JP3083917B2 - Method of stretching base material for fluoride glass optical waveguide - Google Patents
Method of stretching base material for fluoride glass optical waveguideInfo
- Publication number
- JP3083917B2 JP3083917B2 JP19097192A JP19097192A JP3083917B2 JP 3083917 B2 JP3083917 B2 JP 3083917B2 JP 19097192 A JP19097192 A JP 19097192A JP 19097192 A JP19097192 A JP 19097192A JP 3083917 B2 JP3083917 B2 JP 3083917B2
- Authority
- JP
- Japan
- Prior art keywords
- base material
- optical waveguide
- fluoride glass
- stretching
- glass optical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01205—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
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/80—Non-oxide glasses or glass-type compositions
- C03B2201/82—Fluoride glasses, e.g. ZBLAN glass
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
- Glass Compositions (AREA)
- Lasers (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、主として光通信システ
ムの中継部に使用される光増幅用光導波路（光ファイバ
を含む）に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide for optical amplification (including an optical fiber) mainly used in a relay section of an optical communication system.
【０００２】[0002]
【従来の技術】光通信システムは発光部、中継部および
受光部から構成され、これらの間は光導波路で結ばれて
いる。この中継部は、伝送する信号光が光導波路中を伝
搬する際の伝送損失およびパルスの広がりを補償するも
のである。従来、その構成は信号光を一度電気信号に変
換して補償した後、半導体レーザを用いて信号光に変換
するというものであった。しかしながら、この方法は装
置の構成が極めて複雑であるため高価であるという欠点
があった。そこで最近、発光源として希土類元素を用い
ることが考えられている。希土類ガラスをホストガラス
にドープしたものをコア部として光導波路を作製し、こ
の光導波路により波長が 1.3μｍまたは1.55μｍの信号
光を直接増幅することが試みられている。特に、これら
の希土類元素のうち、プラセオジウム(Pr)をコア部にド
ープした ZBLAN(ZrF4 -BaF4 -LaF3 -AlF3 -NaF) 系フッ
化物ガラスのシングルモード型光導波路は、波長が 1.3
μｍの信号光を効率よく増幅するものとして注目されて
いる。2. Description of the Related Art An optical communication system includes a light emitting section, a relay section, and a light receiving section, and these are connected by an optical waveguide. The repeater compensates for transmission loss and pulse spread when the signal light to be transmitted propagates in the optical waveguide. Conventionally, the configuration is such that the signal light is once converted into an electric signal, compensated, and then converted into the signal light using a semiconductor laser. However, this method has a drawback that the apparatus is extremely complicated and expensive. Therefore, use of a rare earth element as a light emitting source has recently been considered. Attempts have been made to fabricate an optical waveguide with a core portion made of a rare earth glass doped into host glass, and to directly amplify a signal light having a wavelength of 1.3 μm or 1.55 μm using this optical waveguide. In particular, among these rare earth elements, the single mode optical waveguide of ZBLAN (ZrF 4 -BaF 4 -LaF 3 -AlF 3 -NaF) based glass doped with praseodymium (Pr) in the core has a wavelength of 1.3
Attention has been paid to amplifying the μm signal light efficiently.
【０００３】通常、フッ化物ガラスでシングルモード用
光導波路用母材を作成する場合の延伸・線引工程は以下
の通りである。 コア部用母材を延伸し、別の工程で作成したクラッド
部用パイプに挿入して両者を溶融・一体化させる。 このの工程を経た母材を延伸する。 このままでは、クラッド部層の厚さが足りないので、
で延伸した母材を更に別の工程で作製したクラッド部
用パイプの内部に挿入し、この状態のままロッドインチ
ューブ法で線引する。 これらの工程においては、ガラスの失透を防止するた
め、不活性ガス中に母材を置き、外部から電気炉にて加
熱しながら母材を引き延ばす方法が採用されている。
尚、不活性ガス雰囲気中で加熱延伸する理由は、失透
が、フッ化物ガラスが酸素に対して不安定なために起こ
るガラスの結晶化、大気中の水などとの化学反応などが
原因となって起こるからである。すなわち、大気中の酸
素や水から母材を遮断する必要があるためである。上記
に述べた理由により、酸水素炎による母材の直接加熱
は、酸化を引き起こすため行うことができず、また酸水
素炎以外の火炎による直接加熱もフッ化物ガラスが熱に
対して不安定であることから行われていない。[0003] Usually, the stretching and drawing steps in the case of preparing a single mode optical waveguide base material using fluoride glass are as follows. The base material for the core portion is stretched and inserted into a clad portion pipe prepared in another process to fuse and integrate them. The base material after this step is stretched. In this state, the thickness of the cladding layer is not enough.
The base material stretched in the step is inserted into the cladding pipe produced in another step, and drawn in this state by a rod-in-tube method. In these steps, in order to prevent devitrification of the glass, a method is employed in which the base material is placed in an inert gas and the base material is stretched while being externally heated in an electric furnace.
In addition, the reason for heating and stretching in an inert gas atmosphere is that devitrification is caused by crystallization of the glass caused by the instability of the fluoride glass with respect to oxygen, chemical reaction with water in the atmosphere, and the like. Because it happens. That is, it is necessary to shield the base material from oxygen and water in the atmosphere. For the reasons described above, direct heating of the base material by an oxyhydrogen flame cannot be performed because it causes oxidation, and direct heating by a flame other than the oxyhydrogen flame is also unstable with fluoride glass. Not done from there.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、現在行
われているフッ化物ガラス光導波路母材の電気炉による
延伸は、電気炉のヒートゾーンが大きすぎるなどの理由
から、加熱による延伸中のガラスの粘度制御（温度制
御）が極めて難しく、母材が延伸中に失透する、あるい
は曲がる、所定の外径に延伸することが難しい、などと
いう問題があり、大量生産には適さない技術であった。However, in the current stretching of a fluoride glass optical waveguide base material by an electric furnace, the glass being stretched by heating is not used because the heat zone of the electric furnace is too large. It is very difficult to control the viscosity (temperature control), the base material is devitrified or bent during stretching, and it is difficult to stretch to a predetermined outer diameter. .
【０００５】[0005]
【課題を解決するための手段】本発明の目的は、フッ化
物ガラス光導波路用母材の失透、曲がりを防止し、所定
の外径に延伸することができる方法、すなわち大量生産
も可能となる製造方法を提供することにある。したがっ
て、本発明によれば、フッ化物ガラス光導波路用母材を
不活性ガスの気流中で加熱し、延伸する方法において、
前記フッ化物ガラス光導波路用母材を透明なガラス容器
内に収納した状態で前記ガラス容器の外部から火炎で加
熱することを特徴とするフッ化物ガラス光導波路用母材
の延伸方法が提供される。SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of preventing the devitrification and bending of a base material for a fluoride glass optical waveguide and extending the material to a predetermined outer diameter, that is, mass production is possible. Another object of the present invention is to provide a manufacturing method. Therefore, according to the present invention, in a method of heating the base material for a fluoride glass optical waveguide in a stream of an inert gas and stretching the same,
A method for stretching a preform for a fluoride glass optical waveguide is provided, wherein the preform for a fluoride glass optical waveguide is heated by a flame from the outside of the glass container while the preform for a fluoride glass optical waveguide is housed in a transparent glass container. .
【０００６】[0006]
【作用】現在までの延伸工程を検討した結果、以下のよ
うな点が判明した。 電気炉を用いた装置ではヒートゾーンが大きすぎ、微
妙な温度制御を必要とするフッ化物ガラスの延伸には適
さない。（石英ガラスの場合は加熱点と延伸点の位置に
差があるが、フッ化物ガラスの場合は加熱点＝延伸点で
ある。） 延伸箇所がヒータで覆われているため、外部からはど
の箇所が延伸されているのか確認できない。 延伸径が延伸時にすぐ確認できない。 すなわち、一度母材が低粘度になった場合、適切な粘度
（または温度）に戻そうとすると電気炉では熱容量が大
きいため時間がかかる。このため、加熱条件が不安定と
なって化学反応を誘因し、失透などが起こっていた。ま
た、延伸すべき箇所・延伸径などが電気炉に邪魔されて
容易に確認できないために、所定の外径に延伸するに
は、熟練を要し、一定状態に延伸することは難しかっ
た。The following points have been found as a result of studying the stretching process up to now. In an apparatus using an electric furnace, the heat zone is too large, and is not suitable for stretching fluoride glass that requires delicate temperature control. (In the case of quartz glass, there is a difference between the positions of the heating point and the stretching point. However, in the case of fluoride glass, the heating point is the stretching point.) Since the stretching portion is covered with a heater, any portion from the outside is required. It cannot be confirmed that the film is stretched. The stretching diameter cannot be confirmed immediately at the time of stretching. That is, once the base material has a low viscosity, it takes time to return to an appropriate viscosity (or temperature) because of the large heat capacity of the electric furnace. For this reason, the heating conditions became unstable, causing a chemical reaction, and devitrification occurred. In addition, since the place to be stretched and the stretching diameter cannot be easily checked because of the obstruction of the electric furnace, stretching to a predetermined outer diameter requires skill and it is difficult to stretch to a constant state.
【０００７】そこで、これらの問題を解決するために検
討した結果、改良点は以下の２点に絞られることを見い
だした。 延伸する母材を大気から遮断すること。 微妙な温度制御ができるよう、比較的ヒートゾーンの
小さい加熱源を用いること。 延伸する母材の状態を目視出来ること。 これらをすべて満足する方法を種々検討した結果、不活
性ガスをフッ化物ガラス光導波路用母材外部に流し、こ
の外側に透明な容器、具体的には透明なガラス容器、好
ましくは石英ガラス製の容器を配し、この容器の外側か
らフッ化物ガラス光導波路用母材を火炎で加熱する方法
を考えだした。この方法によれば、実施例に示すように
フッ化物ガラス光導波路用母材の失透や曲がりを防止
し、かつ所定の外径に対して精度良く延伸することがで
きた。実施例では火炎として酸水素炎を使用したが、フ
ッ化物ガラスの溶融温度を考えると酸水素炎にこだわる
必要はなく、例えば、都市ガス＋酸素炎でも可能であっ
た。また実施例での延伸母材としては、コア部用母材と
クラッド部用母材の一部とを溶融一体化させた段階のも
のを用いたが、コア部用母材のみの段階、もしくは最終
段階の母材などすべての場合において適用できた。Therefore, as a result of studying to solve these problems, it has been found that the improvements are limited to the following two points. Shield the stretched base material from the atmosphere. Use a heating source with a relatively small heat zone so that delicate temperature control can be performed. Be able to see the state of the base material being stretched. As a result of various studies on a method that satisfies all of them, an inert gas was caused to flow outside the preform for the fluoride glass optical waveguide, and a transparent container, specifically a transparent glass container, preferably made of quartz glass was provided outside the inert gas. A method of arranging a container and heating the base material for a fluoride glass optical waveguide with a flame from outside of the container was devised. According to this method, as shown in the examples, it was possible to prevent devitrification and bending of the base material for a fluoride glass optical waveguide, and to accurately stretch the base material for a predetermined outer diameter. In the embodiment, the oxyhydrogen flame was used as the flame. However, considering the melting temperature of the fluoride glass, it is not necessary to stick to the oxyhydrogen flame. For example, a city gas + oxygen flame can be used. Further, as the stretched base material in the examples, a stage in which the core base material and a part of the clad base material were melted and integrated was used, but the stage of the core base material alone, or It was applicable in all cases, such as the last stage base material.
【０００８】[0008]
【実施例】以下本発明の実施例を詳細に説明する。装置
の概要を図１に示した。フッ化物ガラス光導波路用母材
６として、外径15mmで長さが 100mmの ZBLAN系ガラス母
材（コア部用母材とクラッド部用母材の一部とを溶融一
体化した段階のもの）、不活性ガスとして窒素ガスをそ
れぞれ使用した。フッ化物ガラス光導波路用母材６を石
英ガラスからなる透明容器４中央に設置し、マスフロー
コントローラ３で流量を調節しつつ不活性ガスを入口８
から出口９へと流しながら、前記フッ化物ガラス光導波
路用母材６を所定の回転数で回転させつつ、移動可能な
加熱源としてバーナ１を用いて約 300℃になるようにこ
れを加熱し、外径 5mmになるように延伸した。延伸方法
は、外径、延伸箇所をバーナ１の近傍に配した外径測定
器２で確認しながら行った。尚、石英ガラス管からなる
透明容器はガス・シール部材５ａ、５ｂによって密閉し
た。この方法により、失透・曲がりを生じることなく、
外径が5.02±0.05mmで長さが 550mmのロッドに延伸でき
た。尚、図１においてバーナ１および外径測定器２が両
方向に動くがごとく矢印を付してあるが、これは延伸工
程を複数回繰り返すことにより、所望の外径に延伸する
ため、バーナ１、外径測定器２は矢印のごとく両方向に
移動可能であることを示すためである。実際に延伸工程
においては、図１の場合、バーナ１、外径測定器２共に
所定速度で左方向に動く。Embodiments of the present invention will be described below in detail. The outline of the apparatus is shown in FIG. As the base material 6 for a fluoride glass optical waveguide, a ZBLAN-based glass base material having an outer diameter of 15 mm and a length of 100 mm (a stage where a base material for a core part and a part of a base material for a clad part are fused and integrated). Nitrogen gas was used as an inert gas. The fluoride glass optical waveguide base material 6 is placed in the center of the transparent container 4 made of quartz glass, and the inert gas is introduced into the inlet 8 while controlling the flow rate with the mass flow controller 3.
Is heated to about 300 ° C. by using the burner 1 as a movable heating source while rotating the fluoride glass optical waveguide base material 6 at a predetermined number of revolutions while flowing from the outlet 9 to the outlet 9. The film was stretched so as to have an outer diameter of 5 mm. The stretching method was performed while checking the outer diameter and the stretched position with an outer diameter measuring device 2 arranged near the burner 1. The transparent container made of a quartz glass tube was sealed with gas sealing members 5a and 5b. By this method, without devitrification and bending,
It was able to stretch to a rod with outer diameter of 5.02 ± 0.05mm and length of 550mm. In FIG. 1, arrows are attached as if the burner 1 and the outer diameter measuring device 2 move in both directions. This is because the burner 1 and the outer diameter measuring device 2 are stretched to a desired outer diameter by repeating the stretching process a plurality of times. This is to indicate that the outer diameter measuring device 2 can be moved in both directions as indicated by arrows. Actually, in the stretching step, in the case of FIG. 1, both the burner 1 and the outer diameter measuring device 2 move leftward at a predetermined speed.
【０００９】比較例として、図２に示すように、実施例
においての酸水素炎バーナ部と同じ位置にヒータがリン
グ状の電気炉７を配し、実施例と同様にして延伸を行っ
た。この結果、電気炉７が邪魔になって延伸点を外径測
定器２で測定できなかった。そのため、母材は外径が 5
mm± 3mm程度の精度にしか延伸できず、さらに曲がりを
防ぐこともできなかった。また、試験的に外径が太いと
ころを再度加熱し延伸をすることを試みたが、結局細い
ところが更に延伸・溶断されてしまって、上手く延伸す
ることができなかった。As a comparative example, as shown in FIG. 2, a ring-shaped electric furnace 7 having a heater was arranged at the same position as the oxyhydrogen flame burner section in the example, and stretching was performed in the same manner as in the example. As a result, the stretching point could not be measured by the outer diameter measuring device 2 because the electric furnace 7 was in the way. Therefore, the outer diameter of the base material is 5
It could be stretched only to an accuracy of about mm ± 3 mm, and could not prevent bending. In addition, a trial was conducted in which a portion having a large outer diameter was reheated and stretched on a test basis. However, the thin portion was further stretched and blown, and could not be stretched well.
