JP3557966B2

JP3557966B2 - Optical communication module with light blocking filter

Info

Publication number: JP3557966B2
Application number: JP31810699A
Authority: JP
Inventors: 直樹木村
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1999-11-09
Filing date: 1999-11-09
Publication date: 2004-08-25
Anticipated expiration: 2019-11-09
Also published as: JP2001133666A

Description

【０００１】
【発明の属する技術分野】
本発明は光通信モジュール、とくに遮光フィルタ付きの光通信モジュールに関する。
【０００２】
【従来の技術】
アクセス系光通信システムでは、局舎と加入者側との間を光ファイバで結び、局舎側からは１．３μｍ光及び１．５５μｍ光を加入者側へ伝送し、加入者側から局舎側へは１．３μｍ光を伝送する波長多重と双方向伝送の技術を併用した方式が開発されつつある。１．３μｍ光は双方向の通信に、１．５５μｍ光は局舎側からのみの放送用の伝送に用いられる。光アクセス系システム実現の鍵はシステムの低価格化にあり、とくに光モジュールの低価格化を図ることが重要である。
【０００３】
光モジュールには上記の波長多重分離機能と双方向伝送機能が必要であるが、現状のモジュールは送信モジュール、受信モジュール及び光カプラ等を組み合わせてこれらの機能を実現しているが、値段の高い部品を多く使用するためコスト高を免れない。上記の機能を一つのモジュールの中に集積化して低コスト化を図る努力が行われている。
【０００４】
集積化された光通信モジュールにおいては、上記の如く異なる波長の光を分離して受光すると同時に、モジュール自体が備える発光素子からの後方出力光などによる迷光や散乱光、また導波路からの散乱光等の光の回り込みを無くすことが必要である。受光素子の光検出部以外の部分に光が入射した場合、素子の応答速度が遅くなるためである。このため、モジュールに集積される受光素子には遮光フィルタを設けることが求められる。
【０００５】
遮光フィルタを使用した光集積回路の従来例としては、例えば図１１（Ａ）に示す特開平８−１４８６６８に記載された技術が知られている。この従来例は、光導波路の出射端周辺に放射される雑音光の影響を小さくすることを目的としており、受光素子の光検出部に窓開けを有する遮光フィルタ（図１１（Ｂ））が被され、窓開けを出射端と位置合わせして受光素子が光導波路基板に取り付けられる構造である。窓開けの大きさは出射端のビーム断面とほぼ同じ大きさあるいは若干大きくなっており、信号光以外の迷光が受光素子の光検出部以外には入射しないため、出力の電気信号のＳ／Ｎ比が悪くならない。
【０００６】
しかし、この従来技術の遮光フィルタとは、単に周囲の光を遮光することだけが目的であり、波長選択性を持つ波長フィルタではないため、窓開け部分についてはすべての波長の光を透過してしまう。光通信用モジュールでは、波長λ２（例えば波長１．５５μｍ光）の光の受光素子への入射、およびその反射光の伝送路への戻りを防止し、かつ波長λ１（ここでは１．３μｍ光）の迷光が受光素子に入射するのを防止するような、多重の遮光機能が必要であるため、上記の従来技術を光通信用モジュールに適用しても、高品質にしてかつ低価格の光通信用モジュールを得ることは不可能である。
【０００７】
光通信用モジュールの受光部に波長フィルタを設けた従来技術としては、特開平５−２１００２７に開示されている技術がある。この先行技術の特徴は、ピンホール付きのホルダに波長フィルタを貼って一体化した部品、または、ピンホールを持った波長フィルタをホルダに貼って一体化した部品を受光素子の受光面上に被せ、受光素子が導波路出射光以外の迷光から遮断されるように、遮光フードを設けたり、構造的に凹型の箱底に受光素子が位置するようにするというものである。波長フィルタによる波長選択透過／反射とピンホールや構造的な工夫による迷光除去の機能を備えているが、特性上またコスト上不十分である。その理由の第１は、導波路光出射面とフィルタ反射面と垂直に相対しており、導波路端面やフィルタでの反射光が導波路に再入射し、反射戻り光を発生させ、通信のＳ／Ｎ比を悪くする点であり、第２はフードやホルダや受光素子が凹部の底に位置するような機構的な部品等を必要とするため、部品点数、実装工数並びに光学調整工数が増加し、コストの増大が避けられない点である。
【０００８】
【発明が解決しようとする課題】
本発明はこのような従来技術の難点に鑑みて成されたものであって、本発明によれば、反射光の伝送路への戻りを防止する機能を有し、波長λ２の光の受光素子への入射、および波長λ１の光の迷光が受光素子の光検出部以外の部分に入射するのを防止する遮光機能を併せ有し、かつ、低コストで生産できる遮光フィルタ付き光通信用モジュールを得ることが可能である。
【０００９】
【課題を解決するための手段】
本発明の請求項１に係わる発明の遮光フィルタ付き光通信モジュールは、光ファイバと受光素子と半導体レーザと前記半導体レーザの出力光を前記光ファイバに接続し、前記光ファイバからの光を前記受光素子に接続する光導波路を形成した光集積基板を含み、複数波長光を用い、双方向の通信を行うための光通信モジュールであって、前記光集積基板の前記光導波路を前記受光素子に接続する第１の端面を、前記光導波路に前記光ファイバを接続する第２の端面に対して角度をもって対向させ、前記光導波路を、前記第２の端面と直交し前記第１の端面と斜交する直線によって形成し、前記第１の端面に接着した、一方の主面は特定の波長の光を透過する帯域通過フィルタ特性を有する膜を有し、他方の主面は光を透過する空間的且つ部分的であり、前記基板の一つの辺に沿って設けられた窓を有した遮光膜で覆われた前記複数波長光のうち前記受光素子にて受光不要な光を遮光する遮光フィルタを配設し、前記遮光フィルタの背後に前記受光素子を配設した、ことを特徴とする遮光フィルタ付き光通信モジュール、である。
