JPS621586B2 - - Google Patents
Info
- Publication number
- JPS621586B2 JPS621586B2 JP18920483A JP18920483A JPS621586B2 JP S621586 B2 JPS621586 B2 JP S621586B2 JP 18920483 A JP18920483 A JP 18920483A JP 18920483 A JP18920483 A JP 18920483A JP S621586 B2 JPS621586 B2 JP S621586B2
- Authority
- JP
- Japan
- Prior art keywords
- base material
- porous base
- refractive index
- optical fiber
- porous
- 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
- 239000000463 material Substances 0.000 claims description 52
- 238000009826 distribution Methods 0.000 claims description 21
- 239000013307 optical fiber Substances 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 239000011521 glass Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 11
- 229910005793 GeO 2 Inorganic materials 0.000 claims description 9
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 238000006460 hydrolysis reaction Methods 0.000 claims description 3
- 230000007062 hydrolysis Effects 0.000 claims description 2
- 238000005245 sintering Methods 0.000 claims 1
- 239000000835 fiber Substances 0.000 description 12
- 239000007789 gas Substances 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000000460 chlorine Substances 0.000 description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- 229910003902 SiCl 4 Inorganic materials 0.000 description 3
- 229910052801 chlorine Inorganic materials 0.000 description 3
- 239000000567 combustion gas Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- RLOWWWKZYUNIDI-UHFFFAOYSA-N phosphinic chloride Chemical compound ClP=O RLOWWWKZYUNIDI-UHFFFAOYSA-N 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000004017 vitrification Methods 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]
- C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
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)
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Description
【発明の詳細な説明】
本発明は広帯域の光フアイバ母材を再現性よく
製造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reproducibly manufacturing broadband optical fiber preforms.
グレーテイド型フアイバで広帯域な特性を実現
するにはコア内の屈折率分布を精密に制御しなけ
ればならない。理想的な屈折率分布は下式(1)に示
される。 In order to achieve broadband characteristics with a graded fiber, the refractive index distribution within the core must be precisely controlled. The ideal refractive index distribution is shown in equation (1) below.
Δｎ（ｒ）＝Δn0｛１−（ｒ／ａ）〓｝ ………(1)
但し、Δｎはコアとクラツドの屈折率差、Δn0
はコア中心とクラツドとの屈折率差、ａはコア半
径、αはプロフアイル指数である。ここでプロフ
アイル指数αは下式(2)に示すように、伝送する波
長λに依存する値である。 Δn(r)=Δn 0 {1-(r/a)} ………(1) However, Δn is the refractive index difference between the core and the cladding, Δn 0
is the refractive index difference between the core center and the cladding, a is the core radius, and α is the profile index. Here, the profile index α is a value that depends on the transmitted wavelength λ, as shown in equation (2) below.
α＝２＋Δ（λ） ………(2)
このように、理想的屈折率分布Δｎ（ｒ）は、
伝送する波長λに依存することとなる。従つて、
各波長ごとに(1)(2)式を満足する理想的屈折率分布
を実現できなければ、広帯域のグレーデイド型光
フアイバを得ることができないこととなる。 α=2+Δ(λ) ………(2) In this way, the ideal refractive index distribution Δn(r) is
It depends on the wavelength λ to be transmitted. Therefore,
Unless an ideal refractive index distribution satisfying equations (1) and (2) can be realized for each wavelength, a broadband graded optical fiber cannot be obtained.
一方、光フアイバ通信では石英系フアイバの伝
送損失の谷間であるλ＝0.85μｍ、1.3μｍ、1.55
μｍ付近の波長がそれぞれのシステム要求に従つ
て使用されている。従つて、光伝送路である光フ
アイバは、使用される波長帯において広帯域とな
るよう、言い替れば上記(1)(2)式を満足するよう
に、使用される波長帯ごとに異つた屈折率分布を
実現する必要がある。 On the other hand, in optical fiber communication, λ = 0.85 μm, 1.3 μm, 1.55 μm, which is the valley of transmission loss of silica fiber.
Wavelengths around μm are used depending on the respective system requirements. Therefore, the optical fiber, which is an optical transmission line, has different wavelength bands for each wavelength band used, so that it has a wide band in the wavelength band used, or in other words, satisfies equations (1) and (2) above. It is necessary to realize a refractive index distribution.
このように屈折率分布の異なつたフアイバを製
造するため、従来VAD法では、多孔質母材を作
製する条件、すなわち、燃焼用ガス（H2、O2）あ
るいは原料ガス（SiCl4、GeCl4）等の供給量又は
多孔質母材とバーナの位置関係等を組み合せて調
整している。しかしながら、これらの方法は火炎
内の気相反応効率、また多孔質母材表面での
GeO2の固容率、揮散率の温度依存性等が複雑に
からみ合うため、屈折率分布の異なるフアイバを
均一に再現性よく製造することが困難であつた。 In order to manufacture fibers with different refractive index distributions in this way, the conventional VAD method requires the use of combustion gases (H 2 , O 2 ) or raw material gases (SiCl 4 , GeCl 4 ), etc., and the positional relationship between the porous base material and the burner. However, these methods have problems with gas phase reaction efficiency within the flame and on the surface of the porous matrix.
Because the solidity ratio of GeO 2 and the temperature dependence of the volatilization rate are intricately intertwined, it has been difficult to manufacture fibers with different refractive index distributions uniformly and with good reproducibility.
本発明者らは、VAD法で作製された多孔質母
材を塩素系ガス中で加熱処理すると多孔質母材か
らGeO2が揮散することに着目し、この揮散の機
構を利用すれば、その機構の解析が比較的容易で
あることと相まつて、屈折率分布の異なるフアイ
バを再現性よく製造できることを見い出し、本発
明を完成するに至つたものである。即ち、本発明
の構成は火炎加水分解法によりガラス微粒子を反
応発生させ、このガラス微粒子を軸方向に堆積さ
せて多孔質母材を作成した後、塩素系ガスを含む
雰囲気中でこの多孔質母材の全長にわたり局部的
加熱を少なくとも２回以上繰り返して施すことに
より、該多孔質母材からGeO2を適当量揮散させ
てその屈折率分布を修正制御し、その後塩素系ガ
スを含まない雰囲気中で多孔質母材を焼結して透
明ガラス化し、光フアイバ母材を製造することを
特徴とする。 The present inventors focused on the fact that GeO 2 volatilizes from the porous base material when the porous base material produced by the VAD method is heat-treated in chlorine gas. The inventors discovered that the mechanism is relatively easy to analyze and that fibers with different refractive index distributions can be manufactured with good reproducibility, leading to the completion of the present invention. That is, the structure of the present invention is to react and generate glass particles using a flame hydrolysis method, deposit the glass particles in the axial direction to create a porous base material, and then process the porous base material in an atmosphere containing chlorine gas. By repeating local heating at least twice over the entire length of the material, an appropriate amount of GeO 2 is volatilized from the porous base material to modify and control its refractive index distribution, and then heated in an atmosphere containing no chlorine gas. The method is characterized in that the porous base material is sintered and made into transparent glass to produce an optical fiber base material.
以下、本発明の光フアイバ母材の製造方法を実
施例に基づいて詳細に説明する。 Hereinafter, the method for manufacturing an optical fiber base material of the present invention will be explained in detail based on Examples.
まず、本発明では、燃焼用ガス（H2、O2）、原
料ガス（SiCl4、GeCl4）等を噴出させて、これら
を火炎加水分解反応させ、反応発生したガラス微
粒子を軸方向に堆積させて多孔質母材を作製す
る。多孔質母材作製工程における諸条件は、屈折
率分布の異なるフアイバを製造する場合でも、一
定で良い。屈折率分布の形状はこの後修整制御す
る時に決定できるからである。この後、第２図に
示すように、多孔質母材１３を昇降機１１に吊り
下げると共に多孔質母材１３の外周に環状の抵抗
加熱炉１２を遊嵌する。多孔質母材１３の周囲を
塩素系ガスを含む雰囲気で満たし、昇降機１１に
て多孔質母材１３を回転させながら上下に昇降動
させ、該多孔質母材１３の全長にわたり局部的加
熱を繰り返して施した。高温となつた多孔質母材
１３からGeO2が適当量揮散し、多孔質母材の屈
折率分布が修正制御される。この場合のプロフア
イル指数αと多孔質母材１３の移動回数との関係
を第１図に示す。同図に示されるように、移動回
数を増すとプロフアイル指数が小さくなる。従つ
て、このようなGeO2の揮散の機構を利用し、多
孔質母材１３の移動回数を選択すれば、任意の屈
折率分布の光フアイバを得ることができる。具体
的には、0.85μｍ帯で使用する光フアイバを製造
する場合には多孔質母材１３の移動回数を３回と
し、1.3μｍ帯で使用する光フアイバを製造する
場合には、多孔質母材１３の移動回数を５回とす
れば、広帯域なフアイバとなる。尚、第１図中に
おいて移動回数は多孔質母材１３の１往復を２回
として計算し、またプロフアイル指数αは透明ガ
ラス化した後のものである。 First, in the present invention, combustion gases (H 2 , O 2 ), raw material gases (SiCl 4 , GeCl 4 ), etc. are ejected to cause a flame hydrolysis reaction, and the resulting glass particles are deposited in the axial direction. to produce a porous base material. The various conditions in the porous base material manufacturing process may be constant even when manufacturing fibers with different refractive index distributions. This is because the shape of the refractive index distribution can be determined during subsequent modification control. Thereafter, as shown in FIG. 2, the porous base material 13 is suspended from the elevator 11, and the annular resistance heating furnace 12 is loosely fitted around the outer periphery of the porous base material 13. The surroundings of the porous base material 13 are filled with an atmosphere containing chlorine-based gas, and the porous base material 13 is moved up and down while rotating with the elevator 11, and local heating is repeated over the entire length of the porous base material 13. I applied it. An appropriate amount of GeO 2 is volatilized from the porous base material 13 which has reached a high temperature, and the refractive index distribution of the porous base material is corrected and controlled. The relationship between the profile index α and the number of times the porous base material 13 is moved in this case is shown in FIG. As shown in the figure, the profile index decreases as the number of movements increases. Therefore, by utilizing such a GeO 2 volatilization mechanism and selecting the number of times the porous base material 13 is moved, an optical fiber with an arbitrary refractive index distribution can be obtained. Specifically, when manufacturing an optical fiber for use in the 0.85 μm band, the porous base material 13 is moved three times, and when manufacturing an optical fiber for use in the 1.3 μm band, the porous base material 13 is moved three times. If the number of times the material 13 is moved is five times, a broadband fiber will be obtained. In FIG. 1, the number of movements is calculated assuming that one round trip of the porous base material 13 is two times, and the profile index α is the value after the porous base material 13 is made into transparent glass.
引き続き、このように屈折率分布の修正制御さ
れた多孔質母材１３を、塩素系ガスを含まない雰
囲気中で焼結して透明ガラス化し、光フアイバ母
材を製造した。 Subsequently, the porous base material 13 whose refractive index distribution was modified and controlled in this manner was sintered in an atmosphere not containing chlorine-based gas to form transparent glass, thereby producing an optical fiber base material.
上記構成を有する本発明の光フアイバ母材の製
造方法では、多孔質母材を作製後、該多孔質母材
を透明ガラス化する前に、屈折率分布を修正制御
するので、従来と異なり、多孔質母材の作製条件
を一定にすることができる。しかも、修正制御は
解析が比較的容易なGeO2の揮散機構を利用して
いるので、屈折率分布の異なるフアイバを均一に
再現性よく製造することが可能である。尚、単に
塩素系ガスを含む雰囲気中で多孔質母材を加熱処
理してもGeO2は揮散するが、本発明のように、
多孔質母材の全長にわたり局部的加熱を繰り返し
て施すほうが、GeO2の揮散の再現性が高く、屈
折率分布を高精度に制御できる。尚上記実施例で
は、塩素系ガスを含む雰囲気中で多孔質母材１３
の全長にわたり局部的加熱を繰り返して施す方法
として、環状の抵抗加熱炉１２を固定し、多孔質
母材１３を可動としているが、これに限らず逆に
抵抗加熱炉１２を可動とし、多孔質母材１３を固
定するようにしても良い。 In the method for manufacturing an optical fiber preform of the present invention having the above configuration, the refractive index distribution is corrected and controlled after producing the porous preform and before converting the porous preform into transparent vitrification. The manufacturing conditions of the porous base material can be kept constant. Moreover, since the correction control utilizes the GeO 2 volatilization mechanism, which is relatively easy to analyze, it is possible to manufacture fibers with different refractive index distributions uniformly and with good reproducibility. Note that even if the porous base material is simply heat-treated in an atmosphere containing chlorine-based gas, GeO 2 will volatilize, but as in the present invention,
Repeated local heating over the entire length of the porous base material provides better reproducibility of GeO 2 volatilization and enables more precise control of the refractive index distribution. In the above embodiment, the porous base material 13 is heated in an atmosphere containing chlorine gas.
As a method of repeatedly applying local heating over the entire length of the porous base material, the annular resistance heating furnace 12 is fixed and the porous base material 13 is movable. The base material 13 may be fixed.
次に本発明の具体的実施例について説明する。 Next, specific examples of the present invention will be described.
実施例
石英製の多重管バーナに原料ガスとしてSiCl4
を250c.c.／分、GeCl4を20c.c.／分、POCl3を２c.c.／
分、燃焼用ガスとしてH2を3.5／分、O2を7.5
／分、シールガスとしてArを1.5／分の割合
で供給し、外径65mmφ、長さ400mmの多孔質母材
を８本作製した。この多孔質母材を第２図に示す
装置に装着し、その屈折率分布を修正制御した。
即ち、上記８本の多孔質母材からランダムに４本
の多孔質母材を選択し、これらを順次昇降機１１
に装着し、５mm／分の速度で上下に３回移動させ
ながら、該多孔質母材１３を抵抗加熱炉１２によ
り約1060℃に加熱した。このとき雰囲気ガスとし
てCl2を200c.c.／分、Heを６／分の割合で流し
た。残り４本の多孔質母材１３についても、移動
回数を５回とした他は同じ条件で屈折率分布を修
正制御した。このように修正制御された８本の多
孔質母材の雰囲気としてHeを６／分の割合で
供給し、約1620℃に加熱した抵抗加熱炉１２を５
mm／分の速度で移動させ該多孔質母材を透明ガラ
ス化した。得られた透明ガラスロツドを12mmφに
延伸し、外径26mmφの市販の石英管に挿入し、融
着し一体化した。得られたプリフオーム母材を抵
抗加熱炉にて線引きした。得られたフアイバの帯
域巾の測定を光の波長λ＝0.85μｍと1.3μｍ半
導体レーザにより実施したところ、移動回数３回
の多孔質母材から得られたフアイバではλ＝0.85
μｍ帯で870MHz・Ｋｍ、λ＝1.30μｍ帯で
390MHz・Ｋｍの平均値が得られ、また移動回数
５回の多孔質母材から得られたフアイバではλ＝
0.85μｍ帯で420MHz・Ｋｍ、λ＝1.30μｍ帯で
1010MHz・Ｋｍの平均値が得られた。このよう
に、移動回数を変化させると異つた波長帯で広帯
域なフアイバを製造することができる。Example: Using SiCl 4 as raw material gas in a quartz multi-tube burner
250c.c./min, GeCl 4 at 20c.c./min, POCl 3 at 2c.c./min.
min, H 2 as combustion gas 3.5/min, O 2 7.5/min
Ar was supplied as a seal gas at a rate of 1.5/min, and eight porous base materials each having an outer diameter of 65 mmφ and a length of 400 mm were prepared. This porous base material was installed in the apparatus shown in FIG. 2, and its refractive index distribution was corrected and controlled.
That is, four porous base materials are randomly selected from the eight porous base materials, and these are sequentially moved to the elevator 11.
The porous base material 13 was heated to about 1060° C. in the resistance heating furnace 12 while being moved up and down three times at a speed of 5 mm/min. At this time, as atmospheric gases, Cl 2 was flowed at a rate of 200 c.c./min and He was flowed at a rate of 6/min. Regarding the remaining four porous base materials 13, the refractive index distribution was corrected and controlled under the same conditions except that the number of movements was five times. The resistance heating furnace 12 heated to about 1620°C was heated to about 1620°C by supplying He at a rate of 6/min as the atmosphere for the eight porous base materials that were modified and controlled in this way.
The porous matrix was transformed into transparent glass by moving at a speed of mm/min. The obtained transparent glass rod was stretched to 12 mmφ, inserted into a commercially available quartz tube with an outer diameter of 26 mmφ, and fused and integrated. The obtained preform base material was drawn in a resistance heating furnace. The bandwidth of the obtained fiber was measured using a light wavelength λ = 0.85 μm and a 1.3 μm semiconductor laser, and it was found that λ = 0.85 for the fiber obtained from the porous base material that was moved three times.
870MHz Km in μm band, λ=1.30μm band
An average value of 390 MHz Km was obtained, and for the fiber obtained from the porous matrix with 5 moves, λ =
420MHz・Km in 0.85μm band, λ=1.30μm band
An average value of 1010MHz·Km was obtained. In this way, by varying the number of moves, broadband fibers can be produced in different wavelength bands.
以上、実施例に基づいて説明したように本発明
によれば、多孔質母材の作製条件を一定にして
も、屈折率分布の異なる光フアイバを再現性よく
均一に製造することができる。 As described above based on the embodiments, according to the present invention, optical fibers with different refractive index distributions can be uniformly manufactured with good reproducibility even if the manufacturing conditions of the porous base material are kept constant.
第１図及び第２図は本発明に係り、第１図は多
孔質母材の移動回数に対するプロフアイル指数α
の関係を示すグラフ、第２図は多孔質母材の全長
にわたり局部的加熱を施す装置の説明図である。
図面中、１１は昇降機、１２は抵抗加熱炉、１
３は多孔質母材である。
1 and 2 relate to the present invention, and FIG. 1 shows the profile index α with respect to the number of movements of the porous base material.
FIG. 2 is an explanatory diagram of a device that locally heats the entire length of a porous base material. In the drawing, 11 is an elevator, 12 is a resistance heating furnace, 1
3 is a porous base material.
Claims (1)
生させ、このガラス微粒子を軸方向に堆積させて
多孔質母材を作成した後、塩素系ガスを含む雰囲
気中でこの多孔質母材の全長にわたり局部的加熱
を少なくとも２回以上繰り返して施すことによ
り、該多孔質母材からGeO2を適当量揮散させて
その屈折率分布を修正制御し、その後塩素系ガス
を含まない雰囲気中で多孔質母材を焼結して透明
ガラス化し、光フアイバ母材を製造することを特
徴とする光フアイバ母材の製造方法。1 Glass particles are reacted and generated by a flame hydrolysis method, and the glass particles are deposited in the axial direction to create a porous base material.Then, the glass particles are locally deposited over the entire length of the porous base material in an atmosphere containing chlorine gas. By repeating heating at least twice, an appropriate amount of GeO 2 is volatilized from the porous base material to modify and control its refractive index distribution, and then the porous base material is heated in an atmosphere free of chlorine gas. 1. A method for producing an optical fiber preform, which comprises producing an optical fiber preform by sintering it to make it transparent and vitrifying it.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18920483A JPS6081036A (en) | 1983-10-12 | 1983-10-12 | Manufacture of base material for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18920483A JPS6081036A (en) | 1983-10-12 | 1983-10-12 | Manufacture of base material for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6081036A JPS6081036A (en) | 1985-05-09 |
| JPS621586B2 true JPS621586B2 (en) | 1987-01-14 |
Family
ID=16237268
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18920483A Granted JPS6081036A (en) | 1983-10-12 | 1983-10-12 | Manufacture of base material for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6081036A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4741748A (en) * | 1986-01-30 | 1988-05-03 | Corning Glass Works | Heating oven for preparing optical waveguide fibers |
| US4812153A (en) * | 1987-01-12 | 1989-03-14 | American Telephone And Telegraph Company | Method of making a glass body having a graded refractive index profile |
-
1983
- 1983-10-12 JP JP18920483A patent/JPS6081036A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6081036A (en) | 1985-05-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2685543B2 (en) | How to make an optical fiber preform | |
| Blankenship et al. | The outside vapor deposition method of fabricating optical waveguide fibers | |
| JPS5927728B2 (en) | Manufacturing method of sooty glass rod | |
| GB2027224A (en) | High bandwidth gradient index optical filament and method of fabrication | |
| JPS5945609B2 (en) | Optical fiber manufacturing method | |
| JP2959877B2 (en) | Optical fiber manufacturing method | |
| AU706562B2 (en) | Method for fabricating glass preform for optical fiber | |
| JPS61219729A (en) | Manufacture of optical waveguide tube | |
| US3932160A (en) | Method for forming low loss optical waveguide fibers | |
| KR100518058B1 (en) | The fabrication of optical fiber preform in mcvd | |
| CN101097273A (en) | Macro-bending insensitive optical fiber | |
| JPS621586B2 (en) | ||
| US4116653A (en) | Optical fiber manufacture | |
| JPS599491B2 (en) | Method for manufacturing base material for optical fiber | |
| JPH0476936B2 (en) | ||
| JP3562545B2 (en) | Method for producing glass preform for optical fiber | |
| US4341541A (en) | Process for the production of optical fiber | |
| JPH0820574B2 (en) | Dispersion shift fiber and manufacturing method thereof | |
| JPH0210095B2 (en) | ||
| JPH0316930A (en) | Production of optical fiber having complicate refractive index distribution | |
| JPH0559052B2 (en) | ||
| JP3635906B2 (en) | Optical fiber preform manufacturing method | |
| JPS591222B2 (en) | Optical fiber manufacturing method | |
| EP0135175B1 (en) | Methods for producing optical fiber preform and optical fiber | |
| JPS62162639A (en) | Production of preform for w-type single mode optical fiber |