JP2004045901A - Optical waveguide device and communication equipment using optical waveguide device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide device such as a demultiplexer, a multiplexer and an optical switch which is small-sized and prevents crosstalk and to provide communication equipment which uses the optical waveguide device. <P>SOLUTION: The optical waveguide device 12a comprises a substrate 13, a lower clad layer 14, cores 15a, 15b, and 15c, an upper clad layer 16, a glass substrate 17, and a filter 18 which reflects only a specified wavelength band and transmits other light. End surfaces of the cores 15a to 15c are connected to an optical fiber, a projecting element, a photodetecting element, etc. The cores 15a to 15c are not connected, but independent in themselves, so light which is propagated in the cores 15a and 15c and transmitted through the filter 18 never leaks to the core 15c. <P>COPYRIGHT: (C)2004,JPO

Description

（コア１５ａの幅と、コア１５ａとコア１５ｃの隙間δは考慮せず）
を満たさなければならない。
【００４０】
しかしながら、コア１５ｃの幅は、光入射端付近で上記値を満たしていればよいので、受光素子２３の受光面の大きさ等を考慮して、図８（ａ）（ｂ）に示すようにコア１５ｃの側面にはテーパーを設けてもよい。図８（ａ）に示すコア１５ｃは、光入射端から光出射端に向けてコアの幅が徐々に狭くなっている。また、図８（ｂ）に示すコア１５ｃは、光入射端が略半円状になっており、コア１５ｃの幅の中心方向に光を集光した後、直線状コアで伝搬させるようになっている。図８（ａ）（ｂ）に示す形状のコア１５ｃによっては、コア１５ｃに光学的に接続した受光素子２３との接続損失を抑制することができる。
【００４１】
コア１５ａから出射され、フィルタ１８で反射された光は、コア１５ｃに達するまでに設置溝１９又は下部クラッド層１４の内部で厚み方向にも広がるので、、図３に示すようにコア１５ｃの光入射端の厚みをコア１５ａの厚みよりも厚くしておけば受光面積が大きくなって損失光を抑制することができる。しかしながら、コア１５ｃでの受光量に問題がなければ、図９（ａ）に示すようにコア１５ａの厚みとコア１５ｃの厚みを同じ厚みにしておいてもよい。
【００４２】
また、図９（ｂ）に示すように受光素子の受光面の大きさや形状に合わせてコア１５ｃの厚み方向でもテーパーを設けば、受光素子の受光面積が小さいときにも、接続損失を抑制することができる。なお、テーパーは幅方向と厚み方向の両方に設けても、いずれか一方のみに設けるようにしても良い。
【００４３】
（第２の実施形態）
図１０は本発明の一実施形態である光導波路装置（光トランシーバ）１２ｂの概略斜視図である。本発明の光導波路装置１２ｂは、支持基板２９、導波路基板３１及びフィルタ１８から構成されている。導波路基板３１は、上下反転した状態で支持基板２９に設置されており、基板１３、高屈折率の光学材料からなる下部クラッド層１４及び上部クラッド層１６、下部クラッド層１４より高屈折率の光学材料からなるコア１５ａ，１５ｂ，１５ｃから構成されている。
【００４４】
コア１５ａ，１５ｂ，１５ｃは、いずれも断面矩形の直線状をしたコアであって、各コア１５ａ，１５ｂ，１５ｃは独立している。コア１５ｃ端面とコア１５ａの側面は５μｍ以上離れており、間には下部クラッド層１４が挟まれている。コア１５ａとコア１５ｂは、同一直線上に光軸が並ぶように設置溝１９を隔てて配置され、また、コア１５ｃの光軸は、コア１５ａ，１５ｂの光軸と垂直をなしている。コア１５ａ，１５ｂはシングルモードの光信号を伝搬する幅の狭いコアであるが、コア１５ｃはマルチモードの光信号を伝搬するコアであってコア１５ａ，１５ｂよりも幅が広くなっている。
【００４５】
フィルタ１８は特定の波長域の光のみを透過させ、特定の波長域以外の光を反射させる光学素子であって、導波路基板３１に設けられた設置溝１９に挿入されている。下部クラッド層１４内に埋め込まれているコア１５ａ及びコア１５ｂはフィルタ１８を介して一直線上に並んでいる。また、コア１５ｃは、両コア１５ａ，１５ｂの光軸に対して９０度の角度を持つようにして配置されている。
【００４６】
支持基板２９の表面には、上記光導波路基板３１を積層するための導波路固定領域３０（図示せず）が形成され、その周囲にはＶ溝状の光ファイバガイド２８、凹状をした光学素子設置部２６ａ，２６ｂが設けられている。各光学素子設置部２６ａ，２６ｂ内には、投光素子や受光素子を実装するための素子実装用ベンチ（電極パッド）２７ａ，２７ｂが形成されている。
【００４７】
図１０に示す光導波路装置１２ｂにおいては、上記光導波路基板３１は、上下反転された状態で設置されており、光ファイバガイド２８及び素子実装用ベンチ２７ａ，２７ｂは光導波路基板３１から露出している。
【００４８】
図１１は上記光導波路装置１２ｂに投光素子２２と受光素子２３を実装し、光ファイバ２１をつないだ状態を示す平面図である。光学素子設置部２６ａ，２６ｂ内の素子実装用ベンチ２７ａ，２７ｂには、下面電極をダイボンドすることにより、それぞれ受光素子２３と投光素子２２が実装されており、受光素子２３はコア１５ｃの端面に対向し、投光素子２２はコア１５ｂの端面に対向している。また、投光素子２２及び受光素子２３の上面電極はボンディングワイヤで回路基板などに接続される。光ファイバ２１は、光ファイバガイド２８に納めて位置決めした状態で接着剤により固定されており、それによってコア１５ａの光軸と光ファイバ２１の光軸が自動的に調芯されている。
【００４９】
この光導波路装置１２ｂにおいてフィルタ１８は、投光素子２２から出射される波長λ１の光を透過し、光ファイバ２１から出射される波長λ２の光を反射する特性のものを用いている。しかして、投光素子２２からコア１５ｂに光（送信信号）を照射すると、光はコア１５ｂの内部を伝搬し、フィルタ１８を透過してコア１５ａの内部を伝搬し、光ファイバ２１に入射して光ファイバ２１内を送信される。また、光ファイバ２１を伝搬してきた光（受信信号）は、コア１５ａに入射して、フィルタ１８で反射し、コア１５ｃを伝搬して受光素子２３に受信される。このようにして光導波路装置１２ｂは、一本の光ファイバ２１を通じて繋がっている外部の他の装置と信号の送受信を行うことができる。
【００５０】
本実施形態の光導波路装置１２ｂでは、コア１５ａとコア１５ｃとを完全に分離して、コア１５ｃの端面とコア１５ａの間にコア１５ａ，１５ｂ，１５ｃよりも屈折率の小さな下部クラッド層１４を挟んでいる。しかして、コア１５ｂを伝搬してフィルタ１８を透過した光は、コア１５ｃに入射することなくコア１５ａを伝搬することになる。また、コア１５ａを伝搬し、フィルタ１８で反射した光は、臨界角よりも小さい角度で下クラッド層１４に入射するために、コア１５ａよりも屈折率の小さい下クラッド層１４でも反射されず、コア１５ｃの端面に入射することになる。したがって、本発明の光導波路装置１２ａは、クロストークが発生することのない、高精度の光トランシーバにすることができる。
【００５１】
以下に、図１２〜図１７を用いて本発明の光導波路装置１２ｂの製造方法を説明する。まず、支持基板２９の親基板になるガラス基板やシリコン基板などの大面積のベース基板２９ａの表面に、図１２に示すように導波路固定領域３０、光学素子設置部２６ａ，２６ｂ、ファイバガイド２８を複数組形成し、光学素子設置部２６ａ，２６ｂの内部に素子実装用ベンチ２７ａ，２７ｂを電極材料によって形成する。図１２のベース基板２９ａを用いれば一度に４個の光導波路装置１２ｂを製造できるが、より大面積のベース基板２９ａを用いれば、光導波路装置１２ｂの大量生産が可能になる。
【００５２】
また、ベース基板２９ａと同面積以上のガラス基板１３ａ上に下部クラッド層１４と複数組のコア１５ｃ，１５ｄを形成した導波路基板３１を複製法（スタンパ法）等で製造する。複製法によるより詳しい製造方法は、第１の実施形態で説明している。
【００５３】
次に、図１３に示すように、光導波路基板３１の表面に、未硬化の紫外線硬化樹脂１６ａを滴下し、樹脂１６ａによって光導波路基板３１とベース基板２９ａとを接着する。ベース基板２９ａと光導波路基板３１とを接着するときには、ファイバガイド２８や光学素子設置部２６ａ，２６ｂとコア１５ｃ，１５ｄを精密に位置合わせをしておく必要がある。そのためには、光導波路基板３１とベース基板２９ａに設けたアライメントマークにより精度良く位置合せを行って光導波路基板３１とベース基板２９ａを接着すればよい。大面積のベース基板２９ａと大面積の光導波路基板３１とで位置合わせを行えば、個々の部品どうしを位置合わせするような煩雑さがなく、一度に複数のコアとファイバガイド等との位置合わせを精度良く行えるため効率的である。
