JP2005060143A - Method of manufacturing optical fiber preform - Google Patents

Method of manufacturing optical fiber preform Download PDF

Info

Publication number
JP2005060143A
JP2005060143A JP2003290068A JP2003290068A JP2005060143A JP 2005060143 A JP2005060143 A JP 2005060143A JP 2003290068 A JP2003290068 A JP 2003290068A JP 2003290068 A JP2003290068 A JP 2003290068A JP 2005060143 A JP2005060143 A JP 2005060143A
Authority
JP
Japan
Prior art keywords
core rod
optical fiber
magnification
cutoff wavelength
fiber 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.)
Granted
Application number
JP2003290068A
Other languages
Japanese (ja)
Other versions
JP4300932B2 (en
Inventor
Sumio Hoshino
寿美夫 星野
Kiichiro Kawasaki
希一郎 川崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP2003290068A priority Critical patent/JP4300932B2/en
Publication of JP2005060143A publication Critical patent/JP2005060143A/en
Application granted granted Critical
Publication of JP4300932B2 publication Critical patent/JP4300932B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

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
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments

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

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical fiber preform by which the variation in the mode field diameter is reduced even when the difference of specific refractive index is varied and the increase in the variation in cutoff wavelength is minimized. <P>SOLUTION: In the method of manufacturing the optical fiber preform, a core rod magnification Ra in which the cutoff wavelength of the optical fiber after being drawn becomes the target value and a core rod magnification Rb in which the mode field diameter becomes the target value are determined from the refractive index distribution of a measured core rod 11, the core rod magnification R is set using both core rod magnification Ra and Rb, and the optical fiber preform is manufactured on the basis of the R. The dependency of the mode field diameter on the specific refractive index is decreased while adjusting the cutoff wavelength to the target value since the optical preform 10 is manufactured on the basis of the core rod magnification R and even when the specific refractive index difference is varied, the variation of the cutoff wavelength is decreased and the increase of the variation of the cutoff wavelength is minimized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

この発明は、光ファイバ母材の製造方法に関するものである。   The present invention relates to a method for manufacturing an optical fiber preform.

コア部とクラッド部とからなるコアロッドを所定の延伸径に延伸して、これをジャケット石英管にロッドインし、同時線引きして光ファイバを製造する技術が開示されている（例えば、特許文献１参照。）。   A technique is disclosed in which an optical fiber is manufactured by drawing a core rod composed of a core part and a clad part to a predetermined drawing diameter, rod-in it to a jacket quartz tube, and drawing it simultaneously (for example, Patent Document 1). reference.).

この技術は、コアロッドの線引予定部分をプリフォームアナライザで測定して屈折率分布を求め、この分布から所定式でＥＳＩ（Ｅｐｕｉｖａｌｅｎｔ Ｓｔｅｐ Ｉｎｄｅｘ）分布の等価的なコア半径を算出する。さらに、このコア半径等を用いて所定式によりコアロッドの延伸径を決定するものである。これにより、従来用いられていた補正係数を用いる必要がなくなり、個人差によらず再現性良くカットオフ波長を制御することができる。   In this technique, a portion to be drawn of a core rod is measured by a preform analyzer to obtain a refractive index distribution, and an equivalent core radius of an ESI (Epivalent Step Index) distribution is calculated from this distribution by a predetermined formula. Further, the core rod extension diameter is determined by a predetermined formula using the core radius and the like. As a result, it is not necessary to use a conventionally used correction coefficient, and the cut-off wavelength can be controlled with good reproducibility regardless of individual differences.

また、コア部材の廃棄量を少なくし、且つカットオフ波長の特性の安定した光ファイバを製造する技術が公開されている（例えば、特許文献２参照。）。   In addition, a technique for manufacturing an optical fiber that reduces the amount of discarded core members and has stable cutoff wavelength characteristics is disclosed (for example, see Patent Document 2).

この技術では、コア部材を分割することにより、コア部材の屈折率分布の変動量を小さく分割する。これにより、屈折率分布の変動が大きな１本のコア部材を、屈折率分布の変動の小さな複数のコア部材にすることができる。   In this technique, by dividing the core member, the fluctuation amount of the refractive index distribution of the core member is divided into small parts. Thereby, one core member with a large fluctuation | variation of refractive index distribution can be made into several core members with a small fluctuation | variation of refractive index distribution.

また、カットオフ波長を精度良く計算する方法が開示されている（例えば、特許文献３参照。）。   Further, a method for calculating the cutoff wavelength with high accuracy is disclosed (for example, see Patent Document 3).

この技術では、光ファイバ用プリフォームの中心から半径０．９５倍以下の範囲までは屈折率測定値を採用し、この範囲を外れて無制限までは一定値を採用するものである。これにより、様々な屈折率分布の形状を有する現実の光ファイバ用プリフォームからでも、再現精度良くカットオフ波長を得ることができる。
特開昭６３−８５０２１号公報（第３頁、第１図） 特開２０００−６３１３８号公報（第５頁、第３図） 特開２００１−２８１０９４号公報（第２頁、第１図） In this technique, a refractive index measurement value is adopted from the center of the optical fiber preform to a radius of 0.95 times or less, and a constant value is adopted from this range until unlimited. As a result, the cut-off wavelength can be obtained with high reproducibility even from actual optical fiber preforms having various refractive index distribution shapes.
JP-A-63-85021 (page 3, FIG. 1) JP 2000-63138 A (page 5, FIG. 3) Japanese Patent Laid-Open No. 2001-281094 (2nd page, FIG. 1)

ところで、モードフィールド径の変動が大きいと光ファイバの接続の際の接続損失が大きくなるため小さい方が望ましいが、特許文献１で示した技術によると、カットオフ波長の変動は低減できるもののモードフィールド径については考慮されていない。これは、コアロッドの段階で測定した屈折率分布からロッド径を決定する際に、カットオフ波長が目標値となるようにコアロッド倍率を決定していたため、結果的にモードフィールド径はコア部とクラッド部の比屈折率差（ΔＮ）のばらつきに対応して変動が大きくなってしまう。   By the way, when the variation in the mode field diameter is large, the connection loss at the time of connecting the optical fiber is large. Therefore, it is desirable that the mode field diameter is small. The diameter is not considered. This is because when determining the rod diameter from the refractive index distribution measured at the core rod stage, the core rod magnification was determined so that the cutoff wavelength would be the target value. The fluctuation increases corresponding to the variation in the relative refractive index difference (ΔN) of the part.

また、特許文献２で示した技術によると、カットオフ波長の変動を低減することはできるものの、モードフィールド径の変動については低減することがむずかしい。   Further, according to the technique shown in Patent Document 2, although it is possible to reduce the variation of the cutoff wavelength, it is difficult to reduce the variation of the mode field diameter.

また、特許文献３で示した技術によると、カットオフ波長を精度良く計算で推定できるものの、モードフィールド径については記載されていない。   Further, according to the technique disclosed in Patent Document 3, although the cutoff wavelength can be estimated with high accuracy, the mode field diameter is not described.

本発明の目的は、比屈折率差の変動があってもモードフィールド径の変動を低減し、同時にカットオフ波長の変動の増加を最小限に抑えることのできる光ファイバ母材の製造方法を提供することにある。   An object of the present invention is to provide a method of manufacturing an optical fiber preform that can reduce fluctuations in the mode field diameter even when there are fluctuations in the relative refractive index difference, and at the same time minimize the increase in fluctuations in the cutoff wavelength There is to do.

本発明にかかる光ファイバ母材の製造方法によれば、測定したコアロッドの屈折率分布から、線引後の光ファイバのカットオフ波長が目標値となるコアロッド倍率と、モードフィールド径が目標値となるコアロッド倍率を求め、両コアロッド倍率を用いて目標コアロッド倍率を求める。そして、この目標コアロッド倍率により光ファイバ母材を製造するので、カットオフ波長を目標値に合わせつつ、モードフィールド径の比屈折率差への依存性を小さくすることができ、比屈折率差の変動があってもモードフィールド径の変動を低減するとともにカットオフ波長の変動の増加を最小限に抑えることができる。   According to the optical fiber preform manufacturing method according to the present invention, from the measured refractive index distribution of the core rod, the core rod magnification at which the cut-off wavelength of the optical fiber after drawing is a target value, and the mode field diameter is the target value. And the target core rod magnification is obtained using both core rod magnifications. And since the optical fiber preform is manufactured with this target core rod magnification, the dependence of the mode field diameter on the relative refractive index difference can be reduced while adjusting the cutoff wavelength to the target value, and the relative refractive index difference can be reduced. Even if there is a variation, the variation in the mode field diameter can be reduced and the increase in the variation in the cutoff wavelength can be minimized.

前述した目的を達成するために、本発明にかかる光ファイバ母材の製造方法は、コアロッドの屈折率分布を長手方向の複数の測定位置で測定し、前記測定位置毎に屈折率分布の測定結果から光ファイバとなったときのカットオフ波長が目標値となるコアロッド倍率（以下、Ｒａという）とモードフィールド径（以下、ＭＦＤという）が目標値となるコアロッド倍率（以下、Ｒｂという）をそれぞれ求め、ＲａとＲｂから前記コアロッドに対する目標コアロッド倍率（以下、Ｒという）を設定し、Ｒに基づいて光ファイバ母材を製造することを特徴としている
このように構成された光ファイバ母材の製造方法においては、長手方向の複数の測定位置で測定したコアロッドの屈折率分布から、線引後の光ファイバのＲａとＲｂを求め、これらＲａ、Ｒｂを用いてＲを求める。そして、このＲにより光ファイバ母材を製造するので、カットオフ波長を目標値に合わせつつ、モードフィールド径の比屈折率差への依存性を小さくすることができ、比屈折率差の変動があってもモードフィールド径の変動を低減するとともにカットオフ波長の変動の増加を最小限に抑えることができる。なお、ここで、コアロッド倍率とは、光ファイバ母材の外径／コアロッドの外径である。 In order to achieve the above-described object, the optical fiber preform manufacturing method according to the present invention measures the refractive index distribution of the core rod at a plurality of measurement positions in the longitudinal direction, and the measurement result of the refractive index distribution at each measurement position. The core rod magnification (hereinafter referred to as Ra) at which the cutoff wavelength when the optical fiber becomes an optical fiber becomes a target value and the core rod magnification (hereinafter referred to as Rb ) at which the mode field diameter (hereinafter referred to as MFD) becomes a target value are obtained. A target core rod magnification (hereinafter referred to as R) for the core rod is set from Ra and Rb , and an optical fiber preform is manufactured based on R. A method of manufacturing an optical fiber preform configured as described above in, the refractive index distribution of the core rod was measured at a plurality of measurement positions in the longitudinal direction to obtain the Ra and Rb of the after drawing the optical fiber, these R Obtains the R with Rb. Since the optical fiber preform is manufactured by this R , the dependence of the mode field diameter on the relative refractive index difference can be reduced while adjusting the cutoff wavelength to the target value, and the fluctuation of the relative refractive index difference can be reduced. Even in such a case, it is possible to reduce the variation of the mode field diameter and minimize the increase of the variation of the cutoff wavelength. Here, the core rod magnification is the outer diameter of the optical fiber preform / the outer diameter of the core rod .

また、本発明にかかる光ファイバ母材の製造方法は、Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの関係式において、Ｋ値、ＭＦＤ、カットオフ波長の関係を求め、その関係から最適Ｋ値を決めることを特徴としている。 The optical fiber preform manufacturing method according to the present invention obtains the relationship between the K value, MFD, and cutoff wavelength in the relational expression R = (1-K) × Ra + K × Rb, and determines the optimum K value from the relationship. It is characterized by determining .

このように構成された光ファイバ母材の製造方法においては、係数Ｋを小さな値に設定して製造すると、カットオフ波長が目標値に近づくためカットオフ波長の製造ばらつきが小さくなる。一方、係数Ｋを大きい値に設定して製造すると、モードフィールド径が目標値に近づくことになって、モードフィールド径の製造ばらつきが小さくなる傾向がある。そこで、Ｋ値、ＭＦＤ、カットオフ波長の関係を求め、その関係から最適Ｋ値を決めることが望ましい。 In the manufacturing method of the optical fiber preform configured as described above, when the coefficient K is set to a small value, the cutoff wavelength approaches the target value, so that the manufacturing variation of the cutoff wavelength is reduced. On the other hand, when manufacturing with the coefficient K set to a large value, the mode field diameter tends to approach the target value, and the manufacturing variation of the mode field diameter tends to be small. Therefore, it is desirable to obtain the relationship between the K value, MFD, and cutoff wavelength and determine the optimum K value from the relationship.

また、本発明にかかる光ファイバ母材の製造方法は、前記関係式Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの係数Ｋが０．４以下であることが望ましい。   In the method for manufacturing an optical fiber preform according to the present invention, the coefficient K of the relational expression R = (1−K) × Ra + K × Rb is preferably 0.4 or less.

このように構成された光ファイバ母材の製造方法においては、関係式Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの係数Ｋが小さい領域では、カットオフ波長のばらつきはさほど増加せず、且つモードフィールド径のばらつきが比較的大きく改善されることから、Ｋ＝０．４以下とした。   In the optical fiber preform manufacturing method configured as described above, the variation in the cutoff wavelength does not increase so much in the region where the coefficient K of the relational expression R = (1−K) × Ra + K × Rb is small, and the mode. Since the variation in field diameter is relatively large, K = 0.4 or less.

また、本発明にかかる光ファイバ母材の製造方法は、前記カットオフ波長が目標値になるコアロッド倍率を、有限要素法により求めることが望ましい。   Further, in the method for manufacturing an optical fiber preform according to the present invention, it is desirable to obtain a core rod magnification at which the cutoff wavelength becomes a target value by a finite element method.

このように構成された光ファイバ母材の製造方法においては、モードフィールド径のばらつき低減を優先する場合は、カットオフ波長のばらつきが増加するため、カットオフ波長の計算方法は精度の高いものが必要である。そこで、有限要素法を用いて、高精度な計算を行うようにした。   In the optical fiber preform manufacturing method configured as described above, when priority is given to reducing variation in mode field diameter, variation in cutoff wavelength increases. is necessary. Therefore, the finite element method was used to perform highly accurate calculations.

以下、本発明に係る光ファイバ母材の製造方法の実施の形態を図面に基づいて詳細に説明する。図１は本発明に係る光ファイバ母材の製造方法を示すフローチャート、図２はコアロッド倍率の説明図である。   Embodiments of a method for manufacturing an optical fiber preform according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart showing a method of manufacturing an optical fiber preform according to the present invention, and FIG. 2 is an explanatory diagram of core rod magnification.

本発明では、コア部とクラッド部の比屈折率差（以後この項においては、「ΔＮ」で示す。）の変動があってもモードフィールド径の変動を低減し、同時にカットオフ波長の変動の増加を最小限に抑えて光ファイバ母材を製造する方法を提供する。   In the present invention, even if there is a variation in the relative refractive index difference between the core and the cladding (hereinafter referred to as “ΔN” in this section), the variation in the mode field diameter is reduced, and at the same time, the variation in the cutoff wavelength. A method of manufacturing an optical fiber preform with minimal increase is provided.

このように、カットオフ波長とモードフィールド径の両方を目標とする値にするためには、まずΔＮが適正である必要がある。しかし、製造上の変動でΔＮが適正値からずれる場合がある。このような場合に、従来はカットオフ波長を目標値とするようなコアロッド倍率を決定して光ファイバ母材の製造を行っていた。   Thus, in order to set both the cutoff wavelength and the mode field diameter to the target values, ΔN must first be appropriate. However, ΔN may deviate from an appropriate value due to manufacturing variations. In such a case, conventionally, the optical fiber preform is manufactured by determining the core rod magnification with the cutoff wavelength as a target value.

その結果、ΔＮが適正値より大きい場合にはモードフィールド径が目標値より小さくなり、ΔＮが適正値より小さい場合にはモードフィールド径が適正値より大きくなっていた。   As a result, when ΔN is larger than the proper value, the mode field diameter is smaller than the target value, and when ΔN is smaller than the proper value, the mode field diameter is larger than the proper value.

そこで、本発明では、カットオフ波長の目標値になるコアロッド倍率と、モードフィールド径の目標値になるコアロッド倍率を求め、両コアロッド倍率を適当な比率で平均して目標コアロッド倍率を求めて、光ファイバ母材の製造を行うこととした。   Therefore, in the present invention, the core rod magnification that becomes the target value of the cutoff wavelength and the core rod magnification that becomes the target value of the mode field diameter are obtained, and the target core rod magnification is obtained by averaging both core rod magnifications at an appropriate ratio. The fiber preform was manufactured.

すなわち、図１に示すように、本発明に係る光ファイバ母材の製造方法では、まず使用するコアロッドの屈折率分布を測定する（ステップＳ１）。次に、屈折率分布の測定結果から光ファイバとなったときのカットオフ波長の目標値を設定し（ステップＳ２）、カットオフ波長が目標値となるコアロッド倍率Ｒａを算出する（ステップＳ３）。このとき、有限要素法を用いて高精度で算出する（ステップＳ４）。   That is, as shown in FIG. 1, in the optical fiber preform manufacturing method according to the present invention, first, the refractive index distribution of the core rod to be used is measured (step S1). Next, the target value of the cutoff wavelength when the optical fiber is obtained is set from the measurement result of the refractive index distribution (step S2), and the core rod magnification Ra at which the cutoff wavelength becomes the target value is calculated (step S3). At this time, calculation is performed with high accuracy using the finite element method (step S4).

ここで、コアロッド倍率とは、図２に示すように、コアロッド１１の周囲にクラッド部１２を付けた光ファイバ母材１０の外径Ｄと、コアロッド１１の外径ｄの比であり、Ｄ／ｄで与えられる。   Here, the core rod magnification is a ratio of the outer diameter D of the optical fiber preform 10 with the cladding portion 12 around the core rod 11 and the outer diameter d of the core rod 11 as shown in FIG. It is given by d.

一方、モードフィールド径の目標値を設定し（ステップＳ５）、モードフィールド径が目標値となるコアロッド倍率Ｒｂを求める（ステップＳ６）。そして、カットオフ波長とモードフィールド径の重視の割合を考慮して、係数Ｋを設定する（ステップＳ７）。   On the other hand, the target value of the mode field diameter is set (step S5), and the core rod magnification Rb at which the mode field diameter becomes the target value is obtained (step S6). Then, the coefficient K is set in consideration of the importance of the cutoff wavelength and the mode field diameter (step S7).

ここで、係数Ｋは、後述する式（１）においてモードフィールド径を重視する割合である。図３には、係数Ｋと、カットオフ波長およびモードフィールド径の標準偏差比率の関係の一例が示されている。図３に示すように、係数Ｋが小さい領域ではカットオフ波長のばらつきはさほど増加せず、一方で、モードフィールド径のばらつきは大きく改善されることから、係数Ｋは、０．４以下に設定するのが望ましい。   Here, the coefficient K is a ratio in which the mode field diameter is emphasized in the equation (1) described later. FIG. 3 shows an example of the relationship between the coefficient K and the standard deviation ratio of the cutoff wavelength and the mode field diameter. As shown in FIG. 3, in the region where the coefficient K is small, the variation in the cut-off wavelength does not increase so much. On the other hand, the variation in the mode field diameter is greatly improved, so the coefficient K is set to 0.4 or less. It is desirable to do.

次に、カットオフ波長が目標値になるコアロッド倍率Ｒａと、モードフィールド径が目標値になるコアロッド倍率Ｒｂから、次式（１）により目標コアロッド倍率Ｒを求める（ステップＳ８）。
Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂ……（１）
そして、この目標コアロッド倍率Ｒに基づいて光ファイバ母材１０の製造を行う。 Next, the target core rod magnification R is obtained from the following equation (1) from the core rod magnification Ra at which the cutoff wavelength is the target value and the core rod magnification Rb at which the mode field diameter is the target value (step S8).
R = (1-K) × Ra + K × Rb (1)
Then, the optical fiber preform 10 is manufactured based on the target core rod magnification R.

次に、具体例について説明する。   Next, a specific example will be described.

コアロッドの段階で、プリフォームアナライザーにより屈折率分布を測定し、光ファイバのカットオフ波長の目標が１２６０ｎｍになるコア径と、モードフィールド径の目標が９．２μｍになるコア径をそれぞれ計算により求めた。   At the core rod stage, the refractive index distribution is measured by a preform analyzer, and the core diameter at which the target of the cutoff wavelength of the optical fiber is 1260 nm and the core diameter at which the target of the mode field diameter is 9.2 μm are obtained by calculation. It was.

その結果、カットオフ波長が１２６０ｎｍになるためのコア径は８．１０μｍと算出され、モードフィールド径が９．２μｍとなるコア径は７．９０μｍと算出された。   As a result, the core diameter for the cutoff wavelength of 1260 nm was calculated to be 8.10 μm, and the core diameter for the mode field diameter of 9.2 μm was calculated to be 7.90 μm.

なお、ここではコアロッド倍率ではなくコア径に付いて記載したが、コア径に付いてもコアロッド倍率と同様に考えることができる。すなわち、目標のカットオフ波長になるコア径ａaと、目標のモードフィールド径になるコア径ａbから、目標コア径ａを、ａ＝（１−Ｋ’）×ａa＋Ｋ’ａbで求めてもよい。ここでＫ’は係数である。 Here, the core diameter is described instead of the core rod magnification, but the core diameter can be considered in the same manner as the core rod magnification. That is, the target core diameter a may be obtained by a = (1−K ′) × aa + K′ab from the core diameter aa that becomes the target cutoff wavelength and the core diameter ab that becomes the target mode field diameter. Here, K ′ is a coefficient.

両コア径を８：２で平均して、線引後にコア径が８．０６μｍとなるようにコアロッド１１の周囲にクラッド部１２を製造した。このようにして光ファイバ母材１０を製造した結果、モードフィールド径のロット間の変動は標準偏差０．１０μｍとなり、カットオフ波長のロット間の変動は標準偏差２０ｎｍとなった。   The clad part 12 was manufactured around the core rod 11 so that both core diameters were averaged at 8: 2 and the core diameter was 8.06 μm after drawing. As a result of manufacturing the optical fiber preform 10 in this way, the variation of the mode field diameter between lots was a standard deviation of 0.10 μm, and the variation of the cutoff wavelength between lots was a standard deviation of 20 nm.

比較例として、従来のように、カットオフ波長のみを考慮して光ファイバ母材１０を製造した場合を示す。   As a comparative example, the case where the optical fiber preform 10 is manufactured in consideration of only the cut-off wavelength as in the prior art is shown.

すなわち、コアロッドの段階で屈折率分布を測定し、その結果からカットオフ波長１２６０ｎｍになるコア径を算出し、線引後にこの値となるようにコアロッド１１の外側にクラッド部１２を形成して製造した。その結果、モードフィールド径のロット間変動は標準偏差０．１２μｍとなり、カットオフ波長のロット間変動は標準偏差で２０ｎｍとなった。   That is, the refractive index distribution is measured at the stage of the core rod, the core diameter at which the cutoff wavelength is 1260 nm is calculated from the result, and the clad portion 12 is formed outside the core rod 11 so as to have this value after drawing. did. As a result, the lot-to-lot variation in mode field diameter was 0.12 μm, and the lot-to-lot variation in cutoff wavelength was 20 nm in standard deviation.

以上、前述した光ファイバ母材の製造方法によれば、測定したコアロッドの屈折率分布から、線引後の光ファイバのカットオフ波長が目標値となるコアロッド倍率Ｒａと、モードフィールド径が目標値となるコアロッド倍率Ｒｂを求め、両コアロッド倍率Ｒａ、Ｒｂを用いて目標コアロッド倍率Ｒを求める。そして、この目標コアロッド倍率Ｒにより光ファイバ母材１０を製造するので、カットオフ波長を目標値に合わせつつ、モードフィールド径のΔＮへの依存性を小さくすることができ、ΔＮの変動があってもモードフィールド径の変動を低減するとともにカットオフ波長の変動の増加を最小限に抑えることができる。   As described above, according to the optical fiber preform manufacturing method described above, from the measured refractive index distribution of the core rod, the core rod magnification Ra at which the cutoff wavelength of the optical fiber after drawing is the target value and the mode field diameter are the target values. The core rod magnification Rb is obtained, and the target core rod magnification R is obtained using both the core rod magnifications Ra and Rb. Since the optical fiber preform 10 is manufactured with the target core rod magnification R, the dependence of the mode field diameter on ΔN can be reduced while adjusting the cutoff wavelength to the target value, and there is a variation in ΔN. In addition, the variation in the mode field diameter can be reduced and the increase in the variation in the cut-off wavelength can be minimized.

また、関係式Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの係数Ｋを０．４以下としたので、カットオフ波長のばらつきはさほど増加せず、且つモードフィールド径のばらつきが比較的大きく改善することができる。   Further, since the coefficient K of the relational expression R = (1−K) × Ra + K × Rb is set to 0.4 or less, the variation in the cut-off wavelength does not increase so much and the variation in the mode field diameter is relatively greatly improved. be able to.

また、カットオフ波長の計算方法として有限要素法を採用することにより、モードフィールド径のばらつき低減を優先してカットオフ波長のばらつきが増加した場合でも、高精度な計算を行うことができる。   Further, by adopting the finite element method as a calculation method of the cut-off wavelength, high-precision calculation can be performed even when the cut-off wavelength variation is increased by giving priority to reducing the variation of the mode field diameter.

なお、本発明の光ファイバ母材の製造方法は、前述した実施形態に限定されるものでなく、適宜な変形、改良等が可能である。   In addition, the manufacturing method of the optical fiber preform of the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.

例えば、前述した各実施形態では、コアロッド１１として純粋にコアからなる場合について説明したが、コアとクラッド（第１クラッド）からなるものをコアロッドとしても良い。この場合には、コアロッドの周囲にジャケット部を付けて光ファイバ母材を製造することになる。   For example, in each of the above-described embodiments, the case where the core rod 11 is made of a pure core has been described. However, a core rod and a clad (first clad) may be used as the core rod. In this case, an optical fiber preform is manufactured by attaching a jacket portion around the core rod.

また、上述した具体例では、係数Ｋを０．２とした場合について説明したが、カットオフ波長を重視するのか、あるいはモードフィールド径を重視するのかによって、係数Ｋは調整可能である。   In the above-described specific example, the case where the coefficient K is set to 0.2 has been described. However, the coefficient K can be adjusted depending on whether the cutoff wavelength is important or the mode field diameter is important.

本発明に係る光ファイバ母材の製造方法の実施形態を示すフローチャートである。It is a flowchart which shows embodiment of the manufacturing method of the optical fiber preform which concerns on this invention. コアロッド倍率の説明図である。It is explanatory drawing of a core rod magnification. 係数Ｋと、モードフィールド径の標準偏差比率およびカットオフ波長の標準偏差比率との関係を示すグラフである。It is a graph which shows the relationship between the coefficient K, the standard deviation ratio of a mode field diameter, and the standard deviation ratio of a cutoff wavelength.

符号の説明Explanation of symbols

１０ 光ファイバ母材
１１ コアロッド
Ｒａ カットオフ波長が目標値となるコアロッド倍率
Ｒｂ モードフィールド径が目標値となるコアロッド倍率
Ｒ 目標コアロッド倍率 10 Optical fiber preform 11 Core rod Ra Core rod magnification Rb at which cutoff wavelength is a target value Core rod magnification at which mode field diameter is a target value R Target core rod magnification

Claims (4)

コアロッドの屈折率分布を長手方向の複数の測定位置で測定し、前記測定位置毎に屈折率分布の測定結果から光ファイバとなったときのカットオフ波長が目標値となるコアロッド倍率（以下、Ｒａという）とモードフィールド径（以下、ＭＦＤという）が目標値となるコアロッド倍率（以下、Ｒｂという）をそれぞれ求め、ＲａとＲｂから前記コアロッドに対する目標コアロッド倍率（以下、Ｒという）を設定し、Ｒに基づいて光ファイバ母材を製造することを特徴とする光ファイバ母材の製造方法。 The refractive index distribution of the core rod is measured at a plurality of measurement positions in the longitudinal direction, and the core rod magnification (hereinafter referred to as Ra below) at which the cutoff wavelength when the optical fiber is obtained from the measurement result of the refractive index distribution at each measurement position becomes the target value. And a core rod magnification (hereinafter referred to as Rb ) at which the mode field diameter (hereinafter referred to as MFD) is a target value, respectively, and a target core rod magnification (hereinafter referred to as R) for the core rod is set from Ra and Rb. An optical fiber preform is produced based on the above, and a method for producing an optical fiber preform. Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの関係式において、Ｋ値、ＭＦＤ、カットオフ波長の関係を求め、その関係から最適Ｋ値を決めることを特徴とする請求項１記載の光ファイバ母材の製造方法。 2. The optical fiber mother unit according to claim 1 , wherein in the relational expression of R = (1-K) * Ra + K * Rb, the relationship between the K value, MFD, and cutoff wavelength is obtained, and the optimum K value is determined from the relationship. A method of manufacturing the material. 前記関係式Ｒ＝（１−Ｋ）×Ｒａ＋Ｋ×Ｒｂの係数Ｋが０．４以下であることを特徴とする請求項２記載の光ファイバ母材の製造方法。 3. A method of manufacturing an optical fiber preform according to claim 2 , wherein a coefficient K of the relational expression R = (1-K) * Ra + K * Rb is 0.4 or less. 前記カットオフ波長が目標値になるコアロッド倍率を、有限要素法により求めることを特徴とする請求項１記載の光ファイバ母材の製造方法。 2. The method of manufacturing an optical fiber preform according to claim 1, wherein a core rod magnification at which the cutoff wavelength is a target value is obtained by a finite element method.
JP2003290068A 2003-08-08 2003-08-08 Optical fiber preform manufacturing method Expired - Fee Related JP4300932B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2003290068A JP4300932B2 (en) 2003-08-08 2003-08-08 Optical fiber preform manufacturing method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2003290068A JP4300932B2 (en) 2003-08-08 2003-08-08 Optical fiber preform manufacturing method

Publications (2)

Publication Number Publication Date
JP2005060143A true JP2005060143A (en) 2005-03-10
JP4300932B2 JP4300932B2 (en) 2009-07-22

Family

ID=34368212

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2003290068A Expired - Fee Related JP4300932B2 (en) 2003-08-08 2003-08-08 Optical fiber preform manufacturing method

Country Status (1)

Country Link
JP (1) JP4300932B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019178030A (en) * 2018-03-30 2019-10-17 古河電気工業株式会社 Method for drawing core preform, method for manufacturing optical fiber preform and method for manufacturing optical fiber

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019178030A (en) * 2018-03-30 2019-10-17 古河電気工業株式会社 Method for drawing core preform, method for manufacturing optical fiber preform and method for manufacturing optical fiber
JP7012411B2 (en) 2018-03-30 2022-02-14 古河電気工業株式会社 A method for stretching a core base material, a method for manufacturing an optical fiber base material, and a method for manufacturing an optical fiber.

Also Published As

Publication number Publication date
JP4300932B2 (en) 2009-07-22

Similar Documents

Publication Publication Date Title
JP5636151B2 (en) Multi-wavelength, multimode optical fiber
JP2002318315A (en) Optical fiber and method for manufacturing the same
JPWO2004092794A1 (en) Optical fiber
US9739935B2 (en) Optical fiber and manufacturing method thereof
JP7019617B2 (en) Optical fiber and manufacturing method of optical fiber
JP6393338B2 (en) Optical fiber and manufacturing method thereof
CN111801609B (en) Optical fiber
CN114993282B (en) Loop tail fiber compensation method of fiber-optic gyroscope and fiber length compensator
JPH1164665A (en) Optical fiber
JP4300932B2 (en) Optical fiber preform manufacturing method
JP2009209039A (en) Photonic bandgap optical fiber
CN110914726B (en) Optical fiber and method for manufacturing the same
NL8200149A (en) OPTICAL FIBER AND METHOD OF MANUFACTURING THE SAME
US8689587B2 (en) Polarization controlling optical fiber preform and preform fabrication methods
US6678451B2 (en) Multimode optical fiber having a structure to reduce scattering loss
JP2965236B2 (en) Manufacturing method of preform for optical fiber
JP2002293563A (en) Method for producing optical fiber preform
WO2019159719A1 (en) Optical fiber
US20140086544A1 (en) Optical fiber
JP7012411B2 (en) A method for stretching a core base material, a method for manufacturing an optical fiber base material, and a method for manufacturing an optical fiber.
JP4730130B2 (en) Optical fiber preform manufacturing method and optical fiber manufacturing method
CN211086681U (en) Polarization maintaining optical fiber
JP2005283771A (en) Distributed refractive index type rod lens and optical component
US20150362670A1 (en) Bend compensation in telecommunications optical fibers
JPH1121142A (en) Optical fiber production and optical fiber

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20051104

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20080716

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20080723

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20080919

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20090331

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120501

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Ref document number: 4300932

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20090413

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130501

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140501

Year of fee payment: 5

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees