JP2000206357A - Optical fiber coupling method - Google Patents

Optical fiber coupling method

Info

Publication number
JP2000206357A
JP2000206357A JP11005650A JP565099A JP2000206357A JP 2000206357 A JP2000206357 A JP 2000206357A JP 11005650 A JP11005650 A JP 11005650A JP 565099 A JP565099 A JP 565099A JP 2000206357 A JP2000206357 A JP 2000206357A
Authority
JP
Japan
Prior art keywords
optical fiber
core diameter
diameter
core
optical
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
Application number
JP11005650A
Other languages
Japanese (ja)
Inventor
Yuichi Masuda
裕一 増田
Shinichi Kamo
信一 加茂
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.)
NEC Engineering Ltd
Original Assignee
NEC Engineering 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 NEC Engineering Ltd filed Critical NEC Engineering Ltd
Priority to JP11005650A priority Critical patent/JP2000206357A/en
Publication of JP2000206357A publication Critical patent/JP2000206357A/en
Pending legal-status Critical Current

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Abstract

PROBLEM TO BE SOLVED: To eliminate a photoreceiving element in a joining part, suppress a joining loss to the lowermost, and attain productivity and economy equivalent to the case where optical fibers having the same core diameters are fused. SOLUTION: A tapered part 2' is formed by extending an end part of an optical fiber 2 having a large core diameter with thermal working so that a core diameter of the optical fiber 2 having the large core diameter is made equal to a core diameter of an optical fiber 1 having a small core diameter, and a free end of the tapered part 2' is fused to a free end of the optical fiber 1 having the small core diameter to align axial centers of the both optical fibers 1, 2.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、光ファイバ結合方
法に関し、特に、石英系ガラス、多成分系ガラス、及び
プラスチック等の材料により形成され、コア径が異なる
光ファイバの結合方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber coupling method, and more particularly to a method for coupling optical fibers formed of a material such as quartz-based glass, multi-component glass, and plastic and having different core diameters.

【0002】[0002]

【従来の技術及びその課題】電気通信ネットワークに使
用される光ファイバケーブルには多種多様な製品が提供
されている。通常、ネットワークを構築する際には、共
通の伝搬モード及び屈折率、機械的仕様を満足する光フ
ァイバ同士を結合するが、光送信部または光受信部の機
器が必要とするデータ通信を実現する上で上記共通仕様
を満足できない場合がある。
2. Description of the Related Art A wide variety of products are provided for fiber optic cables used in telecommunications networks. Normally, when constructing a network, optical fibers satisfying a common propagation mode, refractive index, and mechanical specifications are coupled to each other, but data communication required by devices of an optical transmission unit or an optical reception unit is realized. The above common specifications may not be satisfied above.

【0003】このような場合には、コア径が互いに異な
る光ファイバを結合する必要が生ずることがあり、従
来、単一または複数のレンズをファイバ間に配置し、集
光技術を用いて光結合することが行われている。
In such a case, it may be necessary to couple optical fibers having different core diameters. Conventionally, a single or a plurality of lenses are arranged between the fibers, and the optical coupling is performed by using a condensing technique. That is being done.

【0004】しかし、この場合、理想的な集光状態を実
現したとしても、光入射面における光の反射を完全に防
止することができないため、光結合ロスが生ずるととも
に、レンズ定数やピッチを様々な光ファイバに合わせて
選択する必要があるため、生産性、経済性において問題
があった。
[0004] However, in this case, even if an ideal light-collecting state is realized, it is not possible to completely prevent the reflection of light on the light incident surface, so that an optical coupling loss occurs and the lens constant and the pitch vary. There is a problem in productivity and economy because it is necessary to select an optical fiber according to a suitable optical fiber.

【0005】また、コア径が互いに異なる光ファイバを
直接融着した場合には、面積比の2乗に比例した結合損
失が発生するという問題があった。
Further, when optical fibers having different core diameters are directly fused, there is a problem that a coupling loss proportional to the square of the area ratio occurs.

【0006】上記問題を解決するため、特開平4−98
206号公報には、ドーピング拡散部でコア径を大きく
し、コア径の異なった光ファイバを共通のコア径に変換
したコネクタで結合する技術が開示されている。
To solve the above problem, Japanese Patent Laid-Open Publication No. Hei 4-98
No. 206 discloses a technique in which a core diameter is increased in a doping diffusion portion, and optical fibers having different core diameters are connected with a connector having a common core diameter.

【0007】この結合方法では、コアまたはクラッドに
ドーピング剤がドープされ、コア径またはコアとクラッ
ドの比屈折率差が互いに異なる石英系シングルモード光
ファイバ同士を融着接続し、前記融着接続部付近を該光
ファイバの非溶融温度範囲で局所的に加熱して、前記融
着接続部付近のドーピング剤を拡散させた光ファイバの
ドーピング剤の加熱拡散部以外の部分を整端面としてい
る。
In this coupling method, a doping agent is doped into the core or the clad, and the silica single mode optical fibers having different core diameters or different relative refractive indices between the core and the clad are fusion-spliced to each other. The vicinity is locally heated within the non-melting temperature range of the optical fiber, and a portion other than the heated and diffused portion of the dopant of the optical fiber in which the dopant is diffused near the fusion spliced portion is defined as an end face.

【0008】しかし、本従来例においては、コアまたは
クラッドにドーピング剤をドープすることが必要であっ
て、またコネクタによる結合の場合には、整端面でのコ
アの軸ずれや微小な空隙によるフレネル反射等の損失が
発生するという問題があった。
However, in this conventional example, it is necessary to dope the core or the clad with a doping agent, and in the case of coupling by a connector, the Fresnel due to the core misalignment at the trimmed face and the minute gap. There is a problem that loss such as reflection occurs.

【0009】一方、特開昭54−61946号公報に
は、コア径の大きい光ファイバをテーパ状にすること
で、コア径の異なる光ファイバを共通のコア径に変換
し、かつ接合部に受光素子を設け、テーパ傾斜が伝送光
の臨界角を超えることを特徴とし、接合損失を接合部の
受光素子で補う技術が開示されている。この技術は、特
に、単線双方向伝送を行う光ファイバにおいて、送信光
と受信光を分離する際の損失を十分に小さくした光ファ
イバ結合装置を提供するものである。
On the other hand, Japanese Patent Application Laid-Open No. 54-61946 discloses that an optical fiber having a large core diameter is tapered so that optical fibers having different core diameters are converted into a common core diameter, and light is received at a joint. A technology is disclosed in which an element is provided, and a taper inclination exceeds a critical angle of transmission light, and a joining loss is compensated for by a light receiving element at a junction. This technique is to provide an optical fiber coupling device in which loss in separating transmission light and reception light is sufficiently reduced, particularly in an optical fiber that performs single-wire bidirectional transmission.

【0010】しかし、この従来例においては、コア径の
大きい光ファイバ内を伝送される光の入射角が臨界角を
超えて外部に出力されるようにテーパ状に加工するた
め、接合部に受光素子を設ける必要があるという問題が
あった。
However, in this conventional example, since the light transmitted through the optical fiber having a large core diameter is processed into a tapered shape so that the angle of incidence of the light exceeds the critical angle and is output to the outside, the light is received at the joint. There is a problem that an element needs to be provided.

【0011】そこで、本発明は上記従来の技術における
問題点に鑑みてなされたものであって、接合部に受光素
子を設ける必要がなく、接合損失を最小限に押さえると
ともに、コア径が同一の光ファイバを融着する場合と同
等の生産性、経済性を達成することのできる光ファイバ
結合方法を提供することを目的とする。
Therefore, the present invention has been made in view of the above-mentioned problems in the prior art, and it is not necessary to provide a light receiving element at a joint, so that joint loss can be minimized and the core diameter is the same. It is an object of the present invention to provide an optical fiber coupling method capable of achieving the same productivity and economy as in the case where optical fibers are fused.

【0012】[0012]

【課題を解決するための手段】上記目的を達成するた
め、請求項1記載の発明は、コア径の大きい光ファイバ
のコア径がコア径の小さい光ファイバのコア径と等しく
なるまで、該コア径の大きい光ファイバの端部を加熱加
工により伸張してテーパ部を形成し、両光ファイバのコ
アの軸芯が一致するように、前記テーパ部の開放端を前
記コア径の小さい光ファイバの開放端に融着することを
特徴とする。
In order to achieve the above-mentioned object, the invention according to the first aspect is directed to a method in which the core diameter of an optical fiber having a large core diameter is equal to the core diameter of an optical fiber having a small core diameter. The end of the large-diameter optical fiber is stretched by heating to form a tapered portion, and the open end of the tapered portion is adjusted so that the axes of the cores of both optical fibers coincide with each other. It is characterized by being fused to the open end.

【0013】そして、請求項1記載の発明によれば、コ
ア径の大きい光ファイバ内を伝送される全ての光が臨界
角を超えないでコア径の小さい光ファイバに伝搬される
ように、前記コア径の大きい光ファイバの開口数を選択
することにより、接合部に受光素子を設ける必要がな
く、接合損失を最小限に押さえるとともに、コア径が同
一の光ファイバを融着する場合と同等の生産性、経済性
を達成することができる。また、コア径の小さい光ファ
イバからコア径の大きい光ファイバへの光の伝搬は可能
であるため、光の伝搬方向は一方向に限定されない。
According to the first aspect of the present invention, the light transmitted through the optical fiber having the large core diameter is transmitted to the optical fiber having the small core diameter without exceeding the critical angle. By selecting the numerical aperture of an optical fiber with a large core diameter, it is not necessary to provide a light receiving element at the joint, minimizing the joint loss and at the same time as the fusion of optical fibers with the same core diameter. Productivity and economy can be achieved. Further, since light can be propagated from an optical fiber having a small core diameter to an optical fiber having a large core diameter, the light propagation direction is not limited to one direction.

【0014】[0014]

【発明の実施の形態】次に、本発明にかかる光ファイバ
結合方法の実施の形態の具体例を図面を参照しながら説
明する。
Next, a specific example of an embodiment of the optical fiber coupling method according to the present invention will be described with reference to the drawings.

【0015】本発明は、コア径が互いに異なる光ファイ
バを結合する方法を提供するものであって、特に、機械
的仕様としてコアとクラッドの比屈折率差が互いに異な
る光ファイバを融着して光伝送路を得るための光ファイ
バ結合方法を提供するものである。
The present invention provides a method for coupling optical fibers having different core diameters. In particular, as a mechanical specification, optical fibers having different relative refractive index differences between a core and a clad are fused. An object of the present invention is to provide an optical fiber coupling method for obtaining an optical transmission line.

【0016】図1に示すように、コア径が互いに異なる
光ファイバの1次及び2次の被覆を除去し、コアとクラ
ッドからなる光ファイバを得る。ここで、コア径の小さ
い光ファイバ(以下「小径光ファイバ」という)1と、
コア径の大きい光ファイバ(以下「大径光ファイバ」と
いう)2とを接続する。
As shown in FIG. 1, primary and secondary coatings of optical fibers having different core diameters are removed to obtain an optical fiber comprising a core and a clad. Here, an optical fiber 1 having a small core diameter (hereinafter referred to as “small diameter optical fiber”) 1
An optical fiber 2 having a large core diameter (hereinafter, referred to as “large-diameter optical fiber”) 2 is connected.

【0017】まず、大径光ファイバ2のコア径が小径光
ファイバ1のコア径と略々等しくなるまで大径光ファイ
バ2の端部を加熱加工により伸張し、小径光ファイバ1
のコア径と同一のコア径を有する部分で切断することに
よりテーパ部2’を形成する。次に、通常の光ファイバ
の融着加工と全く同じ工程により、両光ファイバ1、2
のコアの軸芯が一致するように、小径光ファイバ1の開
放端1aと大径光ファイバ2のテーパ部2’の開放端
2’aを融着して接続する。
First, the end of the large diameter optical fiber 2 is expanded by heating until the core diameter of the large diameter optical fiber 2 becomes substantially equal to the core diameter of the small diameter optical fiber 1.
The taper portion 2 'is formed by cutting at a portion having the same core diameter as the core diameter. Next, the two optical fibers 1 and 2 are processed in exactly the same manner as in the normal optical fiber fusion processing.
The open end 1a of the small-diameter optical fiber 1 and the open end 2'a of the tapered portion 2 'of the large-diameter optical fiber 2 are connected by fusion so that the axes of the cores coincide with each other.

【0018】この融着接続法は、光ファイバの端面を溶
かして接続するものであり、溶融方法には、アーク放
電、レーザ光、火炎等による方法がある。
In this fusion splicing method, an end face of an optical fiber is melted for connection. As a fusion method, there is a method using arc discharge, laser light, flame or the like.

【0019】但し、実際には、テーパ状となった光ファ
イバと、コア径の小さい光ファイバが同一径とは限らな
いので、コアの偏芯による損失が増加しないようにSM
型光ファイバのようにコアが極めて細径なときに用いる
コアモニタ法やパワーモニタ法等の手法を用いることが
好適である。また、この際、プリフォームから光ファイ
バを製造するのと同様に屈折率分布を制御して伸張する
ことが最良である。
However, in practice, the tapered optical fiber and the optical fiber having a small core diameter are not always the same in diameter.
It is preferable to use a method such as a core monitoring method or a power monitoring method which is used when the core has an extremely small diameter such as a shaped optical fiber. At this time, it is best to control and expand the refractive index distribution as in the case of manufacturing an optical fiber from a preform.

【0020】以上のように構成することにより、大径光
ファイバ2を伝搬し、小径光ファイバ1へ向かう光信号
は、テーパ部2’で機械的に臨界角が小さくなるので、
NAが大きい場合には、クラッド部分で吸収しきれない
非反射光は損失となる。従って、大径光ファイバ2内を
伝送される全ての光が臨界角を超えないで小径光ファイ
バ1に伝搬されるように大径光ファイバ2の開口数(N
A)を選択することが好適である。尚、GI型光ファイ
バのように屈折率分布が緩やかに変化している場合で
は、テーパ部での損失はほとんど無視できる。
With the above configuration, the optical signal propagating through the large-diameter optical fiber 2 and traveling toward the small-diameter optical fiber 1 is mechanically reduced in critical angle at the tapered portion 2 '.
When the NA is large, non-reflected light that cannot be absorbed by the cladding part is lost. Therefore, the numerical aperture (N) of the large-diameter optical fiber 2 is set so that all light transmitted through the large-diameter optical fiber 2 propagates to the small-diameter optical fiber 1 without exceeding the critical angle.
It is preferred to select A). In the case where the refractive index distribution changes gently as in a GI optical fiber, the loss at the tapered portion can be almost ignored.

【0021】[0021]

【発明の効果】以上説明したように、請求項1記載の発
明によれば、接合部に受光素子を設ける必要がなく、接
合損失を最小限に押さえるとともに、コア径が同一の光
ファイバを融着する場合と同等の生産性、経済性を達成
することのできる光ファイバ結合方法を提供することが
できる。
As described above, according to the first aspect of the present invention, there is no need to provide a light receiving element at the joint, minimizing the joint loss and melting the optical fiber having the same core diameter. It is possible to provide an optical fiber coupling method that can achieve the same productivity and economy as in the case of attaching.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明にかかる光ファイバ結合方法を説明する
ための概略図である。
FIG. 1 is a schematic diagram illustrating an optical fiber coupling method according to the present invention.

【符号の説明】[Explanation of symbols]

1 小径光ファイバ 1a 開放端 2 大径光ファイバ 2’ テーパ部 2’a 開放端 DESCRIPTION OF SYMBOLS 1 Small diameter optical fiber 1a Open end 2 Large diameter optical fiber 2 'Taper part 2'a Open end

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 コア径の大きい光ファイバのコア径がコ
ア径の小さい光ファイバのコア径と等しくなるまで、該
コア径の大きい光ファイバの端部を加熱加工により伸張
してテーパ部を形成し、両光ファイバのコアの軸芯が一
致するように、前記テーパ部の開放端を前記コア径の小
さい光ファイバの開放端に融着することを特徴とする光
ファイバ結合方法。
1. An end of an optical fiber having a large core diameter is expanded by heating until a core diameter of an optical fiber having a large core diameter becomes equal to a core diameter of an optical fiber having a small core diameter to form a tapered portion. An optical fiber coupling method, wherein the open end of the tapered portion is fused to the open end of the optical fiber having a small core diameter such that the axes of the cores of the two optical fibers coincide with each other.
JP11005650A 1999-01-12 1999-01-12 Optical fiber coupling method Pending JP2000206357A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11005650A JP2000206357A (en) 1999-01-12 1999-01-12 Optical fiber coupling method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11005650A JP2000206357A (en) 1999-01-12 1999-01-12 Optical fiber coupling method

Publications (1)

Publication Number Publication Date
JP2000206357A true JP2000206357A (en) 2000-07-28

Family

ID=11617017

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11005650A Pending JP2000206357A (en) 1999-01-12 1999-01-12 Optical fiber coupling method

Country Status (1)

Country Link
JP (1) JP2000206357A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7899288B2 (en) * 2008-01-25 2011-03-01 Fujifilm Corporation Optical fiber structure
CN114518625A (en) * 2022-02-22 2022-05-20 浙江大学温州研究院 LED coupling optical fiber system and preparation method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7899288B2 (en) * 2008-01-25 2011-03-01 Fujifilm Corporation Optical fiber structure
CN114518625A (en) * 2022-02-22 2022-05-20 浙江大学温州研究院 LED coupling optical fiber system and preparation method thereof
CN114518625B (en) * 2022-02-22 2024-04-12 浙江大学温州研究院 LED coupling optical fiber system and preparation method thereof

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