JP2001019460A - Production of base material for gi type optical fiber and preform for gi type optical fiber thus produced - Google Patents
Production of base material for gi type optical fiber and preform for gi type optical fiber thus producedInfo
- Publication number
- JP2001019460A JP2001019460A JP11192997A JP19299799A JP2001019460A JP 2001019460 A JP2001019460 A JP 2001019460A JP 11192997 A JP11192997 A JP 11192997A JP 19299799 A JP19299799 A JP 19299799A JP 2001019460 A JP2001019460 A JP 2001019460A
- Authority
- JP
- Japan
- Prior art keywords
- heat treatment
- optical fiber
- base material
- porous glass
- fiber preform
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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]
- C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
-
- 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]
- C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
- C03B37/0146—Furnaces therefor, e.g. muffle tubes, furnace linings
-
- 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
- C03B2201/08—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
- C03B2201/12—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with fluorine
-
- 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
- C03B2203/26—Parabolic or graded index [GRIN] core profile
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Thermal Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＧＩ型光ファイバ
母材の製造方法およびＧＩ型光ファイバ母材に関する。The present invention relates to a method of manufacturing a GI optical fiber preform and a GI optical fiber preform.
【０００２】[0002]
【従来の技術】例えばレーザーガイド用光ファイバとし
ては、フッ素をドープすることにより光ファイバの屈折
率分布（プロファイル）を制御したフッ素ドープコアフ
ァイバが広く使われている。そして、このような光ファ
イバのプロファイルとしては、完全なステップ型プロフ
ァイルよりは、ステップの角が円くなったＧＩ（Greade
d Index）型の方が特性上良いといわれている。2. Description of the Related Art As an optical fiber for a laser guide, for example, a fluorine-doped core fiber in which the refractive index distribution (profile) of an optical fiber is controlled by doping with fluorine is widely used. As a profile of such an optical fiber, a GI (Greade
It is said that the d Index) type is better in characteristics.
【０００３】このＧＩ型光ファイバは、ステップ型光フ
ァイバに比べて、多モードの光パルス信号を一定時間内
に大量に送る、高速・大容量の伝送に適しており、近
年、特に需要が多くなっているものである。しかし、Ｇ
Ｉ型光ファイバは、ステップ型光ファイバに比べてその
プロファイルを制御して製造することが難しく、製造に
時間がかかり、生産性が低いことが欠点であった。This GI optical fiber is more suitable for high-speed and large-capacity transmission, in which a large number of multi-mode optical pulse signals are transmitted within a fixed time than the step-type optical fiber. Is what it is. But G
The I-type optical fiber has disadvantages in that it is more difficult to manufacture the I-type optical fiber by controlling the profile than in the step-type optical fiber, it takes time to manufacture, and the productivity is low.
【０００４】従来、フッ素をドープする光ファイバ母材
の製造方法としては、以下の方法が行われていた。第１
の方法としては、ＯＶＤ法を利用する方法である。すな
わち、図５に示すように、純シリカガラスから成る出発
母材４を作り（図５（１））、その外周にガラススート
６を堆積させる（図５（２））。その際にガラススート
６の嵩密度分布が所望のプロファイルに合うようにす
る。そして、フッ素を含む雰囲気を満たした加熱炉３中
で脱水と焼結を同時に行い、クラッド部にフッ素をドー
プした光ファイバ母材１を製造する（図５（３））。Conventionally, the following method has been used as a method for producing an optical fiber preform doped with fluorine. First
Is a method using the OVD method. That is, as shown in FIG. 5, a starting base material 4 made of pure silica glass is prepared (FIG. 5A), and a glass soot 6 is deposited on the outer periphery thereof (FIG. 5B). At that time, the bulk density distribution of the glass soot 6 is adjusted to a desired profile. Then, dehydration and sintering are simultaneously performed in the heating furnace 3 filled with an atmosphere containing fluorine to produce the optical fiber preform 1 in which the cladding is doped with fluorine (FIG. 5 (3)).
【０００５】この方法は、所望のプロファイルを持つ大
口径の母材を製造することができることが利点である
が、コアとクラッドの界面に不純物が残り易く低損失化
できないことが欠点である。さらに製造工程が複雑にな
り、生産に長時間を要するという欠点がある。[0005] This method has an advantage that a large-diameter base material having a desired profile can be manufactured, but has a disadvantage that impurities are easily left at an interface between a core and a clad and loss cannot be reduced. Further, there is a disadvantage that the manufacturing process becomes complicated and a long time is required for production.
【０００６】第２の方法としてはＶＡＤ法を利用する方
法がある。図６に示すように、通常のＶＡＤ法によっ
て、シングルモード光ファイバ用のガラススート６を堆
積させるのであるが、その際に、コア用バーナ７には原
料としてＳｉＣｌ4だけ流し、かつ堆積するコアスート
５の嵩密度が非常に高くなるようにして、嵩密度分布が
ＧＩ型になるようにする。その後、ＯＶＤ法を利用する
場合と同様にフッ素を含む雰囲気を流した加熱炉中で脱
水と焼結を同時に行い、嵩密度にしたがって光ファイバ
母材１のプロファイルがＧＩ型になるようにする。As a second method, there is a method using a VAD method. As shown in FIG. 6, a glass soot 6 for a single mode optical fiber is deposited by a normal VAD method. At this time, only SiCl 4 is flowed as a raw material into a core burner 7 and the core soot to be deposited is deposited. The bulk density of Sample No. 5 is made very high so that the bulk density distribution becomes GI type. Then, as in the case of using the OVD method, dehydration and sintering are simultaneously performed in a heating furnace in which an atmosphere containing fluorine flows, so that the profile of the optical fiber preform 1 becomes GI type according to the bulk density.
【０００７】この方法ではＯＶＤ法に比べて生産速度が
速く、簡単な工程で光ファイバ母材の生産を行える点が
利点である。しかし、コアスートの嵩密度が非常に高い
ため、脱水処理のとき、脱水剤がコアスートの内部まで
拡散できず、十分な脱水が不可能である点が欠点であ
る。しかも、所望のＧＩ型プロファイルに制御して光フ
ァイバ母材を製造することが非常に難しいという欠点が
ある。This method has the advantage that the production speed is higher than that of the OVD method, and that the optical fiber preform can be produced by a simple process. However, since the bulk density of the core soot is very high, the dewatering agent cannot be diffused to the inside of the core soot during the dehydration treatment, so that sufficient dewatering is not possible. In addition, there is a disadvantage that it is very difficult to manufacture an optical fiber preform while controlling to a desired GI type profile.
【０００８】さらに、第３の方法として挙げられるの
は、純粋シリカの多孔質ガラス母材をそのまま使用する
方法である。この方法は、図４に示すように、まず多孔
質ガラス母材２を加熱炉３内で脱水する（図４
（１））。次に、加熱炉３の温度を高くして（１３００
〜１４００℃）、加熱炉３内を多孔質ガラス母材２を通
過させることにより収縮熱処理を施し、多孔質ガラス母
材２を収縮させる（図４（２））。この収縮熱処理によ
り多孔質ガラス母材２の嵩密度は中心軸付近が高く、周
縁部が低くなる。その後、加熱炉３内にフッ素を流し
て、加熱炉３内を多孔質ガラス母材２を通過させること
により（通過速度３ｍｍ／ｍｉｎ）、焼結熱処理を施し
てガラス化し、所望のプロファイルを持つ光ファイバ母
材１を製造する（図４（３））。A third method is a method in which a porous silica preform of pure silica is used as it is. In this method, as shown in FIG. 4, first, the porous glass base material 2 is dehydrated in a heating furnace 3 (FIG. 4).
(1)). Next, the temperature of the heating furnace 3 was increased (1300
(1400 ° C.), a heat treatment for shrinkage is performed by passing the porous glass base material 2 through the heating furnace 3 to shrink the porous glass base material 2 (FIG. 4 (2)). By this shrinkage heat treatment, the bulk density of the porous glass base material 2 is high near the central axis and low at the peripheral edge. Then, by flowing fluorine into the heating furnace 3 and passing the porous glass base material 2 through the inside of the heating furnace 3 (passing speed 3 mm / min), a sintering heat treatment is performed and vitrification is performed to obtain a desired profile. The optical fiber preform 1 is manufactured (FIG. 4C).
【０００９】このような方法であれば、上記２つの方法
と異なり、簡単にＧＩ型のプロファイルを持つ光ファイ
バ母材を製造することができる。しかし、この方法では
収縮熱処理と焼結熱処理の熱処理条件を適切に定めるこ
とが重要となるが、従来はこの熱処理条件が明確に判明
しておらず、経験的に決定された熱処理条件により熱処
理が行われていた。そのため、図２に示すように嵩密度
が小さ過ぎて、フッ素がドープされ過ぎてしまったり、
あるいは図３に示すように収縮熱処理により嵩密度を大
きくし過ぎてしまい、フッ素が全くドープされなくなっ
てしまったりすることがしばしば起こり、歩留りの低下
等を招いていた。According to such a method, unlike the above two methods, an optical fiber preform having a GI type profile can be easily manufactured. However, in this method, it is important to appropriately determine the heat treatment conditions of the shrink heat treatment and the sintering heat treatment.However, conventionally, the heat treatment conditions have not been clearly clarified, and the heat treatment is determined by the heat treatment conditions determined empirically. It was done. Therefore, the bulk density is too small as shown in FIG.
Alternatively, as shown in FIG. 3, the bulk density is excessively increased by the shrinkage heat treatment, so that fluorine is often not doped at all, often resulting in a decrease in yield and the like.
【００１０】[0010]
【発明が解決しようとする課題】本発明は上記問題点に
鑑みなされたものであり、多孔質ガラス母材に収縮熱処
理を施し、該収縮熱処理を施した多孔質ガラス母材にフ
ッ素を含む雰囲気下の焼結熱処理を施すＧＩ型光ファイ
バ母材の製造方法において、確実にＧＩ型の所望のプロ
ファイルを持つ光ファイバ母材を製造することができる
ＧＩ型光ファイバ母材の製造方法を提供することを目的
とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. An object of the present invention is to provide a porous glass preform subjected to a shrinkage heat treatment, and the porous glass preform subjected to the shrinkage heat treatment contains an atmosphere containing fluorine. In a method of manufacturing a GI optical fiber preform to be subjected to the following sintering heat treatment, a method of manufacturing a GI optical fiber preform capable of reliably manufacturing an optical fiber preform having a desired GI profile is provided. The purpose is to:
【００１１】[0011]
【課題を解決するための手段】上記目的を達成するた
め、本発明の請求項１に記載した発明は、少なくとも多
孔質ガラス母材に収縮熱処理を施し、該収縮熱処理を施
した多孔質ガラス母材にフッ素を含む雰囲気下の焼結熱
処理を施すＧＩ型光ファイバ母材の製造方法において、
前記収縮熱処理は、熱処理温度を１１５０〜１２１５℃
とし、前記焼結熱処理は、多孔質ガラス母材が加熱源を
通過する速度を５〜１０ｍｍ／ｍｉｎとすることを特徴
とするＧＩ型光ファイバ母材の製造方法である。Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 of the present invention provides a porous glass base material which has been subjected to shrinkage heat treatment at least to a porous glass base material. In a method for producing a GI optical fiber preform, which performs a sintering heat treatment in an atmosphere containing fluorine in the material,
The shrink heat treatment is performed at a heat treatment temperature of 1150 to 1215 ° C.
The sintering heat treatment is a method for manufacturing a GI optical fiber preform, wherein the speed at which the porous glass preform passes through a heating source is 5 to 10 mm / min.
【００１２】このように多孔質ガラス母材に収縮熱処理
を施し、フッ素を含む雰囲気下の焼結熱処理を施すＧＩ
型光ファイバ母材の製造方法において、収縮熱処理は、
熱処理温度を１１５０〜１２１５℃とし、焼結熱処理
は、多孔質ガラス母材が加熱源を通過する速度を５〜１
０ｍｍ／ｍｉｎとすることにより、確実にＧＩ型のプロ
ファイルを持つＧＩ型光ファイバ母材を製造することが
できる。[0012] As described above, the porous glass base material is subjected to shrinkage heat treatment, and sintering heat treatment is performed in an atmosphere containing fluorine.
In the method for producing a type optical fiber preform, the shrinkage heat treatment includes:
The heat treatment temperature is set at 1150 to 1215 ° C., and the sintering heat treatment is performed at a speed at which the porous glass base material passes through the heating source at 5 to 1
By setting it to 0 mm / min, a GI optical fiber preform having a GI profile can be reliably manufactured.
【００１３】また本発明の請求項２に記載した発明は、
少なくとも多孔質ガラス母材に収縮熱処理を施し、該収
縮熱処理を施した多孔質ガラス母材にフッ素を含む雰囲
気下の焼結熱処理を施すＧＩ型光ファイバ母材の製造方
法において、前記収縮熱処理は、熱処理温度を一定温度
の±５℃以内に制御しつつ熱処理を行い、前記焼結熱処
理は、前記多孔質ガラス母材が加熱源を通過する速度を
一定速度の±０．５ｍｍ／ｍｉｎ以内に制御しつつ熱処
理を行うことを特徴とするＧＩ型光ファイバ母材の製造
方法である。The invention described in claim 2 of the present invention provides:
At least a porous glass preform is subjected to a shrinkage heat treatment, and the shrinkage heat treatment is performed on the porous glass preform to be subjected to a sintering heat treatment in an atmosphere containing fluorine. Performing the heat treatment while controlling the heat treatment temperature to within ± 5 ° C. of the constant temperature, and performing the sintering heat treatment by controlling the speed at which the porous glass base material passes through a heating source to within ± 0.5 mm / min of the constant speed. A method for producing a GI optical fiber preform, characterized in that heat treatment is performed while controlling.
【００１４】このように、多孔質ガラス母材に収縮熱処
理を施し、フッ素を含む雰囲気下の焼結熱処理を施すＧ
Ｉ型光ファイバ母材の製造方法において、収縮熱処理は
熱処理温度を一定温度の±５℃以内に制御しつつ熱処理
を行い、焼結熱処理は多孔質ガラス母材が加熱源を通過
する速度を一定速度の±０．５ｍｍ／ｍｉｎ以内に制御
しつつ熱処理を行うことにより、確実にＧＩ型のプロフ
ァイルを持つＧＩ型光ファイバ母材を製造することがで
き、光ファイバ母材のプロファイル等のバラツキを減少
させることができる。Thus, the porous glass base material is subjected to the shrinkage heat treatment, and the sintering heat treatment is performed in an atmosphere containing fluorine.
In the method of manufacturing an I-type optical fiber preform, the shrinkage heat treatment is performed while controlling the heat treatment temperature to within ± 5 ° C. of a fixed temperature, and the sintering heat treatment is performed at a constant speed at which the porous glass preform passes through a heating source. By performing the heat treatment while controlling the speed within ± 0.5 mm / min, the GI optical fiber preform having the GI type profile can be reliably manufactured, and the variation of the profile of the optical fiber preform can be reduced. Can be reduced.
【００１５】この場合、請求項３に記載したように、前
記収縮熱処理は、温度を１１５０〜１２１５℃とするこ
とが好ましい。このように収縮熱処理の温度を１１５０
〜１２１５℃とすれば、熱処理後の多孔質ガラス母材の
嵩密度分布はより適当なものとなり、後の焼結熱処理で
フッ素がドープされ過ぎたり、ドープ量が不足すること
なく、より確実にＧＩ型のプロファイルを持つＧＩ型光
ファイバ母材を製造することができる。[0015] In this case, it is preferable that the temperature of the shrinkage heat treatment is set to 1150 to 1215 ° C. Thus, the temperature of the shrink heat treatment is set to 1150
When the temperature is set to １２1215 ° C., the bulk density distribution of the porous glass base material after the heat treatment becomes more appropriate, and the fluorine is not excessively doped in the subsequent sintering heat treatment, and the doping amount is more reliably prevented. A GI optical fiber preform having a GI profile can be manufactured.
【００１６】この場合、請求項４に記載したように、前
記焼結熱処理は、多孔質ガラス母材が加熱源を通過する
速度を５〜１０ｍｍ／ｍｉｎとすることが好ましい。こ
のように焼結熱処理において、多孔質ガラス母材が加熱
源を通過する速度を５〜１０ｍｍ／ｍｉｎとすることに
より、フッ素のドープ量はより適量となり、その分布も
所望のものとなって、より確実にＧＩ型のプロファイル
を持つＧＩ型光ファイバ母材を製造することができる。In this case, it is preferable that, in the sintering heat treatment, the speed at which the porous glass base material passes through the heating source be 5 to 10 mm / min. As described above, in the sintering heat treatment, by setting the speed at which the porous glass base material passes through the heating source to 5 to 10 mm / min, the doping amount of fluorine becomes more appropriate, and the distribution becomes as desired. A GI optical fiber preform having a GI profile can be more reliably manufactured.
【００１７】そして、請求項５に記載したように、本発
明の方法で製造されたＧＩ型光ファイバ母材は、正確に
所望のＧＩ型のプロファイルを持つ光ファイバ母材とな
るため、これを線引きして諸特性に極めて優れた光ファ
イバを得ることができる。[0017] As described in claim 5, the GI optical fiber preform manufactured by the method of the present invention becomes an optical fiber preform having a desired GI type profile accurately. By drawing, an optical fiber having extremely excellent properties can be obtained.
【００１８】以下、本発明をさらに詳述するが本発明は
これに限定されるものではない。本発明者らは、多孔質
ガラス母材に収縮熱処理を施し、収縮熱処理を施した多
孔質ガラス母材にフッ素を含む雰囲気下の焼結熱処理を
施すＧＩ型光ファイバ母材の製造方法において、確実に
ＧＩ型の所望プロファイルを持つ光ファイバ母材を製造
することができる熱処理条件を見出し、諸条件を精査し
て本発明を完成するに至ったものである。Hereinafter, the present invention will be described in more detail, but the present invention is not limited thereto. The present inventors have performed a shrinkage heat treatment on a porous glass preform, and a GI type optical fiber preform manufacturing method of performing a sintering heat treatment on a porous glass preform subjected to a shrinkage heat treatment in an atmosphere containing fluorine. The present inventors have found heat treatment conditions that can reliably produce an optical fiber preform having a desired GI-type profile, and have scrutinized various conditions to complete the present invention.
【００１９】まず、多孔質ガラス母材の嵩密度を決定す
る条件について本発明者らが実験・調査を行ったとこ
ろ、収縮熱処理においては熱処理温度を１１５０〜１２
１５℃とすることが良いことが判った。この温度は、従
来の脱水熱処理よりやや高い温度であり、従来の収縮熱
処理の温度より低い温度であるが、この温度範囲で収縮
熱処理を施すことにより、後にフッ素を含む雰囲気下で
焼結熱処理を施した際に、多孔質ガラス母材のコア部は
フッ素がドープされにくいように焼き絞めることがで
き、クラッド部はフッ素がドープされやすいように低い
嵩密度のまま保つことができ、所望のＧＩ型プロファイ
ルを持つ光ファイバ母材を得ることができることが判っ
た。First, when the present inventors conducted experiments and investigations on the conditions for determining the bulk density of the porous glass base material, the heat treatment temperature was set to 1150 to 12 in the shrinkage heat treatment.
It was found that the temperature was preferably set to 15 ° C. This temperature is slightly higher than the conventional dehydration heat treatment and is lower than the temperature of the conventional shrink heat treatment.However, by performing the shrink heat treatment in this temperature range, the sintering heat treatment can be performed later in an atmosphere containing fluorine. When applied, the core portion of the porous glass base material can be squeezed and squeezed so as to be hardly doped with fluorine, and the clad portion can be kept at a low bulk density so as to be easily doped with fluorine. It has been found that an optical fiber preform having a mold profile can be obtained.
【００２０】また、上記収縮熱処理の後に行うフッ素を
含む雰囲気下での焼結熱処理においては、多孔質ガラス
母材が加熱炉内の加熱源を通過する速度が重要であり、
その速度を５〜１０ｍｍ／ｍｉｎにすることが良いこと
が判った。この速度は、従来の製造方法における速度の
１．５倍以上の速度であるが、この速度範囲の速度で多
孔質ガラス母材を、ヒータ等の加熱源を通過させること
により、雰囲気中のフッ素が多孔質ガラス母材のコア部
にまで多くドープされる前にガラス化を行うことがで
き、所望のＧＩ型プロファイルを持つ光ファイバ母材を
得ることができることが判った。In the sintering heat treatment in an atmosphere containing fluorine performed after the above-described shrinkage heat treatment, the speed at which the porous glass base material passes through the heating source in the heating furnace is important.
It has been found that the speed should be 5 to 10 mm / min. This speed is at least 1.5 times the speed in the conventional manufacturing method, but by passing the porous glass base material through a heating source such as a heater at a speed in this speed range, the fluorine in the atmosphere is reduced. Can be vitrified before a large amount is doped into the core portion of the porous glass preform, and an optical fiber preform having a desired GI profile can be obtained.
【００２１】さらに本発明者らは、上記収縮熱処理にお
いては熱処理温度を一定温度の±５℃以内に制御し、上
記焼結熱処理においては多孔質ガラス母材が加熱源を通
過する速度を一定速度の±０．５ｍｍ／ｍｉｎ以内に制
御することが重要であることも見出した。これらの条件
を上記のような精度で一定値に制御することにより、プ
ロファイル等の品質のバラツキの少ないＧＩ型光ファイ
バ母材を製造することができ、光ファイバ母材の製造歩
留りを向上させることができる。Further, the present inventors control the heat treatment temperature to within ± 5 ° C. of the fixed temperature in the above-mentioned shrinkage heat treatment, and make the speed at which the porous glass base material passes through the heating source constant in the above-mentioned sintering heat treatment. It has also been found that it is important to control within ± 0.5 mm / min. By controlling these conditions to a constant value with the above-described accuracy, it is possible to manufacture a GI-type optical fiber preform having a small variation in quality such as a profile, and to improve the production yield of the optical fiber preform. Can be.
【００２２】また、この場合においても前述のように、
収縮熱処理の温度は１１５０〜１２１５℃とし、焼結熱
処理においては多孔質がガラス母材が加熱源を通過する
速度を５〜１０ｍｍ／ｍｉｎとすることにより、ガラス
母材のコア部及びクラッド部にフッ素を過不足なくドー
プすることが可能となり、バラツキのない正確に所望の
プロファイルを持つ光ファイバ母材をさらに確実に製造
することができる。本発明は、以上の技術的思想に基づ
き、諸条件を精査して、完成に至ったものである。In this case, as described above,
The temperature of the shrink heat treatment is set to 1150 to 1215 ° C., and the sintering heat treatment is performed by setting the speed at which the glass base material passes through the heating source to 5 to 10 mm / min. Fluorine can be doped without excess and deficiency, and an optical fiber preform having a desired profile without variation can be more reliably manufactured. The present invention has been completed by scrutinizing various conditions based on the above technical idea.
【００２３】[0023]
【発明の実施の形態】次に、本発明の実施の形態につい
て添付した図面に基づき説明するが本発明はこれに限定
されるものではない。本発明の製造方法は、図４に示し
た方法で光ファイバ母材の製造を行い、その際に本発明
の製造方法の条件で行えば良い。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the attached drawings, but the present invention is not limited thereto. In the manufacturing method of the present invention, an optical fiber preform is manufactured by the method shown in FIG. 4, and at that time, it may be performed under the conditions of the manufacturing method of the present invention.
【００２４】まず、純粋シリカからなる多孔質ガラス母
材２を用意する。この段階では多孔質ガラス母材２の嵩
密度分布は一様であってよく、コア部もクラッド部も同
じ嵩密度である。また、この多孔質ガラス母材２自体
は、ＶＡＤ法で製造しても良いし、ＯＶＤ法等により製
造しても良い。First, a porous glass preform 2 made of pure silica is prepared. At this stage, the bulk density distribution of the porous glass base material 2 may be uniform, and the core portion and the clad portion have the same bulk density. Further, the porous glass base material 2 itself may be manufactured by a VAD method, an OVD method, or the like.
【００２５】そして、この多孔質ガラス母材２を加熱炉
３内で脱水を行う（図４（１））。次に加熱炉３の温度
を高くして収縮熱処理を施し、多孔質ガラス母材２を収
縮させる（図４（２））。この際にその温度を一定温度
の±５℃以内に制御しつつ熱処理を行い、その温度は１
１５０〜１２１５℃とする。この場合、この収縮熱処理
の雰囲気に塩素ガス等を使用して脱水も同時に行っても
良い。このようにして収縮熱処理を行うことにより、多
孔質ガラス母材２は確実に所望のＧＩ型の嵩密度分布と
なる。Then, the porous glass base material 2 is dehydrated in the heating furnace 3 (FIG. 4A). Next, the temperature of the heating furnace 3 is increased to perform a shrinkage heat treatment to shrink the porous glass base material 2 (FIG. 4 (2)). At this time, heat treatment is performed while controlling the temperature to within ± 5 ° C. of a constant temperature, and the temperature is set to 1
150 to 1215 ° C. In this case, dehydration may be performed simultaneously using chlorine gas or the like in the atmosphere of the shrinkage heat treatment. By performing the shrinkage heat treatment in this manner, the porous glass base material 2 reliably has a desired GI-type bulk density distribution.
【００２６】その後、加熱炉３内にフッ素を含む雰囲気
を流し、多孔質ガラス母材２に焼結熱処理を施して焼結
させる（図４（３））。この際に、多孔質ガラス母材２
が加熱炉３の加熱源を通過する速度を一定速度の±０．
５ｍｍ／ｍｉｎ以内に制御しつつ熱処理を行い、その速
度は５〜１０ｍｍ／ｍｉｎとする。フッ素を含む雰囲気
としては、例えばＳｉＦ4とＨの混合ガス雰囲気等が挙
げられる。このようにして焼結熱処理を行うことによ
り、多孔質ガラス母材２は適度にフッ素がドープされ、
確実に所望のＧＩ型のプロファイルを持つ光ファイバ母
材１となる。Thereafter, an atmosphere containing fluorine is passed through the heating furnace 3, and the porous glass base material 2 is subjected to a sintering heat treatment and sintered (FIG. 4 (3)). At this time, the porous glass base material 2
At a constant speed of ± 0.
Heat treatment is performed while controlling the temperature within 5 mm / min, and the speed is 5 to 10 mm / min. As an atmosphere containing fluorine, for example, a mixed gas atmosphere of SiF 4 and H can be used. By performing the sintering heat treatment in this manner, the porous glass base material 2 is appropriately doped with fluorine,
The optical fiber preform 1 having a desired GI profile is surely obtained.
【００２７】[0027]
【実施例】次に本発明を実施例および比較例により説明
するが、本発明はこれに限定されるものではない （実施例）図４に示す方法で光ファイバ母材１を製造し
た。まず、ＶＡＤ法により多孔質ガラス母材２を作製し
た。回転している石英棒の下方から酸水素炎ともに原料
ガラスを吹き付けて上方に引き上げ多孔質ガラス母材２
を形成した。この段階ではガラス化は行わず、また多孔
質ガラス母材２の嵩密度分布は一様であり、コア部もク
ラッド部も同じ嵩密度である。この多孔質ガラス母材２
の直径は１７０ｍｍであり、嵩密度は０．２４ｇ／ｃｍ
３であった。そして、この多孔質ガラス母材２を加熱炉
３内で脱水を行った（図４（１））。EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. (Example) An optical fiber preform 1 was manufactured by the method shown in FIG. First, a porous glass base material 2 was produced by the VAD method. The raw material glass is sprayed together with the oxyhydrogen flame from below the rotating quartz rod and pulled up, and the porous glass base material 2
Was formed. At this stage, vitrification is not performed, and the bulk density distribution of the porous glass base material 2 is uniform, and the core portion and the clad portion have the same bulk density. This porous glass base material 2
Has a diameter of 170 mm and a bulk density of 0.24 g / cm
It was 3 . Then, the porous glass base material 2 was dehydrated in the heating furnace 3 (FIG. 4A).
【００２８】次に加熱炉３の温度を高くして収縮熱処理
を施し、多孔質ガラス母材２を収縮させた（図４
（２））。この際にその温度を一定温度の±５℃以内に
制御しつつ熱処理を行い、その温度は１２１０℃とし
た。炉内には、５．０Ｌ／ｍｉｎの流量でＨｅを流し、
多孔質ガラス母材の炉内加熱源通過速度は４．０ｍｍ／
ｍｉｎとした。Next, the temperature of the heating furnace 3 was increased and a shrinkage heat treatment was performed to shrink the porous glass base material 2 (FIG. 4).
(2)). At this time, heat treatment was performed while controlling the temperature to within ± 5 ° C. of a constant temperature, and the temperature was set to 1210 ° C. He is flowed into the furnace at a flow rate of 5.0 L / min,
The rate of passage of the porous glass base material through the heating source in the furnace was 4.0 mm /
min.
【００２９】その後、加熱炉３内にフッ素を含む雰囲気
を流し、多孔質ガラス母材２に焼結熱処理を施して焼結
させた（図４（３））。この際に、多孔質ガラス母材２
が加熱炉３の加熱源を通過する速度を一定速度の±０．
５ｍｍ／ｍｉｎ以内に制御しつつ熱処理を行い、その速
度は７．０ｍｍ／ｍｉｎとした。炉内には３．２５Ｌ／
ｍｉｎでＨｅを、１．７５Ｌ／ｍｉｎでＳｉＦ4をそれ
ぞれ流し、炉内の温度は１３７０℃とした。Thereafter, an atmosphere containing fluorine was passed through the heating furnace 3, and the porous glass base material 2 was subjected to a sintering heat treatment to be sintered (FIG. 4 (3)). At this time, the porous glass base material 2
At a constant speed of ± 0.
The heat treatment was performed while controlling the temperature within 5 mm / min, and the speed was set at 7.0 mm / min. 3.25 L /
He was flowed at a rate of 1.75 L / min, and SiF 4 was flowed at a rate of 1370 ° C.
【００３０】製造された光ファイバ母材のプロファイル
を図１に示す。図１に示すように、この光ファイバ母材
のプロファイルは確実にＧＩ型のプロファイルになって
いることが判る。FIG. 1 shows the profile of the manufactured optical fiber preform. As shown in FIG. 1, it can be seen that the profile of the optical fiber preform is surely a GI type profile.
【００３１】（比較例１）収縮熱処理の温度を１１００
℃とし、この温度の±２０℃で制御しつつ熱処理を行っ
た以外は実施例と同様にして光ファイバ母材を製造し
た。製造された光ファイバ母材のプロファイルを図２に
示す。図２に示すように、この光ファイバ母材のプロフ
ァイルは、収縮熱処理の温度が低すぎたため、コア部と
クラッド部の両方とも嵩密度が低いままであり、そのた
め両者に均一にフッ素がドープされてしまい、コア部ま
でクラッド部と同じ低い屈折率となってしまっているこ
とが判る。また、温度制御の精度が低かったため、同じ
光ファイバ母材でも軸方向の位置によってプロファイル
のバラツキがみられた。(Comparative Example 1) The temperature of the shrinkage heat treatment was 1100
° C and an optical fiber preform was manufactured in the same manner as in Example except that the heat treatment was performed while controlling the temperature at ± 20 ° C. FIG. 2 shows the profile of the manufactured optical fiber preform. As shown in FIG. 2, in the profile of the optical fiber preform, since the temperature of the shrinkage heat treatment was too low, the bulk density of both the core portion and the clad portion remained low, so that both were uniformly doped with fluorine. It can be seen that the refractive index up to the core is as low as that of the clad. In addition, because the accuracy of the temperature control was low, even in the same optical fiber preform, there was variation in the profile depending on the position in the axial direction.
【００３２】（比較例２）収縮熱処理の温度を１２２０
℃とし、この温度の±２０℃で制御しつつ熱処理を行っ
た以外は実施例と同様にして光ファイバ母材を製造し
た。製造された光ファイバ母材のプロファイルを図３に
示す。図３に示すように、この光ファイバ母材のプロフ
ァイルは、収縮熱処理の温度が高すぎたため、コア部と
クラッド部の両方とも嵩密度が高くなってしまい、その
ため両者とも全くフッ素がドープされず、クラッド部ま
でコア部と同じ高い屈折率となってしまっていることが
判る。また、温度制御の精度が低かったため、同じ光フ
ァイバ母材でも軸方向の位置によってプロファイルのバ
ラツキがみられた。(Comparative Example 2) The temperature of the shrinkage heat treatment was set to 1220.
° C and an optical fiber preform was manufactured in the same manner as in Example except that the heat treatment was performed while controlling the temperature at ± 20 ° C. FIG. 3 shows the profile of the manufactured optical fiber preform. As shown in FIG. 3, in the profile of the optical fiber preform, since the temperature of the shrinkage heat treatment was too high, both the core portion and the clad portion had high bulk densities, and therefore both were not doped with fluorine at all. It can be seen that the refractive index up to the cladding is the same as that of the core. In addition, because the accuracy of the temperature control was low, even in the same optical fiber preform, there was variation in the profile depending on the position in the axial direction.
【００３３】尚、本発明は、上記実施形態に限定される
ものではない。上記実施形態は、例示であり、本発明の
特許請求の範囲に記載された技術的思想と実質的に同一
な構成を有し、同様な作用効果を奏するものは、いかな
るものであっても本発明の技術的範囲に包含される。The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the scope of the claims of the present invention. It is included in the technical scope of the invention.
【００３４】例えば、本発明の方法を実施するにあたっ
ては、特別な装置は必要とされず、収縮熱処理の温度を
一定温度の±５℃以内に制御しつつ熱処理を行うことが
でき、焼結熱処理においては、多孔質ガラス母材が加熱
源を通過する速度を一定速度の±０．５ｍｍ／ｍｉｎ以
内に制御しつつ熱処理を行うことができるものであれ
ば、どのようなものでも良く、本発明の方法に適用でき
るものである。For example, in carrying out the method of the present invention, a special apparatus is not required, and the heat treatment can be performed while controlling the temperature of the shrinkage heat treatment within ± 5 ° C. of a certain temperature. In the present invention, any material can be used as long as the heat treatment can be performed while controlling the speed at which the porous glass base material passes through the heating source to within ± 0.5 mm / min of a constant speed. The method can be applied to the above method.
【００３５】また、上記実施形態においては、クラッド
部を１段しか設けなかったが、本発明はこれに限定され
るものではなく、クラッド部を２段、３段と設けても良
い。また、コアとクラッドの領域の比率を変更するため
に、さらにクラッドを重ねることも可能である。Further, in the above embodiment, only one clad portion is provided, but the present invention is not limited to this, and two or three clad portions may be provided. Further, in order to change the ratio of the core and cladding regions, it is possible to further overlap the cladding.
【００３６】[0036]
【発明の効果】以上説明したように、本発明は多孔質ガ
ラス母材に収縮熱処理を施し、該収縮熱処理を施した多
孔質ガラス母材にフッ素を含む雰囲気下の焼結熱処理を
施すＧＩ型光ファイバ母材の製造方法において、上記熱
処理の条件を適切に決定したことにより、確実にＧＩ型
で所望のプロファイルを持つ光ファイバ母材を製造する
ことができるようになる。そのため、ＧＩ型光ファイバ
母材の製造における歩留り等を大幅に向上させることが
できるようになる。As described above, the present invention provides a GI type in which a porous glass preform is subjected to shrinkage heat treatment, and the porous glass preform subjected to the shrinkage heat treatment is subjected to sintering heat treatment in an atmosphere containing fluorine. In the method for manufacturing an optical fiber preform, by appropriately determining the conditions of the heat treatment, it becomes possible to surely manufacture an optical fiber preform having a desired profile of a GI type. Therefore, the yield and the like in the production of the GI optical fiber preform can be greatly improved.
【図１】実施例で製造された光ファイバ母材のプロファ
イルを示した図である。FIG. 1 is a diagram showing a profile of an optical fiber preform manufactured in an example.
【図２】比較例１で製造された光ファイバ母材のプロフ
ァイルを示した図である。FIG. 2 is a diagram showing a profile of an optical fiber preform manufactured in Comparative Example 1.
【図３】比較例２で製造された光ファイバ母材のプロフ
ァイルを示した図である。FIG. 3 is a view showing a profile of an optical fiber preform manufactured in Comparative Example 2.
【図４】（１）〜（３）は、純粋シリカの多孔質ガラス
母材をそのまま使用して、ＧＩ型光ファイバ母材を製造
する方法を示した図である。FIGS. 4 (1) to (3) are diagrams showing a method of manufacturing a GI optical fiber preform using a porous silica preform of pure silica as it is.
【図５】（１）〜（３）は、ＯＶＤ法を利用して、ＧＩ
型光ファイバ母材を製造する方法を示した図である。FIGS. 5 (1) to (3) show GIs using the OVD method.
FIG. 4 is a view showing a method of manufacturing a mold optical fiber preform.