【００５４】
ベース基板２９ａと光導波路基板３１を位置合わせして重ね合わせた後、紫外線を照射する前に、導波路固定領域３０にのみ紫外線が照射されるように、ガラス基板１３ａを図１４に示すような紫外線を透過しないマスク３２で覆っておく。マスク３２で覆われたガラス基板１３ａに紫外線を照射すると、導波路固定領域３０にのみ紫外線が照射されて、樹脂１６ａが硬化し、上部クラッド層１６が形成される。なお、ベース基板２９ａが紫外線を透過する材質であるときには、ベース基板２９ａをマスク３２で覆うようにして、ベース基板２９ａ側から紫外線を照射してもよい。
【００５５】
次に図１５に示すようにダイシングブレードを用いてコア１５ｄをコア１５ａ，１５ｂに分断する設置溝１９を形成する。その後、図１６に二点鎖線で示すように、導波路固定領域３０の縁を通過するよう光導波路基板３１を切断し、コア１９ｃ，１９ｄの端面を形成する。ダイシングブレードでの切断の際には摩擦熱が発生するために、ダイシングブレードには冷却水をかけながら使用するが、この冷却水が上部クラッド層１６を形成したときに未硬化のまま残っていた樹脂１６ａを洗い流すので、導波路固定領域３０以外の不要な導波路基板は簡単に取り除くことができる。また、ダイシングブレードの冷却水だけでは未硬化の樹脂１６ａを完全に除去できなければ、薬品によって未硬化の樹脂を除去すればよい。
【００５６】
次に図１７に示すように、設置溝１９にフィルタ１８を挿入し、フィルタ１８の上方および周辺部に接着剤２０を滴下してフィルタ１８を固定する。なお、フィルタ１８を固定するための接着剤２０は、コア１５ａ，１５ｂ，１５ｃよりも屈折率が小さくなければならない。また、接着剤２０の屈折率は、下部クラッド層１４及び上部クラッド層１６よりも大きい方が望ましい。最後に、図１７に示すベース基板２９ａを導波路装置１２ｂのチップに分断すれば、図１０に示す光導波路装置１２ｂが完成する。なお、フィルタ１８は、チップに分断してから設置溝１９に挿入してもよい。また、フィルタ１８は必ずしも接着剤２０で固定する必要はない。
【００５７】
本発明の光導波路装置を上述の製造方法で製造すれば、大面積の光導波路基板３１と、大面積のベース基板２９ａを上クラッド層２０で接着して、最終工程で光導波路装置１２ｂの個別チップに分割するために、個々の光導波路基板３１と、個々の支持基板とを貼り合わせるよりも効率よく光導波路装置を製造することができ、大量生産に適している。また、大面積のベース基板２９ａと大面積の光導波路基板３１とで位置合わせを行うために、小さな部品どうしで位置合わせをするよりも精度よく位置合わせをすることができる。
【００５８】
本発明の光導波路装置１２ｂは、支持基板２９上に光ファイバガイド２８等が設けられているために、光ファイバ２８等の設置が煩雑でなく、また、高い位置精度でコアと接続することができる。また、各コア１５ａ〜１５ｃが独立しているために、コアｃ内でクロストークが発生することがない。したがって、本発明の光導波路装置１２ｂは、各コア１５ａ〜１５ｃ端面での接続損失や伝搬損失の低い、高品位の光トランシーバにすることができる。
【００５９】
（第３の実施形態）
図１８は本発明のさらに別の実施形態による光導波路装置１２ｂ（２×４光スイッチ）の概略平面図である。また、図１９は、図１８のＢ−Ｂ’線断面に相当する面を示した図である。発明の光導波路装置１２ｂは、ガラス基板１３、下部クラッド層１４、コア１５ａ，１５ｂ，１５ｃ，１５ｄ，１５ｅ，１５ｆ，１５ｇ，１５ｈ，１５ｉ，１５ｊ、上部クラッド層１６、設置溝１９ａ，１９ｂ，１９ｃ内のコア１９ａ〜１９ｊの交差部に挿入されたミラー１８ｄ，１８ｅ，１８ｆ，１８ｇ等から構成されている。コア１５ａ〜１５ｊは、それぞれ独立したコアである。図１９に示すようにミラー１８ｄ〜１８ｇは、アクチュエーターで上下に稼働させることによって、コア１５ａ〜１５ｊの光軸上へ挿入したり、光軸から外すことができるようになっている。本発明の光導波路装置１２ｂには、２箇所の光入射端Ａ，Ｂと、４箇所の光出射端Ｃ，Ｄ，Ｅ，Ｆが設けられている。
【００６０】
すべてのミラー１８ｄ〜１８ｇが挿入されているときに、光入射端Ａから入射た光は、コア１５ａを伝搬し、ミラー１８ｄで反射され、コア１５ｄを伝搬し、ミラー１８ｆで反射され、コア１５ｇを伝搬して、ミラー１８ｇで反射され、コア１５ｊを伝搬して光出射端Ｄから出射される。また、ミラー１８ｄがコア１５ａの光軸外に外されており、その他のミラー１８ｅ，１８ｆ，１８ｇが挿入されているときには、光入射端Ａから入射し、コア１５ａを伝搬した光はコア１５ｂに入射し、ミラー１８ｅで反射されて、コア１５ｅ内を伝搬し、ミラー１８ｇで反射されてコア１５ｈを内を伝搬して光出射端Ｅから出射される。
【００６１】
このように、特定のミラー１８ｄ〜１８ｅを光軸上に挿入したり光軸外に外すことによって、２箇所の光入射端Ａ，Ｂに入射した光を、４箇所の光出射端Ｃ，Ｄ，Ｅ，Ｆの所望する光出射端から出射することができる。
【００６２】
例えばコア１５ａとコア１５ｄの一部が繋がっていれば、ミラー１８ｄが光軸外に外されているときにも、コア１５ａを伝搬した光の一部がコア１５ｄに漏洩するおそれがあるが、本実施形態の光導波路装置１２ｃでは、各コア１５ａ〜１５ｊが独立しているために、クロストーク等の問題が発生する恐れがない。
【００６３】
本発明の光導波路装置の製造工程において、設置溝１９ａ〜１９ｃを形成するまでの工程は第１の実施形態で説明した製造工程と同じである。コア１５ｄ，１５ｅ，１５ｉ，１５ｊの幅は、コア１５ａ，１５ｂ，１５ｃ，１５ｆ，１５ｇ，１５ｈの幅よりも広くなっているために、ダイシングブレードで形成される設置溝１９ａ〜１９ｃの形成位置がずれたときにも、ミラー１８ｄ〜１８ｅで反射された光を垂直方向にあるコアへ入射させることができ、歩留まりのよい光導波路装置にすることができる。
【００６４】
本発明の光導波路装置によれば、ミラーを用いることによって伝搬する光の光軸を９０度変化させることができる。例えばＹ字型に分岐したコアの上部にヒータや電極を設け、ヒータや電極のＯＮ／ＯＦＦによって熱や電界・磁界の変化させて光を伝搬させるコアを切り換えるといった光スイッチでは、分岐部間角度が小さいために、分岐後の長さを充分に取らなければ分岐後のコアの端面に光学素子等を設置するスペースが確保できないために、大型化してしまう。本発明の光導波路装置によれば、分岐したコアのなす角度が直角であるために、分岐したコアの光出射端どうしを分岐部分から短い距離で充分に離すことができ、分岐コアを多くして光出射端を増やした場合にも小さな光導波路にすることができる。なお、本発明の光導波路装置１２ｃの光出射端Ｃ，Ｄ，Ｅ，Ｆを光入射端とし、光入射端Ａ，Ｂを光出射端にしてもよい。
【００６５】
本発明の光導波路１２ｃのミラー１８ｄ〜１８ｅには、上述の可動式ミラー以外にも、透明板の間に封入された前記コアとほぼ同等の屈折率を有する液体を加熱して屈折率を変化させ、光の透過と反射を制御できるミラーなどを用いても
良い。
【００６６】
（第４の実施形態）
図２０、図２１は、本発明のさらに別の実施形態による光導波路装置１２ｄ（分波器）の概略平面図及び概略正面図である。本発明の光導波路装置１２ｄは、基板１３と、下部クラッド層１４、コア１５ａ，１５ｂ，１５ｃ，１５ｄ，１５ｅ，１５ｆ，１５ｇ、上部クラッド層１６、および特定の波長域の光のみ反射し、特定の波長域以外の波長の光は透過するフィルタ１８ａ，１８ｂ，１８ｃから構成されている。フィルタ１８ａは、波長λ１を含む波長域の光のみを反射し、それ以外の波長の光は透過するフィルタである。フィルタ１８ｂは波長λ２を含む波長域の光を反射し、それ以外の波長の光は透過するフィルタである。また、フィルタ１８ｃは波長λ３を含む波長域の光を反射し、それ以外の波長の光は透過するフィルタである。
【００６７】
本発明の光導波路装置１２ｃは、１箇所の光入射端Ａと４箇所の光出射端Ｂ，Ｃ，Ｄ，Ｅを有している。光入射端Ａはコア１５ａの端面であり、光出射Ｂ，Ｃ，Ｄ，Ｅは、コア１５ｅ，１５ｆ，１５ｇの端面である。本発明の光導波路１２ｄは、第１の実施形態で説明した製造方法によって製造できる。
【００６８】
光入射端Ａに、それぞれ異なる波長帯域に属する波長λ１，λ２，λ３，λ４からなる光が入射すると、まず、フィルタ１８ａで波長λ１の光のみがコア１５ｅに反射されて、波長λ１の光はコア１５ｅの光出射端から出射される。同様に、フィルタ１８ｂ，１８ｃでは、波長λ２，λ３の光がそれぞれコア１５ｆ、コア１５ｇに反射され、それぞれ光出射端Ｂ，Ｃから出射される。また、いずれのフィルタも透過した波長λ４の光は、コア１５ｄを伝搬して光出射端Ｅから出射される。
【００６９】
本実施形態の光導波路装置は、コア１５ａ〜１５ｇがそれぞれ独立し、繋がっていないために、クロストークが発生する恐れがない。より具体的には、コア１５ａを伝搬する波長λ２，λ３，λ４の波長の光が、フィルタ１８ａに到達する前にコア１５ｅに漏洩するおそれがない。
【００７０】
本実施形態の光導波路装置は、異なる波長の光を分波して異なる波長毎に異なる出射端から出射する分波器として利用できる。また、光入射端Ａを光出射端とし、光出射端Ｂ，Ｃ，Ｄ，Ｅを光入射端にすれば、合波器として利用できる。
【００７１】
（第５の実施形態）
図２２は、本発明にかかる分波器３３（例えば図２０、図２１に示したような光導波路装置）および光スイッチ３７（例えば、図１８に示したような光導波路装置）を用いた光合分波を行う装置を示す概略図である。分波器３３及び合波器３４は、波長の異なる複数の光信号を一本の光ファイバで伝送する波長多重（ＷＤＭ）方式の光通信システムで用いられる装置である。分波器３３は、一本の光ファイバ３５によって伝送された光信号を波長毎に分波して、波長毎に異なる光ファイバに出力する装置である。また、合波器３４は、複数の光ファイバによって入力された波長の異なる光信号を合波して、一本の光ファイバ３６に出力する装置である。
【００７２】
光スイッチ３７（２×２光スイッチ）は、コア内を伝搬する光の進行方向を切り換えて、選択した特定のコアからのみ光を出射することができる光導波路装置である。また、可変光減衰器（ＶＯＡ）３８，３９は、受光したパワーの異なる光を光を一定のパワーに揃えて出力する装置である。光スイッチ３７には、光入射端が２箇所設けられていて、一方の入射端は光ファイバ４０ａによって分波器３３に接続されており、分波器３３で分波された波長λ１，λ２，…，λＮの光が入力されるようになっている。他方の光入射端は光ファイバ４０ｂによって伝送された光信号の入射端である。なお、光ファイバ４０ｂは分波器３３以外の他の分波器に接続されていてもよい。
【００７３】
また、光スイッチ３７には、光出射端が２箇所設けられていて、一方の光出射端は光ファイバ４０ｃによって可変光減衰器（ＶＯＡ）３８を介して合波器３４に接続されており、他方の光出射端は光ファイバ４０ｄに接続されている。光ファイバ４０ｄは合波器３４以外の他の合波器に接続されていてもよい。
【００７４】
しかして、この光合波分波器を用いた光通信システムにおいては、光ファイバ３５及び光ファイバ３６は例えば都市内ネットワークや都市間ネットワークにおける中継系ネットワーク回線を構成しており、波長多重信号を伝送している。いま、すべての光スイッチ３７が合波器３４側に接続しているとすると、光ファイバ３５からなる中継系ネットワーク回線を伝送されてきた波長多重信号は、分波器３３により各波長λ１，λ２，…，λＮの信号に分波された後、各光スイッチ３７を合波器３４側へ通過し、光減衰器３８によって各波長の信号のパワーを均一に揃えられた後、各波長λ１，λ２，…λＮの信号は再び合波器３４で合波され、さらに光減衰器３９により波長多重信号全体のパワーが規定値となるように調整されて光ファイバ３６からなる中継系ネットワーク回線へ送り出される。
【００７５】
これに対し、例えば波長λ１に対応する光スイッチ３７が合波器側と異なる側へ切り換えられると、分波器３３で分波された信号のうち波長λ１の信号だけが光ファイバ４０ｄからなるアクセスネットワーク回線へ取り出される。また、光ファイバ４０ｂからなるアクセスネットワーク回線から波長λ１の信号が送り込まれていると、この他線からの波長λ１の信号は光スイッチ３７によって合波器３４へ送られ、光ファイバ３５から送られてきた波長多重信号に重畳させて光ファイバ３６からなる中継系ネットワーク回線へ送り出される。
【００７６】
図２３は、光ネットワークシステムにおける、各家庭内などのユーザーネットワークと中継系ネットワークとをアクセスネットワーク（加入者光ファイバ）で結んだ様子を示している。例えばある家庭の電話やパーソナルコンピュータ４２から発信された電気信号は、回線終端装置４３によって光信号に変換され、光ファイバ４４ａによって局外スプリッタ４５に集められる。局外スプリッタ４５は、図２０の光導波路装置１２ｄのような、４箇所の光入射端と１箇所の光出射端を有する合波器を備えており、異なるデータ発信から光ファイバ４４ａ，４４ｂ，４４ｃ，４４ｄによって伝搬されてきた光信号を合波して加入者光ファイバ４１ａに出射することができる。
【００７７】
加入者光ファイバ４１ａは交換局（電話事業者の設備センタ）内の局内スプリッタ４６に接続されている。局内スプリッタ４６は、８箇所の光入射端と、１箇所の光出射端を有する合波器である。加入者光ファイバ４１ａを伝搬してきた光信号は、他の入射光ファイバ４１ｂ，４１ｃ，４１ｄ，４１ｅ，４１ｆ，４１ｇ，４１ｈを伝搬してきた光信号と局内スプリッタ４６で合波され、回線終局装置４７で光信号から電気信号に変換されて他事業者ＩＰ網へと送出される。
【００７８】
図２４は上記回線終端装置４３又は回線終端装置４７の構成を示すブロック図である。回線終端装置４３及び回線終局装置４７は、アクセスネットワークを構成する加入者光ファイバ４１ａによって波長１５５０ｎｍの光信号と波長１３１０ｎｍの光信号を伝送される。光ファイバ４１ａの端面に対向する位置には、ＷＤＭ４８が設けられており、ＷＤＭ４８は光ファイバ４１ａから伝送されてきた波長１５５０ｎｍの光信号を出力部から出力し、入力部から入力された波長１３１０ｎｍの光信号を光ファイバ４１ａに結合させる。
【００７９】
ＷＤＭ４８の出力部から出力された波長１５５０ｎｍの光信号は光／電気変換モジュール（ＰＩＮ−ＡＭＰモジュール）４９に入力される。光／電気変換モジュール４９は、受光素子（フォトダイオード）５０とプリアンプ５１からなり、入力した光信号を受光素子４９で受光することによって電気信号に変換し、プリアンプ５１で増幅した後、データ処理回路５２に入力させる。ついで、データ処理回路５２で処理された電気信号は、回線終端装置４３に接続されているパーソナルコンピュータや電話、また、回線終局装置４７に接続されている電話線などの他事業者ＩＰ網に送られる。
【００８０】
一方、ＷＤＭ４８の入力部につながっている電気／光変換モジュール５３は、発光素子（ＬＤ）５４とモニター用受光素子５５からなり、発光素子５４は波長１３１０ｎｍの光を出射するものであって、発光素子駆動回路５６によって駆動される。また、発光素子５４から出射される光信号をモニター用受光素子５５で受光することにより、発光素子５４から出射される光信号のパワーが一定になるように出力をコントロールしている。しかして、電話や家庭用機器、または他事業者ＩＰ網から送出された電気信号は、発光素子駆動回路５６へ送られ、発光素子駆動回路５６に入力された電気信号によって発光素子５４を駆動することにより電気信号を光信号に変換し、ＷＤＭ４８を通して光ファイバ４１ａへ送信する。
【００８１】
このような回線終端装置４３及び回線終端装置４７においては、本発明にかかる光導波路装置を用いることにより小型化することができる。例えば、図３、図１０に説明したような光導波路装置１２ａ，１２ｂを上記ＷＤＭ４８として用い、光導波路装置１２ａ，１２ｂに実装された受光素子２３を上記光／電気変換モジュール４９の受光素子５０として用い、光導波路装置１２ａ，１２ｂに実装された投光素子２２を上記電気／光変換モジュール５３の発光素子５４として用いればよい。また、図１０に示すような光導波路装置１２ｂの支持基板２９の上に上記プリアンプ５１、データ処理回路５２、モニター用受光素子５５、発光素子駆動回路５６等を実装することにより回線終端装置４３又は回線終局装置４７をワンチップ化することも可能になる。
【００８２】
【発明の効果】
本発明の光導波路装置によれば、クロストークが発生することがなく波長域の異なる複数の信号の伝送を行うことができる。
【図面の簡単な説明】
【図１】従来の光導波路装置の概略斜視図である。
【図２】図１に示す光導波路装置の概略上面図であって、光トランシーバとしての使用態様を説明する図である。
【図３】本発明の光導波路装置の概略斜視図である。
【図４】図３に示す光導波路装置のＡ−Ａ’線断面図である。
【図５】図４に示す光導波路装置の光トランシーバとしての使用態様を説明する図である。
【図６】図６は、図４に示す光導波路装置の製造工程を説明する図である。
【図７】設置溝形成位置ずれによる光の伝搬の様子を説明する図である。
【図８】（ａ）（ｂ）は、コアの形状を説明する図である。
【図９】（ａ）（ｂ）は、コアの断面形状を説明する図である。
【図１０】本発明の別の実施形態による光導波路装置の概略斜視図である。
【図１１】図１０に示す光導波路装置の使用態様を説明する図である。
【図１２】図１２〜図１７は、図１０に示す光導波路装置の製造工程を説明する図である。
【図１３】図１２の続図である。
【図１４】図１３の続図である。
【図１５】図１４の続図である。
【図１６】図１５の続図である。
【図１７】図１６の続図である。
【図１８】本発明のさらに別の実施形態による光導波路装置の概略平面図である。
【図１９】図１８のＢ−Ｂ’線断面に相当する面を示す図である。
【図２０】本発明のさらに別の実施形態による光導波路装置の概略平面図である。
【図２１】図２０に示す光導波路装置の概略正面図である。
【図２２】本発明の光導波路装置を用いた通信用機器を説明する図である。
【図２３】本発明の光導波路装置を用いた光通信システムを説明する図である。
【図２４】回線終端装置又は、回線終局装置のブロック図である。
【符号の説明】
１２ａ　光導波路装置
１３　基板
１４　下部クラッド層
１５ａ〜１５ｃ　コア
１６　上部クラッド層
１７　ガラス基板
１８　フィルタ
１９　設置溝[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical waveguide device in which an optical element such as a filter or a mirror is added to an optical waveguide having a core that propagates light therein and a clad surrounding the core, and a communication device using the optical waveguide device.
[0002]
[Background Art]
In recent years, optical communication using an optical fiber cable as a signal transmission medium has become available in each home, and further use is expected in the future. Along with this, optical waveguide devices such as optical transceivers and optical multiplexers / demultiplexers used at the connection portions and terminal portions of optical fibers can be miniaturized, and high-performance optical waveguide devices can be mass-produced at low cost with high yield. It has become a challenge.
[0003]
FIG. 1 is a schematic perspective view of a conventional optical waveguide device 1. The optical waveguide device 1 includes a substrate 2, a lower cladding layer 3, cores 5a, 5b, 6 formed inside the lower cladding layer 3, an upper cladding layer 4, and a filter 7.
[0004]
The lower cladding layer 3 and the upper cladding layer 4 are made of an optical material having a relatively high refractive index, and the cores 5a, 5b, 6 have a slightly higher refractive index than the lower cladding layer 3 and the upper cladding layer 4. It is formed of an optical material. Thus, light incident from the end faces of the cores 5a, 5b, 6 can propagate inside the cores 5a, 5b, 6 without leaking to the lower cladding layer 3 or the upper cladding layer 4. The cores 5a and 5b intersect at right angles and are integrated. The cores 5a and 6 are arranged linearly via a filter 7. Each of the cores 5a, 5b, 6 is a core having a rectangular cross section, and the width of the core 5b is larger than the width of the cores 5a, 6. Thus, the cores 5a and 6 are cores for transmitting light in a single mode, and the core 5b is a core for transmitting light in a multimode.
[0005]
In the optical waveguide device 1, an installation groove 8 is formed from the upper cladding layer 4 to a depth reaching the substrate 2, and the filter 7 is inserted into the installation groove 8. The filter 7 is an optical element having a characteristic of transmitting only light in a specific wavelength band including the wavelength λ1, and reflecting light in other wavelength bands. As described above, the reason why the width of the core 5b is wider than the core 5a is that the filter 5 propagates through the core 5a even when the formation position of the installation groove 8 is displaced due to a positional accuracy error of dicing or the like. This is to allow the reflected light to enter the core 5b.
[0006]
FIG. 2 shows that the optical fiber 9, the light receiving element 11, and the light projecting element 10 are arranged to face the end faces of the cores 5a, 5b, 6 in order to use the optical waveguide device 1 shown in FIG. 1 as an optical transceiver. It is a top view at the time. The light of wavelength λ2 that has propagated through the optical fiber 9 propagates through the core 5a, enters the filter 7, is reflected by the filter 7, propagates through the core 5b, and is finally received by the light receiving element 11. The light of wavelength λ1 emitted from the light projecting element 10 propagates through the core 6, passes through the filter 7, propagates through the core 5a, and enters the optical fiber 9 connected to another external device. . Thus, the optical waveguide device 1 of the present invention can be used for transmitting and receiving signals to and from other communication devices.
[0007]
According to the optical waveguide device 1 of FIG. 1, since the optical axis of the light propagating through the core 5a can be changed by 90 degrees by being reflected by the filter 7, even if the lengths of the cores 5b and 6 are short, A sufficient space for installing the light receiving element 11 and the light projecting element 10 can be secured at the light emitting end of the core 5b and the light incident end of the core 6, and a small optical waveguide device can be obtained.
[0008]
However, in the conventional optical waveguide device 1, since the core 5a that propagates the wavelengths λ1 and λ2 and the core 5b that propagates only the wavelength λ2 are integrated, the light enters the core 6 and the filter 7 There is a problem that a part of the transmitted light of the wavelength λ1 leaks to the core 5b and crosstalk occurs in the core 5b.
[0009]
DISCLOSURE OF THE INVENTION
The present invention has been made in view of the above-described conventional problems, and has as its object to provide an optical waveguide device such as a duplexer, a multiplexer, an optical switch, and the like, which are small and hardly generate crosstalk. An object of the present invention is to provide a communication device using an optical waveguide device.
[0010]
The optical waveguide device according to claim 1, wherein an optical element that selectively transmits or reflects light, a first core and a second core that are arranged to sandwich the optical element, and a plane that includes the optical element. An optical waveguide device comprising: a third core disposed on the same side as the first core, and a cladding surrounding the first, second, and third cores.
The first core and the third core are independent of each other.
[0011]
The optical element is a filter, a mirror, a half mirror, or the like that transmits only light in a specific wavelength range and reflects light in wavelengths other than the specific wavelength range. Further, that the first core and the third core are independent of each other means that the first core and the third core are not connected, and the first core and the third core are not connected to each other. Means that the core is separated from the light incident end face by the cladding.
[0012]
According to the optical waveguide device of the first aspect, the light propagating in the first core does not leak to the third core before being reflected by the optical element. Therefore, there is no possibility that crosstalk occurs in the core, and the selection of the wavelength can be performed with higher accuracy. In order to prevent leakage of light during propagation of the first core, the closest distance between the light incident end face of the third core and the first core may be 5 to 50 μm, preferably 10 to 50 μm. What is necessary is just 30 micrometers.
[0013]
The optical element according to claim 1 of claim 3 is a mirror that can control the reflection and transmission of light.
[0014]
As a specific example of the optical element according to the third aspect, an optical element that changes a refractive index by heating a liquid having a refractive index substantially the same as that of the core sealed between transparent plates. When the liquid is not heated, light that has entered the optical element from the first core passes through the optical element and enters the second core. Further, if the liquid is heated to generate bubbles, light that has entered the optical element from the first core is reflected by the bubbles and enters the third core.
[0015]
The optical element according to claim 1 is a movable mirror, and the mirror can be moved in and out of an optical axis of the first, second, and third cores. And
[0016]
An optical waveguide device according to a fourth aspect uses a movable mirror as the optical element. For example, when the mirror is inserted on the optical axis, light that propagates through the first core and enters the mirror is reflected by the third core. Further, the light propagating through the first core when the mirror is off the optical axis enters the second core. Therefore, according to the optical waveguide device of the fourth aspect, the propagation path of the optical signal can be selected by selecting the core for transmitting the light by inserting and removing the mirror.
[0017]
When the optical element is a fixed mirror, the optical waveguide device can be used to convert the optical axis.
[0018]
An optical waveguide device according to a sixth aspect is characterized in that the area of the light incident end of the third core is larger than the area of the light exit end of the first core described in the first aspect.
[0019]
In the optical waveguide device according to claim 1, since the first core and the third core are independent, the light propagates through the first core and is reflected by the optical element. Until the light enters the third core, the reflected light spreads in the cladding layer. In the optical waveguide device according to claim 1 of claim 6, the cross-sectional area of the light incident end face of the third core is increased to increase the amount of light received by the third optical waveguide device, Propagation loss from the first core to the third core can be suppressed.
[0020]
8. The optical waveguide device according to claim 7, wherein the first core is a core for transmitting a signal in a single mode, and the third core is a core for transmitting a signal in a multimode. And
[0021]
8. The optical waveguide device according to claim 7, wherein the first core has a narrow width for transmitting single-mode light, and the third core has a width for transmitting light in multi-mode. It has a wide core. When forming a groove for installing the optical element by making a cut with a dicing blade in the clad, if the first core and the third core have the same width, the groove forming position is slightly shifted. Even by itself, the light reflected by the optical element cannot enter the third core, which causes a decrease in yield. However, if the width of the third core is wider than the width of the first core, the third core can be formed even when the groove forming position is shifted or the optical element is tilted. Light can be incident on the Further, if the width of the third core is wide, the light receiving area of the third core is widened, so that the amount of light received by the optical element can be increased.
[0022]
A communication device according to an eighth aspect uses the optical waveguide device according to the first aspect, and includes, for example, a communication device including an optical transceiver, a duplexer, a multiplexer, an optical switch, and the like inside. Refers to equipment.
[0023]
The components of the present invention described above can be combined as much as possible.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
3 and 4 are a schematic perspective view and a cross-sectional view taken along line AA ′ of an optical waveguide device 12a according to an embodiment of the present invention. The optical waveguide device 12a of the present invention includes a substrate 13, a lower cladding layer 14, cores 15a, 15b, 15c formed inside the lower cladding layer 14, an upper cladding layer 16, a cover glass 17, and a filter 18. I have.
[0025]
Each of the cores 15a, 15b, 15c is a linear core having a rectangular cross section, and the cores 15a, 15b, 15c are independent. The cores 15a and 15b are arranged with the installation groove 19 therebetween such that the optical axes are aligned on the same straight line. The optical axis of the core 15c is perpendicular to the optical axes of the cores 15a and 15b. The distance δ between the end surface of the core 15c and the side surface of the core 15a is δ = 5 μm to 50 μm, and more preferably 10 μm to 30 μm. The cores 15a and 15b are narrow cores for transmitting single mode optical signals, while the core 15c is a core for transmitting multimode optical signals and wider than the cores 15a and 15b. The thickness of the core 15c is larger than the thickness of the cores 15a and 15b.
[0026]
The installation groove 19 is formed from the upper surface of the cover glass 17 to a depth reaching the substrate 13. An optical element having a feature that the filter 18 inserted between the core 15a and the core 15b inside the installation groove 19 transmits only light of a specific wavelength band and reflects light of wavelengths other than the specific wavelength band. It is. The lights of wavelengths λ1 and λ2 used for communication are lights of different wavelength bands, and the light of wavelength λ1 is transmitted through the filter 18 and the light of wavelength λ2 is reflected by the filter 18.
[0027]
FIG. 5 is a view for explaining the use of the optical waveguide device 12a of the present invention as an optical transceiver, wherein the optical fiber cable 21, the light projecting element 22, and the light receiving element 23 are opposed to the end faces of the cores 15a, 15b, 15c. FIG. 4 is a top view of the lower cladding layer 14 when it is installed. The optical fiber cable 21 is connected to another external device capable of bidirectional communication. The light of the wavelength λ1 emitted from the light projecting element 22 and propagated through the core 15b and reaches the filter 18 is transmitted through the filter 18, enters the optical fiber cable 21, and is transmitted to another external device. Further, light of wavelength λ2 transmitted from another external device, propagated through the optical fiber cable 21 and incident on the core 15a is reflected by the filter 18, propagates in the core 15c, and is received by the light receiving element 23. . As described above, in the optical waveguide device 12a of the present invention, it is possible to reduce the size of the optical waveguide device because signals having different wavelengths are not propagated in individual cores but are propagated by sharing the same core. it can.
[0028]
When the light projecting element 22, the light receiving element 23, and the optical fiber 21 are installed and used as described above, if the core 15a and the core 15c are connected, one of the light of the wavelength λ1 emitted from the light projecting element 22 is output. After passing through the filter 18, the portion propagates through the core 15 c and enters the light receiving element 23, which may cause crosstalk in the core 15 c.
[0029]
Therefore, in the optical waveguide device 12a of the present invention, the core 15a and the core 15c are completely separated, and the lower cladding layer 14 having a smaller refractive index than the cores 15a, 15b, and 15c is provided between the end face of the core 15c and the core 15a. Is sandwiched. Thus, the light that has propagated through the core 15b and transmitted through the filter 18 propagates through the core 15a without being incident on the core 15c. Further, the light that propagates through the core 15a and is reflected by the filter 18 is incident on the lower cladding layer 14 at an angle smaller than the critical angle, and is not reflected by the lower cladding layer 14 having a smaller refractive index than the core 15a. The light enters the end face of the core 15c. Therefore, the optical waveguide device 12a of the present invention is a small and high-precision optical transceiver that does not generate crosstalk.
[0030]
Next, a method for manufacturing the optical waveguide device 12 of the present invention will be described with reference to FIG. First, in order to form the lower cladding layer 14, as shown in FIG. 6A, an uncured ultraviolet curable resin 14a is dropped on the substrate 13 and pressed with a stamper 25a having the same pattern as the cores 15c and 15d. Then, the lower clad layer 14 is formed by irradiating ultraviolet rays to be cured. Here, the core 15d is a linear core that becomes the core 15a and the core 15b later.
[0031]
Next, in order to form the cores 15c and 15d, an uncured ultraviolet curing resin 15x having a higher refractive index than the lower cladding layer 14 is injected into the core groove 24 of the lower cladding layer 14 as shown in FIG. Then, the burrs formed by the resin 15x overflowing from the core groove 24 to the surface of the lower clad layer 14 are pressed by the flat plate 25b so as to have a thickness as small as possible, and are irradiated with ultraviolet rays to be cured.
[0032]
Thereafter, as shown in FIG. 6C, the same uncured resin 16a as the lower cladding layer 14 is dropped on the lower cladding layer 14 and the cores 15c and 15d, and pressed with the cover glass 17 to obtain the structure shown in FIG. As shown, the cover substrate 17 is bonded simultaneously with the formation of the upper cladding layer 16 to form the waveguide substrate 31. Note that the upper cladding layer 16 does not necessarily need to be covered with the cover glass 17, but if it is covered with the cover glass 17, the cores 15c and 15d and the upper cladding layer 16 are less likely to be affected by environmental changes such as humidity. Wave path performance is more stable.
[0033]
Next, an installation groove 19 for dividing the core 15d into the cores 15a and 15b is formed by using a dicing blade, and a filter 18 is inserted between the cores 15a and 15b of the installation groove 19, whereby the optical waveguide device shown in FIG. 12a is completed. The inclination of the installation groove 19 with respect to the core 15d may be determined in accordance with the characteristics of the filter 18 and the like.
[0034]
After the filter 18 is inserted into the installation groove 19, the filter 18 may be fixed by dropping an adhesive 20 on the upper portion or the peripheral portion of the filter in order to fix the filter 18. In order that the light incident on the adhesive 20 does not leak to the lower clad layer 14 and the upper clad layer 16 and is incident on the cores 15a and 15b, the refractive index of the adhesive 20 is higher than that of the cores 15a, 15b and 15c. Must be small. Further, it is desirable that the refractive index of the adhesive 20 be higher than that of the lower cladding layer 14 and the upper cladding layer 16.
[0035]
The filter 18 does not necessarily need to be fixed with the adhesive 20. However, if the filter 18 is fixed, the filter 18 can be prevented from being displaced or falling off, and if the filter 18 is covered with the adhesive 20, the filter 18 can be fixed. The performance of the optical waveguide device 12a is more stable because it is less susceptible to changes in humidity and the like. Further, since the gap between the filter 18 and the cores 15a, 15b, 15c is filled with the adhesive, Fresnel reflection generated at the interface of the filter 18 can be reduced, so that loss due to reflection and transmission at the filter 18 is reduced. Can be done.
[0036]
If the optical waveguide device of the present embodiment is manufactured by the above-described duplication method (stamper method), a large number of optical waveguide devices can be manufactured at once using a large-area substrate, which is suitable for mass production. However, the optical waveguide substrate may be manufactured by a manufacturing method other than the replication method, and may be, for example, an optical crystal waveguide, a quartz waveguide, a polymer waveguide, or the like.
[0037]
FIG. 5 shows an ideal formation position of the installation groove of the optical waveguide device. However, the installation groove 19 is formed due to a positional shift of the cut by the dicing blade, a variation in the thickness of the dicing blade due to a variation in thickness or abrasion, and the like. It is inevitable that the positions and widths to be formed vary slightly. In the optical waveguide device 12a of the present invention, the width of the core 15c is made wider than the cores 15a and 15b in order to deal with such a problem.
[0038]
The position of the installation groove 19 shown in FIG. 5 is a case where the installation groove 19 is formed without deviation, and the light reflected by the filter 18 enters the center position of the width of the core 15c. The center line of the installation groove 19 at this time is indicated by a one-dot chain line. However, in practice, the installation groove 19 may be formed at a position shifted by ± ΔW due to an error in the formation position accuracy of the dicing blade. FIGS. 7A and 7B show a state where the center line of the installation groove 19 is shifted from the center line shown in FIG. 5 in the + W direction and the −W direction, respectively. The center line is indicated by a two-dot chain line, and the direction and magnitude of the shift are indicated by arrows.
[0039]
The width of the core 15c is set such that the light reflected by the core 15a of the filter 19 enters the core 15c as shown in FIG. 7A even when the installation groove is shifted by + ΔW. As shown in (), the light reflected by the filter 18 is designed to enter the core 19c even when the installation groove is shifted by -ΔW. That is, when the acute angle between the cores 15a and 15b and the installation groove is θ, the width of the core 15c is
(Equation 1)

(The width of the core 15a and the gap δ between the core 15a and the core 15c are not considered)
Must be satisfied.
[0040]
However, the width of the core 15c only needs to satisfy the above value in the vicinity of the light incident end. Therefore, taking into consideration the size of the light receiving surface of the light receiving element 23 and the like, as shown in FIGS. The side surface of the core 15c may be tapered. The width of the core 15c shown in FIG. 8A gradually decreases from the light incident end to the light output end. The light incident end of the core 15c shown in FIG. 8B has a substantially semicircular shape, so that the light is condensed in the center direction of the width of the core 15c and then propagated through the linear core. ing. With the core 15c having the shape shown in FIGS. 8A and 8B, connection loss with the light receiving element 23 optically connected to the core 15c can be suppressed.
[0041]
The light emitted from the core 15a and reflected by the filter 18 also spreads in the thickness direction inside the installation groove 19 or the lower cladding layer 14 before reaching the core 15c. If the thickness of the incident end is made thicker than the thickness of the core 15a, the light receiving area becomes large, and light loss can be suppressed. However, if there is no problem in the amount of light received by the core 15c, the thickness of the core 15a and the thickness of the core 15c may be the same as shown in FIG.
[0042]
Also, as shown in FIG. 9B, if a taper is provided in the thickness direction of the core 15c in accordance with the size and shape of the light receiving surface of the light receiving element, the connection loss is suppressed even when the light receiving area of the light receiving element is small. be able to. The taper may be provided in both the width direction and the thickness direction, or may be provided in only one of them.
[0043]
(Second embodiment)
FIG. 10 is a schematic perspective view of an optical waveguide device (optical transceiver) 12b according to an embodiment of the present invention. The optical waveguide device 12b according to the present invention includes a support substrate 29, a waveguide substrate 31, and a filter 18. The waveguide substrate 31 is placed on the support substrate 29 in an upside-down state, and has a higher refractive index than the substrate 13, the lower cladding layer 14 and the upper cladding layer 16 made of a high refractive index optical material, and the lower cladding layer 14. It is composed of cores 15a, 15b, 15c made of an optical material.
[0044]
Each of the cores 15a, 15b, 15c is a linear core having a rectangular cross section, and the cores 15a, 15b, 15c are independent. The end face of the core 15c is separated from the side face of the core 15a by 5 μm or more, and the lower cladding layer 14 is interposed therebetween. The cores 15a and 15b are arranged with the installation groove 19 therebetween such that the optical axes are aligned on the same straight line, and the optical axis of the core 15c is perpendicular to the optical axes of the cores 15a and 15b. The cores 15a and 15b are narrow cores for transmitting single mode optical signals, while the core 15c is a core for transmitting multimode optical signals and wider than the cores 15a and 15b.
[0045]
The filter 18 is an optical element that transmits only light in a specific wavelength range and reflects light outside the specific wavelength range, and is inserted into the installation groove 19 provided in the waveguide substrate 31. The cores 15a and 15b embedded in the lower cladding layer 14 are arranged in a straight line via the filter 18. The core 15c is disposed so as to have an angle of 90 degrees with respect to the optical axis of both cores 15a and 15b.
[0046]
A waveguide fixing region 30 (not shown) for laminating the optical waveguide substrate 31 is formed on the surface of the support substrate 29, and a V-groove optical fiber guide 28 and a concave optical element are formed therearound. The installation parts 26a and 26b are provided. Element mounting benches (electrode pads) 27a and 27b for mounting a light emitting element and a light receiving element are formed in each of the optical element installation sections 26a and 26b.
[0047]
In the optical waveguide device 12b shown in FIG. 10, the optical waveguide substrate 31 is installed upside down, and the optical fiber guide 28 and the element mounting benches 27a and 27b are exposed from the optical waveguide substrate 31. I have.
[0048]
FIG. 11 is a plan view showing a state where the light projecting element 22 and the light receiving element 23 are mounted on the optical waveguide device 12b and the optical fiber 21 is connected. The light receiving element 23 and the light projecting element 22 are mounted on the element mounting benches 27a and 27b in the optical element installation sections 26a and 26b by die bonding the lower surface electrodes, respectively. The light receiving element 23 is an end face of the core 15c. , And the light projecting element 22 faces the end face of the core 15b. The upper electrodes of the light emitting element 22 and the light receiving element 23 are connected to a circuit board or the like by bonding wires. The optical fiber 21 is fixed to the optical fiber guide 28 by an adhesive while being positioned and positioned, whereby the optical axis of the core 15a and the optical axis of the optical fiber 21 are automatically aligned.
[0049]
In the optical waveguide device 12b, the filter 18 has a characteristic of transmitting light of wavelength λ1 emitted from the light projecting element 22 and reflecting light of wavelength λ2 emitted from the optical fiber 21. Thus, when light (transmission signal) is emitted from the light projecting element 22 to the core 15b, the light propagates inside the core 15b, passes through the filter 18, propagates inside the core 15a, and enters the optical fiber 21. Transmitted through the optical fiber 21. Light (reception signal) propagating through the optical fiber 21 enters the core 15a, is reflected by the filter 18, propagates through the core 15c, and is received by the light receiving element 23. In this manner, the optical waveguide device 12b can transmit and receive signals to and from another external device connected through one optical fiber 21.
[0050]
In the optical waveguide device 12b of this embodiment, the core 15a and the core 15c are completely separated from each other, and the lower cladding layer 14 having a smaller refractive index than the cores 15a, 15b, and 15c is provided between the end face of the core 15c and the core 15a. It is sandwiched. Thus, the light that has propagated through the core 15b and transmitted through the filter 18 propagates through the core 15a without being incident on the core 15c. Further, the light that propagates through the core 15a and is reflected by the filter 18 is incident on the lower cladding layer 14 at an angle smaller than the critical angle, and is not reflected by the lower cladding layer 14 having a smaller refractive index than the core 15a. The light enters the end face of the core 15c. Therefore, the optical waveguide device 12a of the present invention can be a high-precision optical transceiver that does not generate crosstalk.
[0051]
Hereinafter, a method for manufacturing the optical waveguide device 12b of the present invention will be described with reference to FIGS. First, as shown in FIG. 12, the waveguide fixing region 30, the optical element mounting portions 26a and 26b, and the fiber guide 28 are formed on the surface of a large-area base substrate 29a such as a glass substrate or a silicon substrate serving as a parent substrate of the supporting substrate 29. Are formed, and element mounting benches 27a and 27b are formed of the electrode material inside the optical element installation sections 26a and 26b. Although four optical waveguide devices 12b can be manufactured at a time by using the base substrate 29a of FIG. 12, mass production of the optical waveguide devices 12b becomes possible by using the base substrate 29a having a larger area.
[0052]
Further, a waveguide substrate 31 in which a lower cladding layer 14 and a plurality of sets of cores 15c and 15d are formed on a glass substrate 13a having the same area or more as the base substrate 29a is manufactured by a replication method (a stamper method) or the like. A more detailed manufacturing method using the replication method has been described in the first embodiment.
[0053]
Next, as shown in FIG. 13, an uncured ultraviolet curable resin 16a is dropped on the surface of the optical waveguide substrate 31, and the optical waveguide substrate 31 and the base substrate 29a are bonded by the resin 16a. When bonding the base substrate 29a and the optical waveguide substrate 31, it is necessary to precisely align the fiber guide 28, the optical element mounting portions 26a and 26b, and the cores 15c and 15d. For this purpose, the optical waveguide substrate 31 and the base substrate 29a may be bonded with high precision by using the alignment marks provided on the optical waveguide substrate 31 and the base substrate 29a. If the positioning is performed between the large-area base substrate 29a and the large-area optical waveguide substrate 31, there is no need to perform the complicated operation of positioning the individual components, and the positioning of a plurality of cores and the fiber guide at once can be performed. Can be performed with high accuracy, which is efficient.
[0054]
After the base substrate 29a and the optical waveguide substrate 31 are aligned and overlapped with each other, before irradiating the ultraviolet rays, the glass substrate 13a is moved so that only the waveguide fixing region 30 is irradiated with the ultraviolet rays as shown in FIG. It is covered with a mask 32 that does not transmit ultraviolet light. When the glass substrate 13a covered with the mask 32 is irradiated with ultraviolet light, only the waveguide fixing region 30 is irradiated with ultraviolet light, the resin 16a is cured, and the upper clad layer 16 is formed. When the base substrate 29a is made of a material that transmits ultraviolet rays, the base substrate 29a may be irradiated with ultraviolet rays from the side of the base substrate 29a so as to be covered with the mask 32.
[0055]
Next, as shown in FIG. 15, using a dicing blade, an installation groove 19 for dividing the core 15d into the cores 15a and 15b is formed. Thereafter, as shown by a two-dot chain line in FIG. 16, the optical waveguide substrate 31 is cut so as to pass through the edge of the waveguide fixing region 30 to form end faces of the cores 19c and 19d. When cutting with a dicing blade, frictional heat is generated, so that the dicing blade is used while applying cooling water, but this cooling water remains uncured when the upper cladding layer 16 is formed. Since the resin 16a is washed away, unnecessary waveguide substrates other than the waveguide fixing region 30 can be easily removed. If the uncured resin 16a cannot be completely removed only by the cooling water of the dicing blade, the uncured resin may be removed with a chemical.
[0056]
Next, as shown in FIG. 17, the filter 18 is inserted into the installation groove 19, and the adhesive 20 is dropped onto the filter 18 above and around the filter 18 to fix the filter 18. The adhesive 20 for fixing the filter 18 must have a lower refractive index than the cores 15a, 15b, and 15c. Further, it is desirable that the refractive index of the adhesive 20 be higher than that of the lower cladding layer 14 and the upper cladding layer 16. Finally, when the base substrate 29a shown in FIG. 17 is divided into chips of the waveguide device 12b, the optical waveguide device 12b shown in FIG. 10 is completed. The filter 18 may be inserted into the installation groove 19 after being divided into chips. Further, the filter 18 does not necessarily need to be fixed with the adhesive 20.
[0057]
If the optical waveguide device of the present invention is manufactured by the above-described manufacturing method, a large-area optical waveguide substrate 31 and a large-area base substrate 29a are bonded with the upper cladding layer 20, and the individual optical waveguide devices 12b are separated in the final step. The optical waveguide device can be manufactured more efficiently than the case where the individual optical waveguide substrates 31 and the individual support substrates are bonded to be divided into chips, which is suitable for mass production. In addition, since the positioning is performed between the large-area base substrate 29a and the large-area optical waveguide substrate 31, the positioning can be performed more accurately than the positioning performed between the small components.
[0058]
In the optical waveguide device 12b of the present invention, since the optical fiber guide 28 and the like are provided on the support substrate 29, the installation of the optical fiber 28 and the like is not complicated, and the optical waveguide device 12b can be connected to the core with high positional accuracy. it can. Further, since the cores 15a to 15c are independent, no crosstalk occurs in the core c. Therefore, the optical waveguide device 12b of the present invention can be a high-quality optical transceiver with low connection loss and propagation loss at the end faces of the cores 15a to 15c.
[0059]
(Third embodiment)
FIG. 18 is a schematic plan view of an optical waveguide device 12b (2 × 4 optical switch) according to still another embodiment of the present invention. FIG. 19 is a diagram showing a plane corresponding to a cross section taken along line BB ′ of FIG. The optical waveguide device 12b of the present invention comprises a glass substrate 13, a lower cladding layer 14, cores 15a, 15b, 15c, 15d, 15e, 15f, 15g, 15h, 15i, 15j, an upper cladding layer 16, and installation grooves 19a, 19b, 19c. And mirrors 18d, 18e, 18f, 18g and the like inserted at the intersections of the cores 19a to 19j. The cores 15a to 15j are independent cores. As shown in FIG. 19, the mirrors 18d to 18g can be inserted into or removed from the optical axes of the cores 15a to 15j by operating them up and down by actuators. The optical waveguide device 12b of the present invention is provided with two light incidence ends A and B and four light emission ends C, D, E and F.
[0060]
When all the mirrors 18d to 18g are inserted, the light incident from the light incident end A propagates through the core 15a, is reflected by the mirror 18d, propagates through the core 15d, is reflected by the mirror 18f, and is reflected by the mirror 18f. Is reflected by the mirror 18g, propagates through the core 15j, and is emitted from the light emitting end D. When the mirror 18d is off the optical axis of the core 15a and the other mirrors 18e, 18f, and 18g are inserted, the light that enters from the light incident end A and propagates through the core 15a enters the core 15b. The light enters, is reflected by the mirror 18e, propagates through the core 15e, is reflected by the mirror 18g, propagates through the core 15h, and is emitted from the light emitting end E.
[0061]
As described above, by inserting the specific mirrors 18d to 18e on the optical axis or removing them off the optical axis, the light incident on the two light incident ends A and B can be changed to the four light emitting ends C and D. , E, and F from the desired light emitting ends.
[0062]
For example, if the core 15a and a part of the core 15d are connected, even when the mirror 18d is off the optical axis, a part of the light transmitted through the core 15a may leak to the core 15d, In the optical waveguide device 12c of the present embodiment, since the cores 15a to 15j are independent, there is no possibility that a problem such as crosstalk occurs.
[0063]
In the manufacturing process of the optical waveguide device of the present invention, the processes up to forming the installation grooves 19a to 19c are the same as the manufacturing processes described in the first embodiment. Since the widths of the cores 15d, 15e, 15i, 15j are wider than the widths of the cores 15a, 15b, 15c, 15f, 15g, 15h, the positions where the installation grooves 19a to 19c formed by the dicing blade are formed. Even when there is a shift, the light reflected by the mirrors 18d to 18e can be made incident on the core in the vertical direction, and an optical waveguide device with a high yield can be obtained.
[0064]
According to the optical waveguide device of the present invention, the optical axis of the propagating light can be changed by 90 degrees by using the mirror. For example, in the case of an optical switch in which a heater or an electrode is provided above a Y-shaped branched core and the core that transmits light by changing heat, an electric field, or a magnetic field by ON / OFF of the heater or the electrode, an angle between the branched portions is used. If the length after branching is not sufficient, a space for installing an optical element or the like cannot be secured on the end face of the core after branching, which results in an increase in size. According to the optical waveguide device of the present invention, since the angle formed by the branched cores is a right angle, the light emitting ends of the branched cores can be sufficiently separated from the branching portion by a short distance, and the number of branching cores can be increased. Even when the number of light emitting ends is increased, a small optical waveguide can be obtained. Note that the light emitting ends C, D, E, and F of the optical waveguide device 12c of the present invention may be light incident ends, and the light incident ends A and B may be light emitting ends.
[0065]
In addition to the movable mirrors described above, the mirrors 18d to 18e of the optical waveguide 12c of the present invention change a refractive index by heating a liquid having a refractive index substantially equal to that of the core sealed between transparent plates, Even if you use a mirror that can control the transmission and reflection of light,
good.
[0066]
(Fourth embodiment)
20 and 21 are a schematic plan view and a schematic front view of an optical waveguide device 12d (duplexer) according to still another embodiment of the present invention. The optical waveguide device 12d of the present invention reflects only the substrate 13, the lower cladding layer 14, the cores 15a, 15b, 15c, 15d, 15e, 15f, and 15g, the upper cladding layer 16, and light in a specific wavelength range. Are formed of filters 18a, 18b, and 18c that transmit light of wavelengths other than the above wavelength range. The filter 18a is a filter that reflects only light in a wavelength range including the wavelength λ1, and transmits light of other wavelengths. The filter 18b is a filter that reflects light in a wavelength range including the wavelength λ2 and transmits light in other wavelengths. The filter 18c is a filter that reflects light in a wavelength range including the wavelength λ3 and transmits light in other wavelengths.
[0067]
The optical waveguide device 12c of the present invention has one light incidence end A and four light emission ends B, C, D, and E. The light incident end A is an end face of the core 15a, and the light emitting ends B, C, D, and E are end faces of the cores 15e, 15f, and 15g. The optical waveguide 12d of the present invention can be manufactured by the manufacturing method described in the first embodiment.
[0068]
When light having wavelengths λ1, λ2, λ3, and λ4 belonging to different wavelength bands enters the light incident end A, first, only light of wavelength λ1 is reflected by the filter 18a to the core 15e, and light of wavelength λ1 is The light is emitted from the light emitting end of the core 15e. Similarly, in the filters 18b and 18c, the lights having the wavelengths λ2 and λ3 are reflected by the cores 15f and 15g, respectively, and emitted from the light emitting ends B and C, respectively. The light of the wavelength λ4 transmitted through each filter propagates through the core 15d and is emitted from the light emitting end E.
[0069]
In the optical waveguide device of the present embodiment, since the cores 15a to 15g are independent of each other and are not connected, there is no possibility that crosstalk occurs. More specifically, there is no possibility that light of wavelengths λ2, λ3, and λ4 propagating in the core 15a leaks to the core 15e before reaching the filter 18a.
[0070]
The optical waveguide device according to the present embodiment can be used as a duplexer that splits light having different wavelengths and emits light from different emission ends for different wavelengths. If the light incident end A is a light emitting end and the light emitting ends B, C, D, and E are light incident ends, they can be used as a multiplexer.
[0071]
(Fifth embodiment)
FIG. 22 shows an optical coupler using a demultiplexer 33 (for example, an optical waveguide device as shown in FIGS. 20 and 21) and an optical switch 37 (for example, an optical waveguide device as shown in FIG. 18) according to the present invention. It is the schematic which shows the apparatus which performs a demultiplexing. The demultiplexer 33 and the multiplexer 34 are devices used in a wavelength division multiplexing (WDM) optical communication system for transmitting a plurality of optical signals having different wavelengths through one optical fiber. The demultiplexer 33 is a device that demultiplexes an optical signal transmitted by one optical fiber 35 for each wavelength and outputs the demultiplexed optical signal to a different optical fiber for each wavelength. The multiplexer 34 is a device that multiplexes optical signals having different wavelengths input by a plurality of optical fibers and outputs the multiplexed optical signals to a single optical fiber 36.
[0072]
The optical switch 37 (2 × 2 optical switch) is an optical waveguide device that can switch the traveling direction of light propagating in the core and emit light only from the selected specific core. Further, the variable optical attenuators (VOAs) 38 and 39 are devices that output the received lights having different powers while adjusting the lights to a constant power. The optical switch 37 is provided with two light incident ends. One incident end is connected to the demultiplexer 33 by an optical fiber 40a, and the wavelengths λ1, λ2, .., ΛN are input. The other light incident end is the incident end of the optical signal transmitted by the optical fiber 40b. The optical fiber 40b may be connected to another splitter other than the splitter 33.
[0073]
The optical switch 37 is provided with two light emitting ends, and one light emitting end is connected to the multiplexer 34 via a variable optical attenuator (VOA) 38 by an optical fiber 40c. The other light emitting end is connected to the optical fiber 40d. The optical fiber 40d may be connected to a multiplexer other than the multiplexer 34.
[0074]
In the optical communication system using the optical multiplexer / demultiplexer, the optical fiber 35 and the optical fiber 36 constitute, for example, a relay network line in an intra-city network or an inter-city network, and transmit a wavelength multiplexed signal. are doing. Now, assuming that all the optical switches 37 are connected to the multiplexer 34 side, the wavelength division multiplexed signal transmitted through the relay network line composed of the optical fiber 35 is separated by the demultiplexer 33 into each wavelength λ1, λ2. ,..., ΛN, passes through each optical switch 37 to the multiplexer 34 side, and the optical attenuator 38 equalizes the power of each wavelength signal. The signals of λ2,... λN are multiplexed again by the multiplexer 34, and further adjusted by the optical attenuator 39 so that the power of the whole wavelength-division multiplexed signal becomes a specified value, and sent out to the relay network line composed of the optical fiber 36. It is.
[0075]
On the other hand, for example, when the optical switch 37 corresponding to the wavelength λ1 is switched to a side different from the multiplexer side, only the signal of the wavelength λ1 out of the signals demultiplexed by the demultiplexer 33 is accessed by the optical fiber 40d. It is taken out to a network line. If a signal of wavelength λ1 is sent from the access network line composed of the optical fiber 40b, a signal of wavelength λ1 from the other line is sent to the multiplexer 34 by the optical switch 37 and sent from the optical fiber 35. The signal is superimposed on the wavelength-division multiplexed signal and sent to a relay network line composed of an optical fiber 36.
[0076]
FIG. 23 shows a state in which a user network such as in each home and a relay network are connected by an access network (subscriber optical fiber) in the optical network system. For example, an electric signal transmitted from a home telephone or a personal computer 42 is converted into an optical signal by the line terminating device 43, and is collected by the outside office splitter 45 by the optical fiber 44a. The out-of-station splitter 45 is provided with a multiplexer having four light entrance ends and one light exit end, such as the optical waveguide device 12d in FIG. 20, and outputs optical fibers 44a, 44b, and 44b from different data sources. The optical signals propagated by 44c and 44d can be multiplexed and output to the subscriber optical fiber 41a.
[0077]
The subscriber optical fiber 41a is connected to an intra-office splitter 46 in an exchange (an equipment center of a telephone company). The intra-office splitter 46 is a multiplexer having eight light entrance ends and one light exit end. The optical signal that has propagated through the subscriber optical fiber 41a is multiplexed with the optical signal that has propagated through the other incident optical fibers 41b, 41c, 41d, 41e, 41f, 41g, and 41h by the intra-office splitter 46, and the line termination device 47 Is converted from an optical signal to an electric signal and transmitted to the IP network of another provider.
[0078]
FIG. 24 is a block diagram showing a configuration of the line termination device 43 or the line termination device 47. The line termination device 43 and the line termination device 47 transmit an optical signal having a wavelength of 1550 nm and an optical signal having a wavelength of 1310 nm through a subscriber optical fiber 41a constituting an access network. A WDM 48 is provided at a position facing the end face of the optical fiber 41a. The WDM 48 outputs an optical signal having a wavelength of 1550 nm transmitted from the optical fiber 41a from an output section, and outputs a 1310 nm wavelength signal input from an input section. The optical signal is coupled to the optical fiber 41a.
[0079]
The optical signal having a wavelength of 1550 nm output from the output unit of the WDM 48 is input to an optical / electrical conversion module (PIN-AMP module) 49. The optical / electrical conversion module 49 includes a light receiving element (photodiode) 50 and a preamplifier 51, and converts an input optical signal into an electric signal by receiving the light with the light receiving element 49, amplifies the signal with the preamplifier 51, and then converts the data into a data processing circuit. 52. Next, the electric signal processed by the data processing circuit 52 is transmitted to another operator's IP network such as a personal computer or a telephone connected to the line terminating device 43 or a telephone line connected to the line terminating device 47. Can be
[0080]
On the other hand, the electric / optical conversion module 53 connected to the input section of the WDM 48 includes a light emitting element (LD) 54 and a monitoring light receiving element 55. The light emitting element 54 emits light having a wavelength of 1310 nm. Driven by the element drive circuit 56. Further, by receiving the optical signal emitted from the light emitting element 54 with the monitoring light receiving element 55, the output is controlled so that the power of the optical signal emitted from the light emitting element 54 becomes constant. Thus, the electric signal transmitted from the telephone, the home device, or the IP network of another provider is sent to the light emitting element driving circuit 56, and the light emitting element 54 is driven by the electric signal input to the light emitting element driving circuit 56. As a result, the electric signal is converted into an optical signal and transmitted to the optical fiber 41a through the WDM.
[0081]
The line termination device 43 and the line termination device 47 can be downsized by using the optical waveguide device according to the present invention. For example, the optical waveguide devices 12a and 12b described in FIGS. 3 and 10 are used as the WDM 48, and the light receiving element 23 mounted on the optical waveguide devices 12a and 12b is used as the light receiving element 50 of the optical / electric conversion module 49. The light emitting element 22 mounted on the optical waveguide devices 12a and 12b may be used as the light emitting element 54 of the electric / optical conversion module 53. The preamplifier 51, the data processing circuit 52, the monitoring light receiving element 55, the light emitting element driving circuit 56, and the like are mounted on the support substrate 29 of the optical waveguide device 12b as shown in FIG. The line termination device 47 can also be made into one chip.
[0082]
【The invention's effect】
According to the optical waveguide device of the present invention, it is possible to transmit a plurality of signals having different wavelength ranges without generating crosstalk.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a conventional optical waveguide device.
FIG. 2 is a schematic top view of the optical waveguide device shown in FIG. 1, illustrating a usage mode as an optical transceiver.
FIG. 3 is a schematic perspective view of the optical waveguide device of the present invention.
FIG. 4 is a sectional view taken along line AA ′ of the optical waveguide device shown in FIG. 3;
FIG. 5 is a diagram illustrating a use mode of the optical waveguide device shown in FIG. 4 as an optical transceiver.
FIG. 6 is a diagram for explaining a manufacturing process of the optical waveguide device shown in FIG. 4;
FIG. 7 is a diagram illustrating a state of light propagation due to a displacement of an installation groove formation position.
FIGS. 8A and 8B are diagrams illustrating the shape of a core.
FIGS. 9A and 9B are diagrams illustrating a cross-sectional shape of a core.
FIG. 10 is a schematic perspective view of an optical waveguide device according to another embodiment of the present invention.
FIG. 11 is a diagram illustrating a use mode of the optical waveguide device shown in FIG.
FIG. 12 to FIG. 17 are diagrams illustrating the manufacturing process of the optical waveguide device shown in FIG.
FIG. 13 is a continuation diagram of FIG. 12;
FIG. 14 is a continuation diagram of FIG. 13;
FIG. 15 is a continuation diagram of FIG. 14;
FIG. 16 is a continuation diagram of FIG. 15;
FIG. 17 is a continuation diagram of FIG. 16;
FIG. 18 is a schematic plan view of an optical waveguide device according to still another embodiment of the present invention.
FIG. 19 is a diagram showing a plane corresponding to a cross section taken along line BB ′ of FIG. 18;
FIG. 20 is a schematic plan view of an optical waveguide device according to still another embodiment of the present invention.
21 is a schematic front view of the optical waveguide device shown in FIG.
FIG. 22 is a diagram illustrating a communication device using the optical waveguide device of the present invention.
FIG. 23 is a diagram illustrating an optical communication system using the optical waveguide device of the present invention.
FIG. 24 is a block diagram of a line termination device or a line termination device.
[Explanation of symbols]
12a Optical waveguide device
13 Substrate
14 Lower cladding layer
15a-15c core
16 Upper cladding layer
17 Glass substrate
18 Filter
19 Installation groove

Claims (8)

An optical element for selectively transmitting or reflecting light, a first core and a second core disposed with the optical element interposed therebetween, and disposed on the same side as the first core with respect to a plane including the optical element; In the optical waveguide device including a third core and a clad surrounding the first, second, and third cores,
An optical waveguide device wherein the first core and the third core are independent of each other. 2. The optical waveguide device according to claim 1, wherein the optical element transmits only light in a specific wavelength range and reflects light in wavelengths other than the specific wavelength range. 3. The optical waveguide device according to claim 1, wherein the optical element is a mirror capable of controlling reflection and transmission of light. The optical waveguide device according to claim 1, wherein the optical element is a movable mirror, and the mirror can be moved in and out of an optical axis of the first, second, and third cores. . 2. The optical waveguide device according to claim 1, wherein a closest distance between the light incident end face of the third core and the first core is 5 μm or more. 3. The optical waveguide device according to claim 1, wherein an area of a light incident end of the third core is larger than an area of a light output end of the first core. The optical waveguide device according to claim 1, wherein the first core is a core that propagates a signal in a single mode, and the third core is a core that propagates a signal in a multimode. A communication device using the optical waveguide device according to claim 1.

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