JPS6240302B2 - - Google Patents
Info
- Publication number
- JPS6240302B2 JPS6240302B2 JP54134895A JP13489579A JPS6240302B2 JP S6240302 B2 JPS6240302 B2 JP S6240302B2 JP 54134895 A JP54134895 A JP 54134895A JP 13489579 A JP13489579 A JP 13489579A JP S6240302 B2 JPS6240302 B2 JP S6240302B2
- Authority
- JP
- Japan
- Prior art keywords
- quartz tube
- groups
- outer diameter
- tube
- synthetic glass
- 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
Links
- 239000010453 quartz Substances 0.000 claims description 36
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 36
- 239000011521 glass Substances 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 6
- 238000005229 chemical vapour deposition Methods 0.000 claims description 5
- 238000000151 deposition Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000013307 optical fiber Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 20
- 239000007789 gas Substances 0.000 description 11
- 238000005253 cladding Methods 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 8
- 229910004298 SiO 2 Inorganic materials 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 229910005793 GeO 2 Inorganic materials 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004017 vitrification Methods 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004033 diameter control Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
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]
- C03B37/018—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] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01876—Means for heating tubes or rods during or immediately prior to deposition, e.g. electric resistance heaters
-
- 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]
- C03B37/018—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] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01846—Means for after-treatment or catching of worked reactant gases
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General 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)
Description
【発明の詳細な説明】
この発明は、光フアイバの製造方法に関し、特
に、内付けCVD法によつて母材を作る工程に関
するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an optical fiber, and in particular to a process for producing a base material by an internal CVD method.
発明の背景
内付けCVD法においては、石英管を、フアイ
バのジヤケツトとして使う。石英管を、高温で、
長時間加熱するので、石英管内のOH基がコアま
で拡散して、OH基による吸収損失を増大させ
る。それを防ぐため、現在、石英管のジヤケツト
とコアとの中間にクラツドを設けることが行われ
ている。ただしこのクラツドが薄いと、効果が十
分でない。ところが、クラツドを形成するための
加熱は、石英管の外から行う。クラツドの層が厚
くなるにつれて、内部表面への熱の伝導が不十分
になる。そして酸化反能も、透明ガラス化もうま
くゆかなくなる。内面に伝導する熱量を増やすた
めに、加熱温度を上げると、石英管が軟化する。
そして径が縮まる。すると肉厚が厚くなつて、内
部への熱伝導を悪くする。このようなわけで、ク
ラツドを厚くするのにも限度がある。BACKGROUND OF THE INVENTION In internal CVD methods, a quartz tube is used as a jacket for the fiber. quartz tube at high temperature,
Since the tube is heated for a long time, the OH groups in the quartz tube diffuse into the core, increasing the absorption loss due to the OH groups. To prevent this, a cladding is currently provided between the jacket and core of the quartz tube. However, if this cladding is thin, the effect will not be sufficient. However, heating to form the cladding is performed from outside the quartz tube. As the layers of the cladding become thicker, the conduction of heat to the internal surfaces becomes poorer. And the oxidation reaction and transparent vitrification will not go well. In order to increase the amount of heat conducted to the inner surface, increasing the heating temperature softens the quartz tube.
and the diameter decreases. As a result, the wall thickness becomes thicker, which impairs heat conduction to the inside. For this reason, there is a limit to how thick the cladding can be made.
特に1.6μｍ帯まで非常に低損失な、SiO2クラ
ツド、GeO2−SiO2コアの単一モードフアイバの
場合は、クラツドの生成温度が非常に高い。その
ため、クラツドのたい積をますます困難にする。 In particular, in the case of SiO 2 clad or GeO 2 -SiO 2 core single mode fibers, which have very low loss up to the 1.6 μm band, the clad formation temperature is extremely high. This makes crud accumulation increasingly difficult.
そこで、初めからOH基の少い石英管を使用す
ればよいようにも思える。しかし、OH基の少い
石英管は、粘性が大きく、そのため気泡を多く含
む。そのため、強度の面から、光フアイバのジヤ
ケツトには不適当とされている。実用的な、泡の
ない石英管は、120〜200PPMのOH基を含んでい
る。このような石英管を使用して、1.39μｍにお
けるOH基による損失を10dB／Km以下にするに
は、SiO2クラツドの場合、クラツド径／コア径
比を、５以上にしなければならない。 Therefore, it seems like it would be better to use a quartz tube with fewer OH groups from the beginning. However, quartz tubes with few OH groups have high viscosity and therefore contain many bubbles. Therefore, from the viewpoint of strength, it is considered unsuitable for use in optical fiber jackets. A practical, bubble-free quartz tube contains 120-200PPM OH groups. In order to use such a quartz tube and reduce the loss due to OH groups at 1.39 μm to 10 dB/Km or less, the clad diameter/core diameter ratio must be 5 or more in the case of a SiO 2 clad.
それは、従来の方法では不可能である。 That is not possible with traditional methods.
発明の目的
クラツドを厚くすることなしに、石英管のジヤ
ケツトからコアへの、OH基の拡散を少くする。OBJECT OF THE INVENTION To reduce the diffusion of OH groups from the jacket to the core of a quartz tube without increasing the thickness of the cladding.
発明の構成
(1) 内付けCVD法によつて石英管の内面に合成
ガラス膜をたい積させる前に、管内に乾燥ガス
を流すこと、
(2) 乾燥ガスを流しておいて、石英管を軟化点以
上に加熱し、同時に内圧をかけていつたん初期
の外径以上にふくらませてから、また初期の外
径に戻すこと、
(3) 上記の処置がすんでから合成ガラス膜のたい
積を行なうこと、
を特徴とする。Structure of the invention (1) Before depositing a synthetic glass film on the inner surface of a quartz tube using the internal CVD method, a drying gas is flowed into the tube, (2) the drying gas is flowed to soften the quartz tube. (3) After the above steps have been completed, the synthetic glass film is deposited; It is characterized by
より詳しい説明
石英管内におけるOH基の拡散長さ（拒離）Ｌ
は次式で示される。(注)
Ｌ＝√4
ただし
Ｄ＝1.0×10-6exp−１８３００／ＲＴcm2sec-1
ｔ：加熱時間
Ｔ：加熱温度
Ｒ：気体定数
すなわち、Ｌは、加熱の温度と時間に依存す
る。SiO2クラツドをたい積させる条件のもとで
は、Ｌはだいたい50μｍ以内である。したがつ
て、石英管の内壁面のごく近くのOH基の濃度を
少なくするだけで、効果がある。More detailed explanation OH group diffusion length (rejection) L in a quartz tube
is expressed by the following equation. (Note) L=√4 However, D=1.0×10 -6 exp-18300/RTcm 2 sec -1 t: Heating time T: Heating temperature R: Gas constant That is, L depends on the heating temperature and time. Under the conditions for depositing SiO 2 cladding, L is approximately within 50 μm. Therefore, simply reducing the concentration of OH groups very close to the inner wall surface of the quartz tube is effective.
石英管の内壁面のOH基の濃度を減少させるた
めには、石英管内に乾燥ガスを流しながら、石英
管を加熱する。すなわち、たとえば「第１図」の
ように、石英管１０をガラス旋盤のチヤツク１
２，１４にはさんで回転させ、乾燥ガス１６を流
すとともに、酸水素バーナー１８をゆつくりと動
しながら加熱する。 In order to reduce the concentration of OH groups on the inner wall surface of the quartz tube, the quartz tube is heated while flowing dry gas inside the quartz tube. That is, as shown in FIG. 1, the quartz tube 10 is placed in the chuck 1 of a glass lathe
2 and 14 and rotate it, and while drying gas 16 flows through it, the oxyhydrogen burner 18 is slowly moved to heat it.
乾燥ガスには、O2、N2、Arなどで、露点−90
℃以下のものを使用する。 Drying gases include O 2 , N 2 , Ar, etc., with a dew point of -90
Use a temperature below ℃.
加熱温度は、できるだけ高くした方がよい。そ
の方が、OH基の石英管内壁面への拡散が促進さ
れる。1800〜2000℃くらいが適当である。 It is better to set the heating temperature as high as possible. This will promote the diffusion of OH groups to the inner wall surface of the quartz tube. Approximately 1800 to 2000℃ is appropriate.
また「第１図」のように石英管１０に排気筒２
０を接続しておき、排気口２２を調節して、乾燥
ガス１６により内圧をかける。そして、初めの径
以上に太くなるように膨張させる。すると肉厚が
薄くなつて、内壁面への熱の伝導がよくなり、そ
のためにOH基の拡散が促進される。 In addition, as shown in "Fig. 1", the exhaust pipe 2 is attached to the quartz tube 10.
0 is connected, the exhaust port 22 is adjusted, and internal pressure is applied by the dry gas 16. Then, expand it so that it becomes thicker than the initial diameter. This reduces the wall thickness, improves heat conduction to the inner wall surface, and promotes the diffusion of OH groups.