本発明の請求項２に係わる発明の遮光フィルタ付き光通信モジュールは、光ファイバと第１及び第２の受光素子と半導体レーザと前記半導体レーザの出力光を前記光ファイバに接続し、前記光ファイバからの光を前記受光素子に接続する光導波路を有した光集積基板を含み、複数波長光を用い、双方向の通信を行うための光通信モジュールであって、前記光ファイバからの光を前記受光素子に接続する光導波路を前記光集積基板の端面でＶ字型に折り返えす形に形成し、前記光導波路がＶ字型に折り返す前記光集積基板の端面に接着した、一方の主面は特定の波長の光を透過する帯域通過フィルタ特性を有する膜を有し、他方の主面は光を透過する空間的且つ部分的であり、前記基板の一つの辺に沿って設けられた窓を有した遮光膜で覆われた、前記第１の受光素子にて受光不要な光を遮光する遮光フィルタを配設し、前記遮光フィルタの背後に前記第１の受光素子を配設し、前記Ｖ字型に折り返した光導波路が前記Ｖ字型に折り返す前記光集積基板の端面とは別なる光集積基板端面で光出射する位置に前記第２の受光素子を配設した、ことを特徴とする遮光フィルタ付き光通信モジュール、である。
本発明の請求項３に係わる発明の遮光フィルタ付き光通信モジュールは、光ファイバと受光素子と半導体レーザと前記半導体レーザの出力光を前記光ファイバに接続し、前記光ファイバからの光を前記受光素子に接続する光導波路を形成した光集積基板を含み、複数波長光を用い、双方向の通信を行うための光通信モジュールであって、前記光集積基板の前記光導波路を前記受光素子に接続する第１の端面を、前記光導波路に前記光ファイバを接続する第２の端面に対して角度をもって対向させ、前記光導波路を、前記第２の端面と直交し前記第１の端面と斜交する直線によって形成し、前記第１の端面に接着した、一方の主面に特定の波長の光を透過する帯域通過フィルタ特性を有する膜と光を透過する空間的且つ部分的であり、前記基板の一つの辺に沿って設けられた窓を有した遮光膜とを積層して有し前記複数波長光のうち前記受光素子にて受光不要な光を遮光する遮光フィルタを配設し、前記遮光フィルタの背後に前記受光素子を配設した、ことを特徴とする遮光フィルタ付き光通信モジュール、である。
本発明の請求項４に係わる発明の遮光フィルタ付き光通信モジュールは、光ファイバと第１及び第２の受光素子と半導体レーザと前記半導体レーザの出力光を前記光ファイバに接続し、前記光ファイバからの光を前記受光素子に接続する光導波路を有した光集積基板を含み、複数波長光を用い、双方向の通信を行うための光通信モジュールであって、
前記光ファイバからの光を前記受光素子に接続する光導波路を前記光集積基板の端面でＶ字型に折り返えす形に形成し、前記光導波路がＶ字型に折り返す前記光集積基板の端面に接着した、基板の一方の主面に特定の波長の光を透過する帯域通過フィルタ特性を有する膜と光を透過する空間的且つ部分的であり、前記基板の一つの辺に沿って設けられた窓を有した遮光膜とを積層して有し前記第１の受光素子にて受光不要な光を遮光する遮光フィルタを配設し、前記遮光フィルタの背後に前記第１の受光素子を配設し、
前記Ｖ字型に折り返した光導波路が前記Ｖ字型に折り返す前記光集積基板の端面とは別なる光集積基板端面で光出射する位置に前記第２の受光素子を配設した、ことを特徴とする遮光フィルタ付き光通信モジュール、である。
【００１０】
【発明の実施の形態】
本発明の実施の形態について図面を参照して説明する。図１は本発明の遮光フィルタ付き光通信モジュールの第一の実施例の構成図であり、図１（Ａ）はその平面図、図１（Ｂ）は正面図であって、ここではとくに、導波路と受光素子との光結合部付近のみを示している。本モジュールは、図２に示す遮光フィルタ１、光導波路基板２、キャリア８に搭載された受光素子３から構成される。光導波路基板２には、遮光フィルタ１で反射した波長λ２の光がそのまま導波路に戻ることを防ぐために遮光フィルタ１に対して斜めに導波路７が形成される。遮光フィルタ１には、波長λ１の光を透過し、波長λ２の光を遮断するフィルタ膜４が蒸着形成され、フィルタ膜４とフィルタ膜を設けた面とは反対側の面に波長λ１、λ２の光を遮断する遮光メタル５が蒸着形成される。遮光メタル５には導波路７からの出射光が通過できるように窓６が形成される。
遮光フィルタ１は導波路７と窓６の位置が合うように光導波路基板２に接着固定され、受光素子３は導波路７と光検出部９の位置が合うようにキャリア８に半田固定される。
【００１１】
次に、本遮光フィルタ付き光通信モジュールの実施例の動作を説明する。導波路７から入射された波長λ１の光は、導波路７を導波し、遮光フィルタ１のフィルタ膜４、窓６を通過して受光素子３で受光される。導波路７への入射時や導波路７の導波中に発生した波長λ１の迷光は、光導波路基板２または空間を通って遮光フィルタ１に到達するが、遮光メタル５によって反射され、受光素子３の光検出部９以外の部分には入射されない。
【００１２】
導波路７に入射された波長λ２の光は、導波路７を導波して遮光フィルタ１に到達するが、フィルタ膜４によって反射され、受光素子３には入射されない。導波路７がフィルタ膜４に対して斜めに形成されているため、フィルタ膜４によって反射された波長λ２の光も再び導波路には戻らない。
【００１３】
このように、波長λ２の光の受光素子への入射、およびλ１、λ２の反射光の伝送路への戻りを防止する機能を有し、かつ波長λ１の光の迷光が受光素子の光検出部以外の部分に入射するのを防止するための遮光機能を有する光通信用モジュールが得られる。
【００１４】
次に、本発明の遮光フィルタ付き光通信モジュールの他の実施形態について図面を参照して詳細に説明する。図３は本発明の遮光フィルタ付き光通信モジュールの第二の実施形態の構成を示す平面図である。導波路７を斜めに形成する代わりに光導波路基板２の端面を斜めに切断し、遮光フィルタ１を導波路７に対して斜めに貼り付けた遮光フィルタ付き光通信モジュールの一例である。端面を斜めに切断することにより、導波路７を直線にすることが可能である。
【００１５】
