JP2004198977A - Optical fiber fusion splicing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber fusion splicing device which allows a splicing condition to be properly set when fusion splicing is performed to optical fibers of many kinds. <P>SOLUTION: An optical fiber fusion splicing device 1 is provided with a memory 5 and a CPU 7. The memory 5 has a first storage area 33, a second storage area 35, and a third storage area 37. The first storage area 33 stores a category list 39 or the like where categories are classified by the structures of optical fibers is stored. The second storage area 35 stores splicing condition data 43 or the like corresponding to category combinations. The third storage area 37 stores a fiber list 47 or the like indicating the discrimination information of optical fibers. When optical fibers are spliced, splicing condition data 43 corresponding to the category combination of the optical fibers is read. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

この理論式（１）において、α₁は光損失、ｄは軸ずれ量、ｗ₁は光ファイバ３ａのスポットサイズ、ｗ₂は光ファイバ３ｂのスポットサイズである。ここで、スポットサイズは、ＭＦＤを２で割って求めることができる。なお、角度ずれ量に関する項を理論式（１）の右辺に設けることにより、角度ずれ量も加味した光損失を推定することが可能である。
【００３４】
また、損失推定手段２９は、メモリ５の第２の記憶領域３５に記憶されている補正情報４５に基づいて接続部分３ｃにおける光損失の推定結果を補正する機能を備えている。損失推定手段２９は、操作手段１５から作業者により入力された光ファイバ３ａ及び３ｂの識別情報Ｓ１を認識する。そして、損失推定手段２９は、認識した識別情報が属するカテゴリを、カテゴリリスト３９に基づいて認識する。そして、損失推定手段２９は、光ファイバ３ａ及び３ｂそれぞれのカテゴリ組み合わせに応じた補正情報４５を読み出し、推定結果の補正に使用する。
【００３５】
ここで、補正情報４５の一例を説明する。次式（２）は、上記したＭＡＲＣＵＳＥによる理論式（１）により求めた光損失α₁を補正するための補正式である。
【数２】

この補正式（２）において、α₂は補正後の光損失、Ｋは傾き係数、Ｄは加算係数である。傾き係数Ｋおよび加算係数Ｄは、カテゴリ組み合わせに応じて、ＭＡＲＣＵＳＥによる理論式（１）により求めた光損失α₁と実験等により求めた実際の光損失とを比較することにより求めることができる。補正情報４５は、例えばカテゴリ組み合わせに応じた傾き係数Ｋ及び加算係数Ｄを含んでいる。なお、これらの係数については、後述する実施例において詳細に説明する。
【００３６】
損失推定手段２９は、補正後の光損失α₂を光損失に関する推定情報Ｓ８として表示手段１７に送る。表示手段１７は、損失推定手段２９から入力した推定情報Ｓ８を画面に表示する。作業者は、画面に表示された推定情報Ｓ８により、接合が適切に行われたか否かを判断する。
【００３７】
上記した実施形態に係る光ファイバ融着接続装置１の動作について説明する。図２は、メモリ５内部のデータ構造を示す図である。まず、図２を参照して、メモリ５における情報管理について説明する。すなわち、作業者は、メモリ５の情報を管理し、不足している情報を記憶させる。作業者は、まず光ファイバ３ａ及び３ｂそれぞれのカテゴリを第１の記憶領域３３に記憶されているカテゴリリスト３９から探す。該当するカテゴリがカテゴリリスト３９になければ、新たに登録するとともに、当該カテゴリに応じたプロファイル情報４１を第１の記憶領域３３に記憶させる。こうして、第１の記憶領域３３にはカテゴリリスト３９と、カテゴリリスト３９に含まれるカテゴリの数と同数のプロファイル情報４１が記憶される。
【００３８】
次に、作業者は、光ファイバ３ａ及び３ｂそれぞれの識別情報を第３の記憶領域３７に記憶されているファイバリスト４７から探す。該当する識別情報がファイバリスト４７になければ、新たに登録するとともに、当該識別に応じたＭＦＤデータ４９を第３の記憶領域３７に記憶させる。こうして、第３の記憶領域３７にはファイバリスト４７と、ファイバリスト４７に含まれる識別情報の数と同数のＭＦＤデータ４９が記憶される。
【００３９】
続いて、作業者は、光ファイバを接続する際に、光ファイバ３ａ及び３ｂの識別情報をファイバリスト４７の中から選択する。また、作業者は、光ファイバ３ａ及び３ｂそれぞれのカテゴリ組み合わせに応じた接続条件データ４３及び補正情報４５を第２の記憶領域３５から探す。該当する接続条件データ４３及び補正情報４５がなければ、新たに作成し、記憶させる。なお、この段階で、光ファイバ３ａ及び３ｂそれぞれの識別情報、カテゴリ、及び互いの接続条件を含む接続条件リスト５１を作成してもよい。
【００４０】
以上のようにして、作業者はメモリ５に記憶される情報を管理する。続いて、光ファイバ３ａ及び３ｂを接続する際の光ファイバ融着接続装置１の動作を以下に説明する。
【００４１】
まず、作業者は、光ファイバ３ａ及び３ｂそれぞれを支持台１３ａ及び１３ｂそれぞれに固定する。そして、作業者は、操作手段１５を用いて光ファイバ３ａ及び３ｂそれぞれの識別情報Ｓ１を入力する。
【００４２】
次に、観察手段９が光ファイバ３ａ及び３ｂそれぞれを観察した観察データＳ５をコア検出手段２１に送る。コア検出手段２１は、メモリ５の第１の記憶領域３３からプロファイル情報４１を読み出す。コア検出手段２１は、観察データＳ５及びプロファイル情報４１に基づいて、コア領域の位置や外径などを検出する。コア検出手段２１は、コア領域の位置や外径などの情報を第１のコア領域情報Ｓ６として調心制御手段２３に送る。
【００４３】
調心制御手段２３は第１のコア領域情報Ｓ６に基づいて、光ファイバ３ａ及び３ｂのコア領域が整合されるように支持台１３ａ及び１３ｂを移動させるための制御信号Ｓ３及びＳ４それぞれを生成し、支持台１３ａ及び１３ｂそれぞれに送る。支持台１３ａ及び１３ｂそれぞれは、制御信号Ｓ３及びＳ４それぞれに従って移動する。こうして、光ファイバ３ａ及び３ｂのコア領域の位置が互いに整合される。
【００４４】
続いて、条件設定手段２７がメモリ５の第２の記憶領域３５から接続条件データ４３を読み出す。条件設定手段２７は、接続条件データ４３に基づいて放電条件などの接続条件を設定し、設定した接続条件に基づいて融着接続過程を制御するための接続制御信号Ｓ２を放電回路１９へ送る。放電回路１９は接続制御信号Ｓ２に基づいた放電電圧Ｖ１を２つの電極１１の間に印加する。そして、２つの電極１１の間に放電が起こり、光ファイバ３ａ及び３ｂそれぞれの端面が融着接続されて接続部分３ｃが形成される。
【００４５】
続いて、観察手段９が光ファイバ３ａ及び３ｂそれぞれの接続部分３ｃ付近を観察した観察データＳ５をコア検出手段２１に送る。コア検出手段２１は、メモリ５の第１の記憶領域からプロファイル情報４１を読み出す。コア検出手段２１は、観察データＳ５及びプロファイル情報４１に基づいて、コア領域の軸ずれ量や角度ずれ量などを検出する。コア検出手段２１は、コア領域の軸ずれ量や角度ずれ量などの情報を第２のコア領域情報Ｓ７として損失推定手段２９に送る。
【００４６】
損失推定手段２９は、メモリ５の第３の記憶領域３７からＭＦＤデータ４９を読み出す。損失推定手段２９は、第２のコア領域情報Ｓ７及びＭＦＤデータ４９に基づいて、光損失を推定する。さらに、損失推定手段２９は、メモリ５の第２の記憶領域３５に記憶されている補正情報４５を読み出す。損失推定手段２９は、補正情報４５に基づいて光損失の推定結果を補正し、補正後の光損失推定結果を推定情報Ｓ８として表示手段１７に送る。推定情報Ｓ８は、表示手段１７の画面に表示される。
【００４７】
本実施形態による光ファイバ融着接続装置１は、以上に説明した構成及び動作により光ファイバ３ａ及び３ｂを融着接続するとともに、接続部分３ｃの光損失を推定する。
【００４８】
本実施形態による光ファイバ融着接続装置１は、以下に説明する効果を得る。すなわち、光ファイバ融着接続装置１においては、光ファイバをその構造により複数のカテゴリに分類してメモリ５の第１の記憶領域３３に記憶させる。そして、光ファイバ３ａ及び３ｂそれぞれのカテゴリに応じた接続条件が条件設定手段２７により設定され、放電手段１９及び電極１１を有する接続手段により融着接続される。光ファイバは、その構造が似ていれば融着接続時の特性においても似た傾向を示すので、光ファイバをその構造によりカテゴリ分類し、カテゴリ組み合わせに応じて接続条件を設定することにより光ファイバを好適に融着接続できる。
【００４９】
また、光ファイバ融着接続装置１は、カテゴリリスト３９を記憶する第１の記憶領域３３を備えることにより、接続しようとする光ファイバのカテゴリを容易に管理することができる。さらに、光ファイバ融着接続装置１は、接続条件データ４３を記憶する第２の記憶領域３５を備えることにより、カテゴリに応じた適切な接続条件を作業者が容易に管理し、設定することができる。また、光ファイバ融着接続装置１は、作業者が識別できない光ファイバであっても、そのカテゴリがわかっていれば適切な接続条件を設定することが可能である。
【００５０】
また、光ファイバ融着接続装置１において、メモリ５の第１の記憶領域３３は、カテゴリリスト３９に含まれる複数のカテゴリとして、ＤＳＦを含むカテゴリ及びＬＣＦを含むカテゴリを記憶している。これにより、特性の差が著しいこれらの光ファイバの接続条件を作業者が容易に管理し、設定することができる。
【００５１】
また、光ファイバ融着接続装置１においては、光ファイバの構造に関するプロファイル情報４１がカテゴリリスト３９と対応づけられている。これにより、作業者は多品種である光ファイバのプロファイル情報４１を数種類のカテゴリに応じて用意すればよく、プロファイル情報４１を容易に管理できる。
【００５２】
ここで、コア調心型の光ファイバ融着接続装置においては、コア領域情報を正確に検出することが重要である。しかし、例えばＬＣＦは中心のコア領域の両側に高屈折率部分を有するため、これが観察データＳ５に現れる。このような高屈折率部分は中心のコア領域と紛らわしく、コア領域情報の検出を誤る可能性がある。これに対し、予め光ファイバのカテゴリと当該カテゴリのプロファイル情報とがわかっていれば、コア領域のおよその構造がわかるので、観察データＳ５においてコア領域を探す範囲を限定できる。本光ファイバ融着接続装置では、コア検出手段２１が、メモリ５の第１の領域３３に記憶された、光ファイバ３ａ及び３ｂのカテゴリに対応するプロファイル情報４１と観察手段９における観察データＳ５とを照合して観察結果が正確か否かを判断する。このように、カテゴリリスト３９と対応づけられたプロファイル情報４１を利用することにより、光ファイバ３ａ及び３ｂのコア領域の外径、位置、軸ずれ量、角度ずれ量といったコア領域情報を正確に検出できる。
【００５３】
また、光ファイバ融着接続装置１においては、調心手段が、コア検出手段２１からのコア領域情報のうちコア領域の位置及び外径などに関する第１のコア領域情報Ｓ６に基づいて、光ファイバ３ａ及び３ｂのコア領域同士を整合させている。これにより、光ファイバ３ａ及び３ｂを融着接続する際に、互いのコア領域を整合して接続部分３ｃにおける光損失を小さくできる。また、コア検出手段２１が生成したコア領域情報は正確なので、調心手段も正確にコア領域を整合することができる。
【００５４】
また、光ファイバ融着接続装置１において、損失推定手段２９は、コア検出手段２１からの第２のコア領域情報Ｓ７に基づいて、接続部分３ｃにおける光損失を推定している。コア検出手段２１によって正確に検出された第２のコア領域情報Ｓ７に基づいて光損失を推定することによって、損失推定手段２９は接続部分３ｃにおける光損失を適切に推定することができる。さらに、損失推定手段２９は、ＭＦＤデータ４９にさらに基づいて接続部分３ｃにおける光損失を推定している。予めメモリ５の第３の記憶領域３７に記憶されているＭＦＤデータ４９を使用することにより、損失推定手段２９は接続部分３ｃにおける光損失をさらに適切に推定することができる。
【００５５】
また、光ファイバ融着接続装置１は、メモリ５の第２の領域３５が、カテゴリリスト３９におけるカテゴリの組み合わせに応じた補正情報４５をさらに記憶している。そして、損失推定手段２９が、カテゴリ組み合わせ次第で不正確となり得る接続部分３ｃにおける光損失の推定結果を補正情報４５に基づいて補正している。これにより、接続部分３ｃにおける光損失をさらに適切に推定することができる。なお、カテゴリ組み合わせに応じた推定結果の補正について、後述する実施例において詳細に説明する。
【００５６】
また、光ファイバ融着接続装置１は、メモリ５が第１の記憶領域３３、第２の記憶領域３５、及び第３の記憶領域３７を備えている。そして、第１の記憶領域３３にはカテゴリリスト３９及びプロファイル情報４１が記憶されている。第２の記憶領域３５には接続条件データ４３及び補正情報４５が記憶されており、第３の記憶領域３７にはファイバリスト４７及びＭＦＤデータ４９が記憶されている。このように、（１）カテゴリに基づく情報、（２）カテゴリ組み合わせに基づく情報、（３）光ファイバの識別に基づく情報をそれぞれ階層別にメモリ５に記憶させることにより、作業者にとって情報の管理が容易になる。
【００５７】
ここで、図３（ａ）及び（ｂ）、並びに図４（ａ）及び（ｂ）は、各カテゴリの光ファイバ断面の屈折率分布を示す図である。以下に説明する内容は、メモリ５の第１の記憶領域３３に記憶されるプロファイル情報４１が含む光ファイバに関する情報の一例である。
【００５８】
図３（ａ）は、ＳＭＦの断面における屈折率分布を示している。図中のａ１はコア領域Ａ１の外径、ａ２は光ファイバの外径を示している。また、ｂ１はコア領域Ａ１とクラッド領域Ａ２との屈折率差を示している。図３（ａ）に示されるとおり、ＳＭＦはステップ型の屈折率分布を有している。また、図３（ｂ）は、ＤＳＦの断面における屈折率分布を示している。ＤＳＦは、階段状の屈折率分布、すなわちコア領域として中心部分の第１のコア領域Ａ３と、第１のコア領域Ａ３の周囲に第１のコア領域Ａ３よりも屈折率が小さい第２のコア領域Ａ４とを有している。図中のａ３は第１のコア領域Ａ３の外径を、ａ４は第２のコア領域Ａ４の外径を、ａ５は光ファイバの外径を、それぞれ示している。また、ｂ２は第２のコア領域Ａ４とクラッド領域Ａ５との屈折率差を、ｂ３は第１のコア領域Ａ３と第２のコア領域Ａとの屈折率差を、それぞれ示している。
【００５９】
図４（ａ）は、ＬＣＦの断面における屈折率分布を示している。ＬＣＦは、分割型の屈折率分布、すなわち高屈折率部分が分割されて中心コア領域Ａ６と、中心コア領域Ａ６の周囲に低屈折率部分であるディップ領域Ａ７をはさんで設けられたリングコア領域Ａ８とを有している。図中のａ６は中心コア領域Ａ６の外径を、ａ７はディップ領域Ａ７の外径を、ａ８はリングコア領域Ａ８の外径を、ａ９は光ファイバの外径を、それぞれ示している。また、ｂ４はリングコア領域Ａ８とクラッド領域Ａ９との屈折率差を、ｂ５は中心コア領域Ａ６とディップ領域Ａ７との屈折率差を、それぞれ示している。また、図４（ｂ）は、図４（ａ）に示されたＬＣＦの変形例である。図４（ｂ）に示されたＬＣＦでは、ディップ領域Ａ７の屈折率がクラッド領域Ａ９の屈折率よりも小さくなっている。図中のｂ６はリングコア領域Ａ８とディップ領域Ａ７との屈折率差を示している。
【００６０】
メモリ５の第１の記憶領域３３に記憶されるプロファイル情報４１は、コア領域の外径に関する情報として例えば以上に説明したａ１〜ａ９のような情報を含むとよい。また、プロファイル情報４１は、光ファイバの屈折率差に関する情報として、例えばｂ１〜ｂ６のような情報を含むとよい。
【００６１】
また、図５（ａ）及び（ｂ）は、コア検出手段２１におけるコア検出方法の一例を説明するための図である。図５（ａ）は、ＬＣＦの軸に垂直な方向の断面に関する観察データＳ５の一例を示す輝度波形である。図５（ａ）では、縦軸に輝度、横軸にＬＣＦの径方向の位置が示されている。図５（ａ）に示された輝度波形Ｂ１を参照すると、ＬＣＦの観察データＳ５には中心コア領域、リングコア領域などの高屈折率部分が複数存在する集光明部Ｃが現れる。このような観察データＳ５からコア領域情報を正確に検出するために、コア検出手段２１において、図５（ａ）に示された輝度波形を微分した微分波形を求めるとよい。このような微分波形の一例を、図５（ｂ）に示す。図５（ｂ）において、微分波形Ｂ２が０となる回数を求めることにより、コア領域近傍の高屈折率部分の数を知ることができる。また、複数の高屈折率部分が存在しても、コア領域はその屈折率の高さにより微分波形中において際立っているので、微分波形Ｂ２の最大値Ｄ１、最小値Ｄ２の径方向位置を求めることによりコア領域情報を得ることができる。なお、コア領域が偏心している場合も同様にコア領域情報を得ることができる。
【００６２】
しかし、輝度波形Ｂ１及び微分波形Ｂ２においてコア領域が際立っておらず、コア領域を明瞭に判別できない場合もあり得る。このような場合には、光ファイバの構造に関するプロファイル情報４１を参照することにより正確にコア領域を判別できる。すなわち、得られたコア領域情報が、光ファイバのカテゴリに応じたプロファイル情報４１から予測されるコア領域情報とは大きく異なる場合、得られたコア領域情報は誤ったものであると判断される。そして、適正な径方向位置において再度検出される。あるいは、最初から適正な径方向位置にあるコア領域候補を優先して判定してもよい。以上のようにコア領域情報を検出することによって、コア領域情報を正確に検出することができる。
【００６３】
次に、本発明による光ファイバ融着接続装置の損失推定に関わる実施例を説明する。
【００６４】
図６〜図１２は、本発明による光ファイバ融着接続装置の実施例を示す図である。本実施例では、光ファイバ（ＳＭＦ、ＤＳＦ、ＬＣＦ）を用意し、上記したＭＡＲＣＵＳＥによる理論式（１）から算出された光損失の推定値と、実際に測定された光損失とを比較することによって得られた、補正情報の一例を示す。
【００６５】
図６は、本実施例において使用した光ファイバの識別、カテゴリ、及びＭＦＤを示す図表である。図６に示されるとおり、本実施例では識別の異なる７種類の光ファイバを用い、識別情報はそれぞれＳＭＦ１〜３、ＤＳＦ１及び２、ＬＣＦ１及び２とした。ＳＭＦ１〜３のカテゴリはステップ型の断面屈折率分布を有するＳＭＦであり、ＭＦＤはそれぞれ１０．０μｍ、１０．２μｍ、１０．０μｍである。ＤＳＦ１及び２のカテゴリは階段型の断面屈折率分布を有するＤＳＦであり、ＭＦＤはそれぞれ８．７μｍ、８．４μｍである。ＬＣＦ１及び２のカテゴリは分割型の断面屈折率分布を有するＬＣＦであり、ＭＦＤはそれぞれ９．５μｍ、９．４μｍである。
【００６６】
図７〜図１２は、光損失の推定値（理論計算ロス）を横軸に、光損失の実測値（実測ロス）を縦軸にとり、光ファイバの組み合わせ毎にプロットしたグラフである。光損失の推定値と実測値とが略等しい場合には、傾きが１の直線付近にプロットされる。
【００６７】
図７は、ＳＭＦ１〜３の６通りの組み合わせ（同じ識別の光ファイバ同士の組み合わせを含む）のそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、傾きが１の直線Ｅ付近にプロットされているので、光損失の推定値と実測値とがほぼ等しいことがわかる。
【００６８】
図８は、ＤＳＦ１及び２の３通りの組み合わせ（同じ識別の光ファイバ同士の組み合わせを含む）のそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、プロットされた点が傾き２の直線Ｆ１に近似されるので、光損失の実測値は推定値のほぼ２倍であることがわかる。また、プロットされた点は傾き１．５の直線Ｆ２と傾き２．５の直線Ｆ３との間にほぼ収まっている。
【００６９】
図９は、ＬＣＦ１及び２の３通りの組み合わせ（同じ識別の光ファイバ同士の組み合わせを含む）のそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、プロットされた点が傾き３の直線Ｆ４に近似されるので、光損失の実測値は推定値のほぼ３倍であることがわかる。また、プロットされた点は傾き２．５の直線Ｆ５と傾き３．５の直線Ｆ６との間にほぼ収まっている。
【００７０】
図１０は、ＤＳＦ１及び２とＳＭＦ１〜３との６通りの組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、傾きが１の直線Ｅ付近にプロットされているので、光損失の推定値と実測値とがほぼ等しいことがわかる。ただし、プロットされた点は、直線Ｅと直線Ｅを実測値方向に０．０５ｄＢ移動した直線Ｆ７との間に多く集まっている。
【００７１】
図１１は、ＬＣＦ１及び２とＳＭＦ１〜３との６通りの組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、傾きが１であり、実測値方向の切片が０．２ｄＢである直線Ｆ８付近にプロットされている。また、プロットされた点は、傾きが１であり実測値方向の切片が０．１８ｄＢの直線Ｆ９と、傾きが１であり実測値方向の切片が０．２５ｄＢの直線Ｆ１０との間に多く集まっている。
【００７２】
図１２は、ＬＣＦ１及び２とＤＳＦ１及び２との４通りの組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。このグラフでは、傾きが１．３であり、実測値方向の切片が０．１ｄＢである直線Ｆ１１付近にプロットされている。また、プロットされた点は、傾きが１．２であり実測値方向の切片が０．０７ｄＢの直線Ｆ１２と、傾きが２であり実測値方向の切片が０．１２ｄＢの直線Ｆ１３との間に多く集まっている。
【００７３】
図１３は、本実施例により得られた補正情報を示す図表である。ＳＭＦ、ＤＳＦ、及びＬＣＦそれぞれのカテゴリ組み合わせは、図１３に示されるように６パターンの組み合わせが存在する。これらのパターンについては、既に図７〜図１２に基づいて説明した。そして、上記した実施形態における数式（２）の傾き係数Ｋ及び加算係数Ｄは、直線Ｆ１〜Ｆ１３に基づいて図１３のように設定するとよい。なお、図１３において括弧内の数値は、好適な範囲を示している。
【００７４】
従来より、ＭＡＲＣＵＳＥによる理論式（１）などにより光損失を推定することは行われてきた。しかしながら、発明者は、このような理論式により求められた光損失の推定値と実際の光損失とが合致しないケースが存在し、それは光ファイバのカテゴリ組み合わせに関係があることを見出した。そして、本実施例において、上記したようにカテゴリ組み合わせに応じた傾き係数Ｋや加算係数Ｄといった補正情報を求め、光損失の推定値を好適に補正して正確な推定情報を得ることができた。
【００７５】
本発明による光ファイバ融着接続装置は、上記した実施形態及び実施例に限られるものではなく、様々な変形が可能である。例えば、上記した実施形態ではメモリ５に記憶される情報を作業者が入力しているが、光ファイバ融着接続装置の製造時に予め記憶させておいてもよい。
【００７６】
また、カテゴリ情報に含まれる光ファイバのカテゴリはＳＭＦ、ＤＳＦ、及びＬＣＦに限るものではない。例えば、今後新たに開発されたプロファイル構造を有する光ファイバを、新たなカテゴリとして登録することも可能である。
【００７７】
【発明の効果】
本発明による光ファイバ融着接続装置は、光ファイバをその構造によりカテゴリ分類し、カテゴリ組み合わせに応じて接続条件を設定することにより、多品種である光ファイバを融着接続する際に適切に接続条件を設定できる。
【図面の簡単な説明】
【図１】本発明による光ファイバ融着接続装置の実施形態を示すブロック図である。
【図２】実施形態における、メモリ内部のデータ構造を示す図である。
【図３】各カテゴリの光ファイバ断面の屈折率分布を示す図である。
【図４】各カテゴリの光ファイバ断面の屈折率分布を示す図である。
【図５】コア検出手段におけるコア検出方法の一例を説明するための図である。
【図６】実施例において使用した光ファイバの識別、カテゴリ、及びＭＦＤを示す図表である。
【図７】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図８】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図９】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図１０】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図１１】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図１２】カテゴリ組み合わせのそれぞれにおいて光損失の推定値及び実測値に基づいてプロットしたグラフである。
【図１３】実施例により得られた補正情報を示す図表である。
【符号の説明】
１…光ファイバ融着接続装置、３ａ…第１の光ファイバ、３ｂ…第２の光ファイバ、５…メモリ、７…ＣＰＵ、９…観察手段、１１…電極、１３ａ、１３ｂ…支持台、１５…操作手段、１７…表示手段、１９…放電回路、２１…コア検出手段、２３…調心制御手段、２７…条件設定手段、２９…損失推定手段、３１…データベース領域、３３…第１の記憶領域、３５…第２の記憶領域、３７…第３の記憶領域、３９…カテゴリリスト、４１…プロファイル情報、４３…接続条件データ、４５…補正情報、４７…ファイバリスト、４９…ＭＦＤデータ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical fiber fusion splicing device for fusion splicing end faces of a first optical fiber and a second optical fiber.
[0002]
[Prior art]
As a method for connecting the end faces of the two optical fibers to each other, there is a connection by fusion, in addition to a connection by an optical connector. In the fusion splicing, two optical fibers are connected to each other by heating the end faces of the two optical fibers by electric discharge or the like and fusing them.
[0003]
When the optical fibers are fusion spliced in this manner, it is necessary to set connection conditions such that light loss at the connection portion is minimized. For example, in the fusion splicing method of an optical fiber disclosed in Patent Document 1, a splicing condition for fusion splicing two optical fibers is determined based on an image obtained by imaging a joint portion of the optical fiber. You have set.
[0004]
[Patent Document 1]
JP-A-5-150131
[0005]
[Problems to be solved by the invention]
However, in recent years, the variety of optical fibers has been increasing, and the combination at the time of fusion splicing optical fibers has become complicated. Since there has been no effective means for managing the connection conditions according to such a complicated combination, there is a risk that an operator may incorrectly set the connection conditions. Further, there have been cases where an operator cannot set connection conditions.
[0006]
The present invention has been made in view of such a problem, and an object of the present invention is to provide an optical fiber fusion splicing apparatus that can appropriately set connection conditions when fusion splicing various types of optical fibers. I do.
[0007]
[Means for Solving the Problems]
An optical fiber fusion splicing device according to the present invention is an optical fiber fusion splicing device for fusion splicing first and second optical fibers to each other, wherein category information in which the optical fibers are classified into a plurality of categories according to their structures, Storage means for storing connection conditions corresponding to combinations of data and categories, and read and set connection conditions applied to the first and second optical fibers based on the category information stored in the storage means. It is characterized by comprising a condition setting means and a connection means for fusion splicing the end faces of the first and second optical fibers based on the connection conditions set by the condition setting means.
[0008]
In the optical fiber fusion splicing apparatus according to the present invention, the optical fibers are classified into a plurality of categories according to their structures and stored in the storage means. Then, the connection condition according to the category of each of the first and second optical fibers is set by the condition setting means, and the splicing is performed by the connection means. This allows the operator to easily manage and set appropriate connection conditions according to the category.
[0009]
Further, the optical fiber fusion splicing device may be configured such that the storage means stores at least a category including a dispersion-shifted optical fiber having a step-shaped profile and another category including a dispersion-shifted optical fiber having a split-type profile. It may be a feature. Thereby, the operator can easily manage and set the connection conditions of these optical fibers having a remarkable difference in characteristics.
[0010]
Further, in the optical fiber fusion splicing apparatus, the storage unit further stores profile information associated with the category information, and irradiates the first and second optical fiber side surfaces with light, and An observing unit for observing light transmitted through the second optical fiber, and, based on the category information, reading out profile information corresponding to the categories of the first and second optical fibers from the storage unit. A core detecting means for detecting core area information of the first and second optical fibers based on the observation result may be further provided. In this optical fiber fusion splicing apparatus, the core detection unit compares the profile information corresponding to the first and second optical fiber categories stored in the storage unit with the observation result of the observation unit, and obtains the observation result. Determine if it is accurate. This allows the operator to prepare profile information of various types of optical fibers according to several types of categories, and can easily manage the profile information. In addition, by using the profile information associated with the category information, for example, the core area information such as the outer diameter and position of the core area of the first and second optical fibers, the axis shift amount and the angle shift amount can be accurately obtained. Can be detected.
[0011]
Further, the optical fiber fusion splicing device may be configured to perform the first and second optical fibers based on the core area information detected by the core detecting means before the first and second optical fibers are fusion spliced by the connecting means. The optical fiber may further include a centering means for moving each of the first and second optical fibers so that the positions of the core regions of the respective fibers are aligned with each other. In this optical fiber fusion splicer, the aligning means moves each of the first and second optical fibers based on the core region information to align the position of the core region. Accordingly, when the first and second optical fibers are fusion-spliced, the core regions can be aligned with each other to reduce optical loss.
[0012]
In the optical fiber fusion splicing apparatus, the storage unit further stores identification information of the optical fiber and optical characteristic information corresponding to the identification information of the optical fiber, and the first and second optical fibers store the information. Based on the core area information detected by the core detecting means after fusion splicing by the connecting means and the optical characteristic information corresponding to the identification information corresponding to the first and second optical fibers stored in the storage means. , A loss estimating means for estimating an optical loss at a connection portion between the first and second optical fibers. In this optical fiber fusion splicer, the loss estimating means estimates the optical loss based on the accurate core area information detected by the core detecting means and the optical characteristic information stored in the storage means. Accordingly, it is possible to appropriately estimate the optical loss at the connection portion between the first and second optical fibers.
[0013]
In the optical fiber fusion splicing apparatus, the storage unit further stores correction information corresponding to a combination of categories based on the category information, and the loss estimating unit estimates the optical loss at the connection portion based on the correction information. It may be characterized by correcting the result. In this optical fiber fusion splicing apparatus, based on correction information obtained through experiments and the like, the optical loss estimation result that may be incorrect depending on the category combination is corrected. This makes it possible to more appropriately estimate the optical loss at the connection between the first and second optical fibers.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.
[0015]
FIG. 1 is a block diagram showing an embodiment of the optical fiber fusion splicing apparatus according to the present invention. The optical fiber fusion device 1 according to the present embodiment is a device for fusion-splicing a first optical fiber 3a and a second optical fiber 3b by discharge heating.
[0016]
The optical fiber fusion splicing apparatus 1 includes a memory 5 as storage means and a CPU 7 as arithmetic processing means. Further, the optical fiber fusion splicing apparatus 1 includes an observation unit 9, an electrode 11, supports 13 a and 13 b, an operation unit 15, a display unit 17, and a discharge circuit 19.
[0017]
The memory 5 has a database storage area 31. The database storage area 31 has a structure in which a first storage area 33, a second storage area 35, and a third storage area 37 are provided. The first storage area 33 stores a category list 39 and profile information 41. The second storage area 35 stores the connection condition data 43 and the correction information 45. The third storage area 37 stores a fiber list 47 and MFD data 49.
[0018]
The category list 39 is category information in which various types of optical fibers are classified into a plurality of categories according to their structures. The first storage area 33 according to the present embodiment includes, as a plurality of categories in the category list 39, a category including a step-type single mode fiber (Single Mode Fiber, hereinafter referred to as SMF) and a dispersion-shifted optical fiber having a step-shaped profile. A category including a Dispersion Shifted Fiber (hereinafter, referred to as DSF) and a category including a dispersion-shifted optical fiber (Large Core Fiber, hereinafter referred to as LCF) having an enlarged effective area having a split type profile are stored. The category list 39 is used to categorize the optical fibers 3a and 3b based on the identification information S1 corresponding to the optical fibers 3a and 3b, which is input by the operator from the operation unit 15.
[0019]
The profile information 41 is information on the structure of the optical fiber, which is associated with the category list 39. The profile information 41 includes information such as an outer diameter of the optical fiber, a core diameter, a difference in refractive index, and an additive. Further, the profile information 41 may include information such as a combination of an outer diameter, a core diameter, and a refractive index difference. The profile information 41 is used to obtain information on the fiber structure of each of the optical fibers 3a and 3b based on the categories of the optical fibers 3a and 3b classified by the category list 39.
[0020]
Note that DSF, which is a general dispersion-shifted optical fiber, has a step-shaped refractive index distribution in its cross-sectional structure, and has a mode field diameter (Mode Field Diameter, hereinafter referred to as MFD) of 8 to 9 μm. On the other hand, the LCF, which is a dispersion-shifted optical fiber with an enlarged effective cross-sectional area, has a divided refractive index distribution in its cross-sectional structure, has an MFD of 9 to 10 μm, and is larger than DSF. Since the DSF and the LCF have such a difference in cross-sectional structure, the first storage area 33 of the memory 5 stores, as a plurality of categories included in the category list 39, a category including at least the DSF and a category including the LCF. Preferably.
[0021]
The connection condition data 43 is data for setting connection conditions when the optical fibers are fusion-spliced. The connection condition data 43 is prepared according to a combination of categories of optical fibers to be connected. Since the optical fiber fusion splicing apparatus 1 according to the present embodiment fusion-splices optical fibers by discharge heating, the connection condition data 43 mainly includes discharge conditions. The discharge conditions are determined by experiments and the like when the optical fiber fusion splicer 1 is manufactured. The connection condition data 43 is used for setting connection conditions at the time of fusion splicing the optical fibers 3a and 3b according to the combination of the respective categories of the optical fibers 3a and 3b.
[0022]
Further, the correction information 45 is information for the loss estimating means 29 described later to more accurately estimate the optical loss at the connection portion 3c of the optical fibers 3a and 3b. The correction information 45 is prepared according to a combination of categories of the optical fiber to be connected. The correction information 45 will be described in detail in an embodiment described later.
[0023]
The fiber list 47 is identification information for identifying various types of optical fibers, for example, for each product number. The fiber list 47 is used to identify the optical fibers 3a and 3b based on the identification information S1 of the optical fibers 3a and 3b input by the operator from the operation unit 15.
[0024]
The MFD data 49 is optical characteristic information such as an MFD corresponding to the fiber list 47. The MFD data 49 is prepared for each identification of the optical fiber to be connected. The MFD data 49 is used when the loss estimating means 29 described later estimates an optical loss in the connection portion 3c.
[0025]
Each information stored in the first storage area 33, the second storage area 35, and the third storage area 37 of the memory 5 is input by an operator before connecting the optical fibers 3a and 3b. It is good to memorize it.
[0026]
The CPU 7 includes a core detection unit 21, an alignment control unit 23, a condition setting unit 27, and a loss estimation unit 29. These means are realized by the CPU 7 reading and executing a program stored in a storage device inside or outside the CPU 7.
[0027]
The core detecting means 21 provided in the CPU 7 is means for detecting core area information of the optical fibers 3a and 3b. Here, the core area information includes information such as the outer diameter, the position, the axis shift amount, and the angle shift amount of the core area. The core detecting unit 21 detects core area information based on observation data S5 input from the observation unit 9 described later. At this time, the core detecting means 21 detects the core area further based on the profile information 41 stored in the first storage area 33 of the memory 5. That is, the core area is accurately detected by comparing the profile information 41 with the observation data 5. The profile information 41 to be used is read out according to the category of each of the optical fibers 3a and 3b based on the identification information of the optical fibers 3a and 3b input from the operation unit 15 by the operator. The core detecting means 21 detects the outer diameter and the position of each of the core areas of the optical fibers 3a and 3b from the core area information before fusion splicing, and sends the first core area information S6 to the alignment control means 23. send. Further, the core detecting means 21 detects the amount of axial deviation and the amount of angular deviation between the core regions of the optical fibers 3a and 3b after fusion splicing, and sends the second core region information S7 to the loss estimating unit 29. send.
[0028]
The observation means 9 is a means for irradiating the side surfaces of the optical fibers 3a and 3b with light and observing the light transmitted through the optical fibers 3a and 3b. That is, the observation unit 9 includes a light source such as an LED, a lens, and an imaging device such as a CCD that receives transmitted light. When transmitting the light emitted from the light source, the optical fibers 3a and 3b refract the light according to the refractive index distribution of the cross section of the optical fiber. The light transmitted in this manner is received by the imaging device, and observation data S5, which is an observation result, is generated. The observation unit 9 sends the generated observation data S5 to the core detection unit 21.
[0029]
The alignment control means 23 provided in the CPU 5 constitutes alignment means for moving the optical fibers 3a and 3b together with the supports 13a and 13b such that the core regions of the optical fibers 3a and 3b are aligned with each other. The supports 13a and 13b support the optical fibers 3a and 3b. In addition, the supports 13a and 13b are provided movably. Before the fusion splicing of the optical fibers 3a and 3b, the alignment control means 23 controls the movement of the supports 13a and 13b so that the positions of the core regions of the optical fibers 3a and 3b are aligned with each other. S3 and S4 are sent to the supports 13a and 13b, respectively. At this time, the position of the core region is recognized based on the first core region information S6 detected by the core detecting unit 21 before the fusion splicing. The supports 13a and 13b move according to the control signals S3 and S4 to align the core regions of the optical fibers 3a and 3b.
[0030]
The condition setting means 27 provided in the CPU 7 is a means for reading and setting connection conditions applied to the optical fibers 3 a and 3 b from the connection condition data 43 stored in the second storage area 35. The condition setting unit 27 recognizes the identification information S1 of the optical fibers 3a and 3b input by the operator from the operation unit 15. Then, the condition setting unit 27 recognizes the category to which the recognized identification information belongs based on the category list 39. Then, the condition setting means 27 reads out connection conditions according to the category combination of the optical fibers 3a and 3b from the connection condition data 43 and sets them. That is, the condition setting means 27 sends a connection control signal S2 for controlling the fusion splicing process to the discharge circuit 19 based on the read connection conditions.
[0031]
The discharge circuit 19 and the electrode 11 constitute connection means for fusion-splicing the end faces of the optical fibers 3a and 3b based on the connection conditions set by the condition setting means 27. The discharge circuit 19 is means for applying a discharge voltage V1 to the electrode 11. The electrode 11 includes two electrodes, and is provided so that the two electrodes face each other with the end faces of the optical fibers 3a and 3b interposed therebetween. When a discharge voltage V1 based on the connection control signal S2 is applied to the electrode 11 from the discharge circuit 19, a discharge occurs between the two electrodes 11, and the end faces of the optical fibers 3a and 3b are fusion-spliced to form a connection portion. 3c is formed.
[0032]
The loss estimating unit 29 provided in the CPU 7 is a unit for estimating the optical loss at the connection portion 3c. The loss estimating means 29 estimates an optical loss based on the second core area information S7 detected by the core detecting means 21 after fusion splicing the optical fibers 3a and 3b. Further, the loss estimating unit 29 recognizes the identification information S1 of the optical fibers 3a and 3b input by the operator from the operating unit 15, and stores the information in the fiber list 47 stored in the third storage area 37 of the memory 5. From the optical fibers 3a and 3b. Then, the loss estimating means 29 reads the MFD data 49 corresponding to the selected identification information. The loss estimating means 29 uses the MFD data 49 when estimating the optical loss at the connection portion 3c.
[0033]
The loss estimating means 29 estimates the optical loss at the connection portion 3c based on the second core area information S7 and the MFD data 49 as described above. When estimating the optical loss, for example, the following theoretical equation (1) by MARCUSE is used.
(Equation 1)

In this theoretical equation (1), α ₁ Is the optical loss, d is the amount of axial deviation, w ₁ Is the spot size of the optical fiber 3a, w _Two Is the spot size of the optical fiber 3b. Here, the spot size can be obtained by dividing MFD by 2. By providing a term relating to the amount of angle shift on the right side of the theoretical equation (1), it is possible to estimate the light loss taking into account the amount of angle shift.
[0034]
Further, the loss estimating means 29 has a function of correcting the estimation result of the optical loss in the connection portion 3c based on the correction information 45 stored in the second storage area 35 of the memory 5. The loss estimating unit 29 recognizes the identification information S1 of the optical fibers 3a and 3b input by the operator from the operating unit 15. Then, the loss estimating unit 29 recognizes the category to which the recognized identification information belongs based on the category list 39. Then, the loss estimating unit 29 reads out the correction information 45 corresponding to the category combination of each of the optical fibers 3a and 3b, and uses it for correcting the estimation result.
[0035]
Here, an example of the correction information 45 will be described. The following equation (2) is an optical loss α obtained by the above-mentioned theoretical equation (1) based on MARCUSE. ₁ Is a correction equation for correcting
(Equation 2)

In this correction equation (2), α _Two Is a light loss after correction, K is a slope coefficient, and D is an addition coefficient. The slope coefficient K and the addition coefficient D are calculated based on the optical loss α obtained by the theoretical equation (1) using MARCUSE according to the category combination. ₁ It can be obtained by comparing the actual light loss obtained by experiments and the like. The correction information 45 includes, for example, a slope coefficient K and an addition coefficient D according to the category combination. In addition, these coefficients will be described in detail in examples described later.
[0036]
The loss estimating means 29 calculates the corrected optical loss α _Two Is sent to the display means 17 as the estimated information S8 on the optical loss. The display unit 17 displays the estimation information S8 input from the loss estimating unit 29 on a screen. The operator determines whether or not the joining has been properly performed based on the estimated information S8 displayed on the screen.
[0037]
The operation of the optical fiber fusion splicer 1 according to the above-described embodiment will be described. FIG. 2 is a diagram showing a data structure inside the memory 5. First, information management in the memory 5 will be described with reference to FIG. That is, the worker manages the information in the memory 5 and stores the missing information. The operator first searches for the category of each of the optical fibers 3 a and 3 b from the category list 39 stored in the first storage area 33. If the corresponding category is not in the category list 39, it is newly registered and the profile information 41 corresponding to the category is stored in the first storage area 33. Thus, the first storage area 33 stores the category list 39 and the same number of profile information 41 as the number of categories included in the category list 39.
[0038]
Next, the operator searches the fiber list 47 stored in the third storage area 37 for identification information of each of the optical fibers 3a and 3b. If the corresponding identification information does not exist in the fiber list 47, it is newly registered and the MFD data 49 corresponding to the identification is stored in the third storage area 37. Thus, the third storage area 37 stores the fiber list 47 and the same number of MFD data 49 as the number of pieces of identification information included in the fiber list 47.
[0039]
Subsequently, when connecting the optical fibers, the operator selects the identification information of the optical fibers 3a and 3b from the fiber list 47. Further, the operator searches the second storage area 35 for the connection condition data 43 and the correction information 45 according to the category combination of each of the optical fibers 3a and 3b. If there is no corresponding connection condition data 43 and correction information 45, a new one is created and stored. At this stage, the connection condition list 51 including the identification information, the category, and the connection condition of each of the optical fibers 3a and 3b may be created.
[0040]
As described above, the worker manages the information stored in the memory 5. Subsequently, the operation of the optical fiber fusion splicer 1 when connecting the optical fibers 3a and 3b will be described below.
[0041]
First, the operator fixes the optical fibers 3a and 3b to the supports 13a and 13b, respectively. Then, the operator uses the operation means 15 to input the identification information S1 of each of the optical fibers 3a and 3b.
[0042]
Next, the observation unit 9 sends observation data S5 obtained by observing the optical fibers 3a and 3b to the core detection unit 21. The core detecting unit 21 reads out the profile information 41 from the first storage area 33 of the memory 5. The core detecting unit 21 detects the position and the outer diameter of the core region based on the observation data S5 and the profile information 41. The core detection unit 21 sends information such as the position and the outer diameter of the core region to the alignment control unit 23 as first core region information S6.
[0043]
The alignment control means 23 generates control signals S3 and S4 for moving the supports 13a and 13b such that the core areas of the optical fibers 3a and 3b are aligned based on the first core area information S6. To each of the support tables 13a and 13b. The supports 13a and 13b move according to the control signals S3 and S4, respectively. Thus, the positions of the core regions of the optical fibers 3a and 3b are aligned with each other.
[0044]
Subsequently, the condition setting means 27 reads the connection condition data 43 from the second storage area 35 of the memory 5. The condition setting means 27 sets a connection condition such as a discharge condition based on the connection condition data 43, and sends a connection control signal S2 for controlling the fusion splicing process to the discharge circuit 19 based on the set connection condition. The discharge circuit 19 applies a discharge voltage V1 between the two electrodes 11 based on the connection control signal S2. Then, a discharge occurs between the two electrodes 11, and the end faces of the optical fibers 3a and 3b are fusion-spliced to form a connection portion 3c.
[0045]
Subsequently, the observation unit 9 sends observation data S5 obtained by observing the vicinity of the connection portion 3c of each of the optical fibers 3a and 3b to the core detection unit 21. The core detecting unit 21 reads out the profile information 41 from the first storage area of the memory 5. The core detecting unit 21 detects the amount of axial deviation or the amount of angular deviation of the core region based on the observation data S5 and the profile information 41. The core detecting unit 21 sends information such as the amount of axial deviation and the amount of angular deviation of the core region to the loss estimating unit 29 as second core region information S7.
[0046]
The loss estimating means 29 reads the MFD data 49 from the third storage area 37 of the memory 5. The loss estimating unit 29 estimates an optical loss based on the second core area information S7 and the MFD data 49. Further, the loss estimating means 29 reads the correction information 45 stored in the second storage area 35 of the memory 5. The loss estimating unit 29 corrects the estimation result of the optical loss based on the correction information 45, and sends the corrected optical loss estimation result to the display unit 17 as the estimation information S8. The estimation information S8 is displayed on the screen of the display unit 17.
[0047]
The optical fiber fusion splicing apparatus 1 according to the present embodiment fusion splics the optical fibers 3a and 3b by the configuration and operation described above, and estimates the optical loss of the connection portion 3c.
[0048]
The optical fiber fusion splicing apparatus 1 according to the present embodiment has the effects described below. That is, in the optical fiber fusion splicing apparatus 1, the optical fibers are classified into a plurality of categories according to their structures and stored in the first storage area 33 of the memory 5. Then, connection conditions according to the respective categories of the optical fibers 3 a and 3 b are set by the condition setting means 27, and fusion splicing is performed by the connection means having the discharge means 19 and the electrode 11. If the optical fiber has a similar structure, the characteristics at the time of fusion splicing tend to be similar.Therefore, the optical fiber is classified into categories according to its structure, and the optical fiber is set by setting the connection conditions according to the category combination. Can be suitably fusion-spliced.
[0049]
Further, the optical fiber fusion splicing apparatus 1 includes the first storage area 33 for storing the category list 39, so that the category of the optical fiber to be connected can be easily managed. Furthermore, since the optical fiber fusion splicing apparatus 1 includes the second storage area 35 for storing the connection condition data 43, the operator can easily manage and set appropriate connection conditions according to the category. it can. In addition, the optical fiber fusion splicing apparatus 1 can set appropriate connection conditions even if the category is known, even for an optical fiber that cannot be identified by an operator.
[0050]
Further, in the optical fiber fusion splicer 1, the first storage area 33 of the memory 5 stores a category including DSF and a category including LCF as a plurality of categories included in the category list 39. Thereby, the operator can easily manage and set the connection conditions of these optical fibers having a remarkable difference in characteristics.
[0051]
Further, in the optical fiber fusion splicer 1, the profile information 41 relating to the structure of the optical fiber is associated with the category list 39. Thus, the operator only has to prepare the profile information 41 of various types of optical fibers according to several categories, and the profile information 41 can be easily managed.
[0052]
Here, in the core alignment type optical fiber fusion splicing apparatus, it is important to accurately detect the core area information. However, for example, the LCF has high refractive index portions on both sides of the central core region, and this appears in the observation data S5. Such a high refractive index portion is confusing with the central core region, and there is a possibility that the core region information is erroneously detected. On the other hand, if the category of the optical fiber and the profile information of the category are known in advance, the approximate structure of the core region can be known, so that the range for searching for the core region in the observation data S5 can be limited. In the present optical fiber fusion splicing apparatus, the core detecting means 21 uses the profile information 41 corresponding to the categories of the optical fibers 3 a and 3 b stored in the first area 33 of the memory 5 and the observation data S 5 in the observing means 9. To determine whether the observation result is accurate. As described above, by using the profile information 41 associated with the category list 39, the core area information such as the outer diameter, the position, the axis shift amount, and the angle shift amount of the core areas of the optical fibers 3a and 3b can be accurately detected. it can.
[0053]
Further, in the optical fiber fusion splicing apparatus 1, the aligning means uses the optical fiber based on the first core area information S <b> 6 regarding the position and outer diameter of the core area among the core area information from the core detecting means 21. The core regions 3a and 3b are aligned with each other. Accordingly, when the optical fibers 3a and 3b are fusion-spliced, the core regions of the optical fibers 3a and 3b are aligned with each other, so that the optical loss at the joint 3c can be reduced. Further, since the core area information generated by the core detecting means 21 is accurate, the centering means can also accurately match the core area.
[0054]
Further, in the optical fiber fusion splicing apparatus 1, the loss estimating means 29 estimates the optical loss at the connecting portion 3c based on the second core area information S7 from the core detecting means 21. By estimating the optical loss based on the second core area information S7 accurately detected by the core detecting means 21, the loss estimating means 29 can appropriately estimate the optical loss at the connection portion 3c. Further, the loss estimating means 29 estimates the optical loss at the connection portion 3c further based on the MFD data 49. By using the MFD data 49 stored in the third storage area 37 of the memory 5 in advance, the loss estimating means 29 can more appropriately estimate the optical loss at the connection portion 3c.
[0055]
In the optical fiber fusion splicer 1, the second area 35 of the memory 5 further stores correction information 45 corresponding to a combination of categories in the category list 39. Then, the loss estimating unit 29 corrects the estimation result of the optical loss at the connection portion 3c, which may be incorrect depending on the category combination, based on the correction information 45. Thereby, it is possible to more appropriately estimate the optical loss at the connection portion 3c. The correction of the estimation result according to the category combination will be described in detail in an embodiment described later.
[0056]
In the optical fiber fusion splicing apparatus 1, the memory 5 includes a first storage area 33, a second storage area 35, and a third storage area 37. The category list 39 and the profile information 41 are stored in the first storage area 33. The second storage area 35 stores connection condition data 43 and correction information 45, and the third storage area 37 stores a fiber list 47 and MFD data 49. As described above, by storing (1) information based on the category, (2) information based on the category combination, and (3) information based on the identification of the optical fiber in the memory 5 for each hierarchy, information management for the worker can be achieved. It will be easier.
[0057]
Here, FIGS. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b) are diagrams showing the refractive index distribution of the optical fiber cross section of each category. The content described below is an example of information on an optical fiber included in the profile information 41 stored in the first storage area 33 of the memory 5.
[0058]
FIG. 3A shows a refractive index distribution in a cross section of the SMF. In the figure, a1 indicates the outer diameter of the core region A1, and a2 indicates the outer diameter of the optical fiber. In addition, b1 indicates a difference in refractive index between the core region A1 and the cladding region A2. As shown in FIG. 3A, the SMF has a step-type refractive index distribution. FIG. 3B shows a refractive index distribution in a cross section of the DSF. The DSF has a step-like refractive index distribution, that is, a first core region A3 in a central portion as a core region, and a second core having a smaller refractive index than the first core region A3 around the first core region A3. And an area A4. In the figure, a3 indicates the outer diameter of the first core region A3, a4 indicates the outer diameter of the second core region A4, and a5 indicates the outer diameter of the optical fiber. In addition, b2 indicates a refractive index difference between the second core region A4 and the cladding region A5, and b3 indicates a refractive index difference between the first core region A3 and the second core region A.
[0059]
FIG. 4A shows a refractive index distribution in a cross section of the LCF. The LCF is a split type refractive index distribution, that is, a ring core region in which a high refractive index portion is divided and a central core region A6 is provided and a dip region A7 which is a low refractive index portion is provided around the central core region A6. A8. In the figure, a6 indicates the outer diameter of the central core area A6, a7 indicates the outer diameter of the dip area A7, a8 indicates the outer diameter of the ring core area A8, and a9 indicates the outer diameter of the optical fiber. Further, b4 indicates a refractive index difference between the ring core region A8 and the cladding region A9, and b5 indicates a refractive index difference between the central core region A6 and the dip region A7. FIG. 4B is a modification of the LCF shown in FIG. In the LCF shown in FIG. 4B, the refractive index of the dip region A7 is smaller than the refractive index of the cladding region A9. B6 in the figure indicates the difference in the refractive index between the ring core region A8 and the dip region A7.
[0060]
The profile information 41 stored in the first storage area 33 of the memory 5 may include, for example, information such as a1 to a9 described above as information on the outer diameter of the core area. Further, the profile information 41 may include, for example, information such as b1 to b6 as information relating to the refractive index difference of the optical fiber.
[0061]
FIGS. 5A and 5B are diagrams for explaining an example of a core detection method in the core detection unit 21. FIG. FIG. 5A is a luminance waveform illustrating an example of observation data S5 regarding a cross section in a direction perpendicular to the axis of the LCF. In FIG. 5A, the vertical axis indicates luminance, and the horizontal axis indicates the radial position of the LCF. Referring to the luminance waveform B1 shown in FIG. 5A, a light-collecting bright portion C including a plurality of high refractive index portions such as a central core region and a ring core region appears in the observation data S5 of the LCF. In order to accurately detect the core area information from the observation data S5, the core detecting means 21 may obtain a differential waveform obtained by differentiating the luminance waveform shown in FIG. An example of such a differential waveform is shown in FIG. In FIG. 5B, the number of high refractive index portions near the core region can be known by calculating the number of times that the differential waveform B2 becomes 0. Further, even if there are a plurality of high refractive index portions, the core region stands out in the differential waveform due to the height of the refractive index, so that the radial position of the maximum value D1 and the minimum value D2 of the differential waveform B2 is obtained. As a result, core region information can be obtained. In addition, even when the core region is eccentric, the core region information can be obtained similarly.
[0062]
However, the core region may not be distinguished in the luminance waveform B1 and the differential waveform B2, and the core region may not be clearly distinguished. In such a case, the core area can be accurately determined by referring to the profile information 41 on the structure of the optical fiber. That is, if the obtained core area information is significantly different from the core area information predicted from the profile information 41 corresponding to the category of the optical fiber, it is determined that the obtained core area information is incorrect. Then, it is detected again at an appropriate radial position. Alternatively, the core region candidate located at an appropriate radial position from the beginning may be preferentially determined. By detecting core region information as described above, core region information can be accurately detected.
[0063]
Next, an embodiment relating to loss estimation of the optical fiber fusion splicing apparatus according to the present invention will be described.
[0064]
6 to 12 are views showing an embodiment of the optical fiber fusion splicing apparatus according to the present invention. In this embodiment, an optical fiber (SMF, DSF, LCF) is prepared, and the estimated value of the optical loss calculated from the above-mentioned theoretical equation (1) by MARCUSE is compared with the actually measured optical loss. An example of the correction information obtained by the above is shown.
[0065]
FIG. 6 is a chart showing the identification, the category, and the MFD of the optical fibers used in the present embodiment. As shown in FIG. 6, in this embodiment, seven types of optical fibers having different identifications are used, and the identification information is SMF1 to 3, SDF1 and 2, and LCF1 and 2, respectively. The categories of the SMFs 1 to 3 are SMFs having a step type sectional refractive index distribution, and the MFDs are 10.0 μm, 10.2 μm, and 10.0 μm, respectively. The categories of DSFs 1 and 2 are DSFs having a step-shaped sectional refractive index distribution, and the MFDs are 8.7 μm and 8.4 μm, respectively. The categories of LCF1 and LCF2 are LCFs having a divided sectional refractive index distribution, and the MFDs are 9.5 μm and 9.4 μm, respectively.
[0066]
7 to 12 are graphs plotting the estimated value of optical loss (theoretical calculation loss) on the horizontal axis and the measured value of optical loss (actually measured loss) on the vertical axis for each combination of optical fibers. When the estimated value of the light loss is substantially equal to the measured value, the slope is plotted near a straight line having a slope of 1.
[0067]
FIG. 7 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the six combinations of SMF1 to 3 (including the combination of optical fibers having the same identification). In this graph, since the slope is plotted near the straight line E, the estimated value and the measured value of the optical loss are almost equal.
[0068]
FIG. 8 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the three combinations of the DSFs 1 and 2 (including the combination of the optical fibers having the same identification). In this graph, the plotted points are approximated to the straight line F1 having a slope of 2, so that the measured value of the optical loss is almost twice the estimated value. Further, the plotted point is substantially located between a straight line F2 having a slope of 1.5 and a straight line F3 having a slope of 2.5.
[0069]
FIG. 9 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the three combinations of LCFs 1 and 2 (including the combination of optical fibers having the same identification). In this graph, the plotted points are approximated to a straight line F4 having a slope of 3, so it can be seen that the measured value of the optical loss is almost three times the estimated value. Further, the plotted point is substantially located between a straight line F5 having a slope of 2.5 and a straight line F6 having a slope of 3.5.
[0070]
FIG. 10 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the six combinations of DSFs 1 and 2 and SMFs 1 to 3. In this graph, since the slope is plotted near the straight line E, the estimated value and the measured value of the optical loss are almost equal. However, many plotted points are located between the straight line E and the straight line F7 obtained by moving the straight line E by 0.05 dB in the measured value direction.
[0071]
FIG. 11 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the six combinations of LCF1 and LCF2 and SMF1-3. In this graph, the slope is 1 and the intercept in the measured value direction is plotted near a straight line F8 having 0.2 dB. In addition, the plotted points are concentrated between a straight line F9 having a slope of 1 and an intercept in the measured value direction of 0.18 dB, and a straight line F10 having a slope of 1 and an intercept in the measured value direction of 0.25 dB. ing.
[0072]
FIG. 12 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the four combinations of LCFs 1 and 2 and DSFs 1 and 2. In this graph, the inclination is 1.3, and the intercept in the direction of the actually measured value is plotted near a straight line F11 having an intercept of 0.1 dB. The plotted point is between a straight line F12 having a slope of 1.2 and an intercept in the measured value direction of 0.07 dB, and a straight line F13 having a slope of 2 and an intercept in the measured value direction of 0.12 dB. Many are gathered.
[0073]
FIG. 13 is a chart showing the correction information obtained by the present embodiment. As shown in FIG. 13, there are six combinations of the category combinations of the SMF, the DSF, and the LCF. These patterns have already been described with reference to FIGS. Then, the slope coefficient K and the addition coefficient D of the equation (2) in the above embodiment may be set as shown in FIG. 13 based on the straight lines F1 to F13. In FIG. 13, the numerical values in parentheses indicate a suitable range.
[0074]
Conventionally, light loss has been estimated using the theoretical formula (1) based on MARCUSE and the like. However, the inventor has found that there is a case where the estimated value of the optical loss obtained by such a theoretical formula does not match the actual optical loss, which is related to the category combination of the optical fibers. Then, in the present embodiment, as described above, correction information such as the slope coefficient K and the addition coefficient D according to the category combination was obtained, and the estimated value of the optical loss was appropriately corrected to obtain accurate estimated information. .
[0075]
The optical fiber fusion splicing device according to the present invention is not limited to the above embodiments and examples, and various modifications are possible. For example, in the above-described embodiment, an operator inputs information stored in the memory 5, but the information may be stored in advance when the optical fiber fusion splicing device is manufactured.
[0076]
The category of the optical fiber included in the category information is not limited to SMF, DSF, and LCF. For example, an optical fiber having a profile structure newly developed in the future can be registered as a new category.
[0077]
【The invention's effect】
The optical fiber fusion splicing device according to the present invention classifies optical fibers into categories according to their structures, and sets connection conditions according to the category combination, thereby appropriately connecting various types of optical fibers when fusion splicing. You can set conditions.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an optical fiber fusion splicing apparatus according to the present invention.
FIG. 2 is a diagram illustrating a data structure inside a memory in the embodiment.
FIG. 3 is a diagram showing a refractive index distribution of an optical fiber cross section of each category.
FIG. 4 is a diagram showing a refractive index distribution of an optical fiber cross section of each category.
FIG. 5 is a diagram illustrating an example of a core detection method in a core detection unit.
FIG. 6 is a table showing the identification, category, and MFD of the optical fibers used in the example.
FIG. 7 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 8 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 9 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 10 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 11 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 12 is a graph plotted based on the estimated value and the measured value of the optical loss in each of the category combinations.
FIG. 13 is a chart showing correction information obtained by the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical fiber fusion splicer, 3a ... 1st optical fiber, 3b ... 2nd optical fiber, 5 ... Memory, 7 ... CPU, 9 ... Observation means, 11 ... Electrode, 13a, 13b ... Support base, 15 ... operation means, 17 ... display means, 19 ... discharge circuit, 21 ... core detection means, 23 ... centering control means, 27 ... condition setting means, 29 ... loss estimation means, 31 ... database area, 33 ... first storage Area, 35: second storage area, 37: third storage area, 39: category list, 41: profile information, 43: connection condition data, 45: correction information, 47: fiber list, 49: MFD data.

Claims (6)

An optical fiber fusion splicing device for fusion splicing first and second optical fibers to each other,
Storage means for storing category information in which the optical fiber is classified into a plurality of categories by its structure, and connection conditions corresponding to a combination of the categories;
Condition setting means for reading out and setting the connection conditions applied to the first and second optical fibers from the storage means based on the category information stored in the storage means,
An optical fiber fusion splicing device, comprising: splicing means for fusion splicing the end faces of the first and second optical fibers based on the splicing conditions set by the condition setting means. 2. The storage unit according to claim 1, wherein the storage unit stores at least a category including a dispersion-shifted optical fiber having a step-type profile and another category including a dispersion-shifted optical fiber having a split-type profile. Optical fiber fusion splicer. The storage means further stores profile information associated with the category information,
Observation means for irradiating the first and second optical fibers with light and observing light transmitted through the first and second optical fibers;
Based on the category information, the profile information corresponding to the category of the first and second optical fibers is read from the storage unit, and based on the profile information and the observation result of the observation unit, the The optical fiber fusion splicing apparatus according to claim 1, further comprising: a core detection unit configured to detect core area information of the first and second optical fibers. The core area of each of the first and second optical fibers is determined based on the core area information detected by the core detection section before the first and second optical fibers are fusion-spliced by the connection section. The optical fiber fusion splicing apparatus according to claim 3, further comprising alignment means for moving each of the first and second optical fibers so that the positions of the first and second optical fibers are aligned with each other. The storage means further stores identification information of the optical fiber and optical property information corresponding to the identification information of the optical fiber,
The core area information detected by the core detecting means after the first and second optical fibers are fusion-spliced by the connecting means, and the first and second optical fibers stored in the storage means 4. The apparatus according to claim 3, further comprising: a loss estimating unit configured to estimate an optical loss at a connection portion between the first and second optical fibers based on the optical characteristic information corresponding to the identification information corresponding to The optical fiber fusion splicing apparatus according to claim 1. The storage unit further stores correction information corresponding to a combination of the categories based on the category information,
The optical fiber fusion splicing apparatus according to claim 5, wherein the loss estimating means corrects an estimation result of the optical loss at the connection portion based on the correction information.

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