なお、「第１図」の２４は外径制御系で、これ
によつて石英管１０の外径が一定になるように加
熱温度を調節する。また、石英管１０の外径を、
酸水素バーナー１８のただ１回の移動だけで、一
気に大きくするより、何回かトラバースしなが
ら、徐々に大きくする方が、外径の変動を起さな
い。 Note that 24 in FIG. 1 is an outer diameter control system, which adjusts the heating temperature so that the outer diameter of the quartz tube 10 is constant. In addition, the outer diameter of the quartz tube 10 is
Rather than increasing the size all at once by moving the oxyhydrogen burner 18 only once, it is better to gradually increase the size while traversing several times to avoid fluctuations in the outer diameter.
実施例
出発石英管は、外径18mm、内径16mm、長さ1000
mm。それに、容積やく1000c.c.の排気筒２０を接
続。露点−90℃の乾燥したO2ガスを、２／min
で流し、内圧が、50mmAqかかるようにした。酸
水素バーナーを10cm／minで動かしながら、1800
℃に加熱し、まず外径を20mmまで膨張させた。こ
れを２回くりかえし、最終的に、外径28mmとし
た。その後、加熱を続けながら、内圧を通常状態
にし、外径をほぼ初めと同じ18mmにもどした。Example The starting quartz tube has an outer diameter of 18 mm, an inner diameter of 16 mm, and a length of 1000 mm.
mm. Connect an exhaust pipe 20 with a capacity of about 1000 c.c. to it. Dry O 2 gas with a dew point of -90°C at 2/min
The internal pressure was set to 50 mmAq. 1800 while operating the oxyhydrogen burner at 10cm/min.
℃, and the outer diameter was first expanded to 20 mm. This process was repeated twice to finally obtain an outer diameter of 28 mm. Afterwards, while heating was continued, the internal pressure was brought to normal, and the outer diameter was returned to 18 mm, which was almost the same as before.
そのときの、管壁内のOH基濃度分布は、「第
２図」のようであつて、内壁面（厚さにして、や
く50μｍ）のOH基含有量を、やく1/3に減少で
きた。 At that time, the OH group concentration distribution within the tube wall is as shown in Figure 2, and the OH group content on the inner wall surface (thickness approximately 50 μm) can be quickly reduced to 1/3. Ta.
その後、従来と同じ方法で、SiO2クラツド、
GeO2−SiO2コアの単一モードフアイバを作つ
た。その諸元は次のとおり。 After that, SiO 2 cladding,
A single mode fiber with GeO 2 −SiO 2 core was fabricated. Its specifications are as follows.
カツトオフ波長 1.22μｍ
比屈折率差 やく0.2％
コア径 やく10μｍ
クラツド径／コア径比 4.5
損失波長特性を、「第３図」に、実線Ａで示し
た。また、石英管未処理のものを、点線Ｂで示し
た。Ａの示すように、1.39μｍでのOH基吸収損
失は、やく4dB／Kmである。なお、クラツド径／
コア径比を3.6と小さくしたときでも、同損失は
やく6dB／Kmであつた。Cut-off wavelength: 1.22 μm Relative refractive index difference: 0.2% Core diameter: 10 μm Clad diameter/core diameter ratio: 4.5 The loss wavelength characteristics are shown by the solid line A in Figure 3. In addition, a dotted line B indicates an untreated quartz tube. As shown in A, the OH group absorption loss at 1.39 μm is approximately 4 dB/Km. In addition, the cladding diameter/
Even when the core diameter ratio was reduced to 3.6, the loss was still 6 dB/Km.
発明の効果
石英管内に乾燥ガスを流しておいて、石英管を
加熱するので、上記のように、石英管内面近くの
OH基が相当量除去され、そのために、その後実
際にCVD法によつて合成ガラス膜をたい積させ
るとき、石英管の内面近くから、たい積した合成
ガラス膜内へと拡散してゆくOH基は非常に少な
くなる。Effects of the invention Since the quartz tube is heated by flowing dry gas inside it, as mentioned above, the dry gas near the inner surface of the quartz tube is
A considerable amount of OH groups are removed, and therefore, when a synthetic glass film is actually deposited using the CVD method, the OH groups that diffuse into the deposited synthetic glass film from near the inner surface of the quartz tube are very small. will decrease.
しかも石英管を軟化点以上まで加熱し、いつた
ん初期の外径以上にふくらませるので、内面近く
のOH基はより多く除去される。その理由は、石
英管の加熱は、管の外から行なうから、内面の温
度は外面より低いのであるが、ふくらませると管
の肉厚が薄くなつて内面への熱の伝導がよくな
り、ふくらませないときに比べて、より高温まで
加熱されるからである。 Furthermore, since the quartz tube is heated to above its softening point and then expanded to exceed its initial outer diameter, more OH groups near the inner surface are removed. The reason for this is that quartz tubes are heated from outside the tube, so the temperature on the inside is lower than on the outside.However, when the tube is inflated, the wall thickness of the tube becomes thinner, which improves the conduction of heat to the inside, making it difficult to inflate. This is because it is heated to a higher temperature than in other cases.
以上のようなわけで、たとえばSiO2クラツド
のように、透明ガラス化温度の高いガラスのフア
イバを製造する場合でも、ジヤケツトの石英管か
らコアまで拡散してゆくOH基の量をたいへん少
なくすることができる。 For this reason, even when producing glass fibers with a high transparent vitrification temperature, such as SiO 2 clad, it is necessary to greatly reduce the amount of OH groups that diffuse from the quartz tube of the jacket to the core. Can be done.
(注) T.Bell et al phy.Chem.Class ３ No.５
（1964）P.141(Note) T.Bell et al phy.Chem.Class 3 No.5
(1964) P.141
第１図はこの発明の概略説明図、第２図は石英
管を処理した後におけるOH基の濃度分布図、第
３図はフアイバの損失波長特性である。
１０：石英管、１６：乾燥ガス、１８：酸水素
バーナー。
FIG. 1 is a schematic explanatory diagram of the present invention, FIG. 2 is a concentration distribution diagram of OH groups after processing a quartz tube, and FIG. 3 is a loss wavelength characteristic of the fiber. 10: Quartz tube, 16: Dry gas, 18: Oxygen hydrogen burner.
Claims (1)
成ガラス膜をたい積させて母材を製造する場合に
おいて、 前記合成ガラス膜をたい積させる前に、 前記石英管内に乾燥ガスを流しながら、石英管
を軟化点以上に加熱するとともに、前記乾燥ガス
によつて内圧をかけて、いつたん初期の外径以上
にふくらませた後再び初期の外径まで戻し、 その後前記合成ガラス膜をたい積させること、 を特徴とする光フアイバの製造方法。[Claims] 1. When manufacturing a base material by depositing a synthetic glass film on the inner surface of a quartz tube by an internal CVD method, before depositing the synthetic glass film, drying the inside of the quartz tube. While flowing gas, the quartz tube is heated to above its softening point, and internal pressure is applied by the drying gas to inflate it to more than the initial outer diameter, and then return to the initial outer diameter, and then the synthetic glass A method for manufacturing an optical fiber, comprising: depositing a film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13489579A JPS5659638A (en) | 1979-10-19 | 1979-10-19 | Manufacture of optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13489579A JPS5659638A (en) | 1979-10-19 | 1979-10-19 | Manufacture of optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5659638A JPS5659638A (en) | 1981-05-23 |
| JPS6240302B2 true JPS6240302B2 (en) | 1987-08-27 |
Family
ID=15139023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13489579A Granted JPS5659638A (en) | 1979-10-19 | 1979-10-19 | Manufacture of optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5659638A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63170602U (en) * | 1987-04-27 | 1988-11-07 | ||
| JPH0246103U (en) * | 1988-09-22 | 1990-03-29 |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010102276A (en) * | 2008-09-26 | 2010-05-06 | Mitsubishi Cable Ind Ltd | Optical fiber and method for manufacturing the same |
| JP5768112B2 (en) * | 2013-11-22 | 2015-08-26 | 株式会社フジクラ | Optical fiber preform manufacturing method and optical fiber manufacturing method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5210385B2 (en) * | 1972-07-19 | 1977-03-23 | ||
| JPS542140A (en) * | 1977-06-07 | 1979-01-09 | Nippon Telegr & Teleph Corp <Ntt> | Preform producing apparatus for optical fibers |
| JPS54156826A (en) * | 1978-05-23 | 1979-12-11 | Sumitomo Electric Ind Ltd | Metod of making glass fiber for light transmission |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5210385U (en) * | 1975-07-10 | 1977-01-25 |
-
1979
- 1979-10-19 JP JP13489579A patent/JPS5659638A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5210385B2 (en) * | 1972-07-19 | 1977-03-23 | ||
| JPS542140A (en) * | 1977-06-07 | 1979-01-09 | Nippon Telegr & Teleph Corp <Ntt> | Preform producing apparatus for optical fibers |
| JPS54156826A (en) * | 1978-05-23 | 1979-12-11 | Sumitomo Electric Ind Ltd | Metod of making glass fiber for light transmission |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63170602U (en) * | 1987-04-27 | 1988-11-07 | ||
| JPH0246103U (en) * | 1988-09-22 | 1990-03-29 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5659638A (en) | 1981-05-23 |
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