JP4134639B2 - Multi-fiber optical connector and optical module - Google Patents

Description

なる式で定義される。この［数１］中にある変数ｒは、光ファイバの光軸からの径方向の距離である。φ（ｒ）は、径方向の光の電界分布であり、光の波長により異なる。
【００２５】
また、上記目的を達成するための本発明に係る光モジュールは、１６心以上の光ファイバが１本以上の光ファイバテープ心線として構成されており、光ファイバテープ心線の一端側が、請求項１または２に記載の多心光フェルールに結線され、光ファイバテープ心線の他端側が、光ファイバアレイに接続されていることを特徴とする。
このような構成の光モジュールによれば、１６心の光ファイバテープ心線を用い、使用するコネクタの数を少なくすることができるので、光モジュールの小型化と低コスト化を図ることができる。
【００２６】
また、本発明に係る光モジュールにおいて、光ファイバのガラス部分の外径が８０μｍであり、光ファイバテープ心線の光ファイバの配列ピッチが１６０μｍ以上であって、２本の光ファイバテープ心線の他端側が、光ファイバテープ心線の横幅方向にずれて積層された状態で、光ファイバアレイに接続されていることが望ましい。
このような構成の光モジュールによれば、外径８０μｍの光ファイバを用いて、光ファイバアレイを従来よりも高密度化することができる。
【００２７】
また、本発明に係る光モジュールにおいて、多心光フェルールの光ファイバ挿入穴のピッチＰ（μｍ）が、１８７≧Ｐ≧１８４、１８２≧Ｐ≧１８０、１７７≧Ｐ≧１７４、１７２≧Ｐ≧１６０、の何れかの範囲内に設定されている。
このような構成の光モジュールによれば、光ファイバ挿入穴の好適なピッチを設定することで、ＭＴコネクタとの誤接続を防止することができる。また、好ましくは、光ファイバテープ心線のピッチを光ファイバ挿入穴と同等にすると良い。
【００２８】
【発明の実施の形態】
以下、本発明に係る多心光コネクタ、及び光モジュールの一実施形態を図１〜５に基づいて説明する。
図１は、本発明に係る多心光コネクタの一実施形態を示す斜視図である。図２は図１における多心光フェルールを示す正面図である。図３は図１に示す多心光コネクタを用いた光モジュールを示す模式図である。図４は図３における光ファイバテープ心線のＸ−Ｘ断面を示す要部断面図である。図５は、図３における光ファイバアレイを示す斜視図である。
【００２９】
本実施形態の多心光フェルールは、ＭＴフェルールと同一の外形及びガイドピン穴を有し、一次元配列された光ファイバ挿入穴に１６心の光ファイバを結線できることを特徴としている。
図１に示すように、本実施形態の多心光コネクタ１は、ＭＴコネクタと類似した構成を有し、多心光フェルール２と、ブーツ５と、光ファイバテープ心線６とを備えている。多心光フェルール２には、光ファイバテープ心線６の一端側が挿入され、ブーツ５を介して多心光フェルール２と光ファイバテープ心線６とが相互に固定されている。ブーツ５はゴム製であり、多心光フェルール２の後端から導出された光ファイバテープ心線６を、急激に折れ曲がることのないように保護している。
【００３０】
多心光フェルール２は、ＭＴフェルールと同一の外形を有し、接続する方向に向かって前方側のフェルール本体３と、後方側のつば部４とから構成されている。また、多心光フェルール２はエポキシ樹脂等によって一体的に成形されている。フェルール本体３は、横幅方向の両端部近傍にガイドピン穴７が設けられており、この２つのガイドピン穴７の間には、１６心の光ファイバ挿入穴８が設けられている。
【００３１】
ガイドピン穴７は、多心光コネクタ１が、ＭＴコネクタに接続可能なアダプタや、別の多心光コネクタ１等に接続されるときにガイドピンを挿入することで、接続時の位置決めを行うものである。ガイドピンは、ＭＴコネクタにおいて使用されるものと同一のものが使用できる。
【００３２】
ここで、多心光フェルール２の各寸法ａ〜ｇ、及びガイドピン穴７の直径は、上述したＭＴコネクタにて規定されている寸法と同一である。特に、多心光コネクタ１にＭＴコネクタと同様のハウジングを装着するためには、フェルール本体３に関わる寸法、すなわち、横幅ａ、縦幅ｃ、接続方向の長さｄ、ガイドピン穴の直径及び中心間の距離ｂを、図６に示したＭＴコネクタと同一にすることが必要である。さらに望ましくは、つば部４に関わる寸法である、横幅ｅ、縦幅ｆ、接続方向の長さｇもＭＴコネクタと同一にすることによって、より一層の汎用性を得ることができる。
【００３３】
また、光ファイバ挿入穴８は、光ファイバテープ心線６の端部から被覆を除去したガラス部分の光ファイバを１心づつ挿入して、結線できるように構成されている。例えば、光ファイバ挿入穴８の最小内径を、１２５μｍ〜１２６μｍとすれば、通常使用されている光ファイバとして最も一般的な、ガラス部分の直径が１２５μｍである光ファイバを結線することができる。
また、光ファイバ挿入穴８の最小内径を、８０μｍ〜８１μｍとすれば、細径の光ファイバとして一般的な、ガラス部分の直径が８０μｍである光ファイバを結線することができる。このような細径の光ファイバ挿入穴８を形成する場合には、細径の成形ピンを高精度に位置決めしなければならないために、高い成形精度を得ることが困難になる。ここで、本実施形態の多心光フェルール２の場合は一次元配列であるため、二次元配列する場合と比較して成形ピンを高精度に位置決めすることが容易である。したがって、光ファイバ挿入穴８を高精度成形することができる。
【００３４】
図２に示すように、１６心の光ファイバ挿入穴８（８ａ〜８ｐ）は、２つのガイドピン穴７の中心間を結ぶ基準線Ｌ上に、各々の中心軸が等ピッチで、かつ一列（一次元）になるように並列されている。さらに、光ファイバ挿入穴８は、基準線Ｌの中点Ｏを原点として対称となる位置に配置されている。すなわち、中点Ｏを中心として、図中左方に位置する８心の光ファイバ挿入穴８ａ〜８ｈと、図中右方に位置する８心の光ファイバ挿入穴８ｉ〜８ｐとが、それぞれ対称の位置関係を有している。このように、光ファイバ挿入穴８を対称形状で規則的に配列することにより、高い成形精度が得られやすい。
【００３５】
また、多心光フェルール２の強度をＭＴコネクタと同等にするために、最も外側に配列された光ファイバ挿入穴８ａ、８ｐは、ガイドピン穴７との間隔Ｑ₁が０．４５ｍｍ以上となるように配置されている。なお、１２心形のＭＴコネクタの規格では、ガイドピン穴と光ファイバ挿入穴との間隔が０．４５ｍｍとなっている。
【００３６】
また、多心光フェルール２を成形する樹脂には、寸法精度を向上させるためにシリカフィラを高い濃度で含有させている。このシリカフィラの最外径は３０μｍ程度である。多心光フェルール２を成形する際に、光ファイバ挿入穴８を形成するための成形ピンの間に樹脂を流入させるためには、隣り合う成形ピンの間隙をシリカフィラが通過するように設ける必要がある。そのため、成形ピンの間隔を３５μｍ以上とすることが好ましい。このように、成形時の成形ピンの間隔を設定することによって、成形された多心光フェルール２は、隣り合う各光ファイバ挿入穴８の間隔Ｑ２が３５μｍ以上となる。
なお、最外径が３０μｍより小さいシリカフィラ、またはシリカフィラに代えて代用可能なフィラを用いた場合には、その大きさによって各光ファイバ挿入穴８の間隔Ｑ２を適宜変更することが可能である。
【００３７】
このように、本実施形態の多心光フェルール２は、全体が樹脂によって一体成形されているため、製造コストを安価に抑えることができる。さらに、ガイドピン穴と光ファイバ挿入穴の設計値を上記のように設けることにより、ＭＴコネクタと同等の強度と高い成形精度を得ることができる。
【００３８】
次に、光ファイバ挿入穴８のピッチＰについて好適な態様を説明する。
上述したように、本発明に用いられる多心光フェルールは、ＭＴコネクタのフェルールと同一の外形及びガイドピン穴を有している。そのため、本発明に用いられる多心光フェルールはＭＴコネクタと機械的に接続することが可能である。
また、本発明に用いられる多心光フェルールは、光モジュールやボード内の配線で光入出力素子や光制御回路等と接続されることが多いため、多系統でＭＴコネクタが使用されていた場合に、誤ってそのＭＴコネクタと接続されてしまう場合が考えられる。
誤接続によってＭＴコネクタと光が導通した場合には、回路が上手く機能しないだけでなく、接続された素子を損傷させてしまう可能性がある。特に、近年のＷＤＭやラマン増幅等の光通信技術の進展に伴い、光ファイバに大出力の光が伝送されている場合が多く、誤接続による機器の損傷対策が重要になっている。
そこで、本発明者らは、ＭＴコネクタと誤接続した際にも光ファイバ間で光が導通することのないように、光ファイバ挿入穴８のピッチＰについて好適な設計値を見出した。
【００３９】
まず、本発明に用いられる多心光フェルールと従来のＭＴフェルールとが誤接続されたときに、互いの光ファイバ挿入穴が重なって光が導通する場合のピッチを求める。
ここで、光ファイバ挿入穴８ａ〜８ｐのうち、中点Ｏに最も近く、内側に位置する８ｈ及び８ｉを１番心と呼び、それぞれ外側に向かって順次２番心、３番心、…８番心と呼ぶこととする。すなわち、最も外側に位置する８ａ及び８ｐが８番心となる。また、一次元配列のＭＴコネクタにおける最大心数の１２心ＭＴコネクタにおいても、１２心の光ファイバ挿入穴を同様に１番心から６番心と呼ぶこととする。上述したように、ＭＴコネクタにおける光ファイバ挿入穴のピッチは２５０μｍである。
【００４０】
本実施形態の多心光フェルール２のｎ番心（ｎ：１以上の整数）と、ＭＴフェルールのｍ番心（ｍ：１〜６の整数）が重なるときのピッチＰ（μｍ）は、多心光フェルール２の心数が偶数の場合は、次に示す（１）式で求められる。
Ｐ＝２５０×（２ｍ−１）／（２ｎ−１） …（１）
この（１）式より、ｎが１〜８である１６心の多心光フェルールを考えた場合の、ｎ番心とｍ番心が重なるピッチＰは、次に示す表の通りである
。
【００４１】
【表１】

【００４２】
この表１により、光ファイバ挿入穴の重なりが生じるピッチＰが判る。例えば、ピッチＰを８３．３μｍに設定すると、ＭＴフェルールの１番心と多心光フェルール２の２番心、ＭＴフェルールの２番心と多心光フェルール２の５番心、及びＭＴフェルールの３番心と多心光フェルール２の８番心が重なることが判る。このピッチＰのときに互いの光ファイバ挿入穴の中心軸が一致するので、光ファイバ同士の光を導通させないためには、この位置から充分な軸ずれ量が確保されれば良い。
ここで、ピッチＰと軸ずれ量Ｄ（μｍ）の関係は、次に示す（２）式により求められる（｜…｜は絶対値を示す）。
Ｄ＝｜（ｎ−ｍ）×２５０−（２ｎ−１）×（２５０−Ｐ）／２｜ …（２）
【００４３】
ずらすべき軸ずれ量Ｄは、使用する光ファイバの実効コア径であるモードフィールド径（以下、ＭＦＤと呼ぶ）に依存する。ＭＦＤの大きさ以上の軸ずれ量を確保すると光が全く導通しなくなるが、その場合、選択できるピッチＰの値が狭められてしまうため、本実施形態ではＭＦＤの半分以上の軸ずれ量を確保することとする。これにより、３ｄＢ以上の伝送量の低減が見込まれるため、実際の光伝送において機器の損傷を防止できる充分なパワー低減効果が得られる。
【００４４】
本実施形態では、使用波長１．５５μｍにおけるＭＦＤ６．５μｍ〜９．５μｍのシングルモード光ファイバを用いることを想定して、軸ずれ量Ｄを５μｍ以上に設定する。例えば、ＭＴフェルールの６番心と多心光フェルール２の７番心との軸ずれ量Ｄが５μｍ以上となる範囲は、上記（２）式にｍ＝６、ｎ＝７を代入することで、２１０．７μｍ以下もしくは２１２．３μｍの範囲であることが判る。同様にして、ＭＴフェルールの各番心と多心光フェルール２の各番心との組み合わせにおいて上記（２）式を計算すると、全ての光ファイバ挿入穴８において光が導通しないか、あるいは光伝送量が充分に低減されるピッチＰの範囲が求められる。
【００４５】
さらに、光ファイバ挿入穴８に結線する光ファイバの直径を８０μｍ〜１２５μｍとして、上述したように光ファイバ挿入穴８とガイドピン穴７との間隔Ｑ１が０．４５ｍｍ以上となり、隣り合う各光ファイバ挿入穴８の間隔Ｑ２が３５μｍ以上となるようにピッチＰを計算する。その結果、ピッチＰの値は、次に示す（３）式〜（６）式のいずれかの範囲内に設定すれば良いことが判る。
１８７≧Ｐ≧１８４ …（３）
１８２≧Ｐ≧１８０ …（４）
１７７≧Ｐ≧１７４ …（５）
１７２≧Ｐ≧１６０ …（６）
【００４６】
また、光ファイバ挿入穴８は、高精度に成形及び配置がなされているため、設計値に対して光ファイバの光軸ずれが極めて小さい。したがって、光ファイバ挿入穴８に結線される光ファイバとして、波長１．５５μｍにおけるＭＦＤが６．５μｍ以下である光ファイバを好適に用いることができる。ＭＦＤの小さい光ファイバを用いることにより、曲げに対する伝送損失の増加を抑えることができ、多心光コネクタ１の伝送特性を向上させることができる。
また、光ファイバテープ心線６の光ファイバの配列ピッチを光ファイバ挿入穴８と同等にすると良い。これにより、光ファイバ挿入穴８に対して光ファイバテープ心線６を結線しやすくなる。
【００４７】
さらに、本実施形態のように、ＭＴフェルールに対して意図的に軸ずれを起こさせる場合、光伝送パワーが大きいと、光ファイバの端部が発熱して多心光フェルール２が高温に加熱されてしまう可能性が考えられる。多心光フェルール２の材質を、難燃性材質としておくことで、加熱による変形や燃焼等の不具合を防止することができる。ここで、多心光フェルール２の樹脂材料に要求される難燃性として、ＵＬのＶ０規格に相当する程度の難燃性を有していることが望ましい。この難燃性を得ることのできる難燃性材料として、射出成形で一般的に使用されるＰＰＳ（ポリフェニレンサルファイド）樹脂を用いることができる。
【００４８】
次に、上述した多心光コネクタ１を用いた光モジュールについて説明する。
図３に示すように、光モジュール１０は、上述した多心光コネクタ１の、光ファイバテープ心線６の他端側が光ファイバアレイ１１に接続されている。光ファイバアレイ１１は、例えばＡＷＧ回路基板等の光導通路２０の端部に設けられている。
光ファイバテープ心線６は、樹脂１３が被覆された１６心の光ファイバを一列に並列させた状態で一括被覆層１４により被覆したものである（図４参照）。また、光ファイバテープ心線６の別の態様として、１つの多心光コネクタ１につき、例えば８心の光ファイバテープ心線が２本、横幅方向に並列した状態で接続されていても良い。
【００４９】
また、図３に示すように、光ファイバアレイ１１には、２つの多心光コネクタ１の光ファイバテープ心線６，６を重ねて接続することができる。ここで、積層された光ファイバテープ心線６，６の断面（図中Ｘ−Ｘ断面）を図４に示す。
また、２本の光ファイバテープ心線６，６が積層されて光ファイバアレイ１１に接続された状態の斜視図を図５に示す。
【００５０】
図３〜図５に示すように、２本の光ファイバテープ心線６，６は、光ファイバアレイ１１に接続された他端側が、横幅方向にずれて積層されている。好ましくは、図４に示すように、光ファイバテープ心線６内に配列された光ファイバ１２の配列ピッチＰ₁を基準として、上下の光ファイバテープ心線６，６が配列ピッチＰ₁の半分の距離Ｐ₂だけ互いにずれて配置されていると良い。
この積層状態のまま、光ファイバテープ心線６の端部において被覆１３が除去された光ファイバ１２は、光ファイバアレイ１１のＶ溝１１ａによって固定され、接続されている。このとき、各光ファイバ１２は、上下の光ファイバテープ心線６，６から交互に配列されてＶ溝１１ａに案内されている。また、隣接する光ファイバ１２同士は、互いに接触するほど近接した状態となっている。したがって、光ファイバアレイ１１に対して光ファイバ１２を高密度に接続することができる。
【００５１】
また、細径の光ファイバを用いると、効果的に高密度化を図ることができる。
例えば、ガラス部分の光ファイバ１２の外径を８０μｍとして、配列ピッチＰ₁を１６０μｍとすると良い。
【００５２】
このように、本実施形態の光モジュール１０は、高密度化を図った多心光コネクタ１を用いて、多心の光ファイバテープ心線６を光ファイバアレイ１１に高密度に接続させている。そのため、使用する多心光コネクタ１の数を減らすことができる。さらに、光モジュール１０の小型化と低コスト化を図ることができる。
また、多心光コネクタ１の光ファイバ挿入穴のピッチＰを、上記（３）式〜（６）式のいずれかの範囲内に設定することにより、ＭＴコネクタとの誤接続を防止して、導波路等の機器に損傷が発生することを防ぐことができる。
【００５３】
なお、上述した実施形態においては、１６心の多心光フェルール、多心光コネクタ、及びこれらを用いた光モジュールについて述べたが、本発明においてはさらなる多心化を図ることも可能である。
【００５４】
【発明の効果】
以上説明したように、本発明によれば、ＭＴコネクタ用のハウジングを利用可能であって、高精度成形が容易である、１６心以上の多心光コネクタ、及びこれらを用いた光モジュールを提供することができる。
【図面の簡単な説明】
【図１】本発明に係る多心光コネクタの一実施形態を示す斜視図である。
【図２】図１における多心光フェルールを示す正面図である。
【図３】図１に示す多心光コネクタを用いた光モジュールを示す模式図である。
【図４】図３における光ファイバテープ心線のＸ−Ｘ断面を示す要部断面図である。
【図５】図３における光ファイバアレイを示す斜視図である。
【図６】従来のＭＴコネクタを示す斜視図である。
【符号の説明】
１ 多心光コネクタ
２ 多心光フェルール
３ フェルール本体
４ つば部
５ ブーツ
６ 光ファイバテープ心線
７ ガイドピン穴
８ 光ファイバ挿入穴
１０ 光モジュール
１１ 光ファイバアレイ[0001]
BACKGROUND OF THE INVENTION
The present inventionManyMore particularly, the present invention relates to a multi-fiber optical fiber having a plurality of optical fiber insertion holes and two guide pin holes.LeThe present invention relates to a multi-fiber optical connector and an optical module used.
[0002]
[Prior art]
In recent years, large-capacity optical communication networks based on wavelength division multiplexing (WDM) transmission technology have been developed in the field of optical communication using optical fibers. Along with this, multi-fiber optical connectors that can connect a plurality of optical fibers in a lump are often used in an optical waveguide or the like for constructing an optical access network.
As a multi-fiber optical connector, a format called an MT connector is defined by an international standard (IEC) related to optical communication (see Non-Patent Document 1). Further, in the Japanese Industrial Standard (JIS), an F12 type multi-core optical fiber connector similar to the MT connector is defined in accordance with IEC (see Non-Patent Document 2).
[0003]
FIG. 6 is a perspective view of an 8-core MT connector.
The MT connector 100 includes a ferrule 101, a boot 104, and an optical fiber tape core wire 105. One end of an optical fiber ribbon 105 is inserted into the ferrule 101, and the ferrule 101 and the optical fiber ribbon 105 are fixed to each other via a boot 104.
[0004]
The ferrule 101 is composed of a ferrule body 102 on the front side and a collar portion 103 on the rear side in the connecting direction, and the whole is integrally formed of epoxy resin or the like. The ferrule body 102 is provided with guide pin holes 106 in the vicinity of both end portions in the width direction, and eight optical fiber insertion holes 107 are provided between the two guide pin holes 106.
[0005]
The guide pin hole 106 is used for positioning at the time of connection by inserting a guide pin when the MT connector 100 is connected to an adapter or another MT connector.
The optical fiber insertion holes 107 are arranged in parallel on a reference line connecting the centers of the two guide pin holes 106 so that the central axes thereof are at an equal pitch and in a single row (one dimension). Furthermore, the optical fiber insertion hole 107 is disposed at a position that is symmetrical with the midpoint O of the reference line as the origin. The pitch P between the central axes of the optical fiber insertion holes 107 is set to 250 μm, which is equivalent to the arrangement pitch of the optical fibers in a normal optical fiber ribbon. The eight optical fiber insertion holes 107 are configured to connect up to eight optical fibers in the glass portion from which the coating has been removed at the end of the optical fiber ribbon 105.
[0006]
Here, main dimensions prescribed for the ferrule 101 will be described.
The ferrule body 102 has a horizontal width a of 6.4 mm and a vertical width c of 2.5 mm. The two guide pin holes 106 have a diameter of 0.7 mm (tolerance ± 0.001 mm) and a center-to-center distance b of 4.6 mm (tolerance ± 0.003 mm). Further, the length d in the connecting direction of the ferrule body 102 is 6.0 mm.
The lateral width e of the collar portion 103 is 7.0 mm, and the vertical width f is 3.0 mm (tolerance ± 0.1 mm). Further, the length g in the connecting direction of the collar portion 103 is 2.0 mm (tolerance ± 0.1 mm).
[0007]
In addition to the above-described 8-core type, the MT connector is also defined for 2-core, 4-core, 10-core, and 12-core shapes. In all MT connectors, the optical fiber insertion holes are arranged at symmetrical positions with the midpoint O of the reference line as the origin, and the pitch is defined as 250 μm.
[0008]
In order to further increase the number of multi-fiber optical connectors, there has been proposed a ferrule having a shape similar to that of an MT connector ferrule and having a two-dimensional array of optical fiber insertion holes. For example, see Patent Document 1).
Furthermore, a ferrule has also been proposed in which the ferrule of the MT connector is made larger in the lateral width direction than the prescribed dimension, and 16 optical fiber insertion holes are arranged one-dimensionally (see, for example, Patent Document 2).
[0009]
(Non-Patent Document 1)
“Connectors for optical fibers and cables. Part 16: Sectional specification for fiber optic connector. Type MT” September 94 IEC 60874-16
(Non-Patent Document 2)
"F12 type multi-core optical fiber connector" Japanese Standards Association 1998 JIS C 5981
(Patent Document 1)
Japanese Patent Laid-Open No. 11-84177 (second page, FIG. 4)
(Patent Document 2)
JP 2001-51154 A (page 3, FIG. 2)
[0010]
[Problems to be solved by the invention]
By the way, the ferrule as described above is integrally formed of resin. As the molding method, two types of mold molding, transfer molding and injection molding, are widely used. In any method, the guide pin hole and the optical fiber insertion hole are generally formed by placing a molding pin in a mold.
Here, when the optical fiber insertion holes are arranged in a vertical and horizontal two-dimensional arrangement, positioning during molding must be performed in two directions, the vertical direction and the horizontal direction, and the structure of the mold becomes complicated. In the case of a one-dimensional arrangement, all of the guide pin holes and the optical fiber insertion holes may be formed in parallel in a row, and positioning is easy, whereas in the case of a two-dimensional arrangement, guide pin holes and 2 It is necessary to form the optical fiber insertion holes in the rows by positioning them in the vertical direction.
[0011]
Therefore, when the optical fiber insertion holes are two-dimensionally arranged, it is difficult to form the optical fibers with high accuracy, and the optical axes of the optical fibers may be displaced when connected to other ferrules.
The ferrule having two-dimensionally arranged optical fiber insertion holes is arranged such that when inserting an optical fiber ribbon, two optical fiber ribbons are arranged vertically, or a multi-fiber optical fiber tape. The core wire had to be branched up and down, and the work was difficult.
[0012]
Further, as described above, when the optical fiber insertion holes are one-dimensionally arranged to further increase the number of cores, the outer shape of the ferrule and the arrangement of the guide pin holes are different from the standard MT connector. For this reason, the housings for MT connectors that have already been distributed cannot be used, and the versatility of the product is lacking.
[0013]
Furthermore, in an optical module for connecting a communication device or the like to an optical fiber array provided at an end portion of an optical waveguide, a multi-fiber optical connector capable of connecting multi-core optical fibers has been desired. .
[0014]
The object of the present invention is to make use of a housing for an MT connector, and high precision molding is easy.ManyOptical fiber connector and connectorThisIt is to provide an optical module used.
[0015]
[Means for Solving the Problems]
Multi-centered light according to the present invention for achieving the above objectconnectorIs a multi-fiber optical ferrule having a plurality of optical fiber insertion holes and two guide pin holesAnd a multi-fiber optical connector in which one or more optical fibers are connected,The outer shape of the multi-core optical ferrule and the guide pin hole are configured in the same shape and arrangement as the MT ferrule defined in IEC 60874-16,In the optical fiber insertion hole, 16 core holes are juxtaposed on a reference line connecting the centers of the two guide pin holes so that each central axis is arranged in a line at an equal pitch, and the reference line Mode at the wavelength of 1.55 μm of the optical fiber with respect to each central axis of the optical fiber insertion hole in the MT ferrule. The pitch P (μm) between the central axes is 187 ≧ P ≧ 184, 182 ≧ P ≧ 180, 177 ≧ P ≧ 174, 172 ≧ P ≧ 160. Is set within the rangeIt is characterized by that.
[0016]
Multi-core light with this configurationconnectorSince it is possible to connect 16 or more optical fibers and the outer shape is the same as that of the MT ferrule, the versatility of the ferrule is further increased compared to standards such as IEC. You can be minded. Moreover, since the optical fiber insertion holes are arranged in a line (one dimension), high-precision molding is possible.Further, it is possible to connect more optical fibers than the MT connector, and the connected optical fibers are arranged with high accuracy. Further, the same housing as the MT connector can be used, and the versatility is excellent. Further, each central axis of the optical fiber insertion hole is disposed at a position more than half of the mode field diameter with respect to each central axis of the optical fiber insertion hole in the MT ferrule, and the optical fiber insertion hole has two guides. Since the central axes of the pin holes are arranged in parallel so as to form a line at equal pitches on the reference line connecting the centers of the pin holes, and are arranged at symmetrical positions with the midpoint of the reference line as the origin It is possible to easily prevent light from being conducted between optical fibers when erroneously connected to an MT connector of another system. Also, 16 optical fiber insertion holes are provided, and the pitch P (μm) between the central axes is 187 ≧ P ≧ 184, 182 ≧ P ≧ 180, 177 ≧ P ≧ 174, 172 ≧ P ≧. 160 is set within the range of 160. Therefore, when an optical fiber having a mode field diameter of 10.0 μm or less (for example, 6.5 μm to 9.5 μm) is used, erroneous connection with the MT connector is caused. Can be prevented.
[0017]
In the multi-core optical ferrule according to the present invention, it is desirable that the entire multi-core optical ferrule is integrally formed of resin.
According to the multi-core optical ferrule having such a configuration, the manufacturing cost can be reduced as compared with the case where a material other than the resin is used together or the multi-core optical ferrule is configured by a plurality of members.
[0018]
In the multi-fiber optical ferrule according to the present invention, it is desirable that the minimum inner diameter of the optical fiber insertion hole is 125 μm to 126 μm.
According to the multi-core optical ferrule having such a configuration, it is possible to connect an optical fiber having a diameter of 125 μm, which is most common as an optical fiber.
[0019]
In the multi-fiber optical ferrule according to the present invention, it is desirable that the minimum inner diameter of the optical fiber insertion hole is 80 μm to 81 μm.
According to the multi-core optical ferrule having such a configuration, it is possible to connect an optical fiber having a glass portion diameter of 80 μm, which is common as a thin optical fiber.
In addition, when forming such a small-diameter optical fiber insertion hole, it is difficult to position because a small-diameter molding pin is used. Therefore, it is easy to position the forming pin with high accuracy as compared with the case of two-dimensional arrangement.
[0020]
In the multi-core optical ferrule according to the present invention, it is desirable that the distance between the optical fiber insertion hole and the guide pin hole is 0.45 mm or more, and the distance between adjacent optical fiber insertion holes is 35 μm or more.
According to the multi-core optical ferrule having such a configuration, sufficient strength and molding accuracy can be obtained when the optical fiber insertion hole and the guide pin hole are molded with resin.
[0022]
In the multi-fiber optical connector according to the present invention, the optical fiber desirably has a mode field diameter of 6.5 μm or less at a wavelength of 1.55 μm.
According to the multi-fiber optical connector having such a configuration, since the optical fibers are arranged with high accuracy, the optical axis deviation from the design value is small. Can be used. Further, by using an optical fiber having a small mode field diameter, it is possible to obtain a multi-fiber optical connector having good transmission characteristics in which transmission loss hardly occurs with respect to bending.
The mode field diameter in the present invention employs the mode field diameter defined by Petermann-I. The mode field diameter (MFD) defined by Petermann-I is
[Expression 1]

Is defined by the expression The variable r in [Expression 1] is a radial distance from the optical axis of the optical fiber. φ (r) is the electric field distribution of light in the radial direction, and varies depending on the wavelength of light.
[0025]
In addition, an optical module according to the present invention for achieving the above object is configured such that 16 or more optical fibers are configured as one or more optical fiber tape cores, and one end side of the optical fiber tape cores is the claim. 1Or 2The other end side of the optical fiber ribbon is connected to the optical fiber array.
According to the optical module having such a configuration, since the number of connectors to be used can be reduced by using 16 optical fiber ribbons, the optical module can be reduced in size and cost.
[0026]
Further, in the optical module according to the present invention, the outer diameter of the glass portion of the optical fiber is 80 μm, the arrangement pitch of the optical fibers of the optical fiber ribbon is 160 μm or more, and the two optical fiber ribbons It is desirable that the other end is connected to the optical fiber array in a state where the other end side is laminated while being shifted in the lateral width direction of the optical fiber ribbon.
According to the optical module having such a configuration, the optical fiber array can be made higher in density than the conventional one by using the optical fiber having an outer diameter of 80 μm.
[0027]
In the optical module according to the present invention, the pitch P (μm) of the optical fiber insertion holes of the multi-core optical ferrule is 187 ≧ P ≧ 184, 182 ≧ P ≧ 180, 177 ≧ P ≧ 174, 172 ≧ P ≧ 160. , Is set within one of the rangesThe
According to the optical module having such a configuration, erroneous connection with the MT connector can be prevented by setting a suitable pitch of the optical fiber insertion holes. Preferably, the pitch of the optical fiber ribbon is set to be equal to that of the optical fiber insertion hole.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention relates toManyOne embodiment of the optical fiber connector and the optical module will be described with reference to FIGS.
FIG. 1 relates to the present invention.ManyIt is a perspective view which shows one Embodiment of the optical fiber connector. FIG. 2 is a front view showing the multi-core optical ferrule in FIG. FIG. 3 is a schematic diagram showing an optical module using the multi-fiber optical connector shown in FIG. 4 is a cross-sectional view of the main part showing the XX cross section of the optical fiber ribbon in FIG. FIG. 5 is a perspective view showing the optical fiber array in FIG.
[0029]
The multi-core optical ferrule of this embodiment has the same outer shape and guide pin hole as the MT ferrule, and is characterized in that 16 optical fibers can be connected to an optical fiber insertion hole arranged one-dimensionally.
As shown in FIG. 1, the multi-fiber optical connector 1 of the present embodiment has a configuration similar to that of an MT connector, and includes a multi-fiber optical ferrule 2, a boot 5, and an optical fiber tape core wire 6. . One end of an optical fiber ribbon 6 is inserted into the multi-fiber optical ferrule 2, and the multi-fiber optical ferrule 2 and the optical fiber ribbon 6 are fixed to each other via a boot 5. The boot 5 is made of rubber and protects the optical fiber tape core wire 6 led out from the rear end of the multi-fiber optical ferrule 2 so as not to be bent suddenly.
[0030]
The multi-core optical ferrule 2 has the same outer shape as the MT ferrule, and includes a ferrule body 3 on the front side and a collar portion 4 on the rear side in the connecting direction. The multi-core optical ferrule 2 is integrally formed of an epoxy resin or the like. The ferrule body 3 is provided with guide pin holes 7 in the vicinity of both ends in the lateral width direction, and 16 optical fiber insertion holes 8 are provided between the two guide pin holes 7.
[0031]
The guide pin hole 7 is positioned at the time of connection by inserting a guide pin when the multi-fiber optical connector 1 is connected to an MT connector or another multi-fiber optical connector 1 or the like. Is. The same guide pin as that used in the MT connector can be used.
[0032]
Here, each dimension ag of the multi-core optical ferrule 2 and the diameter of the guide pin hole 7 are the same as those defined in the MT connector described above. In particular, in order to mount the same housing as the MT connector on the multi-fiber optical connector 1, the dimensions relating to the ferrule body 3, that is, the width a, the length c, the length d in the connection direction, the diameter of the guide pin hole, and The distance b between the centers must be the same as that of the MT connector shown in FIG. More desirably, the horizontal width e, the vertical width f, and the length g in the connecting direction, which are dimensions related to the flange portion 4, are also made the same as those of the MT connector, thereby further increasing versatility.
[0033]
Further, the optical fiber insertion hole 8 is configured so that the optical fibers of the glass portion from which the coating is removed from the end of the optical fiber ribbon 6 can be inserted one by one and connected. For example, when the minimum inner diameter of the optical fiber insertion hole 8 is set to 125 μm to 126 μm, an optical fiber having a diameter of 125 μm, which is most common as a commonly used optical fiber, can be connected.
If the minimum inner diameter of the optical fiber insertion hole 8 is 80 μm to 81 μm, it is possible to connect an optical fiber having a diameter of 80 μm, which is common as a thin optical fiber. When such a small-diameter optical fiber insertion hole 8 is formed, it is difficult to obtain high molding accuracy because the small-diameter molding pin must be positioned with high accuracy. Here, since the multi-fiber optical ferrule 2 of the present embodiment is a one-dimensional array, it is easy to position the forming pin with higher precision than in the case of a two-dimensional array. Therefore, the optical fiber insertion hole 8 can be formed with high accuracy.
[0034]
As shown in FIG. 2, the 16 optical fiber insertion holes 8 (8 a to 8 p) are arranged in a row on the reference line L connecting the centers of the two guide pin holes 7, with each central axis at an equal pitch. Parallel (one-dimensional). Furthermore, the optical fiber insertion hole 8 is disposed at a position that is symmetric with respect to the midpoint O of the reference line L as the origin. That is, the eight optical fiber insertion holes 8a to 8h located on the left side in the figure and the eight optical fiber insertion holes 8i to 8p located on the right side in the figure are symmetrical with respect to the middle point O. The positional relationship is as follows. Thus, high molding accuracy is easily obtained by arranging the optical fiber insertion holes 8 regularly in a symmetrical shape.
[0035]
Further, in order to make the strength of the multi-core optical ferrule 2 equal to that of the MT connector, the optical fiber insertion holes 8a and 8p arranged on the outermost side are spaced from the guide pin hole 7 by a distance Q.₁Is arranged to be 0.45 mm or more. In the 12-core MT connector standard, the distance between the guide pin hole and the optical fiber insertion hole is 0.45 mm.
[0036]
Further, the resin for forming the multi-core optical ferrule 2 contains silica filler at a high concentration in order to improve dimensional accuracy. The outermost diameter of this silica filler is about 30 μm. When the multi-core optical ferrule 2 is molded, in order to allow the resin to flow between the molding pins for forming the optical fiber insertion holes 8, it is necessary to provide a gap between the adjacent molding pins so that the silica filler passes therethrough. There is. Therefore, the distance between the forming pins3It is preferable to be 5 μm or more. In this way, by setting the interval between the forming pins at the time of forming, the formed multi-core optical ferrule 2 has an interval Q2 between the adjacent optical fiber insertion holes 8.35 μm or more.
When a silica filler having an outermost diameter of less than 30 μm or a substitute filler is used instead of the silica filler, the interval Q2 between the optical fiber insertion holes 8 can be appropriately changed depending on the size. is there.
[0037]
As described above, since the multi-fiber optical ferrule 2 of the present embodiment is integrally formed of resin as a whole, the manufacturing cost can be reduced at a low cost. Furthermore, by providing the design values of the guide pin hole and the optical fiber insertion hole as described above, it is possible to obtain the same strength and high molding accuracy as the MT connector.
[0038]
Next, a suitable aspect is demonstrated about the pitch P of the optical fiber insertion hole 8. FIG.
As mentioned above, the present inventionUsedThe multi-fiber optical ferrule has the same outer shape and guide pin hole as the ferrule of the MT connector. Therefore, in the present inventionUsedThe multi-fiber optical ferrule can be mechanically connected to the MT connector.
Also, in the present inventionUsedA multi-core optical ferrule is often connected to an optical input / output element, an optical control circuit, or the like by an optical module or wiring in a board. Therefore, when an MT connector is used in multiple systems, the MT connector is mistakenly used. It may be connected to.
If the MT connector and light are conducted due to incorrect connection, the circuit does not function well, and the connected element may be damaged. In particular, with the progress of optical communication technologies such as WDM and Raman amplification in recent years, there are many cases where high-power light is transmitted to an optical fiber, and countermeasures against equipment damage due to erroneous connection are important.
Therefore, the present inventors have found a suitable design value for the pitch P of the optical fiber insertion hole 8 so that light does not conduct between the optical fibers even when erroneously connected to the MT connector.
[0039]
First, in the present inventionUsedWhen the multi-core optical ferrule and the conventional MT ferrule are erroneously connected, the pitch when the optical fiber insertion holes overlap and the light is conducted is obtained.
Here, among the optical fiber insertion holes 8a to 8p, 8h and 8i that are closest to the middle point O and are located on the inner side are called the first center, and the second center, the third center,. We will call it courier. That is, 8a and 8p located on the outermost side are the eighth center. Also, in the 12-fiber MT connector having the maximum number of cores in the one-dimensional array MT connector, the 12-fiber optical fiber insertion holes are similarly referred to as the first to sixth cores. As described above, the pitch of the optical fiber insertion holes in the MT connector is 250 μm.
[0040]
The pitch P (μm) when the n-th center of the multi-core optical ferrule 2 of the present embodiment (n: an integer of 1 or more) and the m-th center of the MT ferrule (m: an integer of 1 to 6) overlap is large. When the number of hearts of the cardiac optical ferrule 2 is an even number, it is obtained by the following equation (1).
P = 250 × (2m−1) / (2n−1) (1)
From this equation (1), the pitch P at which the n-th and m-th cores overlap when considering a 16-core multi-core optical ferrule with n of 1 to 8 is as shown in the following table.
.
[0041]
[Table 1]

[0042]
Table 1 shows the pitch P at which the optical fiber insertion holes overlap. For example, if the pitch P is set to 83.3 μm, the first core of the MT ferrule and the second core of the multi-fiber optical ferrule 2, the second core of the MT ferrule and the fifth core of the multi-fiber optical ferrule 2, and the MT ferrule It can be seen that the third core and the eighth core of the multi-fiber optical ferrule 2 overlap. Since the center axes of the optical fiber insertion holes coincide with each other at this pitch P, a sufficient amount of axial misalignment is required from this position in order not to conduct light between the optical fibers.
Here, the relationship between the pitch P and the axis deviation D (μm) is obtained by the following equation (2) (| ... | indicates an absolute value).
D = | (n−m) × 250− (2n−1) × (250−P) / 2 | (2)
[0043]
The axis deviation amount D to be shifted depends on a mode field diameter (hereinafter referred to as MFD) which is an effective core diameter of an optical fiber to be used. If the amount of misalignment greater than the size of the MFD is ensured, light will not be conducted at all. However, in this case, the value of the selectable pitch P is narrowed, so in this embodiment, the amount of misalignment more than half of the MFD is ensured. I decided to. Thereby, since the reduction of the transmission amount of 3 dB or more is expected, a sufficient power reduction effect capable of preventing damage to the apparatus in actual optical transmission can be obtained.
[0044]
In the present embodiment, assuming that a single mode optical fiber having an MFD of 6.5 μm to 9.5 μm at a used wavelength of 1.55 μm is used, the axis deviation amount D is set to 5 μm or more. For example, the range in which the axis deviation D between the 6th center of the MT ferrule and the 7th center of the multi-core optical ferrule 2 is 5 μm or more is obtained by substituting m = 6 and n = 7 into the above equation (2). 210.7 μm or less, or 212.3 μm. Similarly, when the above equation (2) is calculated for each combination of the MT ferrule cores and the multi-fiber optical ferrule 2, light is not conducted in all the optical fiber insertion holes 8 or optical transmission is performed. A range of the pitch P in which the amount is sufficiently reduced is required.
[0045]
Further, the diameter of the optical fiber connected to the optical fiber insertion hole 8 is 80 μm to 125 μm, and the distance Q1 between the optical fiber insertion hole 8 and the guide pin hole 7 is 0.45 mm or more as described above, and each adjacent optical fiber Interval Q2 between the insertion holes 83The pitch P is calculated so as to be 5 μm or more. As a result, it can be seen that the value of the pitch P may be set in any one of the following formulas (3) to (6).
187 ≧ P ≧ 184 (3)
182 ≧ P ≧ 180 (4)
177 ≧ P ≧ 174 (5)
172 ≧ P ≧ 160 (6)
[0046]
Further, since the optical fiber insertion hole 8 is molded and arranged with high accuracy, the optical axis deviation of the optical fiber is extremely small with respect to the design value. Therefore, an optical fiber having an MFD at a wavelength of 1.55 μm of 6.5 μm or less can be suitably used as the optical fiber connected to the optical fiber insertion hole 8. By using an optical fiber having a small MFD, an increase in transmission loss due to bending can be suppressed, and the transmission characteristics of the multi-fiber optical connector 1 can be improved.
Further, it is preferable that the arrangement pitch of the optical fibers of the optical fiber ribbon 6 is made equal to that of the optical fiber insertion hole 8. Thereby, it becomes easy to connect the optical fiber ribbon 6 to the optical fiber insertion hole 8.
[0047]
Furthermore, as in the present embodiment, when the MT ferrule is intentionally misaligned, if the optical transmission power is large, the end of the optical fiber generates heat and the multi-core optical ferrule 2 is heated to a high temperature. There is a possibility that By setting the material of the multi-core optical ferrule 2 as a flame retardant material, it is possible to prevent problems such as deformation and combustion due to heating. Here, as the flame retardancy required for the resin material of the multi-core optical ferrule 2, it is desirable to have a flame retardance of a level corresponding to the UL V0 standard. As a flame retardant material capable of obtaining this flame retardancy, a PPS (polyphenylene sulfide) resin generally used in injection molding can be used.
[0048]
Next, an optical module using the multi-fiber optical connector 1 described above will be described.
As shown in FIG. 3, in the optical module 10, the other end side of the optical fiber ribbon 6 of the multi-fiber optical connector 1 described above is connected to the optical fiber array 11. The optical fiber array 11 is provided at the end of an optical path 20 such as an AWG circuit board.
The optical fiber ribbon 6 is made of a 16-core optical fiber coated with a resin 13 and is covered with a collective coating layer 14 in a line (see FIG. 4). Further, as another aspect of the optical fiber ribbon 6, for example, two multi-fiber optical fiber cores 1 may be connected in a state where two optical fiber ribbons are arranged in parallel in the lateral width direction.
[0049]
As shown in FIG. 3, the optical fiber array 11 can be connected with the optical fiber ribbons 6 and 6 of the two multi-fiber optical connectors 1 being overlapped. Here, the cross section (XX cross section in the figure) of the laminated optical fiber ribbons 6 and 6 is shown in FIG.
FIG. 5 shows a perspective view of a state in which two optical fiber ribbons 6 and 6 are laminated and connected to the optical fiber array 11.
[0050]
As shown in FIGS. 3 to 5, the two optical fiber ribbons 6 and 6 are stacked such that the other end side connected to the optical fiber array 11 is shifted in the lateral width direction. Preferably, as shown in FIG. 4, the arrangement pitch P of the optical fibers 12 arranged in the optical fiber ribbon 6.₁The upper and lower optical fiber ribbons 6 and 6 are arranged at the pitch P₁Half the distance P₂It is preferable that they are arranged so as to be shifted from each other.
In this laminated state, the optical fiber 12 from which the coating 13 has been removed at the end of the optical fiber ribbon 6 is fixed and connected by the V groove 11a of the optical fiber array 11. At this time, the optical fibers 12 are alternately arranged from the upper and lower optical fiber ribbons 6 and 6 and guided to the V-groove 11a. Adjacent optical fibers 12 are in close proximity to each other. Therefore, the optical fibers 12 can be connected to the optical fiber array 11 with high density.
[0051]
Further, when a small-diameter optical fiber is used, the density can be effectively increased.
For example, if the outer diameter of the optical fiber 12 in the glass portion is 80 μm, the arrangement pitch P₁Is preferably 160 μm.
[0052]
As described above, in the optical module 10 according to the present embodiment, the multi-fiber optical fiber ribbon 6 is connected to the optical fiber array 11 with high density by using the multi-fiber optical connector 1 with high density. . Therefore, the number of multi-fiber optical connectors 1 to be used can be reduced. Furthermore, the optical module 10 can be reduced in size and cost.
Further, by setting the pitch P of the optical fiber insertion holes of the multi-fiber optical connector 1 within the range of any one of the above formulas (3) to (6), erroneous connection with the MT connector is prevented, It is possible to prevent damage to equipment such as a waveguide.
[0053]
In the above-described embodiment, the 16-core multi-fiber optical ferrule, the multi-fiber optical connector, and the optical module using these are described. However, in the present invention, it is possible to further increase the number of fibers.
[0054]
【The invention's effect】
As described above, according to the present invention, the housing for the MT connector can be used, and high precision molding is easy.ManyAn optical fiber connector and an optical module using them can be provided.
[Brief description of the drawings]
FIG. 1 relates to the present invention.ManyIt is a perspective view which shows one Embodiment of the optical fiber connector.
2 is a front view showing the multi-core optical ferrule in FIG. 1. FIG.
3 is a schematic view showing an optical module using the multi-fiber optical connector shown in FIG. 1. FIG.
4 is a cross-sectional view of the main part showing the XX cross section of the optical fiber ribbon in FIG. 3. FIG.
5 is a perspective view showing the optical fiber array in FIG. 3. FIG.
FIG. 6 is a perspective view showing a conventional MT connector.
[Explanation of symbols]
1 Multi-fiber optical connector
2 Multi-fiber optical ferrule
3 Ferrule body
4 collar
5 Boots
6 Optical fiber ribbon
7 Guide pin hole
8 Optical fiber insertion hole
10 Optical module
11 Optical fiber array

Claims (4)

A plurality center of the optical fiber insertion hole, the multi-fiber optical ferrule with two guide pin holes, a multi-fiber optical connector 1 heart or more optical fibers are connected,
The outer shape of the multi-core optical ferrule and the guide pin hole are configured in the same shape and arrangement as the MT ferrule defined in IEC 60874-16,
In the optical fiber insertion hole, 16 core holes are juxtaposed on a reference line connecting the centers of the two guide pin holes so that each central axis is arranged in a line at an equal pitch, and the reference line Is placed at a symmetrical position with the midpoint of
Each central axis of the optical fiber insertion hole is disposed at a position separated from each central axis of the optical fiber insertion hole in the MT ferrule by more than half of a mode field diameter at a wavelength of 1.55 μm of the optical fiber, and The pitch P (μm) between the respective central axes is set within the range of 187 ≧ P ≧ 184, 182 ≧ P ≧ 180, 177 ≧ P ≧ 174, 172 ≧ P ≧ 160. Features multi-fiber optical connector . 2. The multi-fiber optical connector according to claim 1, wherein an interval between the optical fiber insertion hole and the guide pin hole is 0.45 mm or more, and an interval between the adjacent optical fiber insertion holes is 35 μm or more. multi-fiber optical connector which is characterized. 16 or more optical fibers are configured as one or more optical fiber ribbons, and one end of the optical fiber ribbon is connected to the multi-fiber optical ferrule according to claim 1 or 2 , and the light An optical module, wherein the other end side of the fiber ribbon is connected to an optical fiber array. 4. The optical module according to claim 3 , wherein an outer diameter of the glass portion of the optical fiber is 80 μm, an arrangement pitch of the optical fibers of the optical fiber ribbon is 160 μm or more, and the two optical fibers An optical module, wherein the other end side of the tape core wire is connected to the optical fiber array in a state of being laminated while being shifted in a lateral width direction of the optical fiber tape core wire.

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