JPS5952201A - Light transmitting fiber - Google Patents
Light transmitting fiberInfo
- Publication number
- JPS5952201A JPS5952201A JP57164345A JP16434582A JPS5952201A JP S5952201 A JPS5952201 A JP S5952201A JP 57164345 A JP57164345 A JP 57164345A JP 16434582 A JP16434582 A JP 16434582A JP S5952201 A JPS5952201 A JP S5952201A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- cladding layer
- glass
- cladding
- core layer
- 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.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
- G02B6/03616—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference
- G02B6/03622—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 2 layers only
- G02B6/03633—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 2 layers only arranged - -
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
（ａ） 発明の技術分野
本発明は光伝送用ファイバに係り、特に内付けＣＶＤ法
によって光ファイバを形成する際に、出発材料となる石
英管からコア層へ水酸基が拡散することを防止し、かつ
コア層よりクラッド層へにじみ出る伝送光がクラッド層
の酸化ボロン（Ｂ２０ａ ）に吸収されるのを防止する
構成の光伝送用ファイバの改良に関するものである。Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to an optical transmission fiber, and in particular, when an optical fiber is formed by an internal CVD method, hydroxyl groups are transferred from a quartz tube as a starting material to a core layer. The present invention relates to an improvement in an optical transmission fiber having a structure that prevents light from diffusing and prevents transmitted light leaking from a core layer to a cladding layer from being absorbed by boron oxide (B20a) in the cladding layer.
山） 技術の背景
出発材料となる石英管を用いて内付けＣｖＣ法によって
形成される光通信用のシングルモード光ファイバの伝送
損失は、近年はぼ理論的限界値近くにまで低減されて来
ている。しかしこのような低損失の光ファイバを簡単に
大量的に得るためにはまだ、いくつかの問題を解決しな
ければならない。その一つに以下に記述する低損失化に
起因する光フアイバ母材の変形の問題がある。(Yama) Technical Background In recent years, the transmission loss of single-mode optical fibers for optical communication, which are formed by the internal CvC method using quartz tubes as the starting material, has been reduced to almost the theoretical limit value. There is. However, several problems still need to be solved in order to easily obtain such low-loss optical fibers in large quantities. One of them is the problem of deformation of the optical fiber base material due to loss reduction, which will be described below.
（Ｃ） 従来技術と問題点
出発材料となる石英管を用いて内付けＣＶＤ法によって
形成された従来の光通信用のシングルモード光ファイバ
にあっては、本来コア層を伝送する光信号パワーの一部
が、その周囲を取巻くクラッド層にまでしみ出して伝送
されスこ、Ｉ−カ＞ｔ−、−ｉｌ伝送光がクラッド層内
に出発石英管より拡散された水酸基（ＯＨ基）によって
吸収される伝送損失や、長波長帯域の伝送光が、クラッ
ド層に含まれる屈折率低下用の酸化ボロン（Ｂ２０３）
によって吸収されて伝送損失が生ずるといった欠点を有
していた。(C) Conventional technology and problems In conventional single-mode optical fibers for optical communications formed by internal CVD using a quartz tube as a starting material, the power of the optical signal transmitted through the core layer is A part of the transmitted light seeps into the surrounding cladding layer and is transmitted, and the transmitted light is absorbed by hydroxyl groups (OH groups) diffused from the starting quartz tube into the cladding layer. Boron oxide (B203) is included in the cladding layer to reduce the refractive index.
It has the disadvantage that transmission loss occurs due to absorption by
そこで上記の如き欠点を排除するために、第１図の光フ
アイバ断面図および第２図の屈折率分布に示すように、
例えばＧｅＯ２等を所定の屈折率となるように添加した
Ｓ ｒ ０２ガラス力）らなるコア層１の外周に、Ｂ２
Ｏ３等の不純物を含まない５ｉｏｚからなる薄層の第１
のクラッド層２を介してｓ ｉｏｚに五酸化燐（Ｂ２Ｏ
５）及び酸化硼素（Ｂ２０３）を所定回添加して、クラ
ッド層としての所定屈折率を得るように形成した分厚い
第２クラッド層８を設け、さらにその外周を出発材料の
石英管によって形成された最外Ｊ＃４で被覆した構成が
提案されている。Therefore, in order to eliminate the above-mentioned drawbacks, as shown in the cross-sectional view of the optical fiber in Fig. 1 and the refractive index distribution in Fig. 2,
For example, B2
The first thin layer of 5ioz containing no impurities such as O3
Phosphorous pentoxide (B2O
5) and boron oxide (B203) are added a predetermined number of times to provide a thick second cladding layer 8 formed to obtain a predetermined refractive index as a cladding layer, and the outer periphery of the second cladding layer 8 is formed of a quartz tube as a starting material. A structure coated with outermost J#4 has been proposed.
そしてこの構成によれば前記分厚い第２クラッド層３に
よって最外層４に含まれる水酸基がコア層１近傍に拡散
することを防止することができ、さらにコア層１よりし
み出した光が第１クラッド層２によって第２クラッド層
に含まれるＢ２Ｏ３により吸収されることも防止し得る
ので、低損失でシングルモード光を伝送することができ
る。ところが上記シングルモード光ファイバの構成にお
いては、ＧｅＯ２等を添加することによって融点が低く
なったコア層ｌと、同じ＜Ｐ２Ｏ５およびＢ２Ｏ３を添
加することで低融点化され、熱加工性を容易にした分厚
い第２クラッド層３との間に、極度に融点の高い８ｉ０
２からなる第１のクラッド層２が介在された構成がとら
れているため、例えば当該シングルモード光ファイバを
製作する際の内付けＣＶＤ法でのコラブス工程において
、形成される光フアイバ母材の伺断向が楕円状に変形し
易い欠点があり、結果的には横断向が真円状の光ファイ
バが得られない不都合があった。According to this configuration, the thick second cladding layer 3 can prevent the hydroxyl groups contained in the outermost layer 4 from diffusing into the vicinity of the core layer 1, and furthermore, the light seeping from the core layer 1 can be prevented from spreading to the first cladding layer 3. Since layer 2 can also prevent absorption by B2O3 contained in the second cladding layer, single mode light can be transmitted with low loss. However, in the configuration of the above-mentioned single mode optical fiber, the core layer l has a lower melting point by adding GeO2 etc., and the melting point is lowered by adding the same <P2O5 and B2O3, making thermal processability easier. 8i0, which has an extremely high melting point, is placed between the thick second cladding layer 3 and the thick second cladding layer 3.
Since the first cladding layer 2 consisting of 2 is interposed, for example, in the colab process of the internal CVD method when manufacturing the single mode optical fiber, the optical fiber base material formed is There is a disadvantage that the transverse direction is easily deformed into an elliptical shape, and as a result, an optical fiber having a perfectly circular cross direction cannot be obtained.
（ｄ） 発明の目的
本発明は、上記従来の欠点を除去するため、２重クラッ
ド構造の光ファイバを構成する第１クラッド層に屈折率
を上げる不純物をわづかに添加して、融点を低くシ、横
断面が真円状に形成される構成の低伝送損失の光伝送用
ファイバを提供することを目的とするものである。(d) Purpose of the Invention In order to eliminate the above-mentioned drawbacks of the conventional technology, the present invention has been developed by slightly adding impurities that increase the refractive index to the first cladding layer constituting the double-clad optical fiber to lower the melting point. Another object of the present invention is to provide an optical transmission fiber having a configuration in which a cross section is formed in a perfect circular shape and having a low transmission loss.
（ｅ） 発明の構成
そしてこの目的は本発明によれば、出発材料として用い
たシリカガラスより成る最外層の内側に第１および第２
のクラッド層で被包されたコア層をそなえてなるガラス
ファイバにおいて前記コア層を直接被包する第１のクラ
ッド層がシリカガラスよりも低融点となるように不純物
を添加した薄層のガラス力）らなり、力）つ該第１のク
ラッド層と上記最外層との間に位置する第２のクラッド
層が、最外層力）らの水酸基の浸入を防止するに充分な
厚さを有し、力）つ前記第１のクラッド層よりもさらに
低融点化のために不純物を添加したガラスからなること
を特徴とする光伝送用ファイバを提供することによって
達成される。(e) Structure and object of the invention According to the invention, first and second
In a glass fiber comprising a core layer covered with a cladding layer, a first cladding layer that directly covers the core layer is doped with impurities so that it has a lower melting point than silica glass. The second cladding layer located between the first cladding layer and the outermost layer has a thickness sufficient to prevent penetration of hydroxyl groups from the outermost layer. This is achieved by providing an optical transmission fiber characterized in that it is made of glass doped with impurities to lower the melting point than the first cladding layer.
（ｆ） 発明の実施例
以下図面を用いて本発明の実施例について詳細に説明す
る。(f) Embodiments of the invention Embodiments of the invention will be described in detail below with reference to the drawings.
舘Ｑ （＞Ａもトγｒ端ＡＭ糾大感叩Ｗ練入立俣櫻日フ
ァイバの一実彌例構造を示す横断面図およびその屈折率
分布図であり、第１図と同等部分には同一符号を付して
いる。Tate Q (>A is also a transverse cross-sectional view and its refractive index distribution diagram showing the structure of an actual example of the Tatemata Sakurahi fiber at the γr end. The same symbols are attached.
これら両図によって示されるように本発明の光伝送用フ
ァイバは、５Ｉ０２にＧｅ０ｚが所定の高屈折率となる
ように添加されたコア層ｌの外周に、本発明の特徴とす
る例えば８ｉＱ２にＰ２Ｏ５からなる不純物をわづかに
添加して前記コア層ｌよりも屈折率が第４図に示すよう
に小さく、力）つシリカガラス（Ｓｉ０２）よりも低融
点にした第１のクラッド層＆が設けられている。またそ
の外周に５ｉＯｚにＢ２Ｏ３およびＰ２Ｏ３を、前記第
１のクラッド層澄の屈折率よりも小さく、シリカガラス
（Ｓｉｏ２）と同一の屈折率値となるように、添加して
、前記′第１のクラッド層澄よりもさらに低融点化した
第２のクラッド層８が分厚く設けられ、さらにその外周
に内付けＣＶＤ法において用いた出発材料の石英管を延
伸して形成されたシリカガラス（ＳｉＯｚ）より成る最
外層４が設０られた構造がとられている。As shown in these two figures, the optical transmission fiber of the present invention has P2O5, for example, 8iQ2, which is a feature of the present invention, on the outer periphery of the core layer l, which is 5I02 doped with Ge0z to have a predetermined high refractive index. A first cladding layer & is provided which has a refractive index smaller than that of the core layer l as shown in FIG. It is being Further, 5 iOz of B2O3 and P2O3 are added to the outer periphery so that the refractive index value is smaller than that of the first cladding layer and is the same as that of silica glass (Sio2). A second cladding layer 8 with a lower melting point than that of the cladding layer is thickly provided, and a layer made of silica glass (SiOz) formed by stretching a quartz tube, which is the starting material used in the CVD method, is further attached to the outer periphery of the second cladding layer 8. A structure is adopted in which an outermost layer 4 consisting of 0 is provided.
このような構造を有する光伝送用ファイバを形成するに
は、回転させた出発材料となる石英反応管内に、四塩化
珪素（ＳｉＯ／？４）に三臭化硼素（ＢＢｒ２）と、オ
キシ塩化燐（ＰＯＯ／３）とを混合した原料ガスと酸素
（０２）ガスをジヌ入し、該石英管の外壁を加熱バーナ
によって高温に加熱して８ｉＱ２にＪｊ ２０ ｓ ＋
Ｉ’ ２０５力）らなる不純物か添加されたガラス層
を第２のクラッド層３として分厚く堆積させる。引続い
て前記石英管中に５ｉＯ１４とＰＯＣｌ３とを混合した
ガスとｖ１素（０２）ガスを導入して５ｉ０２にＰ２Ｏ
５＃：らなる不純物が小量添加されたガラス層を第１の
クラッド層３２として薄く堆積させる。To form an optical transmission fiber having such a structure, silicon tetrachloride (SiO/?4), boron tribromide (BBr2), and phosphorus oxychloride are placed in a rotating quartz reaction tube as a starting material. (POO/3) and oxygen (02) gas are injected, and the outer wall of the quartz tube is heated to a high temperature with a heating burner to produce 8iQ2 Jj 20 s +
A glass layer doped with an impurity of I' 205 is thickly deposited as the second cladding layer 3. Subsequently, a mixed gas of 5iO14 and POCl3 and v1 element (02) gas were introduced into the quartz tube to convert P2O into 5i02.
5#: A glass layer doped with a small amount of impurity is thinly deposited as the first cladding layer 32.
さらに引続いて０１ｊ記石英管中に５１ａｌ＜と四塩化
ゲルマニラ（ＧｅＯ１４）との混合ガスと０２ガスとを
導入してＳｉＯ２にＧｅＯ２力）らなる不純物が添加さ
れたガラス層をコア層ｌとして堆積させる。その後上記
石英管の断面積が密になるように加熱して中実化するこ
とにより前記第２クラッド層３力・ら第１クラッド層〜
を介してコア層１との間に従来の如き極端な融点の差か
ないので真円中実棒状の光フアイバ母材が容易に得られ
る。よって前記光フアイバ母材を紡糸装置によって加熱
延伸すれば第８図および第４図に示す構造の横断面が真
円なシングルモード光ファイバが得られる。なおり）か
る光ファイバにおいては第１クラッド層３２の外径がコ
ア層ｌの径の１，５倍とし、第２クラッド層３の外径を
コア層１の径の５倍以上に形成すれば、出発材料である
石英管中の水酸基がコア層ｌへ拡散することもなく、ま
たコア層ｌの外周には該コア層ｌよりも低屈折率で、第
２クラッド層３より高屈折率な薄層の第１クラッド層３
２が設けられているため、コア層ｌよりにじみ出た伝送
光が該第１クラッド層３２中に封止込められ隣接する第
２クラッド層Ｂ中に含まれるＢ２０．に吸収されること
がなくなり、水酸基およびクラッド層のＢ２Ｏ３による
光吸収損失も充分に防止される。Furthermore, a mixed gas of 51al< and tetrachloride gel manila (GeO14) and 02 gas were introduced into the quartz tube described in 01j to form a glass layer to which impurities of SiO2 and GeO2 were added as a core layer l. deposit Thereafter, by heating and solidifying the quartz tube so that the cross-sectional area thereof becomes dense, the second cladding layer 3 is combined with the first cladding layer ~
Since there is no extreme difference in melting point between the core layer 1 and the core layer 1 as in the conventional case, an optical fiber base material in the shape of a perfect round solid rod can be easily obtained. Therefore, if the optical fiber preform is heated and drawn using a spinning device, a single mode optical fiber having the structure shown in FIGS. 8 and 4 and having a perfectly circular cross section can be obtained. Note) In such an optical fiber, the outer diameter of the first cladding layer 32 should be 1.5 times the diameter of the core layer 1, and the outer diameter of the second cladding layer 3 should be 5 times or more the diameter of the core layer 1. For example, the hydroxyl groups in the quartz tube, which is the starting material, do not diffuse into the core layer 1, and the outer periphery of the core layer 1 has a refractive index lower than that of the core layer 1 and higher than the second cladding layer 3. thin first cladding layer 3
2 is provided, the transmitted light seeping out from the core layer l is sealed and contained in the first cladding layer 32 and is contained in the adjacent second cladding layer B. Therefore, light absorption loss due to hydroxyl groups and B2O3 in the cladding layer is sufficiently prevented.
偵） 発明の効果
以上の説明から明ら力）なように本発明に係る光伝送用
ファイバの構成によれば、出発材料管より拡散される水
酸基（ＯＩ（基）および第２クラッド層中のＢ２Ｏ３に
よる伝送光の吸収損失を低下させることは勿論のこと、
中心のコア層より、その外周に順に構成される第１．第
２のクラッド層の各融点が、段階的に低くなっているの
で、横断面が真円状の低伝送損失の光伝送用ファイバが
得られる。Effects of the Invention As is clear from the above explanation, according to the configuration of the optical transmission fiber according to the present invention, the hydroxyl groups (OI groups) diffused from the starting material tube and the hydroxyl groups in the second cladding layer are Of course, it reduces the absorption loss of transmitted light due to B2O3,
The first layer is formed in order from the central core layer to the outer periphery. Since the melting points of the second cladding layers are lowered stepwise, an optical transmission fiber with a perfectly circular cross section and low transmission loss can be obtained.
よって特に長波長帯の光信号をシングルモード伝送する
シングルモード光ファイバに本発明の構成を適用して極
めて有利である。Therefore, it is extremely advantageous to apply the configuration of the present invention to a single-mode optical fiber that transmits an optical signal in a long wavelength band in a single mode.
第１図および第２図は従来の光伝送用ファイバを説明す
る横断面図およびその屈折率分布図、第８図および第４
図は本発明に係る光伝送用ファイバの一実施例を示す横
断面図およびその屈折率分布図である。
図面において、ｌはコア層、８は第２クラッド層、４は
最外層、〜は第１クラッド層を示す。
第１図 第２図Figures 1 and 2 are cross-sectional views and refractive index distribution diagrams for explaining conventional optical transmission fibers, Figures 8 and 4.
The figures are a cross-sectional view and a refractive index distribution diagram showing one embodiment of an optical transmission fiber according to the present invention. In the drawings, l represents the core layer, 8 represents the second cladding layer, 4 represents the outermost layer, and ~ represents the first cladding layer. Figure 1 Figure 2
Claims (1)
側に第１および第２のクラッド層で被包されたコア層を
そなえてなるガラスファイバにおいて、前記コア層を直
接被包する第１のクラッド層がシリカガラスよりも低融
点となるように不純物を添加した薄層のガラスからなり
、力）つ該第１のクラッド層と上記最外層との間に位置
する第２のクラッド層が、最外層からの水酸基の浸入を
防止するに充分な厚さを有し、かつ前記第１のクラッド
層よりもさらに低融点化のために不純物を添加したガラ
スからなることを特徴とする光伝送用ファイバ。In a glass fiber comprising a core layer covered with first and second cladding layers inside an outermost layer made of silica glass used as a starting member, the first cladding layer directly covers the core layer. The second cladding layer is made of a thin layer of glass doped with impurities so that it has a lower melting point than silica glass, and the second cladding layer is located between the first cladding layer and the outermost layer. 1. An optical transmission fiber characterized in that it is made of glass having a thickness sufficient to prevent the infiltration of hydroxyl groups from the glass, and to which impurities are added to lower the melting point than the first cladding layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57164345A JPS5952201A (en) | 1982-09-20 | 1982-09-20 | Light transmitting fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57164345A JPS5952201A (en) | 1982-09-20 | 1982-09-20 | Light transmitting fiber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5952201A true JPS5952201A (en) | 1984-03-26 |
Family
ID=15791399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57164345A Pending JPS5952201A (en) | 1982-09-20 | 1982-09-20 | Light transmitting fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5952201A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7450813B2 (en) * | 2006-09-20 | 2008-11-11 | Imra America, Inc. | Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers |
| US8498046B2 (en) | 2008-12-04 | 2013-07-30 | Imra America, Inc. | Highly rare-earth-doped optical fibers for fiber lasers and amplifiers |
-
1982
- 1982-09-20 JP JP57164345A patent/JPS5952201A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7450813B2 (en) * | 2006-09-20 | 2008-11-11 | Imra America, Inc. | Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers |
| US8213758B2 (en) | 2006-09-20 | 2012-07-03 | Imra America, Inc. | Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers |
| US8542968B2 (en) | 2006-09-20 | 2013-09-24 | Imra America, Inc. | Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers |
| US8498046B2 (en) | 2008-12-04 | 2013-07-30 | Imra America, Inc. | Highly rare-earth-doped optical fibers for fiber lasers and amplifiers |
| US8902493B2 (en) | 2008-12-04 | 2014-12-02 | Imra America, Inc. | Highly rare-earth-doped optical fibers for fiber lasers and amplifiers |
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