【００１０】[0010]
【発明の効果】本発明により、フッ化物ガラス光導波路
母材を透明な容器中、不活性気体を流しながら火炎によ
って延伸することにより、前記フッ化物ガラス光導波路
母材を大気中の酸素、水などから遮断でき、しかも温度
制御・延伸箇所の確認などが容易となり、その結果、失
透・曲がりを生ずることなく、所定の外径に延伸するこ
と、すなわち大量生産が可能となった。According to the present invention, the fluoride glass optical waveguide base material is stretched by a flame while flowing an inert gas in a transparent container, so that the fluoride glass optical waveguide base material can be treated with oxygen and water in the atmosphere. In addition, it is easy to control the temperature and check the stretched portion, and as a result, it is possible to stretch to a predetermined outer diameter without devitrification and bending, that is, mass production is possible.
【図１】本発明の実施例である。FIG. 1 is an embodiment of the present invention.
【図２】本発明に対する比較例である。FIG. 2 is a comparative example for the present invention.
１ バーナ ２ 外径測定器 ３ 不活性ガス用マスフローコントローラ ４ 石英ガラス管からなる透明容器 ５ ガスシール ６ フッ化物ガラス光導波路用母材 ７ 電気炉 ８ 不活性気体の入口 ９ 不活性気体の出口 Reference Signs List 1 burner 2 outer diameter measuring device 3 mass flow controller for inert gas 4 transparent container made of quartz glass tube 5 gas seal 6 base material for fluoride glass optical waveguide 7 electric furnace 8 inert gas inlet 9 inert gas outlet
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平３−50134（ＪＰ，Ａ) 特開 平２−243532（ＪＰ，Ａ) 特開 昭61−295250（ＪＰ，Ａ) 特開 平３−153538（ＪＰ，Ａ) 特開 平２−243529（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C03B 37/012 C03B 23/047 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-50134 (JP, A) JP-A-2-243532 (JP, A) JP-A-61-295250 (JP, A) JP-A-3-295 153538 (JP, A) JP-A-2-243529 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C03B 37/012 C03B 23/047
Claims (1)
ガスの気流中で加熱し、延伸する方法において、前記フ
ッ化物ガラス光導波路用母材を透明なガラス容器内に収
納した状態で前記ガラス容器の外部から火炎で加熱する
ことを特徴とするフッ化物ガラス光導波路用母材の延伸
方法。1. A method for heating and stretching a preform for a fluoride glass optical waveguide in a stream of inert gas, wherein the preform for a fluoride glass optical waveguide is contained in a transparent glass container. A method for stretching a preform for a fluoride glass optical waveguide, characterized by heating with a flame from the outside of the glass container.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19097192A JP3083917B2 (en) | 1992-07-17 | 1992-07-17 | Method of stretching base material for fluoride glass optical waveguide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19097192A JP3083917B2 (en) | 1992-07-17 | 1992-07-17 | Method of stretching base material for fluoride glass optical waveguide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0632634A JPH0632634A (en) | 1994-02-08 |
| JP3083917B2 true JP3083917B2 (en) | 2000-09-04 |
Family
ID=16266724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19097192A Expired - Fee Related JP3083917B2 (en) | 1992-07-17 | 1992-07-17 | Method of stretching base material for fluoride glass optical waveguide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3083917B2 (en) |
-
1992
- 1992-07-17 JP JP19097192A patent/JP3083917B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0632634A (en) | 1994-02-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |