JP2002053344A - Glass preform for optical fiber and optical fiber - Google Patents
Glass preform for optical fiber and optical fiberInfo
- Publication number
- JP2002053344A JP2002053344A JP2000238505A JP2000238505A JP2002053344A JP 2002053344 A JP2002053344 A JP 2002053344A JP 2000238505 A JP2000238505 A JP 2000238505A JP 2000238505 A JP2000238505 A JP 2000238505A JP 2002053344 A JP2002053344 A JP 2002053344A
- Authority
- JP
- Japan
- Prior art keywords
- core
- optical fiber
- chlorine concentration
- clad
- glass 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.)
- Pending
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]
- C03B37/01413—Reactant delivery systems
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C13/00—Fibre or filament compositions
- C03C13/04—Fibre optics, e.g. core and clad fibre compositions
- C03C13/045—Silica-containing oxide glass compositions
-
- 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
- C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
-
- 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
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/31—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/36—Dispersion modified fibres, e.g. wavelength or polarisation shifted, flattened or compensating fibres (DSF, DFF, DCF)
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C2201/00—Glass compositions
- C03C2201/06—Doped silica-based glasses
- C03C2201/08—Doped silica-based glasses containing boron or halide
- C03C2201/11—Doped silica-based glasses containing boron or halide containing chlorine
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C2201/00—Glass compositions
- C03C2201/06—Doped silica-based glasses
- C03C2201/30—Doped silica-based glasses containing metals
- C03C2201/31—Doped silica-based glasses containing metals containing germanium
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、高速大容量光伝送
システムに好適に用いることのできる光ファイバ及びこ
れを作製するための光ファイバ用ガラス母材に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber which can be suitably used for a high-speed, large-capacity optical transmission system, and a glass base material for an optical fiber for producing the same.
【０００２】[0002]
【従来の技術】光伝送システムの伝送の高速化、大容量
化に伴い、高ビットレート通信の検討が進められてい
る。伝送時の信号波形歪みを小さくするためには、光フ
ァイバの分散が小さいことが重要である。この対策とし
て、分散補償ファイバを伝送システムに用いることで、
伝送路全体の波長分散を小さくしているが、光ファイバ
には、波長分散以外にも偏波モード分散が存在し、これ
が大きいと信号波形歪みが大きくなる。2. Description of the Related Art High bit rate communication is being studied with the increase in transmission speed and capacity of optical transmission systems. In order to reduce the signal waveform distortion during transmission, it is important that the dispersion of the optical fiber is small. As a countermeasure, by using dispersion compensating fiber in the transmission system,
Although the chromatic dispersion of the entire transmission line is reduced, polarization mode dispersion other than chromatic dispersion exists in the optical fiber, and when this is large, the signal waveform distortion becomes large.
【０００３】通常のシングルモード光ファイバは、純石
英ガラスにＧｅがドープされたコアと純石英ガラスのみ
のクラッドからなる構造を有している。特開平１１−３
２６６７０号公報では、コアを純石英ガラス、クラッド
をフッ素ドープ石英ガラスで形成することによって、コ
ア・クラッド間の熱膨張係数差を小さくして、光ファイ
バの真円に対する楕円率が同じであっても、偏波モード
分散の比較的小さい光ファイバを実現している。An ordinary single mode optical fiber has a structure including a core made of pure silica glass doped with Ge and a clad made of pure silica glass alone. JP-A-11-3
According to Japanese Patent No. 26670, the core is formed of pure silica glass and the clad is formed of fluorine-doped silica glass, thereby reducing the difference in thermal expansion coefficient between the core and the clad. This realizes an optical fiber having a relatively small polarization mode dispersion.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記純
石英ガラスをコアとする純石英ガラスコア光ファイバ
は、クラッド部にフッ素をドープしなければならないた
め、ガラス母材作製時に、コア・クラッド界面で発泡し
易く、製造が困難であった。本発明は、このような問題
点を解消するためになされたものであり、製造の容易な
従来のＧｅドープコア・純石英ガラスクラッドの構造
で、偏波モード分散が小さい光ファイバ及びこれを作製
するための光ファイバ用ガラス母材を提供することを目
的としている。However, in the pure silica glass core optical fiber having the above-mentioned pure silica glass as a core, the cladding must be doped with fluorine. It easily foamed and was difficult to manufacture. SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an optical fiber having a structure of a conventional Ge-doped core / pure silica glass clad, which is easy to manufacture, and having a small polarization mode dispersion, and to manufacture the same. To provide a glass preform for an optical fiber.
【０００５】[0005]
【課題を解決するための手段】本発明の光ファイバ用ガ
ラス母材は、中央にＧｅがドープされたコアとこの周辺
にクラッドの一部が形成されたコア部とクラッド部から
なる石英製光ファイバ用ガラス母材において、半径方向
に塩素ドープによって形成された塩素濃度分布を有し、
該コア部とクラッド部との界面の近くに塩素濃度の低い
部分を有することを特徴としている。塩素濃度の低い部
分は、コア部とクラッド部の界面の外側近傍に存在する
ようにすることができる。また、コア部を形成している
コアに隣接するクラッドの塩素濃度分布において、半径
方向内側寄りの部分にこの外側寄りの部分よりも塩素濃
度の低い部分を有する構成とすることもできる。さら
に、コア部を形成しているコアに隣接するクラッドの塩
素濃度を、該クラッドに隣接するクラッド部の界面近傍
の塩素濃度より低い構成とすることもできる。According to the present invention, there is provided a glass preform for an optical fiber, comprising a core doped with Ge in the center, a core having a part of a clad formed around the core, and a quartz light source. In the glass preform for fiber, having a chlorine concentration distribution formed by chlorine doping in the radial direction,
It is characterized by having a portion having a low chlorine concentration near the interface between the core and the clad. The portion having a low chlorine concentration can be present near the outside of the interface between the core portion and the clad portion. Further, in the chlorine concentration distribution of the clad adjacent to the core forming the core portion, it may be configured such that a portion closer to the inner side in the radial direction has a portion having a lower chlorine concentration than the portion closer to the outer side. Furthermore, the chlorine concentration of the clad adjacent to the core forming the core portion may be lower than the chlorine concentration near the interface of the clad portion adjacent to the clad.
【０００６】また、塩素濃度の低い部分を、中心から半
径方向に向けて光ファイバ用ガラス母材の径の１０〜５
０％の領域に存在するように設けるとよい。塩素濃度の
低い部分と高い部分との塩素濃度差は、１００ｐｐｍ以
上、あるいは１％以下とするのが好ましい。上記光ファ
イバ用ガラス母材を線引して作製した光ファイバの偏波
モード分散値は、０．１ｐｓ／ｋｍ1/2以下である。Further, the portion having a low chlorine concentration is radially shifted from the center by 10 to 5 times the diameter of the glass base material for an optical fiber.
It is good to provide so that it exists in the area of 0%. It is preferable that the difference in chlorine concentration between a portion having a low chlorine concentration and a portion having a high chlorine concentration is 100 ppm or more, or 1% or less. The polarization mode dispersion value of an optical fiber manufactured by drawing the above glass preform for an optical fiber is 0.1 ps / km 1/2 or less.
【０００７】本発明の光ファイバ用ガラス母材の製造方
法に関する第１の発明は、ＶＡＤ法によって、コア材の
外周にＳｉＯ2微粒子（スート）を堆積させて得たスー
ト堆積体を塩素ガス雰囲気中で脱水した後、焼成ガラス
化してコアとクラッドの一部からなるコア部を形成し、
透明ガラス化してコア部材とし、次いで、スート法によ
ってＳｉＯ2微粒子をコア部材の周囲に、嵩密度が内側
から外側に向って小さくなるように外付けして多孔質ガ
ラス母材とし、塩素ガス雰囲気中で加熱して透明ガラス
化することを特徴としている。製造方法の第２の発明
は、ＶＡＤ法によって、コア材の外周にＳｉＯ2微粒子
（スート）を嵩密度が内側から外側に向って小さくなる
ように堆積させて得たスート堆積体を塩素ガス雰囲気中
で脱水した後、焼成ガラス化してコアとクラッドの一部
からなるコア部を形成し、透明ガラス化してコア部材と
し、次いで、スート法によってＳｉＯ2微粒子をコア部
材の周囲に外付けして多孔質ガラス母材とし、塩素ガス
雰囲気中で加熱して透明ガラス化することを特徴として
いる。製造方法の第３の発明は、ＶＡＤ法によって、コ
ア材の外周にＳｉＯ2微粒子（スート）を堆積させて得
たスート堆積体を焼成ガラス化してコアとクラッドの一
部からなるコア部材を形成した後、該コア部材に合成石
英管を被せ、塩素ガス雰囲気中で加熱し一体化すること
を特徴としている。A first aspect of the present invention relates to a method of manufacturing a glass base material for an optical fiber, wherein a soot deposit obtained by depositing SiO 2 fine particles (soot) on the outer periphery of a core material by a VAD method is subjected to a chlorine gas atmosphere. After dehydration in the, fired vitrification to form a core part consisting of a core and a part of the clad,
Transparent vitrification to form a core member, and then a soot method is used to externally attach SiO 2 fine particles around the core member so that the bulk density decreases from the inside to the outside, thereby forming a porous glass base material, and a chlorine gas atmosphere. It is characterized in that it is heated in a glass to form a transparent glass. According to a second invention of the manufacturing method, a soot deposit obtained by depositing SiO 2 fine particles (soot) on the outer periphery of a core material so as to decrease in bulk density from inside to outside by a VAD method is subjected to a chlorine gas atmosphere. After dehydration in the glass, fired and vitrified to form a core portion consisting of a core and a part of the clad, transparently vitrified to form a core member, and then externally applied SiO 2 fine particles around the core member by a soot method. It is characterized in that it is made of a porous glass base material and is heated in a chlorine gas atmosphere to form a transparent glass. According to a third invention of a manufacturing method, a soot deposit obtained by depositing SiO 2 fine particles (soot) on the outer periphery of a core material is fired and vitrified by VAD to form a core member composed of a core and a part of a clad. After that, the core member is covered with a synthetic quartz tube, and heated and integrated in a chlorine gas atmosphere.
【０００８】[0008]
【発明の実施の形態】光ファイバの偏波モード分散の原
因の一つに、コアの真円度の低下が挙げられる。しか
し、先にＶＡＤ法で作製されるコア部材は真円度が高
く、偏波モード分散を生じる要因は別に存在する。それ
は、コアの周囲に加えられる外部応力が円周方向に非対
称であることによる。コア部径はクラッド部外径のほぼ
３０％前後であり、クラッド部はコア部に比べかなり厚
くなっている。このためクラッド部は、スート堆積体を
加熱焼成して透明化する際の体積収縮率が大きく、真円
度が低下しやすい。コア部が真円であってもクラッド部
の真円度が低下していると、ガラス母材を線引する際
に、加熱されたクラッド部が表面張力で真円に戻ろうと
する力が、ガラス母材に働く。これが光ファイバに残留
歪みとなって残り、光ファイバのコア部に非対称の応力
が働く結果となり、偏波モード分散が増すことになる。DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the causes of the polarization mode dispersion of an optical fiber is a decrease in the roundness of the core. However, the core member previously manufactured by the VAD method has a high roundness, and there is another factor that causes polarization mode dispersion. This is because the external stress applied around the core is circumferentially asymmetric. The core diameter is about 30% of the outer diameter of the clad, and the clad is considerably thicker than the core. For this reason, the clad portion has a large volume shrinkage ratio when the soot deposit is heated and baked to make it transparent, and the roundness tends to decrease. If the circularity of the clad part is reduced even if the core part is a perfect circle, when drawing the glass base material, the force of the heated clad part to return to a perfect circle due to surface tension, Work on glass preform. This remains as a residual strain in the optical fiber, resulting in an asymmetric stress acting on the core of the optical fiber, and increasing the polarization mode dispersion.
【０００９】そこで、本発明は、該コア部とクラッド部
との界面の近くに塩素濃度の低い部分を設けることによ
って、より詳しくは、比較的真円度の高いコアに隣接す
るクラッドもしくは該クラッド界面近傍のクラッド部の
塩素濃度を低くすることによって、コア部への非対称歪
みの影響を小さくするものである。スートを堆積させて
形成したスート堆積体（多孔質ガラス母材）は、加熱焼
成してガラス化する際に、通常、塩素含有ガスで脱水が
行なわれているが、このとき微量の塩素が石英ガラス母
材中に取り込まれる。石英ガラス母材中の塩素の含有量
が多いと、線引き時に加熱された石英ガラス母材の粘度
が小さくなる。In view of the above, the present invention provides a clad having a low chlorine concentration near the interface between the core and the clad. By reducing the chlorine concentration in the cladding near the interface, the effect of asymmetric strain on the core is reduced. When a soot deposit (porous glass base material) formed by depositing soot is vitrified by heating and sintering, it is usually dehydrated with a chlorine-containing gas. It is taken into the glass base material. When the content of chlorine in the quartz glass base material is large, the viscosity of the quartz glass base material heated at the time of drawing becomes small.
【００１０】そこで、塩素濃度の低い部分をコア部とク
ラッド部の界面の外側近傍に存在させることによって
（図１参照）、あるいはコアに隣接するクラッドの半径
方向に塩素濃度分布を設け、比較的真円度の高いコア近
傍寄りの部分にこの外側寄りの部分よりも塩素濃度の低
い部分を設けることによって（図２参照）、もしくはコ
アに隣接するクラッドの塩素濃度をこれに隣接する界面
近傍のクラッド部の塩素濃度より低くすることによって
（図３参照）、これを線引して得られる光ファイバは、
コア近傍のクラッドが真円度を保ったまま比較的早い時
期に固化し、その後コア部分が固化する。このように構
成することにより、クラッド部の外周の楕円の影響がコ
ア部に影響しないため、偏波モード分散値を低く、０．
１ｐｓ／ｋｍ1/2以下に抑制することができる。Therefore, by providing a portion having a low chlorine concentration near the outside of the interface between the core portion and the clad portion (see FIG. 1), or by providing a chlorine concentration distribution in the radial direction of the clad adjacent to the core, By providing a portion closer to the core near the core with a higher roundness and having a lower chlorine concentration than the portion closer to the outside (see FIG. 2), or by changing the chlorine concentration of the cladding adjacent to the core to the vicinity of the interface adjacent thereto. By making the chlorine concentration lower than the clad portion (see FIG. 3), the optical fiber obtained by drawing this is
The clad near the core solidifies at a relatively early stage while maintaining the roundness, and then the core solidifies. With such a configuration, the influence of the ellipse on the outer periphery of the clad portion does not affect the core portion.
It can be suppressed to 1 ps / km 1/2 or less.
【００１１】このため、塩素濃度の低い部分を、中心か
ら半径方向に向けて光ファイバ用ガラス母材の径の１０
〜５０％の領域に形成するものであり、１０％未満の領
域では、塩素濃度を変化させてもＧｅにより粘度が下が
るだけで所望の効果が認められず、５０％を超える領域
では、スート堆積時の密度調整が難しくスート割れなど
の問題が生じるため好ましくない。また、塩素濃度の低
い部分と高い部分との塩素濃度差は、１００ｐｐｍ以上
あるいは１％以下とするのが良く、１００ｐｐｍ未満あ
るいは１％以下では、上記と同様に密度調整が困難であ
り、好ましくない。For this reason, the portion having a low chlorine concentration is radially shifted from the center by 10 mm in diameter of the glass base material for optical fiber.
In a region of less than 10%, even if the chlorine concentration is changed, the desired effect is not recognized only by lowering the viscosity due to Ge, and in a region exceeding 50%, soot deposition is performed. It is not preferable because it is difficult to adjust the density at the time, and problems such as soot cracking occur. Further, the difference in chlorine concentration between the portion having a low chlorine concentration and the portion having a high chlorine concentration is preferably 100 ppm or more or 1% or less. If the chlorine concentration is less than 100 ppm or 1% or less, it is difficult to adjust the density as described above, which is not preferable. .
【００１２】以下、図に基いてさらに詳細に説明する。
なお、図１乃至３の（ａ）は、いずれも光ファイバ用ガ
ラス母材の半径方向の屈折率分布を示し、縦軸は屈折
率、横軸は半径方向の位置を示している。また、図１乃
至３の（ｂ）は、それぞれ対応する図の（ａ）に示した
光ファイバ用ガラス母材の半径方向の塩素濃度分布を示
し、縦軸は塩素濃度、横軸は半径方向の位置を示してい
る。図１は、塩素濃度の低い部分がコア部とクラッド部
の界面の外側近傍に存在している。図２は、コア部を形
成しているコアに隣接するクラッドの塩素濃度分布にお
いて、半径方向内側寄りの部分にこの外側寄りの部分よ
りも塩素濃度の低い部分が形成されている。図３は、コ
ア部を形成しているコアに隣接するクラッドの塩素濃度
を、該クラッドに隣接する界面近傍のクラッド部の塩素
濃度より低くしたものである。The details will be described below with reference to the drawings.
1 to 3A show the refractive index distribution in the radial direction of the glass preform for optical fiber, the vertical axis shows the refractive index, and the horizontal axis shows the position in the radial direction. FIGS. 1 to 3B show the chlorine concentration distribution in the radial direction of the glass preform for optical fiber shown in FIG. 1A, the vertical axis represents the chlorine concentration, and the horizontal axis represents the radial direction. The position of is shown. In FIG. 1, a portion having a low chlorine concentration exists near the outside of the interface between the core portion and the clad portion. FIG. 2 shows that, in the chlorine concentration distribution of the clad adjacent to the core forming the core portion, a portion having a lower chlorine concentration is formed at a portion closer to the radially inner side than at a portion closer to the outer side. FIG. 3 shows the case where the chlorine concentration of the clad adjacent to the core forming the core is lower than the chlorine concentration of the clad near the interface adjacent to the clad.
【００１３】[0013]
【実施例】（実施例１）コア部とクラッド部との界面の
外側近傍に塩素濃度の低い部分を設けた例である。ＶＡ
Ｄ法によって、コア材の外周にＳｉＯ2微粒子（スー
ト）を堆積させて得たスート堆積体を塩素ガス雰囲気中
で脱水した後、焼成ガラス化してコアとクラッドの一部
からなるコア部を形成し、透明ガラス化してコア部材ロ
ッドとした。次に、スート法によってＳｉＯ2微粒子を
コア部材ロッドの周囲に、嵩密度が内側から外側に向っ
て小さくなるように外付けして多孔質ガラス母材とし
た。この多孔質ガラス母材を塩素ガス雰囲気中で加熱し
て透明ガラス化し、透明なガラス母材を作製した。この
ガラス母材の屈折率分布を測定した。さらに、このガラ
ス母材の一部を切断してＥＰＭＡ（電子線走査マイクロ
アナライザ）にて塩素濃度分布を測定し、この結果を図
１に示した。このガラス母材を線引し、得られた光ファ
イバの偏波モード分散を測定したところ０．０５７ｐｓ
・ｋｍ1/2であった。Embodiment 1 This is an example in which a portion having a low chlorine concentration is provided near the outside of the interface between the core portion and the clad portion. VA
A soot deposit obtained by depositing SiO 2 fine particles (soot) on the outer periphery of the core material by the D method is dehydrated in a chlorine gas atmosphere, and then baked and vitrified to form a core portion composed of a core and a part of a clad. Then, it was made into a transparent glass to obtain a core member rod. Then, around the core member rod SiO 2 particles by soot method, the bulk density was a porous glass preform by external to be smaller toward the inside to the outside. This porous glass base material was heated in a chlorine gas atmosphere to be made into a transparent glass, thereby producing a transparent glass base material. The refractive index distribution of this glass base material was measured. Further, a part of the glass base material was cut, and a chlorine concentration distribution was measured by an EPMA (Electron Beam Scanning Microanalyzer). The results are shown in FIG. This glass preform was drawn, and the polarization mode dispersion of the obtained optical fiber was measured.
-It was km 1/2 .
【００１４】（実施例２）コア部のクラッドに塩素濃度
の低い部分を設けた例である。ＶＡＤ法によって、コア
とこの外周に設けるクラッドの嵩密度を内側から外側に
向って小さくなるように形成し、その後、塩素ガス雰囲
気中で１,２００℃に加熱して塩素をドープした後、１,
６００℃で加熱し透明ガラス化してコア部材ロッドとし
た。次に、このコア部材ロッドの周囲にスート法によっ
てＳｉＯ2微粒子を外付けして多孔質ガラス母材とし
た。この多孔質ガラス母材を塩素ガス雰囲気中で加熱し
て透明ガラス化し、透明なガラス母材を作製した。この
ガラス母材の屈折率分布を測定した。さらに、このガラ
ス母材の一部を切断してＥＰＭＡにて塩素濃度分布を測
定し、この結果を図２に示した。このガラス母材を線引
し、得られた光ファイバの偏波モード分散を測定したと
ころ０．０６７ｐｓ・ｋｍ1/2であった。Embodiment 2 This is an example in which a portion having a low chlorine concentration is provided in the clad of the core portion. By VAD method, the bulk density of the core and the clad provided on the outer periphery is formed so as to decrease from the inside to the outside, and then heated to 1,200 ° C. in a chlorine gas atmosphere to dope chlorine. ,
It was heated at 600 ° C. and made vitrified to obtain a core member rod. Next, fine particles of SiO 2 were externally provided around the core member rod by a soot method to obtain a porous glass base material. This porous glass base material was heated in a chlorine gas atmosphere to be made into a transparent glass, thereby producing a transparent glass base material. The refractive index distribution of this glass base material was measured. Further, a part of the glass base material was cut, and a chlorine concentration distribution was measured by EPMA. The results are shown in FIG. This glass preform was drawn, and the polarization mode dispersion of the obtained optical fiber was measured to be 0.067 ps · km 1/2 .
【００１５】（実施例３）コア部とクラッド部との界面
の内側に塩素濃度の低い部分を設けた例である。ＶＡＤ
法によって、コアとクラッドの一部からなるコア部を作
製し、透明ガラス化してコア部材ロッドとした。次に、
このコア部材ロッドに市販の合成石英ガラス管を被せて
塩素ガス雰囲気中で加熱し一体化して、透明なガラス母
材を作製した。このガラス母材の屈折率分布を測定し
た。さらに、このガラス母材の一部を切断してＥＰＭＡ
にて塩素濃度分布を測定し、この結果を図３に示した。
このガラス母材を線引し、得られた光ファイバの偏波モ
ード分散を測定したところ０．０３４ｐｓ・ｋｍ1/2で
あった。(Embodiment 3) This is an example in which a portion having a low chlorine concentration is provided inside the interface between the core portion and the clad portion. VAD
A core portion composed of a core and a part of a clad was produced by a method, and was transparently vitrified to obtain a core member rod. next,
This core member rod was covered with a commercially available synthetic quartz glass tube and heated and integrated in a chlorine gas atmosphere to produce a transparent glass base material. The refractive index distribution of this glass base material was measured. Further, a part of this glass base material is cut to obtain EPMA.
Measured the chlorine concentration distribution, and the results are shown in FIG.
This glass preform was drawn, and the polarization mode dispersion of the obtained optical fiber was measured to be 0.034 ps · km 1/2 .
【００１６】（比較例１）従来のガラス母材の塩素濃度
分布を示した例である。ＶＡＤ法によって、コアとクラ
ッドの一部からなるコア部を作製し、透明ガラス化して
コア部材ロッドとした。次に、このコア部材ロッドに市
販の合成石英ガラス管を被せ、上記実施例１〜３よりも
塩素濃度の低い塩素ガス雰囲気中（従来、脱水に使用さ
れている塩素量）で加熱し一体化して、透明なガラス母
材を作製した。このガラス母材の屈折率分布を測定し
た。さらに、このガラス母材の一部を切断してＥＰＭＡ
にて塩素濃度分布を測定し、この結果を図４に示した。
このガラス母材を線引し、得られた光ファイバの偏波モ
ード分散を測定したところ０．１１２ｐｓ・ｋｍ1/2で
あった。(Comparative Example 1) This is an example showing a chlorine concentration distribution of a conventional glass base material. A core portion composed of a core and a part of a clad was produced by VAD method, and was made vitrified to form a core member rod. Next, this core member rod is covered with a commercially available synthetic quartz glass tube, and is heated and integrated in a chlorine gas atmosphere having a lower chlorine concentration than in Examples 1 to 3 (chlorine amount conventionally used for dehydration). Thus, a transparent glass base material was produced. The refractive index distribution of this glass base material was measured. Further, a part of this glass base material is cut to obtain EPMA.
Measured the chlorine concentration distribution, and the results are shown in FIG.
The glass base material was drawn, and the polarization mode dispersion of the obtained optical fiber was 0.112 ps · km 1/2 .
【００１７】[0017]
【発明の効果】本発明の光ファイバ用ガラス母材は上記
構成からなり、コア部とクラッド部との界面の近くに塩
素濃度の低い部分が設けられているため、加熱時にこの
部分の粘度が相対的に上がり、コア部への非対称歪みの
影響を小さくすることができる。さらに、コア・クラッ
ド界面での発泡は抑制され製造が容易である。このガラ
ス母材を線引して得られる光ファイバは、コア近傍のク
ラッドが真円度を保ったまま比較的早い時期に固化し、
その後コア部分が固化するため、クラッド部の外周の楕
円の影響がコア部に影響せず、偏波モード分散値の小さ
いものとなる。The glass preform for an optical fiber of the present invention has the above-described structure, and a portion having a low chlorine concentration is provided near the interface between the core portion and the clad portion. As a result, the influence of the asymmetrical strain on the core portion can be reduced. Further, foaming at the interface between the core and the clad is suppressed and the production is easy. The optical fiber obtained by drawing this glass base material is solidified relatively early while the clad near the core maintains roundness,
After that, since the core portion is solidified, the influence of the ellipse on the outer periphery of the cladding portion does not affect the core portion, and the polarization mode dispersion value is small.
【図１】 本発明の光ファイバ用ガラス母材の実施例１
に対応する半径方向の屈折率分布（ａ）と塩素濃度分布
（ｂ）を示すグラフである。FIG. 1 is a first embodiment of a glass preform for an optical fiber according to the present invention.
5 is a graph showing a refractive index distribution (a) and a chlorine concentration distribution (b) in the radial direction corresponding to FIG.
【図２】 本発明の光ファイバ用ガラス母材の実施例２
に対応する半径方向の屈折率分布（ａ）と塩素濃度分布
（ｂ）を示すグラフである。FIG. 2 is a second embodiment of the glass preform for an optical fiber of the present invention.
5 is a graph showing a refractive index distribution (a) and a chlorine concentration distribution (b) in the radial direction corresponding to FIG.
【図３】 本発明の光ファイバ用ガラス母材の実施例３
に対応する半径方向の屈折率分布（ａ）と塩素濃度分布
（ｂ）を示すグラフである。FIG. 3 is a third embodiment of the glass preform for an optical fiber of the present invention.
5 is a graph showing a refractive index distribution (a) and a chlorine concentration distribution (b) in the radial direction corresponding to FIG.
【図４】 従来の光ファイバ用ガラス母材の比較例１に
対応する半径方向の屈折率分布（ａ）と塩素濃度分布
（ｂ）を示すグラフである。FIG. 4 is a graph showing a refractive index distribution (a) and a chlorine concentration distribution (b) in a radial direction corresponding to Comparative Example 1 of a conventional glass preform for an optical fiber.
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｇ０２Ｂ 6/10 Ｇ０２Ｂ 6/10 Ａ Ｆターム(参考） 2H050 AA01 AA09 AB05Z AC71 AD01 4G021 BA02 BA03 EA01 EA03 EB02 EB18 EB19 4G062 AA06 AA07 BB02 CC07 DA08 DB01 DC01 DD01 DE01 DF01 EA01 EA10 EB01 EC01 ED01 EE01 EF01 EG01 FA01 FB01 FC01 FD02 FE01 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ06 JJ07 KK01 KK03 KK05 KK07 KK10 LA03 LB10 MM04 Continued on the front page (51) Int.Cl. 7 Identification code FI Theme coat II (reference) G02B 6/10 G02B 6/10 A F term (reference) 2H050 AA01 AA09 AB05Z AC71 AD01 4G021 BA02 BA03 EA01 EA03 EB02 EB18 EB19 4G062 AA06 AA07 BB02 CC07 DA08 DB01 DC01 DD01 DE01 DF01 EA01 EA10 EB01 EC01 ED01 EE01 EF01 EG01 FA01 FB01 FC01 FD02 FE01 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HHH HH HH HH HH HH HH HH HH HH HH HH KK05 KK07 KK10 LA03 LB10 MM04
Claims (11)
辺にクラッドの一部が形成されたコア部とクラッド部か
らなる石英製光ファイバ用ガラス母材において、半径方
向に塩素ドープによって形成された塩素濃度分布を有
し、該コア部とクラッド部との界面の近くに塩素濃度の
低い部分を有することを特徴とする光ファイバ用ガラス
母材。1. A quartz optical fiber glass preform comprising a core doped with Ge in the center, a core part having a part of the cladding formed around the core, and a cladding part, formed by chlorine doping in the radial direction. A glass preform for optical fibers, characterized by having a chlorine concentration distribution and a portion having a low chlorine concentration near an interface between the core portion and the clad portion.
ド部の界面の外側近傍に存在している請求項１に記載の
光ファイバ用ガラス母材。2. The glass preform for an optical fiber according to claim 1, wherein the portion having a low chlorine concentration exists near the outside of the interface between the core portion and the clad portion.
ラッドの塩素濃度分布において、半径方向内側寄りの部
分にこの外側寄りの部分よりも塩素濃度の低い部分を有
する請求項１に記載の光ファイバ用ガラス母材。3. The chlorine concentration distribution of a clad adjacent to a core forming a core portion according to claim 1, wherein a portion closer to the radially inner side has a portion having a lower chlorine concentration than a portion closer to the outer side. Glass preform for optical fiber.
ラッドの塩素濃度が、該クラッドに隣接するクラッド部
の界面近傍の塩素濃度より低い請求項１に記載の光ファ
イバ用ガラス母材。4. The glass preform for an optical fiber according to claim 1, wherein the chlorine concentration of the cladding adjacent to the core forming the core portion is lower than the chlorine concentration near the interface of the cladding portion adjacent to the cladding.
向に向けて光ファイバ用ガラス母材の径の１０〜５０％
の領域に存在する請求項１乃至４のいずれかに記載の光
ファイバ用ガラス母材。5. The portion having a low chlorine concentration is 10 to 50% of the diameter of the glass base material for an optical fiber in a radial direction from the center.
The glass preform for an optical fiber according to any one of claims 1 to 4, wherein the glass preform is present in the region of (1).
濃度差が、１００ｐｐｍ以上である請求項１乃至５のい
ずれかに記載の光ファイバ用ガラス母材。6. The glass preform for an optical fiber according to claim 1, wherein a difference in chlorine concentration between a portion having a low chlorine concentration and a portion having a high chlorine concentration is 100 ppm or more.
濃度差が、１％以下である請求項１乃至６のいずれかに
記載の光ファイバ用ガラス母材。7. The glass preform for an optical fiber according to claim 1, wherein a difference in chlorine concentration between a portion having a low chlorine concentration and a portion having a high chlorine concentration is 1% or less.
Ｏ2微粒子（スート）を堆積させて得たスート堆積体を
塩素ガス雰囲気中で脱水した後、焼成ガラス化してコア
とクラッドの一部からなるコア部を形成し、透明ガラス
化してコア部材とし、次いで、スート法によってＳｉＯ
2微粒子をコア部材の周囲に、嵩密度が内側から外側に
向って小さくなるように外付けして多孔質ガラス母材と
し、塩素ガス雰囲気中で加熱して透明ガラス化すること
を特徴とする光ファイバ用ガラス母材の製造方法。8. The method according to claim 7, wherein the outer periphery of the core material is formed by a VAD method.
After soot deposits obtained by depositing O 2 fine particles (soot) are dehydrated in a chlorine gas atmosphere, they are fired and vitrified to form a core portion composed of a core and a part of a clad, and are then vitrified to form a core member. And then SiO2 by the soot method
(2) A porous glass base material is formed by externally attaching fine particles around the core member so that the bulk density decreases from the inside toward the outside, and is heated in a chlorine gas atmosphere to form a transparent glass. A method for producing a glass base material for optical fibers.
Ｏ2微粒子（スート）を嵩密度が内側から外側に向って
小さくなるように堆積させて得たスート堆積体を塩素ガ
ス雰囲気中で脱水した後、焼成ガラス化してコアとクラ
ッドの一部からなるコア部を形成し、透明ガラス化して
コア部材とし、次いで、スート法によってＳｉＯ2微粒
子をコア部材の周囲に外付けして多孔質ガラス母材と
し、塩素ガス雰囲気中で加熱して透明ガラス化すること
を特徴とする光ファイバ用ガラス母材の製造方法。9. The method according to claim 9, wherein the outer periphery of the core material is formed by a VAD method.
A soot deposit obtained by depositing O 2 fine particles (soot) such that the bulk density decreases from the inside toward the outside is dehydrated in a chlorine gas atmosphere, and then is baked and vitrified to form a core and a part of the clad. A core portion is formed, vitrified to form a core member, and then SiO 2 fine particles are externally provided around the core member by a soot method to form a porous glass base material, which is heated in a chlorine gas atmosphere to form a vitrified transparent glass. A method for producing a glass preform for an optical fiber, comprising:
ｉＯ2微粒子（スート）を堆積させて得たスート堆積体
を焼成ガラス化してコアとクラッドの一部からなるコア
部材を形成した後、該コア部材に合成石英管を被せ、塩
素ガス雰囲気中で加熱し一体化することを特徴とする光
ファイバ用ガラス母材の製造方法。10. The VAD method is applied to the outer periphery of the core material by S
After a soot deposit obtained by depositing iO 2 fine particles (soot) is fired and vitrified to form a core member composed of a core and a part of a clad, a synthetic quartz tube is put on the core member, and the core member is placed in a chlorine gas atmosphere. A method for producing a glass preform for an optical fiber, comprising heating and integrating.
ファイバ用ガラス母材を線引して作製した光ファイバの
偏波モード分散値が、０．１ｐｓ／ｋｍ1/2以下である
ことを特徴とする光ファイバ。11. The polarization mode dispersion value of an optical fiber produced by drawing the glass preform for an optical fiber according to claim 1 is 0.1 ps / km 1/2 or less. An optical fiber, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000238505A JP2002053344A (en) | 2000-08-07 | 2000-08-07 | Glass preform for optical fiber and optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000238505A JP2002053344A (en) | 2000-08-07 | 2000-08-07 | Glass preform for optical fiber and optical fiber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002053344A true JP2002053344A (en) | 2002-02-19 |
Family
ID=18730196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000238505A Pending JP2002053344A (en) | 2000-08-07 | 2000-08-07 | Glass preform for optical fiber and optical fiber |
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| Country | Link |
|---|---|
| JP (1) | JP2002053344A (en) |
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| JP2010522330A (en) * | 2007-03-22 | 2010-07-01 | ゼネラル・エレクトリック・カンパニイ | Fiber optic sensor for detecting multiple parameters in harsh environments |
| US8565567B2 (en) | 2011-11-23 | 2013-10-22 | Sumitomo Electric Industries, Ltd. | Multi-mode optical fiber |
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2000
- 2000-08-07 JP JP2000238505A patent/JP2002053344A/en active Pending
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| JP2010522330A (en) * | 2007-03-22 | 2010-07-01 | ゼネラル・エレクトリック・カンパニイ | Fiber optic sensor for detecting multiple parameters in harsh environments |
| US8565566B2 (en) | 2011-10-05 | 2013-10-22 | Sumitomo Electric Industries, Ltd. | Multi-mode optical fiber |
| US8565567B2 (en) | 2011-11-23 | 2013-10-22 | Sumitomo Electric Industries, Ltd. | Multi-mode optical fiber |
| WO2016164513A1 (en) * | 2015-04-07 | 2016-10-13 | Corning Incorporated | Low attenuation single mode optical fiber with stress relieving layer, its preform and a method of making it |
| US9772445B2 (en) | 2015-04-07 | 2017-09-26 | Corning Incorporated | Low attenuation fiber with stress relieving layer and a method of making such |
| US9778413B2 (en) | 2015-04-07 | 2017-10-03 | Corning Incorporated | Low attenuation fiber with stress relieving layer and a method of making such |
| CN109791250A (en) * | 2016-09-21 | 2019-05-21 | 康宁股份有限公司 | The optical fiber and forming method thereof of coating variations in refractive index |
| US10146008B2 (en) | 2016-09-21 | 2018-12-04 | Corning Incorporated | Optical fibers having a varying clad index and methods of forming same |
| WO2018093451A3 (en) * | 2016-09-21 | 2018-06-28 | Corning Incorporated | Optical fibers having a varying clad index and methods of forming same |
| JP2019530005A (en) * | 2016-09-21 | 2019-10-17 | コーニング インコーポレイテッド | Optical fiber having varying cladding refractive index and method of forming the same |
| US11125937B2 (en) | 2016-09-21 | 2021-09-21 | Corning Incorporated | Optical fibers having a varying clad index and methods of forming same |
| JP2022020689A (en) * | 2016-09-21 | 2022-02-01 | コーニング インコーポレイテッド | Method of forming optical fiber having varying clad index |
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| CN112679087A (en) * | 2020-12-25 | 2021-04-20 | 中国建筑材料科学研究总院有限公司 | Optical fiber panel and preparation method and application thereof |
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