JPH1045421A - Production of optical fiber - Google Patents
Production of optical fiberInfo
- Publication number
- JPH1045421A JPH1045421A JP8201777A JP20177796A JPH1045421A JP H1045421 A JPH1045421 A JP H1045421A JP 8201777 A JP8201777 A JP 8201777A JP 20177796 A JP20177796 A JP 20177796A JP H1045421 A JPH1045421 A JP H1045421A
- Authority
- JP
- Japan
- Prior art keywords
- preform
- optical fiber
- outer diameter
- core
- transmission loss
- 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
- C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
- C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
- C03B37/0253—Controlling or regulating
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2205/00—Fibre drawing or extruding details
- C03B2205/40—Monitoring or regulating the draw tension or draw rate
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は光ファイバを安価に
製造する方法、特に本発明は低損失で、信頼性の高い光
ファイバを経済的に製造する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber at low cost, and more particularly to a method for economically manufacturing an optical fiber having low loss and high reliability.
【０００２】[0002]
【従来の技術】近年光ファイバは生産性を向上させるた
め、プリフォームの大型化が急速に進められてきた。し
かし、光ファイバ用ガラスプリフォームを大型化し、外
径を太くすると、伝送損失が高くなる問題があった。ま
た、伝送損失の増加ばかりでなく、ガラス中に生成され
るガラス欠陥が増加し、水素特性（ガラス中に拡散した
水素がガラス中の欠陥と反応して、伝送損失を増加させ
る現象）を悪くする問題があった。例えば、太径のガラ
スプリフォームを線引し、１２５μｍの光ファイバを製
造するには、ガラスプリフォームを電気炉で加熱し、ガ
ラス粘度を下げて、加熱溶融部を引き伸ばす方法がとら
れている。プリフォーム外径が太くなるにしたがって、
ガラスが十分加熱できなくなり、従来と同様な線引を行
うため、温度を上げて対応してきた。しかしこの結果、
線引時にガラス中に生成するガラス欠陥が増加し、伝送
損失が高くなるとともに、水素特性も悪くなり、長期信
頼性の問題が発生していた。2. Description of the Related Art In recent years, in order to improve the productivity of optical fibers, the size of preforms has been rapidly increased. However, when the glass preform for an optical fiber is increased in size and the outer diameter is increased, there is a problem that transmission loss increases. Further, not only the transmission loss increases, but also glass defects generated in the glass increase, deteriorating the hydrogen characteristics (a phenomenon in which hydrogen diffused in the glass reacts with the defects in the glass to increase the transmission loss). There was a problem to do. For example, in order to draw a large-diameter glass preform and manufacture an optical fiber of 125 μm, a method is used in which the glass preform is heated in an electric furnace, the glass viscosity is reduced, and the heat-melted portion is stretched. . As the outer diameter of the preform increases,
Since the glass cannot be heated sufficiently and the same drawing is performed as before, the temperature has been increased to cope with the draw. But as a result,
Glass defects generated in the glass at the time of drawing are increased, transmission loss is increased, and hydrogen characteristics are also deteriorated, thus causing a problem of long-term reliability.
【０００３】特公平８−９４９０号公報にはガラス欠陥
の発生を防ぎ、長期信頼性の優れた光ファイバを得る為
の指針が示されている。すなわち、光ファイバ母材の一
端部を２０００℃以上の温度で長さＬにわたって該母材
の軟化温度以上に加熱し、線引速度Ｖ1 ≧Ｌ／０．０２
（秒）の速度Ｖ1 で線引することが開示されている。ガ
ラス欠陥を少なくする定性的な手段として、母材半径
を細くすること、線引速度を速くすること、線引炉
長を短くすること及び線引炉温度を低くすることが有
効と記載されている。ガラスプリフォームを太くし、線
引炉温度を高くすると上記とに反することになり、
ガラス欠陥が増加し、伝送損失の増加、水素特性の劣化
につながったものと考えられる。このようなガラス欠陥
を減少させる為、線引炉の温度を低下させると、ガラス
の粘度が大きくなり、無理に線引するとガラス強度が低
下する別の問題が発生した。Japanese Patent Publication No. 8-9490 discloses a guideline for preventing the occurrence of glass defects and obtaining an optical fiber having excellent long-term reliability. That is, one end of the optical fiber preform is heated at a temperature of 2000 ° C. or more to a temperature not lower than the softening temperature of the preform over a length L and a drawing speed V 1 ≧ L / 0.02
To drawing at a speed V 1 of the (s) it is disclosed. It is described that as a qualitative means to reduce glass defects, it is effective to reduce the base material radius, increase the drawing speed, shorten the drawing furnace length and lower the drawing furnace temperature. I have. Thickening the glass preform and raising the drawing furnace temperature would be contrary to the above,
It is considered that glass defects increased, leading to an increase in transmission loss and deterioration of hydrogen characteristics. When the temperature of the drawing furnace is reduced to reduce such glass defects, the viscosity of the glass increases, and another problem occurs in that the glass strength decreases when the drawing is forcibly performed.
【０００４】更に、特公昭５６−４９８５８号公報は、
石英ガラス製プリフォームを加熱延伸して光ファイバを
製造する方法において、クラッド／コア径比が０．７以
下のプリフォームを１９５０〜２１００℃の温度、線引
張力７〜６５ｇ重（プリフォーム１本当たり）で線引す
ることを示している。しかし、これら公知の方法では、
伝送損失が低く、水素特性の優れた光ファイバを取得す
ることはできなかった。Further, Japanese Patent Publication No. 56-49858 discloses that
In a method for producing an optical fiber by heating and stretching a quartz glass preform, a preform having a clad / core diameter ratio of 0.7 or less is drawn at a temperature of 1950 to 2100 ° C. and a drawing tension of 7 to 65 g (preform 1). (Per book). However, in these known methods,
An optical fiber with low transmission loss and excellent hydrogen characteristics could not be obtained.
【０００５】[0005]
【発明が解決しようとする課題】生産性を向上させるた
めプリフォームを大型化すると、プリフォーム外径が大
きくなって伝送損失が増加し、水素特性が劣化するとい
う問題が生じる。本発明は、このような問題を解決する
ことができ、プリフォーム外径が大きくなっても、線引
速度をプリフォーム外径から規定される一定速度以上に
設定しておくことにより、伝送損失が低く、水素特性の
優れた光ファイバを製造することができる光ファイバの
製造方法を提供することを目的とする。When the size of the preform is increased in order to improve the productivity, the outer diameter of the preform increases, the transmission loss increases, and the hydrogen characteristics deteriorate. The present invention can solve such a problem, and even if the outer diameter of the preform becomes large, the drawing speed is set to be equal to or higher than a constant speed defined from the outer diameter of the preform, thereby reducing the transmission loss. It is an object of the present invention to provide a method for producing an optical fiber which can produce an optical fiber having low hydrogen characteristics and excellent hydrogen characteristics.
【０００６】[0006]
【課題を解決するための手段】本発明者らは、上記目的
を達成するために鋭意努力した結果、プリフォームの外
径に対して線引速度を特定範囲に保持することが有効で
あることを発見し本発明に到達した。すなわち、本発明
は、コアとコアの外周に有り、コアより屈折率の低いク
ラッドからなる石英ガラスプリフォームを加熱炉で加
熱、溶融して、光ファイバに線引する方法において、石
英ガラスプリフォームの外径Ｄ（ｍｍ）に対し、線引速
度Ｖ（ｍ／分）をＶ＞６．１Ｄの範囲に設定することを
特徴とする光ファイバの製造方法を提供する。線引速度
Ｖが６．１Ｄ以下であると、線引速度がプリフォーム外
径に対して充分でなく、プリフォーム及びここから線引
されるファイバが高温に保持される時間が長くなり、ガ
ラス中に欠陥が生成されやすくなる。このため、水素特
性の悪化をまねくことになる。一方、線引速度が速くな
りすぎると、線引時に生じた応力が十分に緩和しないで
冷却されてしまうため、残留応力による強度の低下、あ
るいは伝送特性の劣化をまねく。線引速度の好ましい範
囲は１３Ｄ＞Ｖ＞６．１Ｄの範囲にある。更に、線引時
にかかる張力をプリフォームの外径の増加に応じて増加
させると伝送損失を低減させるので好ましい。また、線
引時の張力Ｔを石英ガラスプリフォーム外径Ｄに対しＴ
＝０．７５２Ｄ±１０ｇの範囲とするのが好ましい。Means for Solving the Problems As a result of the present inventors' earnest efforts to achieve the above object, it is effective to keep the drawing speed within a specific range with respect to the outer diameter of the preform. And arrived at the present invention. That is, the present invention relates to a method of heating and melting a quartz glass preform comprising a core and a clad having a lower refractive index than the core in a heating furnace and drawing the optical fiber into the optical fiber. The present invention provides a method for manufacturing an optical fiber, characterized in that the drawing speed V (m / min) is set in a range of V> 6.1 D with respect to the outer diameter D (mm) of the optical fiber. If the drawing speed V is 6.1 D or less, the drawing speed is not sufficient for the outer diameter of the preform, and the time during which the preform and the fiber drawn therefrom are kept at a high temperature is prolonged, and the glass Defects are likely to be generated inside. For this reason, the hydrogen characteristics are deteriorated. On the other hand, if the drawing speed is too fast, the stress generated at the time of drawing is not sufficiently relaxed and is cooled, resulting in a decrease in strength due to residual stress or deterioration of transmission characteristics. A preferred range of the drawing speed is in the range of 13D>V> 6.1D. Further, it is preferable to increase the tension applied at the time of drawing in accordance with the increase in the outer diameter of the preform, since transmission loss is reduced. Further, the tension T at the time of drawing is set to T with respect to the outer diameter D of the quartz glass preform.
= 0.752D ± 10g.
【０００７】[0007]
【発明の実施の形態】本発明者らの研究によると、光フ
ァイバの伝送損失は線引時の線引速度に影響されること
がわかった。図２にプリフォーム外径７０ｍｍの場合の
線引速度と伝送損失の関係を示す。線速が速くなるにし
たがって、伝送損失は低減し、４００ｍ／分前後でほぼ
一定値に飽和する傾向が見られる。この時ファイバにか
かる張力は５０〜７０ｇであった。通常プリフォーム外
径が変わっても、線引張力は一定に保つのが一般的であ
った。このことは、例えば特公昭５６−４９８５８号公
報に記載されている。しかし、本発明者ら等が注意深く
調査した結果、プリフォーム外径が変わっても線速に対
する同様の傾向はみられるものの、伝送損失が飽和する
線引速度がプリフォームサイズにより変わることがわか
った。この時ファイバにかかる張力は５０〜７０ｇの一
定値ではなく、プリフォーム外径の太径化に伴い、伝送
損失が低下する張力も増加していることがわかった。DETAILED DESCRIPTION OF THE INVENTION According to the study of the present inventors, it has been found that the transmission loss of an optical fiber is affected by the drawing speed during drawing. FIG. 2 shows the relationship between the drawing speed and the transmission loss when the outer diameter of the preform is 70 mm. As the linear velocity increases, the transmission loss decreases and tends to saturate to a substantially constant value at around 400 m / min. At this time, the tension applied to the fiber was 50 to 70 g. Usually, even when the outer diameter of the preform changes, the drawing tension is generally kept constant. This is described in, for example, Japanese Patent Publication No. 56-49858. However, as a result of careful investigation by the present inventors, it has been found that although the same tendency with respect to the linear velocity is observed even when the outer diameter of the preform changes, the drawing speed at which the transmission loss saturates varies depending on the preform size. . At this time, it was found that the tension applied to the fiber was not a constant value of 50 to 70 g, and the tension at which the transmission loss was reduced increased with the increase in the outer diameter of the preform.
【０００８】この伝送損失が飽和する最低の線引速度を
プリフォーム外径に対してプロットしたものを図１に示
す。ほぼ線形関係にあることがわかる。図１において、
良好な伝送損失を示すのは、直線の上側にあたる。図１
のプロットに対して線引時にかかる張力Ｔはプリフォー
ム外径３５ｍｍ、７０ｍｍ、１００ｍｍに対してそれぞ
れ２０〜３０ｇ、４５〜５５ｇ、６５〜７５ｇであっ
た。この関係はほぼ線形の関係であり、プリフォーム外
径Ｄに対してＴ＝０．７５２Ｄの関係にある。許容範囲
としては±１０ｇが望ましく、さらに好ましくは±５ｇ
が良い。すなわち、プリフォーム外径が大きくなり、線
引する為に線引炉の温度を上げても、線引速度を図１に
対応した線速以上に設定しておくことにより、線引時の
ガラス欠陥の形成が抑制され、伝送損失の良好なファイ
バを安定に製造できる。このとき水素特性も良好なもの
が得られることが確認された。FIG. 1 shows the minimum drawing speed at which the transmission loss is saturated plotted against the outer diameter of the preform. It can be seen that there is a substantially linear relationship. In FIG.
It is above the straight line that shows good transmission loss. FIG.
The tension T applied at the time of drawing to the plot was 20 to 30 g, 45 to 55 g, and 65 to 75 g for the preform outer diameters of 35 mm, 70 mm, and 100 mm, respectively. This relationship is substantially linear, and has a relationship of T = 0.552D with respect to the preform outer diameter D. The allowable range is preferably ± 10 g, more preferably ± 5 g.
Is good. That is, even if the outer diameter of the preform becomes large and the temperature of the drawing furnace is increased for drawing, the drawing speed is set to be equal to or higher than the drawing speed corresponding to FIG. The formation of defects is suppressed, and a fiber with good transmission loss can be manufactured stably. At this time, it was confirmed that good hydrogen characteristics were obtained.
【０００９】[0009]
【実施例】以下、本発明を実施例により更に詳細に説明
するが、本発明を限定する意図のものではない。 （実施例及び比較例）ＧｅＯ2 をドープしたコアとこの
外周に形成した純シリカのクラッドからなるプリフォー
ムを、プリフォーム外径を変えて線引した。このときに
試作したコアの屈折率分布はステップ状で、コア／クラ
ッドの比屈折率差は０．３５％、クラッド／コア外径倍
率は１６倍とした。The present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention. (Examples and Comparative Examples) A preform comprising a core doped with GeO 2 and a clad of pure silica formed on the outer periphery thereof was drawn while changing the outer diameter of the preform. At this time, the refractive index distribution of the prototype core was step-shaped, the relative refractive index difference between the core and the clad was 0.35%, and the outer diameter ratio of the clad / core was 16 times.
【００１０】（１）プリフォーム外径７０ｍｍで線引速
度を３００、５００ｍ／分の２水準で試作した。このと
きファイバにかかる張力を測定したところ、それぞれ３
３ｇ、５５ｇであった。この結果、以下表１に示される
結果が得られた。(1) A prototype was produced at an outer diameter of 70 mm and a drawing speed of 300 or 500 m / min. When the tension applied to the fiber at this time was measured,
3 g and 55 g. As a result, the results shown in Table 1 below were obtained.
【表１】 なお、水素特性は水素１００％雰囲気に１週間放置した
後、１．３８μｍでの伝送損失増加量で評価した。[Table 1] The hydrogen characteristics were evaluated by an increase in transmission loss at 1.38 μm after being left in a 100% hydrogen atmosphere for one week.
【００１１】（２）プリフォーム外径１００ｍｍで線引
速度を４００、７００ｍ／分の２水準で試作した。この
ときファイバにかかった張力は、それぞれ４４ｇ、７８
ｇであった。この結果、以下表２の結果が得られた。(2) A prototype was produced with an outer diameter of 100 mm and a drawing speed of 400 or 700 m / min. At this time, the tension applied to the fiber was 44 g and 78 g, respectively.
g. As a result, the results shown in Table 2 below were obtained.
【表２】 なお、水素特性は水素１００％雰囲気に１週間放置した
後、１．３８μｍでの伝送損失増加量で評価した。[Table 2] The hydrogen characteristics were evaluated by an increase in transmission loss at 1.38 μm after being left in a 100% hydrogen atmosphere for one week.
【００１２】[0012]
【発明の効果】本発明に従い、線引速度をプリフォーム
外径に対して特定の比例関係式以上に保つときは、伝送
損失が低減し、水素特性（１．３８μｍでの損失増加）
が著しく改善される。本発明の効果はコアにＧｅＯ2 を
ドープした光ファイバについて特に有効であり、コアの
ＧｅＯ2 をドープ量に左右されるものではない。例え
ば、コアが階段型の形状を有する分散シフトファイバに
もこの関係を適用することができる。また、プリフォー
ムの製法にも依存しない。ＭＣＶＤ法、ＶＡＤ法、ＯＶ
Ｄ法いずれの方法であっても、ガラス母材を加熱溶融し
て線引する場合には、この方法は有効である。According to the present invention, when the drawing speed is maintained at a specific proportional relation or more with respect to the outer diameter of the preform, the transmission loss is reduced, and the hydrogen characteristic (increase in loss at 1.38 μm) is obtained.
Is significantly improved. Effect of the present invention is particularly effective for optical fiber doped with GeO 2 in the core, not to be left to GeO 2 in the core doping amount. For example, this relationship can be applied to a dispersion-shifted fiber whose core has a stepped shape. Also, it does not depend on the preform manufacturing method. MCVD, VAD, OV
Regardless of the method D, this method is effective when the glass base material is heated and melted for drawing.
【図１】図１は、本発明の効果を発揮する範囲を示すプ
リフォーム外径（ｍｍ）−線引速度（ｍ／ｍｉｎ）の関
係を示すグラフである。FIG. 1 is a graph showing a relationship between an outer diameter (mm) of a preform and a drawing speed (m / min) showing a range in which the effect of the present invention is exhibited.
【図２】図２は、本発明における線引速度（ｍ／ｍｉ
ｎ）と水素特性を表す１．３μｍ伝送損失（ｄＢ／ｋ
ｍ）との関係を示すグラフである。FIG. 2 is a drawing speed (m / mi) according to the present invention.
n) and 1.3 μm transmission loss (dB / k) representing hydrogen characteristics
7 is a graph showing the relationship with m).
Claims (3)
率の低いクラッドからなる石英ガラスプリフォームを加
熱炉で加熱、溶融して、光ファイバに線引する方法にお
いて、石英ガラスプリフォームの外径Ｄ（ｍｍ）に対
し、線引速度Ｖ（ｍ／分）をＶ＞６．１Ｄの範囲に設定
することを特徴とする光ファイバの製造方法。1. A method for heating and melting a quartz glass preform comprising a core and a clad having a lower refractive index than the core on the outer periphery of the core in a heating furnace and drawing the quartz glass preform into an optical fiber. A method for producing an optical fiber, wherein a drawing speed V (m / min) is set in a range of V> 6.1 D with respect to an outer diameter D (mm).
時の張力を増加させることを特徴とする請求項１に記載
の光ファイバの製造方法。2. The method of manufacturing an optical fiber according to claim 1, wherein the tension at the time of drawing is increased in accordance with an increase in the outer diameter of the preform.
ム外径Ｄ（ｍｍ）に対しＴ＝０．７５２Ｄ±１０ｇの範
囲とすることを特徴とする請求項２に記載の光ファイバ
の製造方法。3. The optical fiber according to claim 2, wherein the tension T at the time of drawing is in a range of T = 0.552D ± 10 g with respect to the outer diameter D (mm) of the quartz glass preform. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20177796A JP3511811B2 (en) | 1996-07-31 | 1996-07-31 | Optical fiber manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20177796A JP3511811B2 (en) | 1996-07-31 | 1996-07-31 | Optical fiber manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1045421A true JPH1045421A (en) | 1998-02-17 |
| JP3511811B2 JP3511811B2 (en) | 2004-03-29 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20177796A Expired - Fee Related JP3511811B2 (en) | 1996-07-31 | 1996-07-31 | Optical fiber manufacturing method |
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| Country | Link |
|---|---|
| JP (1) | JP3511811B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2809386A1 (en) * | 2000-05-25 | 2001-11-30 | Cit Alcatel | METHOD FOR MANUFACTURING OPTICAL FIBER WITH CONTROL OF TRANSMISSION CHARACTERISTICS |
| KR100973373B1 (en) * | 2002-07-10 | 2010-07-30 | 스미토모 덴키 고교 가부시키가이샤 | Optical fiber and a method for manufacturing same |
| JP2013238676A (en) * | 2012-05-11 | 2013-11-28 | Fujikura Ltd | Low-loss optical fiber over wide wavelength range and method of manufacturing the same |
| WO2018181047A1 (en) * | 2017-03-27 | 2018-10-04 | 古河電気工業株式会社 | Optical fiber and manufacturing method for optical fiber |
-
1996
- 1996-07-31 JP JP20177796A patent/JP3511811B2/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2809386A1 (en) * | 2000-05-25 | 2001-11-30 | Cit Alcatel | METHOD FOR MANUFACTURING OPTICAL FIBER WITH CONTROL OF TRANSMISSION CHARACTERISTICS |
| EP1160211A1 (en) * | 2000-05-25 | 2001-12-05 | Alcatel | Method of manufacturing an optical fibre with control of the transmission characteristics |
| KR100973373B1 (en) * | 2002-07-10 | 2010-07-30 | 스미토모 덴키 고교 가부시키가이샤 | Optical fiber and a method for manufacturing same |
| JP2013238676A (en) * | 2012-05-11 | 2013-11-28 | Fujikura Ltd | Low-loss optical fiber over wide wavelength range and method of manufacturing the same |
| WO2018181047A1 (en) * | 2017-03-27 | 2018-10-04 | 古河電気工業株式会社 | Optical fiber and manufacturing method for optical fiber |
| JP2018163296A (en) * | 2017-03-27 | 2018-10-18 | 古河電気工業株式会社 | Optical fiber and method of manufacturing optical fiber |
| US11079537B2 (en) | 2017-03-27 | 2021-08-03 | Furukawa Electric Co., Ltd. | Optical fiber and manufacturing method of optical fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3511811B2 (en) | 2004-03-29 |
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