また、図４は本発明の遮光フィルタ付き光通信モジュールの第三の実施形態の構成図であり、図４（Ａ）はその平面図、図４（Ｂ）は正面図を示す。光導波路基板２に斜めの溝１１を形成し、遮光フィルタ１を溝１１に挿入して接着固定した遮光フィルタ付き光通信モジュールである。
【００１６】
また、図５は本発明の遮光フィルタ付き光通信モジュールの第四の実施形態の構成図であり、図５（Ａ）はその平面図、図５（Ｂ）は正面図を示す。光導波路基板２上に受光素子３を搭載し、光導波路基板２に形成された溝１１に遮光フィルタ１を挿入して接着固定した遮光フィルタ付き光通信モジュールの一例である。この構成では、受光素子３には導波路入射型受光素子、もしくは端面入射型受光素子が有効である。
【００１７】
また、図６は本発明の遮光フィルタ付き光通信モジュールの第三の実施形態の構成図であり、図６（Ａ）はその平面図、図６（Ｂ）は正面図を示す。遮光フィルタ１で反射された波長λ２の光が導波路１２を導波され、キャリア１４に搭載された受光素子１３に受光される構造の遮光フィルタ付き光通信モジュールの一例である。導波路７と導波路１２は光導波路基板２の中心線に対して対称な位置に形成される。受光素子１３は、導波路１２と光検出部１５の位置が合うようにキャリア１４に半田固定される。導波路７から入射された波長λ２の光はフィルタ膜４で反射され、導波路１２を導波して受光素子１３で受光される。このように導波路７から入射された波長λ１、λ２の光を分割し、それぞれ受光素子３、受光素子１３で受光する光通信モジュールが実現できる。
【００１８】
また、図７は本発明の遮光フィルタ付き光通信モジュールの第三の実施形態の構成図であり、図７（Ａ）はその平面図、図７（Ｂ）は正面図を示す。光導波路基板２上に波長λ１の発光素子１５が搭載された構造の遮光フィルタ付き光通信モジュールの一例である。光導波路基板２には、受光素子３に入射する導波路１７と反対側の導波路１８と結合するようにＹ分岐１６が形成されている。発光素子１９が光導波路基板２上導波路１８の端に半田固定される。発光素子１５からの波長λ１の光は、導波路１８に結合され、Ｙ分岐１６を通って導波路７から伝送路に伝送される。導波路１８に結合されなかった光や、Ｙ分岐１６での散乱光や発光素子１９からの後方出力光などによる迷光は、遮光メタル５によって反射されるため、受光素子３の光検出部９以外の部分には入射されない。
【００１９】
次に、本発明の遮光フィルタ付き光通信モジュールの各実施形態を構成する遮光フィルタの他の実施例を説明する。図８は、遮光メタル５の窓６の形状を、図２の第一の遮光メタルの実施例から変更し、上側の１辺に沿って窓を開けた形状の遮光フィルタの第二の実施例である。窓６が大きいため、遮光フィルタ１の貼付位置がずれても特性に影響しないため、貼付作業の効率化、歩留まり向上が可能である。
【００２０】
また、図９は、フィルタ膜４と遮光メタル５を同じ側の面に蒸着した遮光フィルタの第三の実施例である。
【００２１】
また、図１０は、遮光メタルの代わりに波長λ２の光を遮断する波長フィルタ膜１０を蒸着した遮光フィルタの第四の実施例である。
【００２２】
【発明の効果】
以上説明したように、本発明による遮光フィルタ付き光通信モジュールは、λ１およびλ２の反射光の伝送路への戻りを防止する機能と、波長λ２の光の受光素子への入射を阻止し、かつ、波長λ１の迷光が受光素子の光検出部以外の部分に入射するのを防止する遮光機能を有する。このため、通信品質の劣化を生ずることない。また、迷光が入射して受光素子内部でのキャリア速度の影響による、応答速度の劣化や感度の劣化が生じることがなく、伝送速度の高速化と送受交互の伝送を行う場合の受信感度の向上が可能となる。
更に、１つのフィルタにフィルタ機能と遮光機能の両方を持たせており、また、このフィルタを導波路端面に直接接着しているために、フィルタと遮光膜それぞれを別々に構成した場合に比べ、また、特別の支持部品を設けるのに比べて部品コスト、実装コスト、並びに調整コストの低減が可能である。
【図面の簡単な説明】
【図１】本発明の遮光フィルタ付き光通信モジュールの第一の実施形態の構成を示す図であり、（Ａ）はその平面図、（Ｂ）は正面図である。
【図２】本発明の第一の実施形態を構成する遮光フィルタの第一の実施例の構成を示す図である。
【図３】本発明の遮光フィルタ付き光通信モジュールの第二の実施形態の構成を示す平面図である。
【図４】本発明の遮光フィルタ付き光通信モジュールの第三の実施形態の構成を示す図であり、（Ａ）はその平面図、（Ｂ）は正面図である。
【図５】本発明の遮光フィルタ付き光通信モジュールの第四の実施形態の構成を示す図であり、（Ａ）はその平面図、（Ｂ）は正面図である。
【図６】本発明の遮光フィルタ付き光通信モジュールの第五の実施形態の構成を示す図であり、（Ａ）はその平面図、（Ｂ）は正面図である。
【図７】本発明の実施形態を構成する遮光フィルタの第二の実施例の構成を示す図である。
【図８】本発明の実施形態を構成する遮光フィルタの第三の実施例の構成を示す図である。
【図９】本発明の実施形態を構成する遮光フィルタの第四の実施例の構成を示す図である。
【図１０】本発明の実施形態を構成する遮光フィルタのまた更に別なる実施例の構成を示す図である。
【図１１】従来例の遮光フィルタを使用した光集積回路であり、（Ａ）は平面図、（Ｂ）は遮光フィルタの構造を示す図である。
【符号の説明】
１遮光フィルタ
２光導波路基板
３受光素子
４フィルタ膜
５遮光メタル
６窓
７導波路
８キャリア
９光検出部
１０波長フィルタ膜
１１溝
１２導波路
１３受光素子
１４キャリア
１５光検出部
１６Ｙ分岐
１７導波路
１８導波路
１９発光素子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical communication module, and more particularly to an optical communication module with a light shielding filter.
[0002]
[Prior art]
In an access optical communication system, a station and a subscriber are connected by an optical fiber, 1.3 μm light and 1.55 μm light are transmitted from the station to the subscriber, and the station is transmitted from the subscriber to the station. To the side, a system using both wavelength multiplexing for transmitting 1.3 μm light and bidirectional transmission technology is being developed. The 1.3 μm light is used for bidirectional communication, and the 1.55 μm light is used for broadcast transmission only from the station side. The key to the realization of the optical access system is to reduce the price of the system, and it is particularly important to reduce the price of the optical module.
[0003]
The optical module needs the wavelength division multiplexing / demultiplexing function and the bidirectional transmission function described above. The current module realizes these functions by combining a transmitting module, a receiving module, an optical coupler, and the like, but is expensive. Since many parts are used, high costs cannot be avoided. Efforts have been made to reduce the cost by integrating the above functions into one module.
[0004]
In an integrated optical communication module, light of different wavelengths is separated and received as described above, and at the same time, stray light or scattered light due to backward output light from a light emitting element included in the module itself, or scattered light from a waveguide. It is necessary to eliminate the wraparound of light such as This is because, when light is incident on a portion other than the light detection unit of the light receiving element, the response speed of the element is reduced. For this reason, it is required that the light receiving element integrated in the module be provided with a light shielding filter.
[0005]
As a conventional example of an optical integrated circuit using a light-blocking filter, a technique described in, for example, JP-A-8-148668 shown in FIG. This conventional example aims at reducing the influence of noise light radiated around the emission end of the optical waveguide, and is provided with a light-blocking filter (FIG. 11B) having a window opening in the light detection section of the light receiving element. In this structure, the light receiving element is attached to the optical waveguide substrate with the window opening aligned with the emission end. The size of the window opening is substantially the same as or slightly larger than the beam cross section at the emission end, and since stray light other than the signal light does not enter the light detection unit other than the light receiving element, the S / N of the output electric signal is reduced. The ratio does not get worse.
[0006]
However, the purpose of this conventional light-blocking filter is merely to block ambient light, and is not a wavelength filter having wavelength selectivity. I will. In the optical communication module, it is possible to prevent light having a wavelength of λ2 (for example, 1.55 μm light) from being incident on the light receiving element and returning the reflected light to the transmission path, and have a wavelength of λ1 (here, 1.3 μm light). It is necessary to have a multiple light shielding function to prevent stray light from entering the light receiving element. Therefore, even if the above-described conventional technology is applied to an optical communication module, high quality and low cost optical communication can be achieved. It is not possible to obtain a module for use.
[0007]
As a conventional technique in which a wavelength filter is provided in a light receiving unit of an optical communication module, there is a technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-210027. The feature of this prior art is that a wavelength filter with a pinhole is integrated with a holder with a pinhole, or a wavelength filter with a pinhole is integrated with a holder on the light receiving surface of the light receiving element. In addition, a light-shielding hood is provided so that the light-receiving element is shielded from stray light other than light emitted from the waveguide, or the light-receiving element is positioned at the bottom of a structurally concave box. Although a function of wavelength selective transmission / reflection by a wavelength filter and a function of removing stray light by a pinhole and structural measures are provided, they are insufficient in characteristics and cost. The first reason is that the waveguide light exit surface and the filter reflection surface are perpendicular to each other, and the light reflected by the waveguide end surface and the filter re-enters the waveguide, generates reflected return light, and causes communication. The second is that the S / N ratio is deteriorated. The second is that mechanical parts such as a hood, a holder, and a light receiving element are located at the bottom of the concave portion, and the like. That is, the cost increases.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of such disadvantages of the related art, and according to the present invention, has a function of preventing reflected light from returning to a transmission path, and has a function of receiving light of wavelength λ2. And an optical communication module with a light-blocking filter that has a light-blocking function that prevents stray light of wavelength λ1 from being incident on portions other than the light-detecting portion of the light-receiving element, and that can be produced at low cost. It is possible to get.
[0009]
[Means for Solving the Problems]
An optical communication module with a light-blocking filter according to claim 1 of the present invention connects an optical fiber, a light receiving element, a semiconductor laser, and output light of the semiconductor laser to the optical fiber, and receives the light from the optical fiber to receive the light. An optical communication module for performing bidirectional communication using light of a plurality of wavelengths, comprising an optical integrated substrate formed with an optical waveguide connected to an element, wherein the optical waveguide of the optical integrated substrate is connected to the light receiving element. The first end face of the optical waveguide faces at an angle to a second end face connecting the optical fiber to the optical waveguide, and the optical waveguide is orthogonal to the second end face and oblique to the first end face. One main surface has a film having a band-pass filter characteristic for transmitting light of a specific wavelength, and the other main surface has a spatial light transmitting characteristic formed by a straight line and adhered to the first end surface. And part A light-blocking filter that blocks light unnecessary to be received by the light-receiving element among the plurality of wavelengths of light covered with a light-blocking film having a window provided along one side of the substrate is provided. An optical communication module with a light-blocking filter, wherein the light-receiving element is disposed behind the light-blocking filter.
An optical communication module with a light-blocking filter according to claim 2 of the present invention connects the optical fiber, the first and second light receiving elements, the semiconductor laser, and the output light of the semiconductor laser to the optical fiber, An optical communication module for performing bidirectional communication, comprising an optical integrated substrate having an optical waveguide for connecting light from the light receiving element to the light receiving element, wherein light from the optical fiber is An optical waveguide connected to a light receiving element is formed in a shape folded back into a V-shape at an end face of the optical integrated substrate, and the optical waveguide is bonded to an end face of the optical integrated board folded into a V-shape, one main surface. Has a film having a band-pass filter characteristic for transmitting light of a specific wavelength, the other main surface being spatial and partial for transmitting light, and a window provided along one side of the substrate Covered with a light-shielding film having A light-blocking filter that blocks light unnecessary to be received by the first light-receiving element, the first light-receiving element is provided behind the light-blocking filter, and the V-shaped optical waveguide is folded. An optical communication module with a light-blocking filter, wherein the second light-receiving element is disposed at a position where light is emitted at an end face of the optical integrated substrate different from the end face of the optical integrated board that is folded back into the V shape. is there.
An optical communication module with a light-blocking filter according to claim 3 of the present invention connects an optical fiber, a light receiving element, a semiconductor laser, and output light of the semiconductor laser to the optical fiber, and receives the light from the optical fiber to receive the light. An optical communication module for performing bidirectional communication using light of a plurality of wavelengths, comprising an optical integrated substrate formed with an optical waveguide connected to an element, wherein the optical waveguide of the optical integrated substrate is connected to the light receiving element. The first end face of the optical waveguide faces at an angle to a second end face connecting the optical fiber to the optical waveguide, and the optical waveguide is orthogonal to the second end face and oblique to the first end face. A film having a band-pass filter characteristic for transmitting light of a specific wavelength on one main surface, which is formed by a straight line and adhered to the first end surface, and a spatial and partial film for transmitting light; A light-shielding filter having a stack of light-shielding films having windows provided along one side, the light-shielding filter being configured to shield light unnecessary to be received by the light-receiving element among the plurality of wavelengths, An optical communication module with a light-blocking filter, wherein the light receiving element is disposed behind the optical communication module.
An optical communication module with a light-blocking filter according to claim 4 of the present invention connects the optical fiber, the first and second light receiving elements, the semiconductor laser, and the output light of the semiconductor laser to the optical fiber, An optical communication module for performing bidirectional communication, including an optical integrated substrate having an optical waveguide that connects light from the light receiving element to the light receiving element,
An optical waveguide for connecting the light from the optical fiber to the light receiving element is formed in a V-shape at the end face of the optical integrated substrate, and the optical waveguide is folded in a V-shape at the end face of the optical integrated board. A film having a band-pass filter characteristic for transmitting light of a specific wavelength on one main surface of the substrate and a spatial and partial film for transmitting light, which is provided along one side of the substrate. A light-shielding filter having a light-shielding film having windows formed thereon for blocking light unnecessary to be received by the first light-receiving element; and disposing the first light-receiving element behind the light-shielding filter. Set up
Wherein the optical waveguide is folded in V-shape is disposed the second light receiving element at a position the light emitted at another that the optical integrated substrate end face is the end face of the optical integrated substrate folding the V-shape, that An optical communication module with a light-blocking filter.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a first embodiment of an optical communication module with a light shielding filter according to the present invention. FIG. 1 (A) is a plan view thereof, and FIG. 1 (B) is a front view thereof. Only the vicinity of the optical coupling portion between the waveguide and the light receiving element is shown. This module includes a light-blocking filter 1, an optical waveguide substrate 2, and a light-receiving element 3 mounted on a carrier 8 shown in FIG. A waveguide 7 is formed on the optical waveguide substrate 2 at an angle to the light-shielding filter 1 in order to prevent the light of the wavelength λ2 reflected by the light-shielding filter 1 from returning to the waveguide as it is. A filter film 4 that transmits light of wavelength λ1 and blocks light of wavelength λ2 is formed on the light-blocking filter 1 by vapor deposition, and wavelengths λ1, λ2 are provided on the surface opposite to the surface on which the filter film 4 and the filter film are provided. A light-shielding metal 5 for blocking the light is formed by vapor deposition. A window 6 is formed in the light shielding metal 5 so that light emitted from the waveguide 7 can pass therethrough.
The light-blocking filter 1 is bonded and fixed to the optical waveguide substrate 2 so that the position of the waveguide 7 and the window 6 match, and the light receiving element 3 is fixed to the carrier 8 by soldering so that the position of the waveguide 7 and the light detection unit 9 match. .
[0011]
Next, the operation of the embodiment of the optical communication module with the light shielding filter will be described. The light of wavelength λ1 incident from the waveguide 7 propagates through the waveguide 7, passes through the filter film 4 of the light-blocking filter 1, and the window 6, and is received by the light receiving element 3. The stray light of the wavelength λ1 generated upon incidence on the waveguide 7 or during the propagation of the waveguide 7 reaches the light-shielding filter 1 through the optical waveguide substrate 2 or the space, but is reflected by the light-shielding metal 5 and is received by the light-receiving element. No light is incident on portions other than the photodetector 9.
[0012]
The light of wavelength λ2 incident on the waveguide 7 is guided through the waveguide 7 and reaches the light shielding filter 1, but is reflected by the filter film 4 and is not incident on the light receiving element 3. Since the waveguide 7 is formed obliquely with respect to the filter film 4, the light of the wavelength λ2 reflected by the filter film 4 does not return to the waveguide again.
[0013]
As described above, the light detecting section of the light receiving element has the function of preventing the light of wavelength λ2 from entering the light receiving element and preventing the reflected lights of λ1 and λ2 from returning to the transmission path. An optical communication module having a light shielding function for preventing light from entering other portions is obtained.
[0014]
Next, another embodiment of the optical communication module with a light shielding filter of the present invention will be described in detail with reference to the drawings. FIG. 3 is a plan view showing a configuration of an optical communication module with a light-blocking filter according to a second embodiment of the present invention. This is an example of an optical communication module with a light-blocking filter in which the end face of the optical waveguide substrate 2 is cut obliquely instead of forming the waveguide 7 obliquely, and the light-shielding filter 1 is attached obliquely to the waveguide 7. The waveguide 7 can be made straight by cutting the end face obliquely.
[0015]
FIG. 4 is a configuration diagram of a third embodiment of an optical communication module with a light-blocking filter according to the present invention. FIG. 4 (A) is a plan view and FIG. 4 (B) is a front view. This is an optical communication module with a light-shielding filter in which an oblique groove 11 is formed in the optical waveguide substrate 2, and the light-shielding filter 1 is inserted into the groove 11 and adhered and fixed.
[0016]
FIG. 5 is a configuration diagram of a fourth embodiment of an optical communication module with a light-blocking filter according to the present invention. FIG. 5 (A) is a plan view and FIG. 5 (B) is a front view. This is an example of an optical communication module with a light-shielding filter in which a light-receiving element 3 is mounted on an optical waveguide substrate 2 and a light-shielding filter 1 is inserted into a groove 11 formed in the optical waveguide substrate 2 and adhered and fixed. In this configuration, a waveguide incident light receiving element or an end face incident light receiving element is effective as the light receiving element 3.
[0017]
6 is a configuration diagram of a third embodiment of an optical communication module with a light-blocking filter according to the present invention. FIG. 6 (A) is a plan view and FIG. 6 (B) is a front view. This is an example of an optical communication module with a light-blocking filter having a structure in which light of wavelength λ2 reflected by the light-blocking filter 1 is guided through the waveguide 12 and received by the light-receiving element 13 mounted on the carrier 14. The waveguide 7 and the waveguide 12 are formed at symmetrical positions with respect to the center line of the optical waveguide substrate 2. The light receiving element 13 is fixed to the carrier 14 by soldering so that the position of the waveguide 12 and the position of the photodetector 15 match. The light of wavelength λ2 incident from the waveguide 7 is reflected by the filter film 4, guided through the waveguide 12 and received by the light receiving element 13. In this manner, an optical communication module that splits the light of wavelengths λ1 and λ2 incident from the waveguide 7 and receives the light with the light receiving element 3 and the light receiving element 13, respectively, can be realized.
[0018]
FIG. 7 is a configuration diagram of a third embodiment of an optical communication module with a light-blocking filter according to the present invention. FIG. 7 (A) is a plan view and FIG. 7 (B) is a front view. This is an example of an optical communication module with a light-blocking filter having a structure in which a light emitting element 15 of wavelength λ1 is mounted on an optical waveguide substrate 2. A Y-branch 16 is formed on the optical waveguide substrate 2 so as to be coupled to a waveguide 18 opposite to the waveguide 17 that enters the light receiving element 3. The light emitting element 19 is fixed to the end of the waveguide 18 on the optical waveguide substrate 2 by soldering. Light having the wavelength λ1 from the light emitting element 15 is coupled to the waveguide 18 and transmitted from the waveguide 7 to the transmission path through the Y branch 16. Light not coupled to the waveguide 18, stray light due to scattered light at the Y-branch 16, or backward output light from the light-emitting element 19 is reflected by the light-shielding metal 5. Is not incident on the portion.
[0019]
Next, other examples of the light-shielding filter constituting each embodiment of the optical communication module with the light-shielding filter of the present invention will be described. FIG. 8 shows a second embodiment of a light-shielding filter in which the shape of the window 6 of the light-shielding metal 5 is changed from that of the first light-shielding metal of FIG. 2 and a window is opened along one upper side. It is. Since the size of the window 6 is large, even if the sticking position of the light shielding filter 1 is shifted, the characteristics are not affected, so that the efficiency of the sticking operation and the yield can be improved.
[0020]
FIG. 9 shows a third embodiment of a light-shielding filter in which the filter film 4 and the light-shielding metal 5 are deposited on the same surface.
[0021]
FIG. 10 shows a fourth embodiment of a light-shielding filter in which a wavelength filter film 10 for blocking light of wavelength λ2 is deposited instead of the light-shielding metal.
[0022]
【The invention's effect】
As described above, the optical communication module with the light-blocking filter according to the present invention has the function of preventing the reflected light of λ1 and λ2 from returning to the transmission path, and preventing the light of wavelength λ2 from entering the light receiving element, and Has a light blocking function of preventing stray light having the wavelength λ1 from entering a portion other than the light detecting portion of the light receiving element. Therefore, the communication quality does not deteriorate. In addition, the response speed and the sensitivity do not deteriorate due to the influence of the carrier speed inside the light receiving element due to the incidence of stray light, and the reception sensitivity is improved when the transmission speed is increased and the transmission and reception are performed alternately. Becomes possible.
Furthermore, since one filter has both a filter function and a light shielding function, and since this filter is directly adhered to the end face of the waveguide, compared to a case where the filter and the light shielding film are separately configured, Also, compared to providing special support components, it is possible to reduce component costs, mounting costs, and adjustment costs.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an optical communication module with a light-blocking filter according to a first embodiment of the present invention, where (A) is a plan view and (B) is a front view.
FIG. 2 is a diagram showing a configuration of a first example of a light-blocking filter constituting a first embodiment of the present invention.
FIG. 3 is a plan view showing a configuration of an optical communication module with a light shielding filter according to a second embodiment of the present invention.
FIGS. 4A and 4B are diagrams showing a configuration of an optical communication module with a light-blocking filter according to a third embodiment of the present invention, wherein FIG. 4A is a plan view and FIG.
FIGS. 5A and 5B are diagrams showing a configuration of an optical communication module with a light-blocking filter according to a fourth embodiment of the present invention, wherein FIG. 5A is a plan view and FIG.
FIGS. 6A and 6B are diagrams showing a configuration of an optical communication module with a light-blocking filter according to a fifth embodiment of the present invention, wherein FIG. 6A is a plan view and FIG. 6B is a front view.
FIG. 7 is a diagram showing a configuration of a second example of the light-blocking filter constituting the embodiment of the present invention.
FIG. 8 is a diagram showing the configuration of a third example of the light-blocking filter constituting the embodiment of the present invention.
FIG. 9 is a diagram showing a configuration of a fourth example of the light-blocking filter constituting the embodiment of the present invention.
FIG. 10 is a diagram showing a configuration of still another example of a light-blocking filter constituting an embodiment of the present invention.
11A and 11B are optical integrated circuits using a light-blocking filter according to a conventional example, wherein FIG. 11A is a plan view and FIG. 11B is a diagram illustrating the structure of the light-blocking filter.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 light shielding filter 2 optical waveguide substrate 3 light receiving element 4 filter film 5 light shielding metal 6 window 7 waveguide 8 carrier 9 light detection unit 10 wavelength filter film 11 groove 12 waveguide 13 light receiving element 14 carrier 15 light detection unit 16 Y branch 17 conduction Waveguide 18 Waveguide 19 Light emitting element

Claims

An optical integrated substrate having an optical fiber, a light receiving element, a semiconductor laser, and an optical waveguide connecting the output light of the semiconductor laser to the optical fiber and connecting the light from the optical fiber to the light receiving element; An optical communication module for performing two-way communication using
A first end face connecting the optical waveguide of the optical integrated substrate to the light receiving element is opposed at an angle to a second end face connecting the optical fiber to the optical waveguide, and the optical waveguide is connected to the second end face. 2 is formed by a straight line orthogonal to the end face and oblique to the first end face,
One main surface adhered to the first end surface has a film having a band-pass filter characteristic for transmitting light of a specific wavelength, and the other main surface is spatial and partial for transmitting light; A light-blocking filter that blocks light unnecessary to be received by the light-receiving element among the plurality of wavelengths of light covered with a light-blocking film having a window provided along one side of the substrate is provided ,
An optical communication module with a light-shielding filter, wherein the light-receiving element is disposed behind the light-shielding filter.

An optical integrated substrate having an optical fiber, first and second light receiving elements, a semiconductor laser, and an optical waveguide for connecting output light of the semiconductor laser to the optical fiber and connecting light from the optical fiber to the light receiving element An optical communication module for performing bidirectional communication using light of a plurality of wavelengths,
Forming an optical waveguide connecting the light from the optical fiber to the light receiving element in a V-shape at the end face of the optical integrated substrate;
One main surface has a film having a band-pass filter characteristic for transmitting light of a specific wavelength, and the other main surface adheres to the end surface of the optical integrated substrate in which the optical waveguide is folded in a V shape. A light-shielding filter that is spatially and partially transmitted, and is covered with a light-shielding film having a window provided along one side of the substrate, and shields light unnecessary to be received by the first light-receiving element. Is arranged ,
Disposing the first light receiving element behind the light shielding filter;
The second light-receiving element is disposed at a position where the optical waveguide folded in the V-shape emits light at an end face of the optical integrated substrate different from the end face of the optical integrated board turned in the V-shape,
An optical communication module with a light-blocking filter, characterized in that:

An optical integrated substrate having an optical fiber, a light receiving element, a semiconductor laser, and an optical waveguide connecting the output light of the semiconductor laser to the optical fiber and connecting the light from the optical fiber to the light receiving element; An optical communication module for performing two-way communication using
A first end face connecting the optical waveguide of the optical integrated substrate to the light receiving element is opposed at an angle to a second end face connecting the optical fiber to the optical waveguide, and the optical waveguide is connected to the second end face. 2 is formed by a straight line orthogonal to the end face and oblique to the first end face,
A film adhered to the first end face and having a band-pass filter characteristic for transmitting light of a specific wavelength on one main surface, and spatially and partially transmitting light, along one side of the substrate; A light-shielding filter that blocks light unnecessary to be received by the light-receiving element among the plurality of wavelength lights is provided by laminating a light-shielding film having a window provided therein,
An optical communication module with a light-shielding filter, wherein the light-receiving element is disposed behind the light-shielding filter.

An optical integrated substrate having an optical fiber, first and second light receiving elements, a semiconductor laser, and an optical waveguide for connecting output light of the semiconductor laser to the optical fiber and connecting light from the optical fiber to the light receiving element An optical communication module for performing bidirectional communication using light of a plurality of wavelengths,
Forming an optical waveguide connecting the light from the optical fiber to the light receiving element in a V-shape at the end face of the optical integrated substrate;
A film having a band-pass filter characteristic for transmitting light of a specific wavelength on one main surface of the substrate, the film being bonded to an end surface of the optical integrated substrate on which the optical waveguide is folded in a V-shape; And a light-blocking filter for laminating a light-blocking film having a window provided along one side of the substrate and blocking light unnecessary to be received by the first light-receiving element. ,
Disposing the first light receiving element behind the light shielding filter;
The second light-receiving element is disposed at a position where the optical waveguide folded in the V-shape emits light at an end face of the optical integrated substrate different from the end face of the optical integrated board turned in the V-shape,
An optical communication module with a light-blocking filter, characterized in that: