD method). VAD method is concentric
An oxyhydrogen flame is formed by a multi-tube burner, and
Glass source gas, for example, SiCl Four, SiHClThreeEtc
And optionally a dopant source gas such as GeC
lFour, POClThree, BClThreeEtc., and flame water content
Glass particles are generated by the dissolution or oxidation reaction,
Place these glass particles on the tip or outer circumference of the starting rod.
To synthesize a glass particle deposit, and then
The transparent glass pre-
It is a way to get the form. Next, using this method,
First, let's talk about the method of making iva.
Core or core containing dopant at the tip of the starting rod.
Synthesize a core base material with a part of the cladding
Then, after dehydration with a halogen-based gas, the glass is transparently vitrified.
After that, the outer periphery of this transparent glass rod is further clad
Synthesize a glass particle deposit. Gala thus obtained
The sludge and the glass particle deposit are again
Preform for optical fiber (preform for optical fiber)
Get). After this, the glass preform for optical fiber
After flame polishing the surface, use an electric furnace or oxy-hydrogen burner.
To make a preform rod of a predetermined thickness.
To make. This preform rod is spun in a drawing furnace.
Thus, an optical fiber is obtained. Glass particle deposit
The preform obtained by vitrification can be used for subsequent flame polishing or
In order to be subjected to the stretching step, as shown in FIG.
A dummy rod 19 is melted at the tip of the
The dummy rod part
The melt is stretched in a heating furnace such as an electric furnace while holding the portion.
【０００３】延伸工程の従来技術としては、例えば特公
昭６２−１６７２３６号公報に提案されているように、
鉛直方向に貫通した開口を有するガラス母材加熱炉と、
該ガラス母材加熱炉の上方に設置され、且つガラス母材
の両端部に一体的に設けられた把持棒（ダミー棒）の一
方を把持する上部チャックと、前記ガラス母材加熱炉の
下方に設置され且つガラス母材のもう一方の把持棒を把
持する下部チャックからなる延伸装置で、該上下のチャ
ックで把持棒が把持されたガラス母材を該ガラス母材加
熱炉に通して加熱した状態で該上下のチャックの一方を
該ガラス加熱炉に対して相対的に近づけ、且つ他方のチ
ャックを該ガラス加熱炉に対して相対的に遠ざけること
により、ガラス母材を延伸する方法がある。[0003] As a prior art of the stretching step, for example, as proposed in Japanese Patent Publication No. 62-167236,
A glass base material heating furnace having an opening penetrating in the vertical direction,
An upper chuck installed above the glass base material heating furnace and holding one of grip bars (dummy bars) integrally provided at both ends of the glass base material; and a lower chuck below the glass base material heating furnace. A stretching apparatus comprising a lower chuck that is installed and holds the other holding rod of the glass base material, in which the glass base material whose holding rod is held by the upper and lower chucks is heated by passing through the glass base material heating furnace. Then, there is a method in which one of the upper and lower chucks is made relatively closer to the glass heating furnace, and the other chuck is made relatively farther from the glass heating furnace, thereby stretching the glass base material.
【０００４】[0004]
【発明が解決しようとする課題】ところで、延伸加工の
ために上下に長尺のダミー棒を溶着一体化すると、その
全長が長くなり取扱いが容易ではなかった。これに対
し、ダミー棒に嵌合部材を取り付け、該嵌合部材の部分
をチャックで把持すれれば、ダミー棒を短くすることが
できる。しかし、嵌合部材で把持して延伸すると曲がり
やすい問題もある。本発明は、光ファイバ用母材に従来
の如く長尺のダミー棒を一体化せずに、しかも曲がりな
く延伸できる方法を課題とするものであり、この課題を
解決することにより大型のプリフォームを高品質で高強
度に合成できる製造方法を提供しようとするものであ
る。By the way, when long dummy rods are welded and integrated vertically for stretching, the overall length becomes long and handling is not easy. On the other hand, if the fitting member is attached to the dummy bar and the portion of the fitting member is gripped by the chuck, the dummy bar can be shortened. However, there is also a problem that it is easy to bend when gripping and extending with the fitting member. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for extending a dummy rod without bending it without integrating a long dummy rod into a base material for an optical fiber as in the prior art. Is intended to provide a production method capable of synthesizing high quality and high strength.
【０００５】[0005]
【課題を解決するための手段】上記問題を解決するため
の本発明の構成は、光ファイバ用母材の両端に一体的に
設けられたダミー棒をチャックにより把持して加熱炉で
加熱溶融することにより該光ファイバ用母材を延伸する
方法において、該ダミー棒は端部に円柱状のピンを挿入
し得るダミー棒中心軸を横切る貫通穴が設けられ、該ダ
ミー棒を挿入し得る凹部を下端に有し且つ該ダミー棒貫
通穴に対応する位置に中心軸に直交する貫通穴を有する
嵌合部材に該ダミー棒を嵌挿し、嵌合部分において両者
の貫通穴に耐熱性のピンを挿入することにより該光ファ
イバ用母材の両端を該嵌合部材で把持し、且つ該嵌合部
材凹部の内径と該嵌合部材凹部内に挿入された該ダミー
棒端部の外径との差を０．２ｍｍ〜４ｍｍの範囲内に、
及び該該ダミー棒の該嵌合部材凹部内に挿入される部分
の長さを５０ｍｍ〜１５０ｍｍとすることを特徴とす
る。本発明において、上記ダミー棒を挿入し得る凹部を
下端に有し且つ該ダミー棒貫通穴に対応する位置に中心
軸に直交する貫通穴を有する嵌合部材が、更に中心軸に
垂直方向で且つ該嵌合部材の外周から中心軸に向かうボ
ルト２〜８個有しており、該ダミー棒を該嵌合部材内に
挿入して両者の貫通穴にピンを挿入し、且つ該ボルトを
用いて該ダミー棒を固定することにより、該ダミー棒の
固定を確実にできる。本発明において、上記延伸を該嵌
合部材の温度が常に１２００℃以下に保つように行なう
ことにより、該嵌合部材の熱による変形を防止できる。
また、本発明において上記延伸は、上記光ファイバ用母
材を鉛直方向に固定し、鉛直方向に延伸することができ
る。In order to solve the above-mentioned problems, the construction of the present invention is to hold a dummy rod integrally provided at both ends of an optical fiber preform with a chuck and heat and melt the dummy rod in a heating furnace. In the method of stretching the optical fiber base material, the dummy bar is provided with a through-hole at the end crossing a dummy rod center axis through which a cylindrical pin can be inserted, and a recess into which the dummy rod can be inserted. The dummy rod is inserted into a fitting member having a lower end and having a through hole orthogonal to the central axis at a position corresponding to the dummy rod through hole, and a heat-resistant pin is inserted into both through holes at the fitting portion. Then, both ends of the optical fiber preform are gripped by the fitting member, and the difference between the inner diameter of the fitting member recess and the outer diameter of the dummy rod end inserted into the fitting member recess. Within the range of 0.2 mm to 4 mm,
And a length of a portion of the dummy rod to be inserted into the concave portion of the fitting member is set to 50 mm to 150 mm. In the present invention, a fitting member having a recess at the lower end in which the dummy rod can be inserted and having a through hole orthogonal to the central axis at a position corresponding to the dummy rod through hole is further perpendicular to the central axis and It has two to eight bolts extending from the outer periphery of the fitting member toward the central axis, inserting the dummy rod into the fitting member, inserting pins into both through holes, and using the bolts. By fixing the dummy bar, the dummy bar can be reliably fixed. In the present invention, by performing the above stretching so that the temperature of the fitting member is always kept at 1200 ° C. or less, deformation of the fitting member due to heat can be prevented.
In the present invention, the stretching can be performed by fixing the optical fiber preform in the vertical direction and stretching in the vertical direction.
【０００６】[0006]
【作用】本発明では、従来使用していた上下の長尺ダミ
ー棒の一部を嵌合部材により代用してダミー棒の長さを
短くし、取扱いを容易にした。また、嵌合部材を両側に
用いる場合、延伸体に曲がりが生じやすくなるが、本発
明ではこの点に関しても研究をすすめ、特に延伸工程に
おいて有利な嵌合部材を用いる方法も開発した。すなわ
ち図１において、端部がダミー棒を嵌合できる構造を有
するガラスロッドを上下の嵌合部材６、７として予め用
意しておく。コアとなる、またはコアとクラッドとなる
部分を有する光ファイバ用ガラス母材１の上下端部に
は、上又は下部嵌合部材６、７にそれぞれ嵌合しうる端
部を有する上部ダミー棒２及び下部ダミー棒３が溶着さ
れている。該上及び下部ダミー棒２，３を溶着一体化さ
せた光ファイバ用母材１のダミー棒２，３を、該ガラス
ロッド（嵌合部材）６，７の嵌合部８，９に夫々挿入
し、図２の（ａ）に示すように、両者に設けられた貫通
穴４と１０、貫通穴５と１１に耐熱性材質からなる円柱
ピンを挿入して該上下部ダミー棒２，３を上下の嵌合部
材６，７に固定し、加熱炉１３の上下に設けられた上下
のチャック１４，１５で該嵌合部材６，７を把持するこ
とにより、光ファイバ用母材１を延伸機に固定して、加
熱延伸する。In the present invention, the length of the dummy bar is shortened by replacing a part of the long dummy bar used in the prior art with the fitting member, thereby facilitating the handling. In addition, when the fitting member is used on both sides, the stretched body is likely to bend. However, in the present invention, studies have been made on this point, and a method using a fitting member which is particularly advantageous in the stretching process has been developed. That is, in FIG. 1, glass rods having a structure in which the ends can be fitted with dummy bars are prepared in advance as upper and lower fitting members 6 and 7. An upper dummy rod 2 having an end that can be fitted to the upper or lower fitting member 6, 7 is provided at the upper and lower ends of the optical fiber glass preform 1 having a part to be a core or a core and a clad. And the lower dummy bar 3 is welded. The dummy rods 2, 3 of the optical fiber preform 1 in which the upper and lower dummy rods 2, 3 are welded and integrated are inserted into fitting portions 8, 9 of the glass rods (fitting members) 6, 7, respectively. Then, as shown in FIG. 2 (a), cylindrical pins made of a heat-resistant material are inserted into the through holes 4 and 10 and the through holes 5 and 11 provided in both, and the upper and lower dummy rods 2 and 3 are inserted. The optical fiber base material 1 is fixed to the upper and lower fitting members 6 and 7, and is gripped by the upper and lower chucks 14 and 15 provided above and below the heating furnace 13. And stretch by heating.
【０００７】固定の方法を更に詳しく説明すると、図２
（ａ）部分又は（ｂ）部分に示す如く、嵌合部材６
（７）の嵌合部８（９）ににダミー棒２（３）を挿入
し、両者に設けられた貫通穴１０（１１），４（５）に
円柱状の耐熱ピンを挿入することで固定する。このと
き、嵌合部材の内径とダミー棒の外径との差（クリアラ
ンス）は０．２ｍｍから４ｍｍの範囲にあり、且つ嵌合
部材に挿入される部分のダミー棒の長さが５０〜１５０
ｍｍであることが重要である。なお、延伸中、嵌合部材
の熱による変形を防ぐため嵌合部材の温度が１２００℃
を超えないよう、ダミー棒の長さを決めておく必要があ
る。嵌合部材の内径とダミー棒の外径との差は少ない程
嵌合部材の中心軸とダミー棒の中心軸が一致するが、
０．２ｍｍ以下になると、嵌合部材とダミー棒の加工精
度をかなり良くしないと挿入できない。また４ｍｍ以上
になると嵌合部材の中心軸とダミー棒の中心軸がズレて
しまい、延伸後の母材に曲がりが生じてしまう。The fixing method will be described in more detail.
As shown in (a) or (b), the fitting member 6
By inserting the dummy bar 2 (3) into the fitting portion 8 (9) of (7) and inserting the columnar heat-resistant pins into the through holes 10 (11) and 4 (5) provided in both. Fix it. At this time, the difference (clearance) between the inner diameter of the fitting member and the outer diameter of the dummy rod is in the range of 0.2 mm to 4 mm, and the length of the dummy rod of the portion inserted into the fitting member is 50 to 150 mm.
mm is important. During the stretching, the temperature of the fitting member is set to 1200 ° C. in order to prevent the deformation of the fitting member due to heat.
It is necessary to determine the length of the dummy bar so that it does not exceed Although the smaller the difference between the inner diameter of the fitting member and the outer diameter of the dummy rod is smaller, the center axis of the fitting member and the central axis of the dummy rod match,
If it is less than 0.2 mm, it cannot be inserted unless the processing accuracy of the fitting member and the dummy bar is considerably improved. On the other hand, if it is 4 mm or more, the center axis of the fitting member and the center axis of the dummy rod are displaced, and the base material after stretching is bent.
【０００８】また、また、嵌合部材の中心軸とダミー棒
の中心軸を更に良く一致させる方法がある。すなわち、
嵌合部材にダミー棒を挿入し、両者に設けられた貫通穴
に耐熱性の円柱状のピンを挿入した後、例えば図２の
（ｂ）部分に示すように、下部嵌合部材７に予め取り付
けておいた下部嵌合部材７の軸中心に向かうボルト１２
を締めることにより、下部ダミー棒３を確実に固定す
る。図示は省略したが上部ダミー棒と上部嵌合部材の場
合も同様である。該ボルト１２の数は２〜８個が望まし
い。ボルトを締めてダミー棒をしっかりと固定すること
により、延伸中においても、嵌合部材の中心軸とダミー
棒の中心軸が一致したままとなる。なお、ボルトの材質
はカーボン、アルミナ等が望ましい。In addition, there is a method in which the center axis of the fitting member and the center axis of the dummy rod are made to better match. That is,
After inserting a dummy rod into the fitting member and inserting a heat-resistant columnar pin into the through holes provided in both of them, for example, as shown in FIG. Bolt 12 heading toward the axial center of lower fitting member 7 that has been attached
To securely fix the lower dummy bar 3. Although not shown, the same applies to the case of the upper dummy bar and the upper fitting member. The number of the bolts 12 is desirably 2 to 8. By firmly fixing the dummy bar by tightening the bolt, the center axis of the fitting member and the center axis of the dummy bar remain aligned even during stretching. The bolt is preferably made of carbon, alumina, or the like.
【０００９】このようなボルトの使用は、特に下部ダミ
ー棒と下部嵌合部材との固定においては、一層重要であ
る。すなわち、下部ダミー棒と下部嵌合部材は延伸の初
期の段階ではお互いに引っ張りあっているため、それぞ
れの中心軸が一直線となりやすい。しかし、延伸が進行
するにつれて、光ファイバ用母材の上部が軟化するよう
になるため、軟化している部分より下の重量が全て下部
嵌合部材にかかるようになり、その結果、下部嵌合部材
と下部ダミー棒はお互いに押し合うようになる。そのと
き、下部嵌合部材に下部ダミー棒がしっかり固定されて
いないと、それぞれの中心軸がずれてしまいって、延伸
母材が曲がってしまうからである。[0009] The use of such bolts is even more important, especially in fixing the lower dummy bar and the lower fitting member. That is, since the lower dummy bar and the lower fitting member are pulling each other in the initial stage of the extension, their respective central axes are likely to be straight. However, as the drawing progresses, the upper portion of the optical fiber preform becomes softer, so that all the weight below the softened portion is applied to the lower fitting member, and as a result, the lower fitting member The member and the lower dummy bar are pressed against each other. At that time, if the lower dummy bar is not firmly fixed to the lower fitting member, the respective central axes are shifted, and the stretched base material is bent.
【００１０】以上述べてきたように、嵌合部材を用いて
延伸をする場合、嵌合部材の内径とダミー棒の外径との
差やボルトを用いてしっかり固定することなどが重要で
あるため、嵌合部材は熱によって変形しないことが必要
である。嵌合部材の材質は不純物の混入を防ぐためにも
光ファイバ用母材と同じ石英ガラスが望ましい。従って
嵌合部材が変形しないため、前記のようにダミー棒の長
さは嵌合部材が１２００℃以下となるように決める必要
がある。As described above, when stretching is performed using a fitting member, it is important that the difference between the inner diameter of the fitting member and the outer diameter of the dummy rod and that the bolt is securely fixed using bolts are important. The fitting member must not be deformed by heat. The material of the fitting member is desirably quartz glass, which is the same as the optical fiber base material, in order to prevent impurities from being mixed. Therefore, since the fitting member does not deform, the length of the dummy bar must be determined so that the temperature of the fitting member is 1200 ° C. or less as described above.
【００１１】本発明においてコア母材の両端につけるダ
ミー棒としては、通常溶融法あるいは合成法で作られた
石英ガラスが用いられる。多少のドーパント、不純物な
どが含有されていても良いが、粘度が極端に低いもので
は、焼結、または延伸時にダミーロッドが熱変形してし
まい好ましくない。In the present invention, as the dummy rods to be attached to both ends of the core base material, quartz glass usually produced by a melting method or a synthesis method is used. It may contain some dopants, impurities, etc., but if the viscosity is extremely low, the dummy rod is undesirably thermally deformed during sintering or stretching.
【００１２】本発明によれば、前記したように光ファイ
バ用母材を延伸する場合、溶着一体化すべきダミー棒の
長さを短くすることができる。すなわち、従来は長尺の
ダミー棒の端部を把持して光ファイバ用母材を延伸して
いたが、図１の（ｂ）に示すように、ダミー棒の一部を
嵌合部材で代用することにより、光ファイバ用母材に溶
着一体化すべきダミー棒の長さを短くできる。そして、
ダミー棒の長さを短くできることの効果は、取扱が容易
になることばかりではない。つまり、延伸すべき光ファ
ィバ用母材は、前述のように火炎中での加水分解反応で
生成されるガラス微粒子をガラスロッドの外周に堆積さ
せてから、加熱透明化して得るのが一般的である。従っ
て、ガラス微粒子を堆積させるガラスロッドの両端にダ
ミー棒を予め溶着一体化させておけば、加熱透明化の後
に直ちに延伸可能となる。プリフォーム段階で改めてダ
ミー棒を溶着する工程はプリフォームを傷つけたり汚染
したりする危険性があるが、このように堆積前からダミ
ー棒を溶着することでこの危険性を避けることができ
る。本発明は上記した光ファイバのコアを含むガラスロ
ッドに予めダミー棒を溶着しておいてガラス微粒子堆積
体を形成してゆく方法は勿論のこと、従来のように焼結
して得られた光ファイバ用プリフオームの段階で新たに
ダミー棒に溶着して延伸する場合のいずれに適用しても
有利である。According to the present invention, when the optical fiber base material is stretched as described above, the length of the dummy rod to be welded and integrated can be shortened. That is, conventionally, the optical fiber preform is stretched by gripping the end of the long dummy rod, but as shown in FIG. 1B, a part of the dummy rod is replaced with a fitting member. By doing so, the length of the dummy rod to be welded and integrated with the optical fiber base material can be shortened. And
The effect of shortening the length of the dummy bar is not only that the handling becomes easy. That is, the optical fiber base material to be stretched is generally obtained by depositing glass fine particles generated by a hydrolysis reaction in a flame on the outer periphery of a glass rod and then heating and clearing the glass rod as described above. is there. Therefore, if dummy rods are previously welded and integrated to both ends of the glass rod on which the glass fine particles are deposited, the glass rod can be stretched immediately after heat transparency. The step of welding the dummy rod again at the preform stage has a risk of damaging or contaminating the preform, but this danger can be avoided by welding the dummy rod before deposition. The present invention is not limited to a method in which a dummy rod is previously welded to a glass rod including the core of an optical fiber to form a glass fine particle deposit, and a light obtained by sintering as in a conventional method. It is advantageous to apply to any of the cases where the fiber is newly welded to the dummy rod and stretched at the stage of the fiber preform.
【００１３】[0013]
【実施例】以下、本発明を実施例を挙げて具体的に説明
するが、本発明はこれに限定されるものではない。EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited thereto.
【００１４】〔実施例１〕図１、図２を参照して説明す
る。 コア及びクラッドの一部を有する出発ロッドの両端に
長さ３００ｍｍのダミー棒２、３を予め取り付け、該出
発ロッド外周にガラス微粒子を堆積させ、加熱透明化す
ることにより光ファイバ用母材１を得た。また、各ダミ
ー棒２、３の端部には、軸方向と垂直に内径４ｍｍの貫
通穴を予め設けておいた。光ファイバ母材の寸法は外径
５８ｍｍ、長さ３００ｍｍであった。 光ファイバ用母材延伸装置は鉛直方向に開口した加熱
炉（抵抗電気炉）１３と、その上下に設けられたチャッ
ク１４，１５とから構成されており〔図１の（ａ）部
分〕、上部チャック１４、下部チャック１５はそれぞれ
独立に鉛直方向に移動できるようになっている。上部チ
ャック１４には、長さ５００ｍｍの嵌合部材６が固定さ
れており、光ファイバ母材１は、その上部に取り付けら
れた上部ダミー棒２を嵌合部材６に挿入して、両者の貫
通穴１０，４にアルミナピンを挿入することにより固定
した〔図１の（ｂ）部分〕。このとき、ダミー棒２の嵌
合部材６に挿入した部分の長さは６０ｍｍ、嵌合部材６
の凹部内径は３０．５ｍｍ、上部ダミー棒２の外径は３
０．０ｍｍであった。その後、上部チャック１４を下降
させることにより光ファイバ母材１を加熱炉１３に貫通
させ、光ファイバ母材１の下部に取り付けてある下部ダ
ミー棒３の下部を加熱炉１３の下部から突出させ〔図１
の（ｂ）〕、下部嵌合部材７に下部ダミー棒３を挿入し
て、両者の貫通穴１１，５にアルミナピンを挿入するこ
とにより、下部嵌合部材７を下部ダミー棒３に固定し
た。更にその後、下部嵌合部材７に取り付けられた４本
のカーボン性のボルト１２を締めつけた。下部嵌合部材
７の内径は３０．５ｍｍ、ダミー棒３の外径は３０．０
ｍｍ、ダミー棒３の下部嵌合部材７の凹部９に挿入した
部分の長さは１００ｍｍであった。 下部嵌合部材７
を固定した後、上部チャック１４を上昇させて、光ファ
イバ母材１の下端をヒーター１７の位置に合わせ、下部
チャック１５で下部嵌合部材７を把持した〔図１の
（ｃ）部分〕。光ファイバ母材１が十分に加熱された
後、上部チャック１４を速度１０ｍｍ／分で下降し、同
時に下部チャック１５を速度５４ｍｍ／分で下降させた
〔図１の（ｄ）部分〕。上部チャック１４を３００ｍｍ
下降させた時点で延伸を終了した〔図１の（ｅ）部
分〕。なお、図１中１６は気密板、１８は下ぶたを意味
する。 以上の結果、外径２５ｍｍ、長さ１．６ｍの曲がりの
ない光ファイバプリフオームが得られた。なお、ヒータ
ー温度は１９５０℃、嵌合部材の最高温度は１０００℃
であった。[Embodiment 1] A description will be given with reference to FIGS. Dummy rods 2 and 3 having a length of 300 mm are previously attached to both ends of a starting rod having a part of a core and a clad, glass fine particles are deposited on the outer periphery of the starting rod, and heated and made transparent to form an optical fiber preform 1. Obtained. At the end of each of the dummy rods 2 and 3, a through-hole having an inner diameter of 4 mm was provided in advance in the direction perpendicular to the axial direction. The dimensions of the optical fiber preform were 58 mm in outer diameter and 300 mm in length. The optical fiber preform stretching apparatus is composed of a heating furnace (resistance electric furnace) 13 opened in the vertical direction, and chucks 14 and 15 provided above and below the furnace (part (a) of FIG. 1). The chuck 14 and the lower chuck 15 can be independently moved in the vertical direction. A fitting member 6 having a length of 500 mm is fixed to the upper chuck 14, and the optical fiber preform 1 is inserted into the fitting member 6 by inserting the upper dummy rod 2 attached to the upper part thereof, and the optical fiber preform 1 penetrates the two. It was fixed by inserting alumina pins into the holes 10 and 4 (portion (b) of FIG. 1). At this time, the length of the portion of the dummy rod 2 inserted into the fitting member 6 is 60 mm,
Has an inner diameter of 30.5 mm and an outer diameter of the upper dummy rod 2 is 30.5 mm.
0.0 mm. Thereafter, the optical fiber preform 1 is caused to penetrate the heating furnace 13 by lowering the upper chuck 14, and the lower part of the lower dummy bar 3 attached to the lower part of the optical fiber preform 1 is projected from the lower part of the heating furnace 13 [ FIG.
(B)], the lower fitting member 7 was fixed to the lower dummy bar 3 by inserting the lower dummy bar 3 into the lower fitting member 7 and inserting the alumina pins into the through holes 11 and 5 of both. . Thereafter, the four carbon bolts 12 attached to the lower fitting member 7 were tightened. The inner diameter of the lower fitting member 7 is 30.5 mm, and the outer diameter of the dummy rod 3 is 30.0 mm.
mm, the length of the portion of the dummy bar 3 inserted into the recess 9 of the lower fitting member 7 was 100 mm. Lower fitting member 7
Then, the upper chuck 14 is raised, the lower end of the optical fiber preform 1 is aligned with the position of the heater 17, and the lower chuck 15 grips the lower fitting member 7 (part (c) of FIG. 1). After the optical fiber preform 1 was sufficiently heated, the upper chuck 14 was lowered at a speed of 10 mm / min, and at the same time, the lower chuck 15 was lowered at a speed of 54 mm / min (part (d) in FIG. 1). 300 mm upper chuck 14
Stretching was completed at the time of lowering (part (e) of FIG. 1). In FIG. 1, 16 indicates an airtight plate, and 18 indicates a lower lid. As a result, a bend-free optical fiber preform having an outer diameter of 25 mm and a length of 1.6 m was obtained. The heater temperature was 1950 ° C, and the maximum temperature of the fitting member was 1000 ° C.
Met.
【００１５】〔比較例１〕実施例１において、下部ダミ
ー棒の外径を２５ｍｍ、すなわち嵌合部材の内径との差
を５．５ｍｍとして、ボルトを付けずに延伸を行ったと
ころ、延伸初期の段階では実施例３と同様にできたが、
延伸開始２０分後、下部ダミー棒の中心軸と下部嵌合部
材の中心軸とがずれ、延伸体が大きく曲がってしまっ
た。[Comparative Example 1] In Example 1, the outer diameter of the lower dummy rod was set to 25 mm, that is, the difference from the inner diameter of the fitting member was set to 5.5 mm. At the stage of, it was made in the same manner as in Example 3, but
Twenty minutes after the start of stretching, the center axis of the lower dummy rod and the center axis of the lower fitting member were shifted, and the stretched body was greatly bent.
【００１６】〔実施例２〕長さ４００ｍｍ、外径６０ｍ
ｍの光ファイバ用母材の両端に、外径３０．０ｍｍ、長
さ３００ｍｍのダミー棒を溶着一体化した。ダミー棒を
溶着一体化した側とは反対側の端部には軸方向と垂直に
内径４ｍｍの貫通穴を予め設けておいた。実施例１と同
様にして延伸した。このとき、ダミー棒２の嵌合部材６
に挿入した部分の長さは６０ｍｍ、嵌合部材６の凹部内
径は３２．５ｍｍ、上部ダミー棒２の外径は３１．０ｍ
ｍであった。本実施例でも曲がりのない延伸体を得るこ
とができた。[Example 2] Length 400mm, outer diameter 60m
A dummy rod having an outer diameter of 30.0 mm and a length of 300 mm was welded and integrated to both ends of the optical fiber base material of m. A through hole having an inner diameter of 4 mm was provided in advance at the end opposite to the side where the dummy rod was welded and integrated, perpendicular to the axial direction. Stretching was performed in the same manner as in Example 1. At this time, the fitting member 6 of the dummy rod 2
Is 60 mm, the inner diameter of the concave portion of the fitting member 6 is 32.5 mm, and the outer diameter of the upper dummy rod 2 is 31.0 m.
m. Also in this example, a stretched body without bending could be obtained.
【００１７】上記実施例では嵌合用ピンとしてアルミナ
ピンを用いた例を挙げたが、セラミックピン、カーボン
製、あるいはカーボンにＳｉＣコートしたものなど、耐
熱性、強度に優れたものであれば他のいずれを用いても
よい。In the above embodiment, an example was described in which an alumina pin was used as the fitting pin. However, other pins having excellent heat resistance and strength, such as ceramic pins, carbon, or carbon coated with SiC, were used. Either may be used.
【００１８】[0018]
【発明の効果】以上説明したように、本発明を用いれば
プリフォームの表面に触れることなく、線引き用のプリ
フォームまで加工することができ、かつ安定したガラス
微粒子堆積体の合成を行うことができる。このため、特
に重量が８〜１０ｋｇを越える大型のプリフォームの製
造を伴う光ファイバ用母材の延伸においては、高品質、
高強度の光ファイバを得ることが可能である。As described above, according to the present invention, it is possible to process a preform for drawing without touching the surface of the preform, and it is possible to stably synthesize a deposit of fine glass particles. it can. For this reason, especially in the drawing of the optical fiber base material accompanying the production of a large preform weighing more than 8 to 10 kg, high quality,
It is possible to obtain a high-strength optical fiber.
【図１】本発明の製法を工程の順に説明する概略図であ
る。FIG. 1 is a schematic diagram for explaining a production method of the present invention in the order of steps.
【図２】本発明におけるダミー棒と嵌合部材の嵌合の状
態を説明する概略図である。FIG. 2 is a schematic diagram illustrating a state of fitting between a dummy bar and a fitting member according to the present invention.
【図３】従来の延伸法において光ファイバ用母材の両端
に長尺のダミー棒を溶着した状態を示す概略図である。FIG. 3 is a schematic view showing a state in which long dummy rods are welded to both ends of an optical fiber preform in a conventional drawing method.
１ 光ファイバ用母材 ２ 上部ダミー棒 ３ 下部ダミー棒 ４ ピン穴 ５ ピン穴 ６ 上部嵌合部材 ７ 下部嵌合部材 ８ 嵌合部分 ９ 嵌合部分 １０ ピン穴 １１ ピン穴 １２ ボルト １３ 加熱炉 １４ 上部チャック １５ 下部チャック １６ 気密板 １７ ヒーター １８ 下ぶた １９ 長尺のダミー棒 DESCRIPTION OF SYMBOLS 1 Preform for optical fiber 2 Upper dummy rod 3 Lower dummy rod 4 Pin hole 5 Pin hole 6 Upper fitting member 7 Lower fitting member 8 Fitting part 9 Fitting part 10 Pin hole 11 Pin hole 12 Bolt 13 Heating furnace 14 Upper chuck 15 Lower chuck 16 Airtight plate 17 Heater 18 Lower lid 19 Long dummy bar
───────────────────────────────────────────────────── フロントページの続き (72)発明者 向井 克蔵 神奈川県横浜市栄区田谷町１番地 住友 電気工業株式会社横浜製作所内 (56)参考文献 特開 平６−24784（ＪＰ，Ａ) 特開 平６−40738（ＪＰ，Ａ) 特開 昭62−167236（ＪＰ，Ａ) 特開 平３−37128（ＪＰ，Ａ) 実開 平３−89127（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) C03B 37/00 - 37/16 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Katsuzo Mukai 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (56) References JP-A-6-24784 (JP, A) JP-A-6-40738 (JP, A) JP-A-62-167236 (JP, A) JP-A-3-37128 (JP, A) JP-A-3-89127 (JP, U) (58) Fields investigated (Int .Cl. 7 , DB name) C03B 37/00-37/16
Claims (4)
られたダミー棒をチャックにより把持して加熱炉で加熱
溶融することにより該光ファイバ用母材を延伸する方法
において、該ダミー棒は端部に円柱状のピンを挿入し得
るダミー棒中心軸を横切る貫通穴が設けられ、該ダミー
棒を挿入し得る凹部を下端に有し且つ該ダミー棒貫通穴
に対応する位置に中心軸に直交する貫通穴を有する嵌合
部材に該ダミー棒を嵌挿し、嵌合部分において両者の貫
通穴に耐熱性のピンを挿入することにより該光ファイバ
用母材の両端を該嵌合部材で把持し、且つ該嵌合部材凹
部の内径と該嵌合部材凹部内に挿入された該ダミー棒端
部の外径との差を０．２ｍｍ〜４ｍｍの範囲内に、及び
該該ダミー棒の該嵌合部材凹部内に挿入される部分の長
さを５０ｍｍ〜１５０ｍｍとすることを特徴とする光フ
ァイバ用母材の延伸方法。1. A method of stretching an optical fiber preform by holding a dummy rod integrally provided at both ends of an optical fiber preform with a chuck and heating and melting the dummy rod in a heating furnace. Is provided with a through-hole at the end crossing the center axis of the dummy rod into which a cylindrical pin can be inserted, and has a recess at the lower end at which the dummy rod can be inserted, and the center axis at a position corresponding to the dummy-rod through-hole. The dummy rod is inserted into a fitting member having a through-hole perpendicular to the optical fiber, and both ends of the optical fiber base material are inserted into the two through-holes at the fitting portions by using the fitting member. The difference between the inner diameter of the fitting member recess and the outer diameter of the dummy rod end inserted into the fitting member recess is in the range of 0.2 mm to 4 mm, and The length of the portion to be inserted into the fitting member recess is 50 mm to 15 mm. A method for stretching a preform for an optical fiber, characterized in that the thickness is 0 mm.
有し且つ該ダミー棒の貫通穴に対応する位置に中心軸に
直交する貫通穴を有する嵌合部材が、更に中心軸に垂直
方向で且つ該嵌合部材の外周から中心軸に向かうボルト
を２〜８個有しており、該ダミー棒を該嵌合部材内に挿
入して両者の貫通穴にピンを挿入し、且つ該ボルトを用
いて該ダミー棒を固定することを特徴とする請求項１記
載の光ファイバ用母材の延伸方法。2. A fitting member having a recess at the lower end into which the dummy rod can be inserted and having a through-hole orthogonal to the central axis at a position corresponding to the through-hole of the dummy rod, the fitting member is further provided in a direction perpendicular to the central axis. And two to eight bolts extending from the outer periphery of the fitting member toward the central axis, inserting the dummy rod into the fitting member, inserting pins into both through holes, and 2. The method of stretching a preform for an optical fiber according to claim 1, wherein the dummy rod is fixed by using the method.
２００℃以下に保って行なうことを特徴とする請求項１
または請求項２に記載の光ファイバ用母材の延伸方法。3. The stretching described above, wherein the temperature of the fitting member is always 1
2. The method according to claim 1, wherein the temperature is maintained at 200 ° C. or lower.
Alternatively, the method for stretching a preform for an optical fiber according to claim 2.
直方向に固定し、鉛直方向に延伸することを特徴とする
請求項１ないし請求項３のいずれかに記載の光ファイバ
用母材の延伸方法。4. The optical fiber preform according to claim 1, wherein the stretching is performed by fixing the optical fiber preform in the vertical direction and extending the optical fiber preform in the vertical direction. Stretching method.
Priority Applications (15)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19388692A JP3141545B2 (en) | 1992-07-21 | 1992-07-21 | Drawing method of preform for optical fiber |
| AU41751/93A AU659020B2 (en) | 1992-07-09 | 1993-07-06 | Method and apparatus for drawing glass preform for optical fiber |
| CA002099942A CA2099942C (en) | 1992-07-09 | 1993-07-06 | Method and apparatus for drawing glass preform for optical fiber |
| EP98119047A EP0885853B1 (en) | 1992-07-09 | 1993-07-08 | Apparatus for drawing a glass preform for optical fibers |
| DE69328572T DE69328572T2 (en) | 1992-07-09 | 1993-07-08 | Method and device for drawing glass preforms for optical fibers |
| DE69324963T DE69324963T2 (en) | 1992-07-09 | 1993-07-08 | Process for drawing glass preforms for optical fiber |
| DE69331917T DE69331917T2 (en) | 1992-07-09 | 1993-07-08 | Device for drawing a glass preform for optical fibers |
| EP93110950A EP0578244B1 (en) | 1992-07-09 | 1993-07-08 | Method for drawing glass preform for optical fiber |
| EP97100122A EP0770583B1 (en) | 1992-07-09 | 1993-07-08 | Method for drawing glass proform for optical fiber |
| KR1019930012908A KR970006995B1 (en) | 1992-07-09 | 1993-07-09 | Method and apparatus for production of glass preform for optical fiber |
| US08/370,233 US5674306A (en) | 1992-07-09 | 1995-01-09 | Method and apparatus for drawing glass preform for optical fiber |
| AU13546/95A AU668330B2 (en) | 1992-07-09 | 1995-02-28 | Method for drawing a glass preform for optical fiber |
| AU13547/95A AU668331B2 (en) | 1992-07-09 | 1995-02-28 | Method and apparatus for drawing a glass preform for optical fiber |
| KR1019960077413A KR970007945B1 (en) | 1992-07-21 | 1996-12-30 | Method and apparatus for drawing glass preform for optical fiber |
| US08/795,016 US5788734A (en) | 1992-07-09 | 1997-02-05 | Method for drawing glass preform for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19388692A JP3141545B2 (en) | 1992-07-21 | 1992-07-21 | Drawing method of preform for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0640737A JPH0640737A (en) | 1994-02-15 |
| JP3141545B2 true JP3141545B2 (en) | 2001-03-05 |
Family
ID=16315377
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19388692A Expired - Fee Related JP3141545B2 (en) | 1992-07-09 | 1992-07-21 | Drawing method of preform for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3141545B2 (en) |
-
1992
- 1992-07-21 JP JP19388692A patent/JP3141545B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0640737A (en) | 1994-02-15 |
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