JP5137393B2

JP5137393B2 - Optical coupler

Info

Publication number: JP5137393B2
Application number: JP2006340711A
Authority: JP
Inventors: 隆裕渡辺; 直之児島
Original assignee: THE FURUKAW ELECTRIC CO., LTD.
Current assignee: THE FURUKAW ELECTRIC CO., LTD.
Priority date: 2006-12-19
Filing date: 2006-12-19
Publication date: 2013-02-06
Anticipated expiration: 2026-12-19
Also published as: JP2008152064A

Description

本発明は、光ファイバ通信や光配線の分野で使用される、受光素子を用いた光結合器に関する。 The present invention is used in the field of optical communications and optical interconnect relates to an optical coupler using a light receiving element.

光ファイバ通信の分野において、信号で変調された光信号を電気信号に変換する場合、一般にフォトダイオード（受光素子）を用いた光結合器が用いられる。 In the field of optical fiber communication, when an optical signal modulated with a signal is converted into an electric signal, an optical coupler using a photodiode (light receiving element) is generally used.

また、近年、半導体からなる集積素子の分野では、高速・高密度化への進展が著しく、従来の電気的な配線による相互接続では、信号の遅延、減衰、干渉等により、十分な特性が期待できなくなることが問題となっている。この問題は、ＩＯボトルネックといわれ、これを解決するために光インターコネクション技術が注目されている。光インターコネクション技術は、通信機器相互間や通信機器内のボード間にとどまらず、一つのボード内の集積回路素子間でも行うことが検討されている。従来、ボード内光インターコネクションを実現するための光結合器として、特許文献１に開示されたものは、いわゆる光ピンと呼ばれるものであり、光ファイバを加工した光ピンを回路付光導波路基板に形成された穴に差し込んで使用するものである。この方式では、回路付光導波路基板に沿って導波路を導波してきた信号光を、差し込まれた光ピンの斜面にて反射させ、回路付光導波路基板に垂直な方向に取り出し、プレーナー型(planar type)のフォトダイオードによって受光して電気信号に変換し、又は、回路付光導波路基板に垂直な方向に面発光型レーザ(VCSEL)から出射された信号光を、差し込まれた光ピンの斜面にて反射させ、回路付光導波路基板に沿って導波路を導波させるものである。 In recent years, in the field of integrated devices made of semiconductors, progress toward high speed and high density has been remarkable, and interconnects using conventional electrical wiring are expected to have sufficient characteristics due to signal delay, attenuation, interference, etc. Inability to do so is a problem. This problem is said to be an IO bottleneck, and optical interconnection technology has attracted attention in order to solve this problem. The optical interconnection technology is being studied not only between communication devices and between boards in a communication device, but also between integrated circuit elements in one board. 2. Description of the Related Art Conventionally, as an optical coupler for realizing intra-board optical interconnection, what is disclosed in Patent Document 1 is a so-called optical pin, and an optical pin obtained by processing an optical fiber is formed on an optical waveguide substrate with a circuit. It is used by inserting it into the hole. In this method, the signal light guided through the waveguide along the optical waveguide substrate with circuit is reflected by the slope of the inserted optical pin, taken out in a direction perpendicular to the optical waveguide substrate with circuit, and planar type ( Planar type) receives light by a photodiode and converts it into an electrical signal, or the signal light emitted from a surface emitting laser (VCSEL) in a direction perpendicular to the optical waveguide substrate with circuit is the slope of the inserted optical pin And the waveguide is guided along the optical waveguide substrate with circuit.

：特開２００４−０８５９１３号: JP-A-2004-085913

フォトダイオードを用いて光信号を電気信号に変換する場合、信号光に大きなモード分散があると、光源からフォトダイオードへの信号光の到達時間にばらつきを生じ、伝送容量が充分に確保できない場合がある。 When using a photodiode to convert an optical signal into an electrical signal, if the signal light has a large mode dispersion, the arrival time of the signal light from the light source to the photodiode may vary, and a sufficient transmission capacity may not be secured. is there.

特に、基板内の光配線に使用されるマルチモード光導波路では、導波路を伝搬する複数のモードの伝搬角度（コア−クラッド界面での全反射角度）の差によって生じるモード分散により、受光素子への信号到達時間のばらつき（スキュー）が著しくなり、伝送容量が十分に確保できない。 In particular, in a multimode optical waveguide used for optical wiring in a substrate, to a light receiving element due to mode dispersion caused by a difference in propagation angles (total reflection angles at a core-cladding interface) of a plurality of modes propagating through a waveguide. The signal arrival time variation (skew) becomes significant, and a sufficient transmission capacity cannot be secured.

このため、光導波路としてシングルモード光導波路を採用したり、屈折率分布型（ＧＲＩＮ）のマルチモード光導波路を採用することも考えられる。しかし、前者の場合には発光素子とシングルモード導波路との光結合が難しくなるという難点がある。また、後者についても、屈折率の制御が難しく、構造が複雑にならざるを得ないという難点がある。 For this reason, it is conceivable to adopt a single-mode optical waveguide as the optical waveguide or a multi-mode optical waveguide of a graded index type (GRIN). However, in the former case, there is a problem that optical coupling between the light emitting element and the single mode waveguide becomes difficult. Further, the latter also has a drawback that the refractive index is difficult to control and the structure must be complicated.

また、光ファイバ通信に受光素子を使用する場合にも、同様にモード分散により伝送容量が制限されることは知られている。 Also, when using a light receiving element for optical fiber communication, it is known that the transmission capacity is similarly limited by mode dispersion.

本発明は、上記課題を解決することのできる光結合器を提供することを目的とする。 An object of this invention is to provide the optical coupler which can solve the said subject.

すなわち、本第１の発明は、受光素子と、前記受光素子を搭載する受光素子搭載基板と、前記受光素子と電気的に接続され、該受光素子の受光面に対向する部分に空孔が形成された電気配線基板と、前記電気配線基板の、前記受光素子が電気的に接続されていない面に積層されたマルチモード光導波路と、光の伝送方向に向かって径が小さくなるコアと該コアを囲むクラッドとからなる受光用光伝送路を介して、前記受光素子に前記マルチモード光導波路を伝送する光を結合させる光結合手段とを備え、前記マルチモード光導波路は、前記電気配線基板に形成された空孔に対応する位置に、当該マルチモード光導波路内を伝搬してきた光を前記受光素子の受光面側に反射させる反射面が形成されており、前記電気配線基板に形成された空孔と前記受光用光伝送路との間に、該電気配線基板の面方向において間隙を有し、前記受光素子搭載基板は半田を介して前記電気配線基板に固定され、前記受光素子搭載基板、前記受光用光伝送路、前記半田及び前記空孔で囲まれた空隙部には、光透過性樹脂が充填されており、前記光結合手段の受光用光伝送路は、前記電気配線基板の空孔内部において、前記マルチモード光導波路の反射面で反射した光が、前記コアに入射する位置に配置されていることを特徴とする光結合器である。 That is, according to the first aspect of the invention, a light receiving element, a light receiving element mounting substrate on which the light receiving element is mounted, and a hole that is electrically connected to the light receiving element and that faces the light receiving surface of the light receiving element are formed. An electrical wiring board, a multimode optical waveguide laminated on a surface of the electrical wiring board where the light receiving element is not electrically connected, a core whose diameter decreases in the light transmission direction, and the core Optical coupling means for coupling the light transmitted through the multimode optical waveguide to the light receiving element via a light receiving optical transmission path comprising a cladding surrounding the multimode optical waveguide, and the multimode optical waveguide is attached to the electrical wiring substrate. A reflection surface for reflecting light propagating in the multimode optical waveguide to the light receiving surface side of the light receiving element is formed at a position corresponding to the formed hole, and the void formed in the electric wiring board is formed. With holes There is a gap in the plane direction of the electric wiring board between the light receiving optical transmission line, and the light receiving element mounting board is fixed to the electric wiring board via solder, and the light receiving element mounting board, the light receiving element A light-transmitting resin is filled in the gap surrounded by the optical transmission path, the solder, and the hole, and the light-receiving optical transmission path of the optical coupling means is inside the hole of the electric wiring board. In the optical coupler, the light reflected by the reflecting surface of the multimode optical waveguide is disposed at a position where the light enters the core.

また、本第２の発明は、受光素子と、前記受光素子を搭載する受光素子搭載基板と、前記受光素子と電気的に接続され、該受光素子の受光面に対向する部分に空孔が形成された電気配線基板と、前記電気配線基板の、前記受光素子が電気的に接続されていない面に積層されたマルチモード光導波路と、前記マルチモード光導波路の比屈折率差よりも小さい比屈折率差を有するコアと該コアを囲むクラッドとからなる受光用光伝送路を介して、前記受光素子に前記マルチモード光導波路を伝送する光を結合させる光結合手段とを備え、前記マルチモード光導波路は、前記電気配線基板に形成された空孔に対応する位置に、当該マルチモード光導波路内を伝搬してきた光を前記受光素子の受光面側に反射させる反射面が形成されており、前記電気配線基板に形成された空孔と前記受光用光伝送路との間に、該電気配線基板の面方向において間隙を有し、前記受光素子搭載基板は半田を介して前記電気配線基板に固定され、前記受光素子搭載基板、前記受光用光伝送路、前記半田及び前記空孔で囲まれた空隙部には、光透過性樹脂が充填されており、前記光結合手段の受光用光伝送路は、前記電気配線基板の空孔内部において、前記マルチモード光導波路の反射面で反射した光が、前記コアに入射する位置に配置されていることを特徴とする光結合器である。 In the second invention, a light receiving element, a light receiving element mounting substrate on which the light receiving element is mounted, and a hole that is electrically connected to the light receiving element and that faces the light receiving surface of the light receiving element are formed. And a multimode optical waveguide laminated on a surface of the electrical wiring board where the light receiving element is not electrically connected, and a relative refractive index smaller than a relative refractive index difference of the multimode optical waveguide. An optical coupling means for coupling the light transmitted through the multimode optical waveguide to the light receiving element via a light receiving optical transmission path composed of a core having a rate difference and a clad surrounding the core; The waveguide is formed with a reflection surface that reflects light propagating through the multimode optical waveguide on the light receiving surface side of the light receiving element at a position corresponding to a hole formed in the electric wiring board, Electrical There is a gap in the surface direction of the electric wiring board between the hole formed in the wiring board and the optical transmission path for light reception, and the light receiving element mounting board is fixed to the electric wiring board via solder. The light receiving element mounting substrate, the light receiving light transmission path, the void surrounded by the solder and the holes are filled with a light transmitting resin, and the light receiving light transmission path of the optical coupling means is The optical coupler is characterized in that the light reflected by the reflecting surface of the multimode optical waveguide is disposed at a position where the light is incident on the core inside the hole of the electric wiring board.

また、本第３の発明は、受光素子と、前記受光素子を搭載する受光素子搭載基板と、前記受光素子と電気的に接続され、該受光素子の受光面に対向する部分に空孔が形成された電気配線基板と、前記電気配線基板の、前記受光素子が電気的に接続されていない面に積層されたマルチモード光導波路と、コアと該コアを囲むクラッドとからなるシングルモード光導波路である受光用光伝送路を介して、前記受光素子に前記マルチモード光導波路を伝送する光を結合させる光結合手段とを備え、前記マルチモード光導波路は、前記電気配線基板に形成された空孔に対応する位置に、当該マルチモード光導波路内を伝搬してきた光を前記受光素子の受光面側に反射させる反射面が形成されており、前記電気配線基板に形成された空孔と前記受光用光伝送路との間に、該電気配線基板の面方向において間隙を有し、前記受光素子搭載基板は半田を介して前記電気配線基板に固定され、前記受光素子搭載基板、前記受光用光伝送路、前記半田及び前記空孔で囲まれた空隙部には、光透過性樹脂が充填されており、前記光結合手段の受光用光伝送路は、前記電気配線基板の空孔内部において、前記マルチモード光導波路の反射面で反射した光が、前記コアに入射する位置に配置されていることを特徴とする光結合器である。 The third aspect of the invention includes a light receiving element, a light receiving element mounting substrate on which the light receiving element is mounted, and a hole that is electrically connected to the light receiving element and faces the light receiving surface of the light receiving element. A single mode optical waveguide comprising: a multimode optical waveguide laminated on a surface of the electrical wiring substrate on which the light receiving element is not electrically connected; and a core and a clad surrounding the core. Optical coupling means for coupling the light transmitted through the multimode optical waveguide to the light receiving element via a light receiving optical transmission line, and the multimode optical waveguide is a hole formed in the electrical wiring substrate. Is formed at a position corresponding to the light-receiving surface of the light-receiving element, the reflection surface reflecting the light propagating in the multimode optical waveguide, and the light-receiving holes and the holes for receiving light are formed. light There is a gap in the surface direction of the electric wiring board between the transmission path, and the light receiving element mounting board is fixed to the electric wiring board via solder, and the light receiving element mounting board, the light receiving optical transmission path The space surrounded by the solder and the holes is filled with a light-transmitting resin, and the light receiving optical transmission path of the optical coupling means is located inside the holes of the electric wiring board. The optical coupler is characterized in that the light reflected by the reflection surface of the mode optical waveguide is disposed at a position where the light enters the core.

また、上記構成の本第１の発明の構成によれば、光の伝送方向に向かって径が小さくなるコアと該コアを囲むクラッドとからなる受光用光伝送路を介して、前記マルチモード光導波路を導波する光を前記受光素子に光結合させるものとなっている。このため、前記マルチモード光導波路を伝搬して受光用光伝送路に入射したマルチモードの入力信号光のうち、基本モードを含む伝搬角度が小さい低次モード光は受光用光伝送路を導波して受光素子に到達するが、該低次モード光以外の伝搬角度が大きい高次モード光は、前記クラッドに放出され、受光素子に到達する強度が低減される。したがって、マルチモード光導波路を導波する光に著しいモード分散が生じていても、基本モードを含む低次モードのみが受光素子により受光されるので、光源から受光素子への信号光の到達時間のばらつきが低減され、伝送容量を向上させることができる。 Further , according to the configuration of the first invention having the above-described configuration, the multimode light guide is provided via a light receiving optical transmission path including a core whose diameter decreases in the light transmission direction and a clad surrounding the core. The light guided through the waveguide is optically coupled to the light receiving element. For this reason, of the multimode input signal light that propagates through the multimode optical waveguide and enters the light receiving optical transmission line, low-order mode light including the fundamental mode and having a small propagation angle is guided through the light receiving optical transmission line. Then, the high-order mode light having a large propagation angle other than the low-order mode light is emitted to the cladding, and the intensity reaching the light-receiving element is reduced. Therefore, even if significant mode dispersion occurs in the light guided through the multimode optical waveguide, only the low-order modes including the fundamental mode are received by the light receiving element, so that the arrival time of the signal light from the light source to the light receiving element is reduced. Variations can be reduced and transmission capacity can be improved.

また、本第２の発明の構成によれば、前記マルチモード光導波路の比屈折率差よりも小さい比屈折率差を有するコアと該コアを囲むクラッドとからなる受光用光伝送路を介して、前記マルチモード光導波路を導波する光を前記受光素子に光結合させるものとなっている。比屈折率差の小さい光伝送路では、コア−クラッド界面での全反射角度が小さいために誘起されるモードの伝搬角度差が小さくなる。このため、前記マルチモード光導波路を伝搬して受光用光伝送路に到達したマルチモードの入力信号光によって、受光用光伝送路のコアに誘起されるモードは、前記マルチモード光導波路のコア中よりも伝搬角度差が小さいものとなり、これが受光素子に到達する。したがって、マルチモード光導波路を導波する光に著しいモード分散が生じていても、伝搬角度差が小さいモードの光が受光素子により受光されるので、光源から受光素子への信号光の到達時間のばらつきが低減され、伝送容量を向上させることができる。 According to the configuration of the second aspect of the invention, the light receiving optical transmission line including the core having a relative refractive index difference smaller than the relative refractive index difference of the multimode optical waveguide and the clad surrounding the core is provided. The light guided through the multimode optical waveguide is optically coupled to the light receiving element. In an optical transmission line with a small relative refractive index difference, the difference in the propagation angle of the induced mode is small because the total reflection angle at the core-cladding interface is small. For this reason, the mode induced in the core of the light receiving optical transmission line by the multi-mode input signal light that has propagated through the multi mode optical waveguide and reached the light receiving optical transmission line is the center of the multi mode optical waveguide. The propagation angle difference is smaller than this, and this reaches the light receiving element. Therefore, even if significant mode dispersion occurs in the light guided through the multimode optical waveguide, the light of the mode having a small propagation angle difference is received by the light receiving element, so that the arrival time of the signal light from the light source to the light receiving element is reduced. Variations can be reduced and transmission capacity can be improved.

また、本第３の発明によれば、コアと該コアを囲むクラッドとからなるシングルモード光導波路である受光用光伝送路を介して、前記マルチモード光導波路を導波する光を前記受光素子に光結合させるものとなっている。このため、受光用光伝送路に到達したマルチモードの入力信号光により、受光用光伝送路のコア内に単一の導波モードのみが誘起され、これが受光素子に到達する。したがって、マルチモード光導波路を導波する光に著しいモード分散が生じていても、主として基本モードが受光素子により受光されるので、光源から受光素子への信号光の到達時間のばらつきが低減され、伝送容量を向上させることができる。 According to the third aspect of the present invention, the light guided through the multi-mode optical waveguide is transmitted through the light-receiving optical transmission line, which is a single-mode optical waveguide including a core and a clad surrounding the core. To be optically coupled. For this reason, only a single waveguide mode is induced in the core of the light receiving optical transmission line by the multi-mode input signal light that has reached the light receiving optical transmission line, and reaches the light receiving element. Therefore, even if significant mode dispersion occurs in the light guided through the multimode optical waveguide, the fundamental mode is mainly received by the light receiving element, so that variations in the arrival time of the signal light from the light source to the light receiving element are reduced, Transmission capacity can be improved.

また、上記第１乃至第３の発明では、光導波路としてマルチモード光導波路を使用しているので、基板に実装された集積回路素子間の光配線に本発明を適用する場合において、光源である垂直キャビティ型半導体レーザ（ＶＣＳＥＬ）等との光結合の容易性を維持しつつ、マルチモード光導波路のモード分散による、信号到達時間のばらつきを低減し、伝送容量を高めることが可能である。 In the first to third aspects of the invention, since the multimode optical waveguide is used as the optical waveguide, it is a light source when the present invention is applied to the optical wiring between the integrated circuit elements mounted on the substrate. While maintaining the ease of optical coupling with a vertical cavity semiconductor laser (VCSEL) or the like, it is possible to reduce variations in signal arrival time due to mode dispersion of a multimode optical waveguide and increase transmission capacity.

また、本第１乃至第３の発明では、前記マルチモード光導波路を伝搬する光を前記受光素子に向かって反射する反射面が前記マルチモード光導波路に形成されている。このため、マルチモード光導波路内の光の伝搬方向と受光素子に入射する光の光軸とが交差する構成となり、光路を変換することができるので、基板に実装された集積回路素子間の光配線に本発明を適用する場合に適した構成となる。 In the first to third aspects of the invention, a reflective surface that reflects light propagating through the multimode optical waveguide toward the light receiving element is formed in the multimode optical waveguide. For this reason, the light propagation direction in the multimode optical waveguide intersects with the optical axis of the light incident on the light receiving element, and the optical path can be changed, so that the light between the integrated circuit elements mounted on the substrate can be changed. The configuration is suitable when the present invention is applied to the wiring.

また、本第１乃至第３の発明では、前記電気配線基板の空孔内部の前記受光用光伝送路が、前記マルチモード光導波路の前記反射面によって反射された光が入射されるように配置されている。本第１乃至第３の発明では、反射面によって光路を変換された光が受光用光伝送路に入射する構成となるので、基板に実装された集積回路素子間の光配線に本発明を適用する場合に、さらに適した構成となる。 In the first to third aspects of the invention, the light receiving optical transmission path inside the hole of the electric wiring board is arranged so that the light reflected by the reflecting surface of the multimode optical waveguide is incident thereon. Has been. In the first to third inventions, the light whose optical path is converted by the reflecting surface is incident on the light receiving optical transmission path, and therefore the present invention is applied to the optical wiring between the integrated circuit elements mounted on the substrate. In this case, the configuration is more suitable.

（第１の実施形態例）
以下、図面に基づいて本発明の実施の形態について詳細に説明する。 (First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

図１は、本発明の第１の実施形態例に係る光結合器の断面図を示したものである。本第１の実施形態例に係る光結合器１は、電気配線基板上に実装されたＬＳＩ等の集積回路素子の光配線に用いられる光結合器であって、受光素子２と、受光素子２を配置固定する電気配線基板３と、マルチモード光導波路４と、マルチモード光導波路４を伝搬してきた光を入射し、受光素子２の方に導波する受光用光伝送路5とを有する。 FIG. 1 is a cross-sectional view of an optical coupler according to a first embodiment of the present invention. An optical coupler 1 according to the first embodiment is an optical coupler used for optical wiring of an integrated circuit element such as an LSI mounted on an electric wiring board, and includes a light receiving element 2 and a light receiving element 2. Are arranged and fixed, a multimode optical waveguide 4, and a light receiving optical transmission line 5 that receives light propagating through the multimode optical waveguide 4 and guides it toward the light receiving element 2.

受光素子２は、プレーナ型（面受光型）のもので、受光素子搭載基板６に固定された状態で、受光面が受光用光伝送路５に対向するように電気配線基板３上に配置固定されている。 The light receiving element 2 is a planar type (surface light receiving type), and is fixed on the electric wiring board 3 so that the light receiving surface faces the light receiving optical transmission path 5 while being fixed to the light receiving element mounting substrate 6. Has been.

電気配線基板３は、絶縁層３ａの片面又は両面に所定の導体パターン層３ｂを形成してなるもので、受光素子２を固定する位置に対応する部分に空孔３ｃが形成されている。電気配線基板３としては、絶縁層３ａとしてガラスエポキシのような剛体性の材料を使用したもののほか、ポリイミド等を使用したフレキシブル基板を使用することも可能である。なお、絶縁層３ａは必須のものではなく、たとえばマルチモード光導波路４上に所望の回路パターンを印刷した導体パターン層３ｂのみを備えるようにしてもよい。 The electrical wiring board 3 is formed by forming a predetermined conductor pattern layer 3b on one side or both sides of an insulating layer 3a, and a hole 3c is formed in a portion corresponding to a position where the light receiving element 2 is fixed. As the electrical wiring board 3, it is possible to use a flexible board using polyimide or the like in addition to a rigid material such as glass epoxy as the insulating layer 3a. The insulating layer 3a is not essential, and for example, only the conductor pattern layer 3b in which a desired circuit pattern is printed on the multimode optical waveguide 4 may be provided.

マルチモード光導波路４は、電気配線基板３の導体パターン層３ｂに沿って順次積層されたクラッド層４ｂ、コア層４ａ、クラッド層４ｂからなるもので、エポキシ系樹脂からなる有機導波路である。コア層４ａの屈折率がクラッド層４ｂの屈折率よりも大きくなるよう、適宜材料の配合が調整されている。なお、マルチモード光導波路４の材料としては、エポキシ系樹脂のほか、用途に応じてポリイミド系樹脂やアクリル系樹脂等も使用可能である。 The multimode optical waveguide 4 includes a clad layer 4b, a core layer 4a, and a clad layer 4b that are sequentially laminated along the conductor pattern layer 3b of the electric wiring board 3, and is an organic waveguide made of an epoxy resin. The blending of the materials is appropriately adjusted so that the refractive index of the core layer 4a is larger than the refractive index of the cladding layer 4b. As a material for the multimode optical waveguide 4, in addition to an epoxy resin, a polyimide resin, an acrylic resin, or the like can be used depending on the application.

マルチモード光導波路４における、電気配線基板３の空孔３ｃに対応する位置には、コア層４ａを伝搬してきた光を受光素子２の方（図１の上方）に反射し、出射部４ｃから出射させるよう、マルチモード光導波路４の光軸に対して４５度の傾きをもつ反射面４ｄが形成され、該反射面４ｄ上には、反射率を高めるためにＡｕ膜が形成されている。 In the multimode optical waveguide 4, the light propagating through the core layer 4 a is reflected toward the light receiving element 2 (upward in FIG. 1) at a position corresponding to the hole 3 c of the electric wiring substrate 3, and is emitted from the emitting portion 4 c. A reflection surface 4d having an inclination of 45 degrees with respect to the optical axis of the multimode optical waveguide 4 is formed so as to emit light, and an Au film is formed on the reflection surface 4d in order to increase the reflectance.

受光用光伝送路５は、エポキシ系樹脂の樹脂から形成されたコア５ａとクラッド５ｂとからなる。受光用光伝送路５は、マルチモード光導波路４を導波し、反射面４ｄで反射して出力部４ｃから出射した信号光がコア５ａに入射するような、電気配線基板３の空孔３ｃ内の位置でマルチモード光導波路４上に固定されている。なお、受光用光伝送路５の材料としては、エポキシ系樹脂に限るものではなく、用途に応じてポリイミド系樹脂やアクリル系樹脂等も使用可能である。 The light receiving optical transmission line 5 is composed of a core 5a and a clad 5b made of epoxy resin. The light receiving optical transmission line 5 is guided through the multi-mode optical waveguide 4, and the holes 3c of the electric wiring board 3 are such that the signal light reflected from the reflecting surface 4d and emitted from the output unit 4c enters the core 5a. It is fixed on the multimode optical waveguide 4 at the inner position. The material of the light receiving optical transmission line 5 is not limited to an epoxy resin, and a polyimide resin, an acrylic resin, or the like can be used depending on the application.

また、受光用光伝送路５のコア５ａの先端部は、上記信号光の伝送方向に向かってその径が小さくなるよう、たとえばテーパー形状となっている。そして、受光素子搭載基板６に固定された受光素子２の受光面は上記受光用伝送路５のコア径の小さい側の端部に対向し、その出射光を受光するように位置合わせされている。この状態で、受光素子搭載基板６は半田７を介して空孔３ｃの周囲にて電気配線基板３の導体パターン層３ｂに固定されている。さらに、受光素子搭載基板６、受光用光伝送路５、半田７、空孔３ｃで囲まれた空隙部には、光透過性樹脂８が充填されている。 Further, the tip of the core 5a of the light receiving optical transmission path 5 has, for example, a tapered shape so that the diameter thereof decreases in the signal light transmission direction. The light receiving surface of the light receiving element 2 fixed to the light receiving element mounting substrate 6 faces the end of the light receiving transmission path 5 on the side with the smaller core diameter, and is aligned so as to receive the emitted light. . In this state, the light receiving element mounting substrate 6 is fixed to the conductor pattern layer 3 b of the electric wiring substrate 3 around the hole 3 c through the solder 7. Further, a light-transmitting resin 8 is filled in a space surrounded by the light receiving element mounting substrate 6, the light receiving light transmission path 5, the solder 7, and the holes 3c.

なお、受光素子搭載基板６の表面には所定の回路パターンが形成されており、半田７を介して電気配線基板３の導体パターン層３ｂと電気的に接続されている。 A predetermined circuit pattern is formed on the surface of the light receiving element mounting substrate 6, and is electrically connected to the conductor pattern layer 3 b of the electric wiring substrate 3 through the solder 7.

上記構成の光結合器は、たとえば次のように作製される。まず第１に、絶縁層３ａの片面又は両面に所定の回路を構成する導体パターン層３ｂを形成した電気配線基板３の一方の面に、エポキシ系樹脂をスピンコートし、クラッド層４ｂ、コア層４ａを形成する。フォトリソグラフィによりコア層４ａをパターニングした後、さらにエポキシ樹脂をスピンコートしてクラッド層４ｂを刑成し、マルチモード光導波路４を完成する。そして、ダイシング加工により、マルチモード光導波路４の所定の位置に斜面（反射面）４ｄを形成し、スパッタリングでＡｕを蒸着する。また、上記所定の位置に対応した電気配線基板３の部分は、レーザ加工及びエッチングにより、空孔３ｃを形成する。かくして、電気配線基板３とマルチモード光導波路４とからなる光回路基板９が構成される。 The optical coupler having the above configuration is manufactured as follows, for example. First, an epoxy resin is spin-coated on one surface of an electrical wiring board 3 on which a conductor pattern layer 3b constituting a predetermined circuit is formed on one surface or both surfaces of an insulating layer 3a, and then a cladding layer 4b, a core layer 4a is formed. After the core layer 4a is patterned by photolithography, an epoxy resin is further spin-coated to form a clad layer 4b, thereby completing the multimode optical waveguide 4. Then, a slope (reflection surface) 4d is formed at a predetermined position of the multimode optical waveguide 4 by dicing, and Au is deposited by sputtering. Further, the hole 3c is formed in the portion of the electric wiring board 3 corresponding to the predetermined position by laser processing and etching. Thus, an optical circuit board 9 composed of the electric wiring board 3 and the multimode optical waveguide 4 is formed.

一方、受光用光伝送路５は、図２に示すように、型枠１０の内部にクラッド５ｂとなる樹脂材を充填し、これが未硬化の状態でテーパー状の先端部を有する型材１１を押し込み、クラッド樹脂を硬化させ、クラッド５ｂを形成する。そして、型材１１を除去し、コアとなる樹脂材を充填して硬化させ、コア５ａを形成する。しかるのち、型枠１０を除去することにより、受光用光伝送路５を得る。 On the other hand, as shown in FIG. 2, the light-receiving optical transmission line 5 is filled with a resin material to be the clad 5b inside the mold 10, and pushes the mold 11 having a tapered tip in an uncured state. Then, the clad resin is cured to form the clad 5b. Then, the mold material 11 is removed, and a resin material to be a core is filled and cured to form the core 5a. Thereafter, the light receiving optical transmission line 5 is obtained by removing the mold 10.

このようにして得られた受光用光伝送路５を、コア径の小さい方の端部が上部となるように電気配線基板３の空孔３ｃ内に配置し、マルチモード光導波路４に光を入射させながら、反射面４ｄで反射され出力部４ｃから出力される光がコア５ａに入射するように位置合わせして接着剤等により固定する。 The light receiving optical transmission line 5 obtained in this way is arranged in the hole 3c of the electric wiring board 3 so that the end portion with the smaller core diameter becomes the upper part, and light is transmitted to the multimode optical waveguide 4. While making it enter, it aligns so that the light reflected by the reflective surface 4d and output from the output part 4c may enter into the core 5a, and it fixes with an adhesive agent etc.

次に、受光素子２を受光素子搭載基板６に固定し、受光素子搭載基板を半田（半田ボール）７を介して受光面を受光用光伝送路５のコア５ａの端部に対向するように配置し、加熱して半田ボールを溶融・凝固させることによって、受光素子２を固定する。 Next, the light receiving element 2 is fixed to the light receiving element mounting substrate 6, and the light receiving surface is opposed to the end of the core 5 a of the light receiving optical transmission path 5 through the solder (solder ball) 7. The light receiving element 2 is fixed by arranging and heating to melt and solidify the solder balls.

最後に、半田７の隙間から、受光素子搭載基板６、受光用光伝送路５、半田７、空孔３ｃで囲まれた空隙部に光透過性樹脂８を注入し、固化させる。 Finally, the light-transmitting resin 8 is injected into the gap surrounded by the light receiving element mounting substrate 6, the light receiving light transmission path 5, the solder 7, and the holes 3c from the gaps of the solder 7 and solidified.

以上のように構成された本第１の実施形態に係る光結合器において、不図示の面発光型半導体レーザ素子（ＶＣＳＥＬ）からマルチモード光導波路に光結合し、伝搬する信号光１２は、マルチモード光導波路内を複数のモードで伝搬する。これら複数のモードは、コア層４ａとクラッド層４ｂとの界面で異なった角度での全反射を繰り返しながら伝搬するため、光源たる半導体レーザ素子から受光素子にまで到達するのに要する時間がそれぞれ異なる。 In the optical coupler according to the first embodiment configured as described above, the signal light 12 that is optically coupled from the surface emitting semiconductor laser element (VCSEL) (not shown) to the multimode optical waveguide and propagates is It propagates in the mode optical waveguide in multiple modes. Since these plural modes propagate while repeating total reflection at different angles at the interface between the core layer 4a and the cladding layer 4b, the time required to reach the light receiving element from the semiconductor laser element as the light source is different. .

このようなマルチモード信号光１２は、反射面４ｄにて反射し、出力部４ｃから受光用光伝送路に結合する。このとき、受光用光伝送路のコア５ａの先端部は、光の進行方向に向かってコア径が小さくなるテーパー形状となっているので、伝搬光のうち、高次モードの光１２ｂは、図１に示すようにクラッドに放射され、主として基本モードを含む伝搬角度が小さい低次モードの光１２ａがコア５ａを導波伝搬して他端に到達し、受光素子２に入射する。このため、伝搬角度が大きいためにコアとクラッドとの間でより多くの全反射を繰り返して伝搬する高次モード光１２ｂが受光素子に到達する強度が低減されるので、光源たる半導体レーザ素子から受光素子にまで到達するのに要する時間のモードによるばらつきが低減されることになる。よって、伝送容量を向上させることができる。 Such multi-mode signal light 12 is reflected by the reflecting surface 4d, and is coupled from the output unit 4c to the light receiving optical transmission line. At this time, the tip portion of the core 5a of the light receiving optical transmission line has a tapered shape in which the core diameter decreases in the light traveling direction. As shown in FIG. 1, a low-order mode light 12 a mainly radiated to the clad and having a small propagation angle including the fundamental mode propagates through the core 5 a to reach the other end and enters the light receiving element 2. For this reason, since the propagation angle is large, the intensity at which the higher-order mode light 12b that repeatedly propagates more total reflection between the core and the clad reaches the light receiving element is reduced. Variations in the mode of time required to reach the light receiving element are reduced. Therefore, the transmission capacity can be improved.

なお、受光用光伝送路５のコア５ａの形状としては、図１又は図２のようなものとしたが、図３に示すように、光の伝送方向に向かって径が減少し、その先端に、シングルモード伝送路部分５ａ１を有するものとしてもよい。このような構成によれば、受光用光伝送路５を介して基本モードの光を受光素子に到達させ、基本モード以外の高次モードの到達強度を低くすることができるので、より好ましい。 The core 5a of the light receiving optical transmission path 5 is shaped as shown in FIG. 1 or FIG. 2, but as shown in FIG. In addition, a single mode transmission line portion 5a1 may be provided. Such a configuration is more preferable because light in the fundamental mode can reach the light receiving element via the light receiving optical transmission line 5 and the arrival intensity of higher-order modes other than the fundamental mode can be lowered.

なお、図４は、本第１の実施形態例の第１の変形例に係る光結合器１’を示したものである。上記第１の実施形態例では、受光用光伝送路５は、電気配線基板３の空孔３ｃに露出したマルチモード光導波路４上に固定されている。これに対し、図４に示す第１の変形例では、受光用光伝送路5が、受光素子２を埋め込むように受光素子搭載基板６上に一体化されている。このような構成は、受光素子とマルチモード光伝送路との位置あわせ作業が簡略化されるという利点を有する。 FIG. 4 shows an optical coupler 1 ′ according to a first modification of the first embodiment. In the first embodiment, the light receiving optical transmission line 5 is fixed on the multimode optical waveguide 4 exposed in the hole 3 c of the electric wiring board 3. On the other hand, in the first modification shown in FIG. 4, the light receiving optical transmission path 5 is integrated on the light receiving element mounting substrate 6 so as to embed the light receiving element 2. Such a configuration has the advantage that the alignment operation between the light receiving element and the multimode optical transmission line is simplified.

また、図５は、本第１の実施形態例の第２の変形例に係る光結合器１’’を示したものである。上記第１の実施形態例では、電気配線基板３は、マルチモード光導波路４の上側において一つの絶縁層３ａの両面に導体パターン層３ｂ、３ｂを形成したものであったが、図５に示す第２の変形例では、電気配線基板３は、マルチモード光導波路４の上側に複数の絶縁層３ａと所定の導体パターン層３ｂとが交互に積層されるとともに、マルチモード光導波路４の下方にも絶縁層３ａと導体パターン層３ｂとを有している。これにより、複雑な電気回路パターンを形成している。その結果、電気配線基板３は、第１の実施形態における電気配線基板（図１）よりも、マルチモード光導波路４の上側の領域において厚くなっている。本発明では、マルチモード光導波路４を導波し、反射面４ｄで受光素子２の方に反射した光が、受光用光伝送路５を介して受光素子の方に導波されるので、本第２の変形例のように、マルチモード光導波路４の出力部４ｃから受光素子２までの距離が大きくならざるを得ない場合であっても、基本モードを含む低次モードの光を、効率よく受光素子２に導くことができる。 FIG. 5 shows an optical coupler 1 ″ according to a second modification of the first embodiment. In the first embodiment, the electrical wiring board 3 has conductor pattern layers 3b and 3b formed on both surfaces of one insulating layer 3a on the upper side of the multimode optical waveguide 4, but is shown in FIG. In the second modification, the electrical wiring board 3 includes a plurality of insulating layers 3 a and predetermined conductor pattern layers 3 b alternately stacked on the upper side of the multimode optical waveguide 4 and below the multimode optical waveguide 4. Also has an insulating layer 3a and a conductor pattern layer 3b. Thereby, a complicated electric circuit pattern is formed. As a result, the electrical wiring board 3 is thicker in the region above the multimode optical waveguide 4 than the electrical wiring board (FIG. 1) in the first embodiment. In the present invention, the light guided through the multimode optical waveguide 4 and reflected toward the light receiving element 2 by the reflecting surface 4d is guided to the light receiving element via the light receiving optical transmission line 5, Even in the case where the distance from the output portion 4c of the multimode optical waveguide 4 to the light receiving element 2 is inevitably increased as in the second modification, the light of the low-order mode including the fundamental mode is efficiently converted. It can be guided to the light receiving element 2 well.

（第２の実施形態例）
本発明の第２の実施形態例を、図６を用いて説明する。なお、第１の実施形態例と同一機能を有する各構成部については同一符号を付して示し、その重複説明は省略する。 (Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. In addition, about each component which has the same function as 1st Embodiment, the same code | symbol is attached | subjected and shown, The duplication description is abbreviate | omitted.

図６は、本発明の第２の実施形態例に係る光結合器２０を示したものである。本第２の実施形態例が第１の実施形態例と異なる特徴的部分は、受光用伝送路として、マルチモード光導波路４の比屈折率差よりも小さな比屈折率差を有する受光用光伝送路１３を有する点にある。なお、図６に示されているように、受光用光伝送路１３のコア１３ａは、光の進行方向に沿って一様な径を有している。 FIG. 6 shows an optical coupler 20 according to the second embodiment of the present invention. The characteristic part of the second embodiment is different from the first embodiment in that the light receiving optical transmission having a relative refractive index difference smaller than the relative refractive index difference of the multimode optical waveguide 4 as a light receiving transmission path. It is in a point having a path 13. As shown in FIG. 6, the core 13a of the light-receiving optical transmission line 13 has a uniform diameter along the light traveling direction.

受光用光伝送路１３とマルチモード光導波路４とは、そのコアサイズはほぼ同一であるが、受光用光伝送路１３の比屈折率差がマルチモード光導波路４のものよりも小さい点で異なっている。このため、受光用光伝送路１３では、コア１３ａとクラッド１３ｂとの界面における全反射可能角度が小さくなるので、本第２の実施形態例における受光用光伝送路１３のコア１３ａを導波可能なモードの伝搬角度は、マルチモード光導波路４のコア層４ａを導波するモードの伝搬角度の範囲でも小さいものに限定される。したがって、マルチモード光導波路４を導波し、反射面４ｄで反射され、出力部４ｃから出射する光により、受光用光伝送路１３には、マルチモード光導波路４ａを導波していたモードの伝搬角度の範囲の中でも、特に小さいモードが誘起される。このモードの光が、受光素子２に到達する。よって、マルチモード光導波路４のコア４ａとクラッド４ｂとの間でより多くの全反射を繰り返して伝搬する伝搬角度が大きな高次モード光１２ｂが受光素子２に到達する強度が低減されるので、光源たる不図示の半導体レーザ素子から受光素子２にまで到達するのに要する時間のモードによるばらつきが低減されることになる。したがって、本第２の実施形態例による光結合器を用いて、伝送容量を向上させることができる。 The light receiving optical transmission line 13 and the multimode optical waveguide 4 have substantially the same core size, but differ in that the relative refractive index difference of the light receiving optical transmission line 13 is smaller than that of the multimode optical waveguide 4. ing. For this reason, in the light receiving optical transmission line 13, the total reflection possible angle at the interface between the core 13 a and the clad 13 b becomes small, so that it is possible to guide the core 13 a of the light receiving optical transmission line 13 in the second embodiment. The propagation angle of such a mode is limited to a small one in the range of the propagation angle of the mode guided through the core layer 4a of the multimode optical waveguide 4. Therefore, the light that has been guided through the multimode optical waveguide 4a is guided to the light receiving optical transmission line 13 by the light that is guided through the multimode optical waveguide 4, reflected by the reflecting surface 4d, and emitted from the output unit 4c. A particularly small mode is induced within the range of propagation angles. The light in this mode reaches the light receiving element 2. Therefore, the intensity at which the high-order mode light 12b having a large propagation angle that propagates by repeating more total reflection between the core 4a and the clad 4b of the multimode optical waveguide 4 reaches the light receiving element 2 is reduced. Variations in the mode of the time required to reach the light receiving element 2 from the semiconductor laser element (not shown) as the light source are reduced. Therefore, the transmission capacity can be improved by using the optical coupler according to the second embodiment.

（第３の実施形態例）
本発明の第３の実施形態例を、図７を用いて説明する。なお、第１の実施形態例と同一機能を有する各構成部については同一符号を付して示し、その重複説明は省略する。 (Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. In addition, about each component which has the same function as 1st Embodiment, the same code | symbol is attached | subjected and shown, The duplication description is abbreviate | omitted.

図７は、本発明の第３の実施形態例に係る光結合器３０を示したものである。本第３の実施形態例が第１の実施形態例と異なる特徴的部分は、受光用伝送路として、シングルモード光導波路である受光用光伝送路１３を有する点にある。シングルモード光導波路は、コア１３ａのサイズを、基本モード以外の高次モードがカットオフとなるようなサイズに選択することによって実現できることは周知の事項である。 FIG. 7 shows an optical coupler 30 according to a third embodiment of the present invention. The third embodiment is different from the first embodiment in that it has a light receiving optical transmission line 13 that is a single mode optical waveguide as a light receiving transmission path. It is a well-known matter that a single mode optical waveguide can be realized by selecting the size of the core 13a so that a higher-order mode other than the fundamental mode is cut off.

本第３の実施形態例では、受光用光伝送路１４は、使用する光の波長に対してシングルモード導波路であるため、マルチモード光導波路４を導波し、反射面４ｄで反射され、出力部４ｃから出射する光により、受光用光伝送路１４のコア１４ａには、基本モードのみが誘起され、主としてこの基本モードの光が受光素子２に到達する。このため、光源たる不図示の半導体レーザ素子から受光素子２にまで到達するのに要する時間のモードによるばらつきが低減されることになる。したがって、本第３の実施形態例による光結合器を用いて、伝送容量を向上させることができる。 In the third embodiment, the light-receiving optical transmission line 14 is a single-mode waveguide with respect to the wavelength of light to be used. Therefore, the light-receiving optical transmission line 14 is guided by the multimode optical waveguide 4 and reflected by the reflecting surface 4d. Only the fundamental mode is induced in the core 14 a of the light receiving optical transmission line 14 by the light emitted from the output unit 4 c, and the light in the fundamental mode mainly reaches the light receiving element 2. For this reason, the dispersion | variation by the mode of the time required to reach | attain to the light receiving element 2 from the semiconductor laser element not shown which is a light source is reduced. Therefore, the transmission capacity can be improved by using the optical coupler according to the third embodiment.

（第４の実施形態例）
本発明の第４の実施形態例を、図８を用いて説明する。図８は、本発明の第４の実施形態例に係る光結合器４０を示したものである。 (Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 shows an optical coupler 40 according to a fourth embodiment of the present invention.

本発明の第４の実施形態に係る光結合器４０は、受光素子搭載基板６に搭載された受光素子２と、受光素子２を埋め込むように受光素子搭載基板６上に一体化された受光用光伝送路１５と、受光用光伝送路１５に接続されたマルチモード光ファイバ（マルチモード光導波路）１６とからなる。本第４の実施形態例では、受光用光伝送路１５は、第１の実施形態例における受光用光伝送路５と同様、コア１５ａの径が、信号光の伝送方向に向かって小さくなるよう、たとえばテーパー形状となっている。また、本第４の実施形態例では、受光用光伝送路１５とマルチモード光ファイバ１６とは、光透過性の接着剤樹脂１７によって、コア１６ａと１５ａとが調芯された状態で直接接合されている。 The optical coupler 40 according to the fourth embodiment of the present invention includes a light receiving element 2 mounted on the light receiving element mounting substrate 6 and a light receiving element integrated on the light receiving element mounting substrate 6 so as to embed the light receiving element 2. It comprises an optical transmission line 15 and a multimode optical fiber (multimode optical waveguide) 16 connected to the light receiving optical transmission line 15. In the fourth embodiment, the light receiving optical transmission line 15 is configured such that the diameter of the core 15a becomes smaller in the signal light transmission direction, like the light receiving optical transmission line 5 in the first embodiment. For example, it has a tapered shape. In the fourth embodiment, the light receiving optical transmission line 15 and the multimode optical fiber 16 are directly joined with the cores 16a and 15a aligned by the light-transmitting adhesive resin 17. Has been.

以上のように構成された本第４の実施形態例に係る光結合器４０では、不図示の光源（半導体レーザ素子など）からマルチモード光ファイバ１６に光結合し、伝搬する信号光１２は、マルチモード光ファイバ１６内を複数のモードで伝搬する。これら複数のモードは、コア１６ａとクラッド１６ｂとの界面で異なった角度での全反射を繰り返しながら伝搬するため、光源たる半導体レーザ素子等から受光素子にまで到達するのに要する時間がそれぞれ異なる。 In the optical coupler 40 according to the fourth embodiment configured as described above, the signal light 12 that is optically coupled to the multimode optical fiber 16 from a light source (not shown) such as a semiconductor laser element is propagated. It propagates in the multimode optical fiber 16 in a plurality of modes. Since these plural modes propagate while repeating total reflection at different angles at the interface between the core 16a and the clad 16b, the time required to reach the light receiving element from the semiconductor laser element as a light source is different.

このようなマルチモード光１２が受光用光伝送路１５に結合するとき、受光用光伝送路１５のコア１５ａの先端部は、光の進行方向に向かってコア径が小さくなるテーパー形状となっているので、伝搬光のうち、高次モードの光１２ｂは、図８に示すようにクラッドに放射され、主として基本モードを含む低次モードの光１２ａがコア１５ａを導波伝搬して受光素子２に入射する。このため、コアとクラッドとの間でより多くの全反射を繰り返して伝搬する高次モード光１２ｂが受光素子に到達する強度が低減されるので、光源から受光素子にまで到達するのに要する時間のモードによるばらつきが低減されることになる。よって、伝送容量を向上させることができる。 When such multimode light 12 is coupled to the light receiving optical transmission line 15, the tip of the core 15a of the light receiving optical transmission line 15 has a tapered shape with a core diameter that decreases in the light traveling direction. Therefore, of the propagating light, the higher-order mode light 12b is radiated to the cladding as shown in FIG. 8, and the lower-order mode light 12a including mainly the fundamental mode propagates through the core 15a and propagates through the core 15a. Is incident on. For this reason, since the intensity at which the higher-order mode light 12b that repeatedly propagates more total reflection between the core and the clad reaches the light receiving element is reduced, the time required for the light source to reach the light receiving element is reduced. Variations due to different modes are reduced. Therefore, the transmission capacity can be improved.

なお、光の伝送方向に向かって径が減少するコア１５ａを有する受光用光伝送路１５に代えて、第２の実施形態例で用いた受光用光伝送路１３のように比屈折率差がマルチモード光ファイバ１６のものよりも小さい受光用光伝送路を使用してもよいし、第３の実施形態例で用いた受光用光伝送路１４のようにシングルモード光導波路である受光用光伝送路を使用してもよい。 Instead of the light receiving optical transmission line 15 having the core 15a whose diameter decreases in the light transmission direction, the relative refractive index difference is different as in the light receiving optical transmission line 13 used in the second embodiment. A light receiving optical transmission line smaller than that of the multimode optical fiber 16 may be used, or a light receiving light which is a single mode optical waveguide like the light receiving optical transmission line 14 used in the third embodiment. A transmission line may be used.

（第５の実施形態例）
本発明の第５の実施形態例を、図９を用いて説明する。図９は、本発明の第５の実施形態例に係る光結合器５０を示したものである。 (Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIG. FIG. 9 shows an optical coupler 50 according to a fifth embodiment of the present invention.

本発明の第５の実施形態に係る光結合器５０は、光ファイバ通信に用いられるものであって、受光素子搭載基板５１に搭載された受光素子２と、受光素子２を埋め込むように受光素子搭載基板５１上に一体化された受光用光伝送路１８と、受光素子搭載基板５１を支持するベース５３と、信号光１２を通過させる窓部５５を有するケース５４と、受光素子搭載基板５１とベース５３とを貫通して外部に導出されたリードピン５２とを有する。受光用光伝送路１８は、第１の実施形態例における受光用光伝送路５と同様、コア１８ａの径が、信号光の伝送方向に向かって小さくなるよう、たとえばテーパー形状となっている。窓部５５を有するケース５４は、ベース５３の周縁部において溶接固定されて受光素子５２を気密に封止している。なお、外部に導出されたリードピン５２は受光素子２に電気的に接続されている。 An optical coupler 50 according to a fifth embodiment of the present invention is used for optical fiber communication, and includes a light receiving element 2 mounted on a light receiving element mounting substrate 51 and a light receiving element embedded in the light receiving element 2. The light receiving optical transmission line 18 integrated on the mounting substrate 51, the base 53 that supports the light receiving element mounting substrate 51, the case 54 having the window portion 55 through which the signal light 12 passes, the light receiving element mounting substrate 51, A lead pin 52 is provided through the base 53 and led out to the outside. The light receiving optical transmission line 18 has, for example, a taper shape so that the diameter of the core 18a becomes smaller in the signal light transmission direction, similarly to the light receiving optical transmission line 5 in the first embodiment. A case 54 having a window 55 is fixed by welding at the peripheral edge of the base 53 to hermetically seal the light receiving element 52. The lead pin 52 led out to the outside is electrically connected to the light receiving element 2.

本第５の実施形態例において、外部から種々のモードで伝搬してきた信号光が、受光用光伝送路１８に入射すると、入射した光のうち、高次モードの光はクラッド１８ｂに放出され、主として基本モードを含む低次モードの光がコア１８ａを伝搬して受光素子２に到達する。したがって、不図示の光源から受光素子にまで到達するのに要する時間のモード、伝搬経路によるばらつきが低減されることになる。よって、伝送容量を向上させることができる。 In the fifth embodiment, when signal light propagated in various modes from the outside is incident on the light receiving optical transmission line 18, among the incident light, higher-order mode light is emitted to the cladding 18 b, Low-order mode light mainly including the fundamental mode propagates through the core 18 a and reaches the light receiving element 2. Therefore, variations due to the mode and propagation path of the time required to reach the light receiving element from a light source (not shown) are reduced. Therefore, the transmission capacity can be improved.

なお、光の伝送方向に向かって径が減少するコア１５ａを有する受光用光伝送路１５に代えて、第３の実施形態例で用いた受光用光伝送路１４のようにシングルモードファイバである受光用光伝送路を使用してもよい。 Instead of the light receiving optical transmission line 15 having the core 15a whose diameter decreases in the light transmission direction, a single mode fiber is used as in the light receiving optical transmission line 14 used in the third embodiment. A light receiving optical transmission line may be used.

本発明の光結合器の第１の実施形態例を示す模式図である。It is a schematic diagram which shows the 1st example of an embodiment of the optical coupler of this invention. 受光用光伝送路の作製プロセスを示す図である。It is a figure which shows the preparation process of the optical transmission path for light reception. 受光用光伝送路５の別の構成を示す図である。It is a figure which shows another structure of the optical transmission path 5 for light reception. 本発明の光結合器の第１の実施形態例の第１の変形例を示す模式図である。It is a schematic diagram which shows the 1st modification of 1st Embodiment of the optical coupler of this invention. 本発明の光結合器の第１の実施形態例の第２の変形例を示す模式図である。It is a schematic diagram which shows the 2nd modification of the 1st Embodiment of the optical coupler of this invention. 本発明の光結合器の第２の実施形態例を示す模式図である。It is a schematic diagram which shows the example of 2nd Embodiment of the optical coupler of this invention. 本発明の光結合器の第３の実施形態例を示す模式図である。It is a schematic diagram which shows the example of 3rd Embodiment of the optical coupler of this invention. 本発明の光結合器の第４の実施形態例を示す模式図である。It is a schematic diagram which shows the example of 4th Embodiment of the optical coupler of this invention. 本発明の光結合器の第５の実施形態例を示す模式図である。It is a schematic diagram which shows the example of 5th Embodiment of the optical coupler of this invention.

Explanation of symbols

１，１’，１’’ 光結合器
２受光素子
３電気配線基板
３ａ絶縁層
３ｂ導体パターン層
３ｃ空孔
４マルチモード光導波路
４ａコア層
４ｂクラッド層
４ｃ出力部
４ｄ反射面
５受光用光伝送路
５ａコア
５ａ１シングルモード光伝送路部分
５ｂクラッド
６受光素子搭載基板
７半田
８光透過性樹脂
９光回路基板
１０型枠
１１型材
１２信号光
１２ａ基本モードを含む低次モード光
１２ｂ高次モード光
１３受光用光伝送路
１３ａコア
１３ｂクラッド
１４受光用光伝送路
１４ａコア
１４ｂクラッド
１５受光用光伝送路
１５ａコア
１５ｂクラッド
１６マルチモード光ファイバ
１６ａコア
１６ｂクラッド
１７光透過性接着剤樹脂
１８受光用光伝送路
１８ａコア
１８ｂクラッド
２０光結合器
３０光結合器
４０光結合器
５０光結合器
５１受光素子搭載基板
５２リードピン
５３ベース
５４ケース
５５窓部 1, 1 ′, 1 ″ Optical coupler 2 Light receiving element 3 Electrical wiring board 3a Insulating layer 3b Conductive pattern layer 3c Hole 4 Multimode optical waveguide 4a Core layer 4b Clad layer 4c Output section 4d Reflecting surface 5 Light transmission for light reception Path 5a Core 5a1 Single mode optical transmission path portion 5b Clad 6 Light receiving element mounting substrate 7 Solder 8 Light transmitting resin 9 Optical circuit board 10 Form 11 Mold material 12 Signal light 12a Low order mode light 12b including fundamental mode High order mode light 13 Light-receiving optical transmission line 13a Core 13b Clad 14 Light-receiving optical transmission line 14a Core 14b Clad 15 Light-receiving optical transmission line 15a Core 15b Clad 16 Multimode optical fiber 16a Core 16b Clad 17 Light-transmitting adhesive resin 18 Light for receiving light Transmission path 18a Core 18b Clad 20 Optical coupler 30 Optical coupler 40 Optical coupler 50 Optical coupler 51 Element mounting substrate 52 lead pins 53 base 54 casing 55 window

Claims

A light receiving element;
A light receiving element mounting substrate on which the light receiving element is mounted;
An electrical wiring board electrically connected to the light receiving element and having a hole formed in a portion facing the light receiving surface of the light receiving element;
A multimode optical waveguide laminated on a surface of the electrical wiring board where the light receiving element is not electrically connected;
Optical coupling means for coupling the light transmitted through the multimode optical waveguide to the light receiving element via a light receiving optical transmission path comprising a core whose diameter decreases in the light transmission direction and a clad surrounding the core; With
The multimode optical waveguide is formed with a reflection surface that reflects light propagating through the multimode optical waveguide toward the light receiving surface of the light receiving element at a position corresponding to a hole formed in the electrical wiring board. And
Between the hole formed in the electrical wiring board and the light receiving optical transmission path, there is a gap in the surface direction of the electrical wiring board,
The light receiving element mounting substrate is fixed to the electric wiring substrate via solder,
The light-receiving element mounting substrate, the light-receiving light transmission path, the void surrounded by the solder and the holes are filled with a light transmissive resin,
The light-receiving optical transmission path of the optical coupling means is disposed at a position where the light reflected by the reflecting surface of the multimode optical waveguide is incident on the core inside the hole of the electrical wiring board. An optical coupler.

A light receiving element;
A light receiving element mounting substrate on which the light receiving element is mounted;
An electrical wiring board electrically connected to the light receiving element and having a hole formed in a portion facing the light receiving surface of the light receiving element;
A multimode optical waveguide laminated on a surface of the electrical wiring board where the light receiving element is not electrically connected;
The multi-mode optical waveguide is transmitted to the light-receiving element via a light-receiving optical transmission line including a core having a relative refractive index difference smaller than that of the multi-mode optical waveguide and a clad surrounding the core. An optical coupling means for coupling light,
The multimode optical waveguide is formed with a reflection surface that reflects light propagating through the multimode optical waveguide toward the light receiving surface of the light receiving element at a position corresponding to a hole formed in the electrical wiring board. And
Between the hole formed in the electrical wiring board and the light receiving optical transmission path, there is a gap in the surface direction of the electrical wiring board,
The light receiving element mounting substrate is fixed to the electric wiring substrate via solder,
The light-receiving element mounting substrate, the light-receiving light transmission path, the void surrounded by the solder and the holes are filled with a light transmissive resin,
The light-receiving optical transmission path of the optical coupling means is disposed at a position where the light reflected by the reflecting surface of the multimode optical waveguide is incident on the core inside the hole of the electrical wiring board. An optical coupler.

A light receiving element;
A light receiving element mounting substrate on which the light receiving element is mounted;
An electrical wiring board electrically connected to the light receiving element and having a hole formed in a portion facing the light receiving surface of the light receiving element;
A multimode optical waveguide laminated on a surface of the electrical wiring board where the light receiving element is not electrically connected;
An optical coupling means for coupling the light transmitted through the multi-mode optical waveguide to the light-receiving element via a light-receiving optical transmission path that is a single-mode optical waveguide composed of a core and a clad surrounding the core;
The multimode optical waveguide is formed with a reflection surface that reflects light propagating through the multimode optical waveguide toward the light receiving surface of the light receiving element at a position corresponding to a hole formed in the electrical wiring board. And
Between the hole formed in the electrical wiring board and the light receiving optical transmission path, there is a gap in the surface direction of the electrical wiring board,
The light receiving element mounting substrate is fixed to the electric wiring substrate via solder,
The light-receiving element mounting substrate, the light-receiving light transmission path, the void surrounded by the solder and the holes are filled with a light transmissive resin,
The light-receiving optical transmission path of the optical coupling means is disposed at a position where the light reflected by the reflecting surface of the multimode optical waveguide is incident on the core inside the hole of the electrical wiring board. An optical coupler.

The light-receiving optical transmission line, surface in contact with the light transmissive resin is light according to any one of claims 1 to 3, characterized in that only the cladding of the light-receiving optical transmission line Combiner.