JP3151358B2 - Manufacturing method of optical fiber preform - Google Patents

Manufacturing method of optical fiber preform

Info

Publication number
JP3151358B2
JP3151358B2 JP19241694A JP19241694A JP3151358B2 JP 3151358 B2 JP3151358 B2 JP 3151358B2 JP 19241694 A JP19241694 A JP 19241694A JP 19241694 A JP19241694 A JP 19241694A JP 3151358 B2 JP3151358 B2 JP 3151358B2
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JP
Japan
Prior art keywords
speed
stretching
outer diameter
average
optical fiber
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 - Lifetime
Application number
JP19241694A
Other languages
Japanese (ja)
Other versions
JPH0859274A (en
Inventor
一宏 濱口
正美 寺嶋
弘行 小出
秀夫 平沢
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shin Etsu Chemical Co Ltd
Original Assignee
Shin Etsu Chemical Co Ltd
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Application filed by Shin Etsu Chemical Co Ltd filed Critical Shin Etsu Chemical Co Ltd
Priority to JP19241694A priority Critical patent/JP3151358B2/en
Publication of JPH0859274A publication Critical patent/JPH0859274A/en
Application granted granted Critical
Publication of JP3151358B2 publication Critical patent/JP3151358B2/en
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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
    • C03B37/014—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
    • 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
    • C03B37/0124—Means for reducing the diameter of rods or tubes by drawing, e.g. for preform draw-down

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は光ファイバ母材の製造方
法、特には光ファイバ母材インゴットをこれより小径の
母材ロッドに延伸する工程において、延伸後の光ファイ
バ母材の全長に渡って光ファイバ母材ロッドの最終外径
の変動を低減化する光ファイバ母材の製造方法に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical fiber preform, and more particularly to a process of stretching an optical fiber preform ingot into a preform rod having a smaller diameter than the entire length of the optical fiber preform after stretching. The present invention relates to a method for manufacturing an optical fiber preform for reducing fluctuations in the final outer diameter of the optical fiber preform rod.

【０００２】[0002]

【従来の技術】光ファイバの製造は母材インゴットをこ
れより小径の母材ロッドに延伸し、ついでこれをファイ
バとするという方法で行なわれているが、この母材イン
ゴットからこれより小径の母材ロッドの製造は、例えば
図５に示されているように、光ファイバ母材をヒーター
で加熱して軟化させ、この加熱溶融部の外径を外径測定
器などを用いて測定し、その測定値に基づいて引取りロ
ーラーによる引取り速度を制御するという方法で行なわ
れているが、この場合には加熱溶融部の外径を一定に制
御することによって延伸後の母材ロッドの最終外径を一
定値に保つようにされている。The manufacture of optical fibers extending to a smaller diameter than the base material rod preform ingot, and then have been done in a way that the fiber this small-diameter mother than this from the base material ingot production of wood rods, as shown in FIG. 5, for example, an optical fiber preform is softened by heating with a heater, to measure the outer diameter of the heat melting unit by using an outer diameter measuring device, the It is performed by controlling the take-off speed by the take-off roller based on the measured value.In this case, the outer diameter of the heated and melted portion is controlled to be constant so that the final outside of the drawn base material rod can be controlled. The diameter is kept constant.

【０００３】[0003]

【発明が解決しようとする課題】この場合、加熱溶融部
の外径を一定に保つためには、延伸中におけるネックダ
ウン部の最も伸び易い部分の外径を制御するので、これ
は外径制御の応答性のすぐれたものとなり、さらに母材
インゴットの外径が一定であればネックダウン部の形状
も母材インゴットの位置によらずにほぼ一定となり、加
熱溶融部の外径を一定に保てば最終外径も一定に保たれ
る。しかし、この母材インゴットは図６に示したよう
に、その両端において母材外径がテーパー状に変化して
おり、ネックダウン部の形状もそれに伴なって変化する
ために、この母材インゴットの直胴部の両末端では前記
のような方法では最終外径を一定に制御するのが困難に
なる。In this case, in order to keep the outer diameter of the heat-melted portion constant, the outer diameter of the most stretchable portion of the neck-down portion during stretching is controlled. If the outer diameter of the base material ingot is constant, the shape of the neck-down part will be almost constant regardless of the position of the base material ingot, and the outer diameter of the heat-melted part will be kept constant. The final outer diameter is kept constant. However, as shown in FIG. 6, the base material ingot has a tapered outer diameter at both ends, and the shape of the neck-down portion also changes accordingly. At both ends of the straight body, it is difficult to control the final outer diameter to be constant by the above method.

【０００４】さらに、この母材インゴットについては図
６に示したように、一部が完全にガラス化されておら
ず、末端にガラス化されていない多孔質シリカ母材部分
がある場合には、この多孔質シリカ母材部分とガラス化
されているガラス部分との物性の違いによって母材イン
ゴットの伸び方が刻一刻変化するために外径制御性が著
しく困難になり、したがって上記したような複雑な外径
変動や物性値の不連続的な変化のある母材インゴットを
加熱溶融部の外径のみに基づいて制御性良く、一定径に
延伸することは極めて困難なものとなっている。Further, as shown in FIG. 6, a part of the base material ingot is not completely vitrified, and there is a non-vitrified porous silica base material part at an end. case, the porous silica preform elongation how the base material ingot by a difference in the physical properties of the material portion and vitrified by being a glass portion becomes the outer diameter controllability is extremely difficult to change every moment, thus the It is extremely difficult to stretch a base material ingot with complicated outer diameter fluctuations and discontinuous changes in physical property values to a constant diameter with good controllability based only on the outer diameter of the heated and melted part. ing.

【０００５】なお、実際にこの図５に示した方法で加熱
溶融部の外径を制御してこれを一定に保つ方法におい
て、延伸初期の母材インゴットの直胴部末端および直胴
部の延伸終了後、引き続き延伸終了部側末端の延伸を行
なうと、図７に示したように最終外径に大きな外径変動
が生じてしまうという問題点がある。これは母材インゴ
ットの直胴部とテーパー部の外径差および多孔質シリカ
母材部分とガラス部分の物性の違いにより、直胴部末端
では加熱溶融部のネックダウン形状が時々刻々に変化す
るためである。In the method of actually controlling the outer diameter of the heat-melted portion by the method shown in FIG. 5 and keeping the outer diameter constant, the end of the straight body portion and the straight body portion of the base material ingot in the initial stage of stretching.
When the end of the end portion of the stretching is continuously stretched after the completion of the stretching of the portion, there is a problem that a large outer diameter variation occurs in the final outer diameter as shown in FIG. This is due to the difference in outer diameter between the straight body and the tapered part of the base material ingot and the difference in physical properties between the porous silica base material part and the glass part. That's why.

【０００６】なお、例えば、延伸終了部側末端にガラス
化されていない多孔質シリカ母材部分が存在する場合に
この直胴部を延伸すると、終了側直胴部末端の部分の粘
度の違いによってネックダウン形状の変化が刻一刻生
じ、溶融部の外径を一定に保っていても、結果的には母
材ロッドの最終外径に変動が生じてしまうという欠点が
あり、この外径制御性の困難さは母材インゴット径が増
大するほど増加するため、大型インゴットほど外径変動
も増大する。If, for example , the non- vitrified porous silica base material portion is present at the end of the stretching end portion, if this straight body portion is stretched, the difference in viscosity at the end portion of the straight body portion at the end side causes a difference. resulting moment change of neck-down shape time, even though maintaining the outer diameter of the molten portion constant, has the disadvantage of resulting in the change in the final outside diameter of the preform rod is caused, the outer diameter controllability The difficulty of the above increases as the diameter of the base material ingot increases, so that the larger the ingot, the larger the outer diameter fluctuation.

【０００７】[0007]

【課題を解決するための手段】本願発明はこのような不
利、欠点、問題点を解決した光ファイバ母材の製造方法
に関するものであり、これは母材インゴットをこれより
小径の母材ロッドに延伸して光ファイバ母材を製造する
方法において、母材インゴットの直胴部と外径差がある
か物性の異なる末端周辺部を延伸する際の延伸条件を、
直胴部での平均引取り速度よりも速い速度で引き伸ばす
区間と直胴部での平均引取り速度よりも遅い速度で引き
伸ばす区間とを有するものとしてなることを特徴とする
ものである。SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing an optical fiber preform which solves such disadvantages, drawbacks and problems, and converts a preform ingot into a preform rod having a smaller diameter. In the method of manufacturing an optical fiber preform by stretching, there is a difference in outer diameter from the straight body of the preform ingot
The stretching conditions when stretching the end peripheral part with different physical properties ,
It is characterized by having a section that extends at a speed higher than the average take-up speed at the straight body portion and a section that extends at a speed lower than the average take-up speed at the straight body portion.

【０００８】すなわち、本発明者らは、光ファイバ母材
をより小径の母材ロッドに延伸して径の均一な光ファイ
バ母材を製造する方法について種々検討した結果、直胴
部末端では母材外径の変化や物性の差によりネックダウ
ン形状が変化するため、このネックダウン形状の変化に
応じてこの引取り速度を平均引取り速度より速い区間と
平均引取り速度より遅い区間に区分して、これらをネッ
クダウン形状に応じて選択すれば、目的とする母材ロッ
ドの最終直径を一定にすることができることを見出して
本発明を完成させた。以下にこれをさらに詳述する。That is, the present inventors have conducted various studies on a method of manufacturing an optical fiber preform having a uniform diameter by stretching the optical fiber preform into a smaller diameter preform rod. Since the neck-down shape changes due to changes in the outer diameter of the material and differences in physical properties, this take-up speed is divided into sections faster than the average take-up speed and sections slower than the average take-up speed according to the change in the neck-down shape. The inventors have found that the final diameter of the target base material rod can be made constant by selecting these in accordance with the neck-down shape, and completed the present invention. This will be described in more detail below.

【０００９】[0009]

【作用】本発明による光ファイバ母材の製造方法は、母
材インゴットの直胴部と外径差があるか物性の異なる末
端周辺部を延伸する際の延伸条件を、直胴部での平均速
度よりも速い速度で引き伸ばす区間と直胴部での平均速
度よりも遅い速度で引き伸ばす区間とを有するものとす
るものである。すなわち、母材インゴットを延伸してこ
れより小径の光ファイバ母材を製造する方法において、
直胴部末端を延伸するときに一定の平均速度で延伸する
と、母材外径の変化や物性の差によりネックダウン形状
が変化するため、溶融部外径と最終外径に変化が生じ
る。Method for manufacturing an optical fiber preform according to the action of the present invention, the stretching conditions in stretching the different end <br/> end peripheral portion of or physical properties is straight body portion and the outer diameter difference of the base material ingot, straight It has a section that extends at a speed higher than the average speed at the trunk and a section that extends at a speed lower than the average speed at the straight body. That is, in a method of manufacturing an optical fiber preform having a smaller diameter by stretching the preform ingot ,
When stretched at a constant average speed when drawing the straight body section ends, since the neck-down shape changes, a change in the melting outer diameter and final outside diameter caused by the difference in the change and physical properties of the base material outer diameter.

【００１０】したがって、例えば 120mmφの光ファイバ
母材を45mmφの母材ロッドに延伸を行なった場合、これ
を図１に示したように直胴部末端の距離に応じてＬ1 、
Ｌ2、Ｌ3 と区分し、溶融部外径を一定に制御するため
に平均引取り速度で延伸を行なったところ、このネック
ダウン形状の変化によって中央直胴部、Ｌ1 、Ｌ2 、Ｌ
3 ではその溶融部外径と最終径について表１に示したよ
うな変動が生じ、中央直胴部では溶融部外径を一定に保
つことができて最終径は45mmに保つことができたが、区
間Ｌ1 では母材の長手方向にわたって外径および物性の
差により溶融部と最終外径の差が大きくなり、最終外径
は41mmと中央定常部の約91％の外径となり、同様に区間
Ｌ3 では最終外径が51mmで中央定常部の約 113％の外径
となった。Accordingly, for example, when the optical fiber preform 120mmφ was performed stretched preform rod 45 mm, L 1 according to the distance of the straight body section end as shown in figure 1,
L 2 and L 3 were separated and stretched at an average take-off speed in order to control the outer diameter of the melted portion constant. Due to this change in the neck-down shape, the central straight body portion, L 1 , L 2 , L
In Fig. 3 , the outer diameter and the final diameter of the fusion zone varied as shown in Table 1, and the outer diameter of the fusion zone could be kept constant and the final diameter could be maintained at 45 mm in the central straight body. , along the longitudinal direction of the section L 1 in the base material difference of the melting section and the final outer diameter by the difference in outer diameter and physical properties is increased, the final outside diameter becomes outside diameter of about 91% of 41mm and a central stationary part, as well the final outer diameter in the section L 3 becomes an outer diameter of approximately 13% of the central stationary part at 51 mm.

【００１１】[0011]

【表１】 [Table 1]

【００１２】そのため、本発明者らはこの最終径を一定
にするための延伸条件について検討した結果、中央直胴
部における延伸速度を平均引取り速度（1.00Ｖm ）とし
て溶融部の設定径を54mmとすることとし、表２に示した
ように、区間Ｌ1 については、最終径が41mmで中央直胴
部の91％であることから溶融部の設定径を58mmとして、
この径になるように引取り速度を平均引取り速度よりも
遅い速度である0.83Ｖm とし、区間Ｌ3 については、最
終外径が51mmで中央直胴部の 113％であることから溶融
部の設定径を48mmとすることにして、この引取り速度を
平均引取り速度より速い速度である1.28Ｖm としたとこ
ろ、各区間での母材ロッドの最終外径を45mmと略々一定
にできることを見出した。[0012] Therefore, the present inventors have results of investigation of drawing conditions for the final diameter constant, setting the diameter of the melted portion of the drawing speed in the central straight body portion as an average take-up speed (1.00 V m) and be 54 mm, as shown in Table 2, for the interval L 1, as 58mm setting size of the molten portion from that the final diameter is 91% of the central cylindrical body portion at 41mm,
The take-up speed such that the diameter and 0.83 V m is slower than the average take-up speed for the section L 3, molten portion since the final outer diameter is 113% of the central cylindrical body portion at 51mm and the preset diameter to a 48 mm, the take-up speed was the 1.28V m is faster than the average take-up speed rates, the final outside diameter to 45mm and substantially constant matrix rod in each section I found what I could do.

【００１３】[0013]

【表２】 [Table 2]

【００１４】また、この場合における引取り速度Ｖm
は、母材インゴットの直胴部の径Ｄ0と延伸後の母材ロ
ッドの径Ｄ1 および母材インゴットの送り込み速度Ｖ0
とから、次式 Ｖm ＝Ｖ0 × (Ｄ0 ／Ｄ1)2 で算出できるので、この引取り速度Ｖ m についてはこの
式から算出される速度で延伸すれば目的とする母材ロッ
ドの外径はこれを一定なものとすることができる。In this case, the take-up speed V m
The velocity V 0 infeed diameter D 1 and the base material ingot preform rod after drawing the diameter D 0 of the straight body portion of the preform ingot
From this, it can be calculated by the following equation: V m = V 0 × (D 0 / D 1 ) 2 , and if this drawing speed V m is stretched at the speed calculated from this equation, the desired base material rod can be obtained. The outer diameter can make this constant.

【００１５】なお、本発明による光ファイバ母材の延伸
は、上記したように平均引取り速度よりも速い速度で延
伸する区間と平均引取り速度よりも遅い速度で延伸する
区間を設けるものであるが、これについては上記した実
験例に示されているように、平均引取り速度よりも速い
速度で延伸する区間と平均引取り速度よりも遅い速度で
延伸する区間との間に、平均引取り速度で延伸する区間
を設けてもよい。また、この平均引取り速度よりも速い
速度で引き伸ばすときの速度についてはこれがあまり速
いと得られる母材の最終外径が細くなってしまうので、
これは平均引取り速度の 110〜 150％、特には 125〜 1
35％の範囲とすることがよく、平均引取り速度よりも遅
い速度で引き伸ばすときの速度もこれが遅すぎると目的
とする母材の最終外径が太くなってしまうので、これは
平均引取り速度の70〜90％、特には80〜90％の範囲とす
ることがよい。The stretching of the optical fiber preform according to the present invention is , as described above, provided with a section for drawing at a speed higher than the average drawing speed and a section for drawing at a speed lower than the average drawing speed. but this, as shown in the experimental example described above for, between the section to be stretched in a section which extends at a faster than the average take-up speed rates average take-up slower than the rate, the average take-up A section for stretching at a speed may be provided. Also, regarding the speed when stretching at a speed higher than the average take-up speed, if this speed is too fast, the final outer diameter of the obtained base material will be thin,
This is 110-150% of the average take-off speed, especially 125-1
It is better to set it in the range of 35%, and if the speed at the time of stretching at a speed lower than the average take-up speed is too slow, the final outer diameter of the target base material becomes large. 70 to 90%, particularly preferably 80 to 90%.

【００１６】[0016]

【実施例】つぎに本発明の実施例、比較例をあげる。 実施例１ 直径が 120mmφの母材インゴットから直径45mmφの光フ
ァイバ母材を製作すべく、延伸開始部から母材中央部ま
では溶融部外径を測定してそれを一定に制御するという
公知の延伸方法で延伸したが、それ以降は図１に示した
ように、母材インゴットの延伸終了側において直胴部末
端部を３つの区間Ｌ1 、Ｌ2 、Ｌ3 に分け、中央よりの
区間Ｌ1 では溶融部外径と最終外径の差が大きくなるた
め、直胴部における平均引取り速度Ｖm の107mm/分より
も遅い引取り速度Ｖ１ ＝ 88.8mm/分（Ｖ1 ＝0.83Ｖ
m ）で引取り、区間Ｌ2 では平均引取り速度Ｖm ＝107m
m/分で引取り、さらに末端よりのＬ3 では溶融部外径と
最終外径との差が小さくなるため、直胴部における平均
引取り速度Ｖm よりも速い引取り速度Ｖ3 ＝137mm/分
（Ｖ3 ＝1.28Ｖm ）で引取るようにした。Next, examples of the present invention and comparative examples will be described. Example 1 In order to produce an optical fiber preform having a diameter of 45 mmφ from a preform ingot having a diameter of 120 mmφ, a known method of measuring an outer diameter of a fusion zone from a stretching start portion to a central portion of the preform and controlling it to be constant. After that, the end portion of the straight body portion was divided into three sections L 1 , L 2 , and L 3 on the side where the stretching of the base material ingot was completed , as shown in FIG. since the difference between the L 1 fused outer diameter and final outside diameter increases, the average take-up speed V m of 107mm / slower take-up than the partial up speed V1 = 88.8mm / min in the straight body portion (V 1 = 0.83 V
m) in the taking, the interval L 2 in average take-up speed V m = 107m
Since m / min take-off, further the difference between the L 3 molten outer diameter and final outside diameter than ends decreases, the average of the straight body portion
The take- off speed V 3 = 137 mm / min (V 3 = 1.28 V m ) was higher than the take-up speed V m .

【００１７】なお、この場合における直胴部における平
均引取り速度Ｖm は、母材インゴットの直胴部の径Ｄ0
と延伸後の母材ロッドの径Ｄ1 および母材インゴットの
送り込み速度Ｖ0 より、次式 Ｖm ＝Ｖ0 × (Ｄ0 ／Ｄ1)2 で求められるが、上記したような引取り条件で延伸を行
なったところ、直胴部末端における溶融部外径は一定値
ではなくなったが、目的とする母材ロッドの最終外径の
変動は、図２に示したように 0.3mmに抑えることができ
た。[0017] The average take-up speed V m of the straight body in this case, the diameter D 0 of the straight body portion of the preform ingot
And the diameter D 1 of the base material rod after stretching and the feed speed V 0 of the base material ingot, can be obtained by the following equation: V m = V 0 × (D 0 / D 1 ) 2. As a result, the outer diameter of the melted portion at the end of the straight body is no longer constant, but the variation in the final outer diameter of the target base material rod must be suppressed to 0.3 mm as shown in Fig. 2. Was completed.

【００１８】実施例２ 母材インゴットを延伸開始部、延伸中央部、延伸終了部
の３つに大きく分け、延伸中央部と延伸終了部について
は実施例１と同一条件で延伸した。しかし、この延伸開
始部については図３に示したように直胴部末端部を２つ
の区間Ｌ4 、Ｌ5 に分け、末端よりの区間Ｌ4 では溶融
部外径と最終外径の差が小さくなるため、この引取り速
度を直胴部における平均引取り速度Ｖm の107mm/分より
も速い引取り速度Ｖ4 ＝127.3mm/分（Ｖ4 ＝1.19Ｖm ）
で引取り、中央よりの区間Ｌ5 では溶融部外径と最終外
径の差が大きくなるため、この引取り速度を直胴部にお
ける平均引取り速度Ｖm よりも遅い引取り速度Ｖ5 ＝ 9
3.1mm/分（Ｖ5 ＝0.87Ｖm ）で引取るようにした。この
ような引取り条件で延伸を行なったところ、図４に示し
たように、延伸開始側の直胴部末端における最終外径の
変動は 0.2mmに抑えることができた。Example 2 A base material ingot was roughly divided into a stretching start portion, a stretching central portion, and a stretching ending portion. The stretching central portion and the stretching ending portion were stretched under the same conditions as in Example 1. However, the straight body portion distal end as shown in Figure 3 for the stretching start portion is divided into two sections L 4, L 5, the difference in melting the outer diameter in the section L 4 and final outside diameter than ends Therefore, the take-up speed V 4 is 127.3 mm / min (V 4 = 1.19 V m ), which is higher than the average take-up speed V m of the straight body portion, which is 107 mm / min.
In taking over, the difference in melting the outer diameter in the section L 5 and the final outside diameter of the center is large, slow take-up speed V than the average take-up speed V m of the take-up speed in the straight body portion 5 = 9
Was引取Ru so at 3.1 mm / min (V 5 = 0.87V m). When stretching was performed under such a take-off condition, as shown in FIG. 4, the fluctuation of the final outer diameter at the end of the straight body at the stretching start side could be suppressed to 0.2 mm.

【００１９】比較例 図５に示したように、電気炉で加熱を行ないながら加熱
溶融部の外径を測定し、この加熱溶融部の外径を一定に
制御する方法で実施例１と同一外径の母材インゴットを
延伸したところ、図７に示したように、母材インゴット
直胴部の両末端部において、溶融部外径は一定値に保つ
ことができたけれども、目的とする母材ロッドの最終外
径については延伸開始側で３mm、延伸終了側で５mmの外
径変動が生じた。この変動量は実施例の外径変動の10倍
以上であり、このままでは母材ロッドを線引きしたとき
に、完全な外径制御が行えず、ファイバ径に変動が生じ
てしまうので、この母材ロッドについては線引き前にガ
ラス旋盤などにより外径修正が必要となった。Comparative Example As shown in FIG. 5, the outer diameter of the heated and melted portion was measured while heating in an electric furnace, and the outer diameter of the heated and melted portion was controlled to be constant. It was stretched preform ingot diameter, as shown in FIG. 7, at both ends of the base material ingot cylindrical body portion, although the molten outer diameter were able to be kept at a constant value, the base material of interest The final outer diameter of the rod fluctuated by 3 mm on the stretching start side and 5 mm on the stretching end side. This variation amount is 10 times or more of the variation of the outer diameter of the embodiment, and if the preform rod is drawn as it is, complete outer diameter control cannot be performed and the fiber diameter will fluctuate. The outer diameter of the rod had to be corrected before drawing using a glass lathe.

【００２０】[0020]

【発明の効果】本発明による光ファイバ母材の製造方法
によれば、母材インゴットの外径の変化や物性の違いに
より溶融部を一定に制御するだけでは最終外径に変動が
生じてしまう場合でも、最終外径をほぼ一定に制御する
ことができる。According to the method of manufacturing an optical fiber preform according to the present invention, a change in the outer diameter of the preform ingot and a difference in physical properties alone cause a variation in the final outer diameter only by controlling the fusion zone to a constant value. Even in this case, the final outer diameter can be controlled to be substantially constant.

【図面の簡単な説明】[Brief description of the drawings]

【図１】 本発明による延伸終了側直胴部末端の延伸方
法の縦断面図を示したものである。[1] shows a longitudinal sectional view of the stretching termination side straight body stretching method of the terminal according to the present invention.

【図２】 本発明の実施例１における延伸ロッドの溶融
部外径と最終外径に関する母材長さと外径との関係グラ
フを示したものである。FIG. 2 is a graph showing the relationship between the base material length and the outer diameter with respect to the outer diameter of the melted portion and the final outer diameter of the stretched rod in Example 1 of the present invention.

【図３】 本発明の実施例２における延伸開始側直胴部
末端の延伸方法の縦断面図を示したものである。FIG. 3 is a longitudinal sectional view showing a method of stretching the end of a straight body portion on the stretching start side in Example 2 of the present invention.

【図４】 本発明の実施例２における延伸ロッドの溶融
部外径と最終外径に関する母材長さと外径との関係グラ
フを示したものである。FIG. 4 is a graph showing the relationship between the base material length and the outer diameter with respect to the outer diameter of the melted portion and the final outer diameter of the stretched rod in Example 2 of the present invention.

【図５】 従来法による母材インゴット延伸方法の縦断
面図を示したものである。[5] shows a longitudinal sectional view of a preform ingot drawing method by the conventional method.

【図６】 母材インゴットの概形縦断面図を示したもの
である。FIG. 6 is a schematic longitudinal sectional view of a base material ingot .

【図７】 従来法の溶融部外径を一定に制御して延伸し
た延伸ロッドの溶融部外径、最終外径に関する母材長さ
と外径との関係グラフを示したものである。7 illustrates molten outer diameter of the stretching rod stretched by controlling the molten portion outer diameter of the prior art constant, a relationship graph between the preform length and outer diameter for the final outside diameter.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 小出 弘行 群馬県安中市磯部２丁目13番１号 信越 化学工業株式会社 精密機能材料研究所 内 (72)発明者 平沢 秀夫 群馬県安中市磯部２丁目13番１号 信越 化学工業株式会社 精密機能材料研究所 内 (56)参考文献 特開 平４−83726（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C03B 37/00 - 37/16 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Koide 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd.Precision Functional Materials Laboratory (72) Inventor Hideo Hirasawa Annaka-shi, Gunma 2-13-1, Isobe Shin-Etsu Chemical Co., Ltd. Precision Functional Materials Laboratory (56) References JP-A-4-83726 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C03B 37/00-37/16

Claims (6)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 母材インゴットをこれより小径の母材ロ
ッドに延伸して光ファイバ母材を製造する方法におい
て、母材インゴットの直胴部と外径差があるか物性の異
なる末端周辺部を延伸する際の延伸条件を、直胴部での
平均引取り速度よりも速い速度で引き伸ばす区間と直胴
部での平均引取り速度よりも遅い速度で引き伸ばす区間
を有するものとしてなることを特徴とする光ファイバ母
材の製造方法。1. A method for the base material ingot by stretching it from the small diameter of the preform rod for manufacturing an optical fiber preform, if the physical properties it is straight body portion and the outer diameter difference of the base material ingot different
The drawing conditions at the time of stretching the distal peripheral part comprising, as having a section stretching at an average take-up speed lower than the speed of the section and the straight body portion stretching at a faster than the average take-up speed at the straight body speed A method for producing an optical fiber preform, comprising: 【請求項２】 平均引取り速度よりも速い速度で引き伸
ばす区間と、平均引取り速度よりも遅い速度で引き伸ば
す区間との間に、平均引取り速度で引き伸ばす区間を設
けてなる請求項１に記載した光ファイバ母材の製造方
法。2. The apparatus according to claim 1, wherein a section for extending at an average take-up speed is provided between a section for extending at a speed higher than the average take-up speed and a section for extending at a speed lower than the average take-up speed. Of manufacturing a preformed optical fiber preform. 【請求項３】 平均引取り速度よりも速い速度で引き伸
ばす速度が平均引取り速度の 110〜 150％の範囲である
請求項１または２に記載した光ファイバ母材の製造方
法。3. The method of manufacturing an optical fiber preform according to claim 1, wherein the stretching speed at a speed higher than the average pulling speed is in the range of 110 to 150% of the average pulling speed. 【請求項４】 平均引取り速度よりも速い速度で引き伸
ばす速度が平均引取り速度の 125〜 135％の範囲である
請求項１または２に記載した光ファイバ母材の製造方
法。4. The method for producing an optical fiber preform according to claim 1, wherein the stretching speed at a speed higher than the average pulling speed is in the range of 125 to 135% of the average pulling speed. 【請求項５】 平均引取り速度よりも遅い速度で引き伸
ばす速度が平均引取り速度の70〜90％の範囲である請求
項１または２に記載した光ファイバ母材の製造方法。5. The method for producing an optical fiber preform according to claim 1, wherein the stretching speed at a speed lower than the average drawing speed is in the range of 70 to 90% of the average drawing speed. 【請求項６】 平均引取り速度よりも遅い速度で引き伸
ばす速度が平均引取り速度の80〜90％の範囲である請求
項１または２に記載した光ファイバ母材の製造方法。6. The method for producing an optical fiber preform according to claim 1, wherein the stretching speed at a speed lower than the average pulling speed is in the range of 80 to 90% of the average pulling speed.
JP19241694A 1994-08-16 1994-08-16 Manufacturing method of optical fiber preform Expired - Lifetime JP3151358B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19241694A JP3151358B2 (en) 1994-08-16 1994-08-16 Manufacturing method of optical fiber preform

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19241694A JP3151358B2 (en) 1994-08-16 1994-08-16 Manufacturing method of optical fiber preform

Publications (2)

Publication Number Publication Date
JPH0859274A JPH0859274A (en) 1996-03-05
JP3151358B2 true JP3151358B2 (en) 2001-04-03

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Country Link
JP (1) JP3151358B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6279353B1 (en) 1997-03-25 2001-08-28 The Furukawa Electric Co., Ltd. Electric furnace extension method and extension apparatus for optical fiber glass preform
DE69800722T2 (en) * 1997-05-30 2001-08-02 Shin-Etsu Chemical Co., Ltd. Procedure for drawing a glass preform into a rod
KR102050060B1 (en) * 2018-01-22 2019-11-28 포항공과대학교 산학협력단 Manufacturing method of ultralong, uniform, and subwavelength-diameter optical fiber

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