【図６】ＶＡＤ法を利用して、ＧＩ型光ファイバ母材を
製造する方法を示した図である。FIG. 6 is a diagram showing a method of manufacturing a GI optical fiber preform by using the VAD method.
１…光ファイバ母材、 ２…多孔質ガラス母材、 ３…
加熱炉、 ４…出発母材、５…コアスート、 ６…ガラ
ススート、 ７…コア用バーナ、８…クラッド用バー
ナ。1: optical fiber preform, 2: porous glass preform, 3:
Heating furnace, 4 ... Starting material, 5: Core soot, 6: Glass soot, 7: Burner for core, 8: Burner for cladding.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 牧川 新二 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 Ｆターム(参考） 2H050 AA01 AB10Z AC05 4G021 CA14 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinji Makikawa 2-13-1 Isobe, Annaka-shi, Gunma Prefecture Shin-Etsu Kagaku Kogyo Co., Ltd. Precision Functional Materials Laboratory F-term (reference) 2H050 AA01 AB10Z AC05 4G021 CA14
Claims (5)
理を施し、該収縮熱処理を施した多孔質ガラス母材にフ
ッ素を含む雰囲気下の焼結熱処理を施すＧＩ型光ファイ
バ母材の製造方法において、 前記収縮熱処理は、熱処理温度を１１５０〜１２１５℃
とし、前記焼結熱処理は、多孔質ガラス母材が加熱源を
通過する速度を５〜１０ｍｍ／ｍｉｎとすることを特徴
とするＧＩ型光ファイバ母材の製造方法。1. A method of manufacturing a GI-type optical fiber preform in which at least a porous glass preform is subjected to a shrinkage heat treatment, and the porous glass preform subjected to the shrinkage heat treatment is subjected to a sintering heat treatment in an atmosphere containing fluorine. The shrink heat treatment is performed at a heat treatment temperature of 1150 to 1215 ° C.
Wherein the sintering heat treatment is performed at a rate at which the porous glass preform passes through a heating source at 5 to 10 mm / min.
理を施し、該収縮熱処理を施した多孔質ガラス母材にフ
ッ素を含む雰囲気下の焼結熱処理を施すＧＩ型光ファイ
バ母材の製造方法において、 前記収縮熱処理は、熱処理温度を一定温度の±５℃以内
に制御しつつ熱処理を行い、前記焼結熱処理は、前記多
孔質ガラス母材が加熱源を通過する速度を一定速度の±
０．５ｍｍ／ｍｉｎ以内に制御しつつ熱処理を行うこと
を特徴とするＧＩ型光ファイバ母材の製造方法。2. A method of manufacturing a GI type optical fiber preform in which at least a porous glass preform is subjected to a shrinkage heat treatment, and the porous glass preform subjected to the shrinkage heat treatment is subjected to a sintering heat treatment in an atmosphere containing fluorine. The shrinkage heat treatment is performed while controlling the heat treatment temperature to within ± 5 ° C. of a certain temperature, and the sintering heat treatment is performed by controlling the speed at which the porous glass base material passes through a heating source at a certain speed of ± 5 ° C.
A method for producing a GI-type optical fiber preform, wherein a heat treatment is performed while controlling the temperature within 0.5 mm / min.
２１５℃とすることを特徴とする請求項２に記載のＧＩ
型光ファイバ母材の製造方法。3. The shrinkage heat treatment is performed at a temperature of 1150-1.
The GI of claim 2, wherein the temperature is 215 ° C.
Of manufacturing optical fiber preform.
加熱源を通過する速度を５〜１０ｍｍ／ｍｉｎとするこ
とを特徴とする請求項２または請求項３に記載のＧＩ型
光ファイバ母材の製造方法。4. The GI optical fiber according to claim 2, wherein in the sintering heat treatment, the speed at which the porous glass base material passes through a heating source is 5 to 10 mm / min. Manufacturing method of base material.
に記載の方法で製造されたＧＩ型光ファイバ母材。5. A GI optical fiber preform manufactured by the method according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19299799A JP3825204B2 (en) | 1999-07-07 | 1999-07-07 | GI type optical fiber preform manufacturing method and GI type optical fiber preform manufactured by this method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19299799A JP3825204B2 (en) | 1999-07-07 | 1999-07-07 | GI type optical fiber preform manufacturing method and GI type optical fiber preform manufactured by this method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JP2001019460A true JP2001019460A (en) | 2001-01-23 |
| JP2001019460A5 JP2001019460A5 (en) | 2004-11-04 |
| JP3825204B2 JP3825204B2 (en) | 2006-09-27 |
Family
ID=16300510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19299799A Expired - Fee Related JP3825204B2 (en) | 1999-07-07 | 1999-07-07 | GI type optical fiber preform manufacturing method and GI type optical fiber preform manufactured by this method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3825204B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1120382A2 (en) * | 2000-01-28 | 2001-08-01 | Shin-Etsu Chemical Co., Ltd. | Glass preform and optical fibre and method of manufacturing the preform |
-
1999
- 1999-07-07 JP JP19299799A patent/JP3825204B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1120382A2 (en) * | 2000-01-28 | 2001-08-01 | Shin-Etsu Chemical Co., Ltd. | Glass preform and optical fibre and method of manufacturing the preform |
| EP1120382A3 (en) * | 2000-01-28 | 2002-07-03 | Shin-Etsu Chemical Co., Ltd. | Glass preform and optical fibre and method of manufacturing the preform |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3825204B2 (en) | 2006-09-27 |
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