JP5701329B2

JP5701329B2 - Receiver module

Info

Publication number: JP5701329B2
Application number: JP2013065459A
Authority: JP
Inventors: 智志西川; 杉原　浩平; 浩平杉原; 裕一郎堀口; 柳生　栄治; 栄治柳生
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2013-03-27
Filing date: 2013-03-27
Publication date: 2015-04-15
Anticipated expiration: 2029-09-29
Also published as: JP2013127651A

Description

本発明は、受光モジュールに関し、特に、複数の光ファイバ等から入力された複数の入力光を複数の受光素子等で受光する受光モジュールに関する。 The present invention relates to a light receiving module, and more particularly to a light receiving module that receives a plurality of input lights input from a plurality of optical fibers or the like by a plurality of light receiving elements or the like.

従来において、複数の光ファイバ等から入力された複数の入力光を複数の受光素子等で受光する受光モジュールは、光ファイバ数分のレンズおよび受光素子を組み合わせることによって単純に構成することができる。しかし、このような構成の受光モジュールでは、構成部品が多くなってしまい、小型化や組み立てが難しくなるという問題があった。 Conventionally, a light receiving module that receives a plurality of input lights input from a plurality of optical fibers or the like by a plurality of light receiving elements or the like can be simply configured by combining lenses and light receiving elements corresponding to the number of optical fibers. However, the light receiving module having such a configuration has a problem that the number of components increases and it is difficult to downsize and assemble.

上記の問題の対策として、部品数を減らして小型化するために、複数の光ファイバについてはフェルール内に複数の光ファイバを有する多芯フェルールを用い、多芯フェルールの各光ファイバから出射された光を１枚のレンズを介して複数の受光素子に集光させる構成とした受光モジュールがある。しかし、このような構成の受光モジュールでは、レンズと受光素子との間隔が小さくなるため、受光素子およびレンズを受光モジュールのパッケージ内に位置調整して固定した後に、他の構成部品の位置調整をして固定する必要があるため、組み立てが煩雑になるという問題があった。 In order to reduce the number of parts by reducing the number of parts as a countermeasure for the above problem, a multi-core ferrule having a plurality of optical fibers in the ferrule is used for a plurality of optical fibers, and the light is emitted from each optical fiber of the multi-core ferrule. There is a light receiving module configured to condense light onto a plurality of light receiving elements via a single lens. However, in the light receiving module having such a configuration, the distance between the lens and the light receiving element becomes small. Therefore, after the light receiving element and the lens are positioned and fixed in the package of the light receiving module, the position adjustment of other components is performed. Therefore, there is a problem that assembly is complicated.

なお、各光ファイバから出射された光を受光素子の各受光面に容易に集光させるためには、受光面を大きくしてレンズ等の位置調整に要求される精度を緩和させる方法が考えられるが、受光面の大きさは受光する信号のレート（通信速度）が高くなるほど小さくする必要がある。従って、信号のレートが高くなるほどレンズ等の位置調整に要求される精度が厳しくなるため、受光面を大きくすることはできない。 In order to easily collect the light emitted from each optical fiber on each light receiving surface of the light receiving element, a method of reducing the accuracy required for adjusting the position of the lens or the like by enlarging the light receiving surface can be considered. However, the size of the light receiving surface needs to be reduced as the rate of the received light signal (communication speed) increases. Accordingly, the accuracy required for position adjustment of the lens and the like becomes stricter as the signal rate becomes higher, so the light receiving surface cannot be enlarged.

また、フェルール内に複数の光ファイバを有する多芯フェルールを用い、多芯フェルールの各光ファイバから出射された光を２枚のレンズを介して複数の受光素子に集光させる、テレセントリック光学系を用いた受光モジュールがある。このような構成の受光モジュールでは、受光素子と、受光素子に近い側のレンズとの距離のばらつきを、他方のレンズの位置調整によって補正できるため、受光素子に近い側のレンズの位置調整を容易にすることができるが、２枚のレンズを使用することによって組み立てが複雑化するという問題があった。 A telecentric optical system that uses a multi-core ferrule having a plurality of optical fibers in the ferrule and condenses light emitted from each optical fiber of the multi-core ferrule onto a plurality of light receiving elements through two lenses. There is a light receiving module used. In the light receiving module having such a configuration, variation in the distance between the light receiving element and the lens closer to the light receiving element can be corrected by adjusting the position of the other lens, so that the position of the lens closer to the light receiving element can be easily adjusted. However, there is a problem that the assembly becomes complicated by using two lenses.

また、レンズに屈折率分布レンズを用いることによってレンズホルダが不要となり、屈折率分布レンズをＶ溝やパイプ等の治具に直接取り付けることができるため、取り付けおよび調芯が容易となる受光モジュールが開示されている（例えば、特許文献１参照）。 In addition, by using a gradient index lens as a lens, a lens holder is not required, and the gradient index lens can be directly mounted on a jig such as a V-groove or a pipe. It is disclosed (for example, see Patent Document 1).

特開２００６−３２３０２０号公報JP 2006-323020 A

しかし、特許文献１に記載の受光モジュールでは、受光素子およびレンズを受光モジュールのパッケージ内に位置調整して固定した後に、他の構成部品の位置調整をして固定する必要があるため、組み立てが煩雑になるという問題があった。また、２芯フェルール内にて所定の間隔で設けられた２つのコアから出射された各々の光を、１枚のレンズを介して受光素子にて所定の間隔で設けられたツインＰＤ（ＰｈｏｔｏＤｉｏｄｅ：フォトダイオード）の各々のＰＤ（光受光部）に集光させる場合において、光学系の倍率、すなわちレンズとＰＤとの距離を正確に調整しなければならないため調芯が煩雑になるという問題があった。 However, in the light receiving module described in Patent Document 1, it is necessary to adjust the position of the other components after fixing the light receiving element and the lens in the package of the light receiving module and then fixing them. There was a problem of becoming complicated. In addition, a twin PD (Photo Diode) provided at a predetermined interval by a light receiving element through a single lens for each light emitted from the two cores provided at a predetermined interval in the two-core ferrule. : When condensing light on each PD (light receiving part) of the photodiode), the magnification of the optical system, that is, the distance between the lens and the PD must be adjusted accurately, so that the alignment becomes complicated. there were.

本発明は、これらの問題を解決するためになされたものであり、光受光部とレンズとの距離のばらつきや多芯フェルールのコア間隔のばらつきによって光学系の倍率がばらついても高効率で光受光部に集光させることが可能な受光モジュールを提供することを目的とする。 The present invention has been made in order to solve these problems. Even if the magnification of the optical system varies due to variations in the distance between the light receiving portion and the lens and variations in the core interval of the multi-core ferrule, the present invention is highly efficient. An object of the present invention is to provide a light receiving module capable of condensing light to a light receiving unit.

上記の課題を解決するために、本発明による受光モジュールは、複数の入力光を受光する受光モジュールにおいて、入射された複数の入力光の各々を次段に出射する複数の光出射部と、複数の光出射部の各々に対応して配列され、複数の光出射部の各々から出射された複数の入力光を受光する複数の光受光部と、複数の光出射部と複数の光受光部との間に配置され、複数の光出射部の各々から出射された複数の入力光を複数の光受光部の各々に集光する１個の凸レンズとを備え、複数の光受光部の各々に集光される各集光スポットの間隔は、複数の光受光部とレンズとの間隔に応じて変わり、複数の光受光部の各々の形状は、レンズの中心軸に対応する中心点と、各光受光部の中点とを結ぶ直線に沿った方向を長手方向とし、長手方向に対して垂直方向を短手方向としたトラック形状であり、複数の光受光部は、中心点を中心として１軸方向に配列され、複数の光受光部の各々の形状は、トラック形状の短手方向の長さが、中心点から長手方向に沿って遠ざかるにつれて徐々に長くなる形状であることを特徴とする。 In order to solve the above problems, a light receiving module according to the present invention is a light receiving module that receives a plurality of input lights. A plurality of light receiving portions that are arranged corresponding to each of the light emitting portions and receive a plurality of input lights emitted from each of the plurality of light emitting portions, a plurality of light emitting portions, and a plurality of light receiving portions, And a convex lens that condenses the plurality of input lights emitted from each of the plurality of light emitting units on each of the plurality of light receiving units, and collects each of the plurality of light receiving units. The interval between the light-collecting spots that are emitted varies depending on the interval between the plurality of light receiving portions and the lens, and the shape of each of the plurality of light receiving portions is a center point corresponding to the central axis of the lens and each light. The direction along the straight line connecting the midpoint of the light receiving unit is the longitudinal direction, and the longitudinal direction is A track shape in a perpendicular direction to the lateral direction, the plurality of light receiving portions are arranged in one axial direction around the center point, each of the plurality of light receiving portion shape, the track shape in the lateral direction The length is a shape that gradually increases from the central point along the longitudinal direction .

本発明によると、複数の入力光を受光する受光モジュールにおいて、入射された複数の入力光の各々を次段に出射する複数の光出射部と、複数の光出射部の各々に対応して配列され、複数の光出射部の各々から出射された複数の入力光を受光する複数の光受光部と、複数の光出射部と複数の光受光部との間に配置され、複数の光出射部の各々から出射された複数の入力光を複数の光受光部の各々に集光する１個の凸レンズとを備え、複数の光受光部の各々に集光される各集光スポットの間隔は、複数の光受光部とレンズとの間隔に応じて変わり、複数の光受光部の各々の形状は、レンズの中心軸に対応する中心点と、各光受光部の中点とを結ぶ直線に沿った方向を長手方向とし、長手方向に対して垂直方向を短手方向としたトラック形状であり、複数の光受光部は、中心点を中心として１軸方向に配列され、複数の光受光部の各々の形状は、トラック形状の短手方向の長さが、中心点から長手方向に沿って遠ざかるにつれて徐々に長くなる形状であるため、光受光部とレンズとの距離のばらつきや多芯フェルールのコア間隔のばらつきによって光学系の倍率がばらついても高効率で光受光部に集光させることが可能となる。
According to the present invention, in the light receiving module that receives a plurality of input lights, the plurality of incident light beams that are emitted to the next stage are arranged in correspondence with each of the plurality of light emission sections. A plurality of light receiving units that receive a plurality of input lights emitted from each of the plurality of light emitting units, and a plurality of light emitting units disposed between the plurality of light emitting units and the plurality of light receiving units. One convex lens that condenses the plurality of input lights emitted from each of the plurality of light receiving units, and the interval between the respective condensing spots collected on each of the plurality of light receiving units is The shape of each of the plurality of light receiving units varies along a straight line connecting the center point corresponding to the central axis of the lens and the midpoint of each light receiving unit. The track shape has the longitudinal direction as the longitudinal direction and the perpendicular direction to the longitudinal direction as the short direction. , The plurality of light receiving portions are arranged in one axial direction around the center point, each of the shapes of the plurality of light receiving portions, the lateral direction of the length of the track shape, and the center point along the longitudinal direction Because the shape gradually increases with distance, even if the magnification of the optical system varies due to variations in the distance between the light receiving portion and the lens or the core spacing of the multi-core ferrule, the light receiving portion can be condensed with high efficiency. Is possible.

本発明の実施形態１による受光モジュールの光学系を示す図である。It is a figure which shows the optical system of the light reception module by Embodiment 1 of this invention. 本発明の実施形態１による受光面の形状を示す図である。It is a figure which shows the shape of the light-receiving surface by Embodiment 1 of this invention. 本発明の実施形態１による受光面の他の形状を示す図である。It is a figure which shows the other shape of the light-receiving surface by Embodiment 1 of this invention. 本発明の実施形態１による図３の形状における受光面と集光スポットとの位置関係を示す図である。It is a figure which shows the positional relationship of the light-receiving surface and the condensing spot in the shape of FIG. 3 by Embodiment 1 of this invention. 本発明の実施形態２による出射部および受光面の形状を示す図である。It is a figure which shows the shape of the output part and light-receiving surface by Embodiment 2 of this invention. 本発明の実施形態３による出射部および受光面の形状を示す図である。It is a figure which shows the shape of the output part and light-receiving surface by Embodiment 3 of this invention. 本発明の実施形態４による受光面の形状を示す図である。It is a figure which shows the shape of the light-receiving surface by Embodiment 4 of this invention. 本発明の実施形態５による出射部および受光面の形状を示す図である。It is a figure which shows the shape of the output part and light-receiving surface by Embodiment 5 of this invention. 本発明の実施形態６による出射部および受光面の形状を示す図である。It is a figure which shows the shape of the output part and light-receiving surface by Embodiment 6 of this invention. 受光面とビームスポットとの位置関係を示す図である。It is a figure which shows the positional relationship of a light-receiving surface and a beam spot.

本発明の実施形態について、図面を用いて以下に説明する。 Embodiments of the present invention will be described below with reference to the drawings.

〈実施形態１〉
図１は、本発明の実施形態１による受光モジュールの光学系を示す図である。図１に示すように、本実施形態１による受光モジュールは、２つの入射光１（入力光）を受光する受光モジュールであり、２本の光ファイバ２によって入射された２つの入射光の各々を次段に出射する２つの出射部６ａ（光出射部）を有する２芯フェルール３ａと、出射部６ａの各々に対応して配置され、出射部６ａの各々から出射された入射光１を受光する２つの受光部６ｂ（光受光部）を有するツインＰＤ５ａと、出射部６ａと受光部６ｂとの間に配置され、出射部６ａの各々から出射された入射光１を受光部６ｂの各々に集光するレンズ４とを備えている。本実施形態では、受光部６ｂの全体が受光面である。また、受光部６ｂの形状は、レンズ４の中心軸に対応する中心点１１と、受光部６ｂの中点とを結ぶ直線に沿って延伸した形状である。なお、本実施形態１では２芯フェルール３ａおよびツインＰＤ５ａを用いているが、多芯フェルールであってもよく、フェルールに設けられる光ファイバの本数と同数の受光部６ｂを設ければよい。 <Embodiment 1>
FIG. 1 is a diagram showing an optical system of a light receiving module according to Embodiment 1 of the present invention. As shown in FIG. 1, the light receiving module according to the first embodiment is a light receiving module that receives two incident lights 1 (input light), and each of the two incident lights incident by the two optical fibers 2 is received. A two-core ferrule 3a having two emission parts 6a (light emission parts) that are emitted to the next stage and the emission part 6a are arranged corresponding to each of the emission parts 6a and receive incident light 1 emitted from each of the emission parts 6a. The twin PD 5a having two light receiving parts 6b (light receiving parts) and the light PD 1a arranged between the emitting part 6a and the light receiving part 6b collect incident light 1 emitted from each of the emitting parts 6a in each of the light receiving parts 6b. The lens 4 which shines is provided. In the present embodiment, the entire light receiving portion 6b is a light receiving surface. The shape of the light receiving portion 6b is a shape extending along a straight line connecting the center point 11 corresponding to the central axis of the lens 4 and the midpoint of the light receiving portion 6b. In the first embodiment, the two-core ferrule 3a and the twin PD 5a are used. However, a multi-core ferrule may be used, and the same number of light receiving units 6b as the number of optical fibers provided in the ferrule may be provided.

受光モジュールの製造手順としては、まず初めにツインＰＤ５ａ（受光素子）を導電性接着剤によって固定し、次に内部にレンズ４を固定されたレンズホルダ（図示せず）を所定の位置にＹＡＧレーザ溶接によって固定する。最後に２芯フェルール３ａ（多芯フェルール）を調芯して固定する。２芯フェルール３ａ（多芯フェルール）の固定は、フェルールをフェルール固定用金属製治具にＹＡＧレーザ溶接によって固定した後に、フェルール固定用金属製治具をモジュール筐体に固定する。 As a manufacturing procedure of the light receiving module, first, the twin PD 5a (light receiving element) is fixed with a conductive adhesive, and then a lens holder (not shown) having the lens 4 fixed therein is placed at a predetermined position with a YAG laser. Fix by welding. Finally, the 2-core ferrule 3a (multi-core ferrule) is aligned and fixed. The two-core ferrule 3a (multi-core ferrule) is fixed by fixing the ferrule to the ferrule fixing metal jig by YAG laser welding, and then fixing the ferrule fixing metal jig to the module housing.

本実施形態１では、２芯フェルール３ａのコア間隔（出射部６ａの間隔）を２５０ｎｍとし、レンズ４は縮小率が約１／２倍の非球面レンズを用いている。また、受光部６ｂは中心間隔が１２５ｎｍとなるように形成されている。このような構成により、２芯フェルール３ａの出射部６ａから出射された光（入射光１）は、レンズ４を介してビーム径とビーム間隔を１／２に縮小して受光部６ｂに集光して受光されている。 In the first embodiment, the core interval of the two-core ferrule 3a (the interval between the emitting portions 6a) is 250 nm, and the lens 4 is an aspherical lens having a reduction ratio of about 1/2. The light receiving portion 6b is formed so that the center interval is 125 nm. With such a configuration, the light (incident light 1) emitted from the emitting portion 6a of the two-core ferrule 3a is condensed to the light receiving portion 6b through the lens 4 with the beam diameter and beam interval reduced to ½. Is received.

なお、図１中において、入射光１の伝搬方向をｚ軸とし、ｚ軸に直交する２軸をそれぞれｘ軸、ｙ軸とする。また、受光部６ｂの形状は、従来のように円形ではなく図２に示すような異方性形状となっている。図２の説明については、後に詳細に説明する。 In FIG. 1, the propagation direction of the incident light 1 is the z-axis, and the two axes orthogonal to the z-axis are the x-axis and the y-axis, respectively. Further, the shape of the light receiving portion 6b is not circular as in the prior art, but is anisotropic as shown in FIG. The description of FIG. 2 will be described later in detail.

ツインＰＤ５ａ（受光素子）の応答周波数帯域は、素子の容量が小さいほど高くすることができるが、受光面の面積が大きいほど素子の容量も大きくなるため、高速信号（高周波数の信号）を受信するためには受光面の面積を小さくする必要がある。例えば、周波数帯域が１０ＧＨｚ級の信号を受信するためには、１００πμｍ²（直径２０μｍの円形の面積）程度の受光面の面積が必要である。受光面の端部にて発生する容量の寄与分もあるが、受光面の面積が概ね同じであれば、形状によらず同程度の素子容量になる。 The response frequency band of the twin PD 5a (light receiving element) can be increased as the element capacity decreases, but the capacity of the element increases as the area of the light receiving surface increases, so high-speed signals (high frequency signals) are received. In order to achieve this, it is necessary to reduce the area of the light receiving surface. For example, in order to receive a signal having a frequency band of 10 GHz, a light receiving surface area of about 100πμm ² (a circular area having a diameter of 20 μm) is required. Although there is a contribution of the capacitance generated at the end of the light receiving surface, if the area of the light receiving surface is substantially the same, the element capacitance is approximately the same regardless of the shape.

次に、出射部６ａから出射された入射光１が受光部６ｂの受光面に集光される場合における、調芯の公差について説明する。 Next, the alignment tolerance when the incident light 1 emitted from the emitting portion 6a is collected on the light receiving surface of the light receiving portion 6b will be described.

図１０は、受光面とビームスポットとの位置関係を示す図である。図１０に示すように、受光面は従来から用いられている円形受光面７ｉとする。また、２芯フェルール（多芯フェルール）を調芯して円形受光面７ｉ上での入射光１のビームスポット（集光スポット）径が最小になるように調整する場合を想定している。 FIG. 10 is a diagram showing the positional relationship between the light receiving surface and the beam spot. As shown in FIG. 10, the light receiving surface is a circular light receiving surface 7i which has been conventionally used. Further, it is assumed that a two-core ferrule (multi-core ferrule) is aligned and adjusted so that the beam spot (condensing spot) diameter of the incident light 1 on the circular light receiving surface 7i is minimized.

組み立て時のばらつきによって受光素子とレンズとの間隔が所定の大きさからずれると、レンズの縮小率（例えば、本実施形態では１／２倍）がずれる。レンズの圧縮率がずれた状態で円形受光面７ｉ上のビームスポット径が最小になるように２芯フェルールを調整すると、ビーム径およびビーム間隔がずれてしまう。図１０（ａ）は、レンズの縮小率が最適に調整されている場合を示しており、ビームスポット１０は円形受光面７ｉの中央に集光されている。図１０（ｂ）は、レンズの縮小率が小さい場合を示しており、ビームスポット１０は円形受光面７ｉのビームスポット１０の間隔が互いに小さくなる側に集光されている。図１０（ｃ）は、レンズの縮小率が大きい場合を示しており、ビームスポット１０は円形受光面７ｉのビームスポット１０の間隔が互いに大きくなる側に集光されている。図１０（ｂ）および（ｃ）に示すように、ビームスポット１０が円形受光面７ｉの端部近傍に位置しているため、円形受光面７ｉでのビームスポット１０の公差が減少していることが分かる。なお、両図において、ビームスポット１０の間隔が大きい場合と小さい場合とでは、光学系（レンズ）の縮小率が異なるため、ビームスポット径もわずかに異なる。また、図１０（ｄ）に示すように、レンズの圧縮率が図１０（ｃ）よりもさらに大きい方にずれると、入射光１の全てを円形受光面７ｉに集光させることができなくなって損失が生じる。 If the distance between the light receiving element and the lens deviates from a predetermined size due to variations during assembly, the reduction ratio of the lens (for example, 1/2 in this embodiment) is shifted. If the two-core ferrule is adjusted so that the beam spot diameter on the circular light receiving surface 7i is minimized in a state where the compression ratio of the lens is shifted, the beam diameter and the beam interval are shifted. FIG. 10A shows a case where the reduction ratio of the lens is optimally adjusted, and the beam spot 10 is condensed at the center of the circular light receiving surface 7i. FIG. 10B shows a case where the reduction ratio of the lens is small, and the beam spot 10 is focused on the side where the interval between the beam spots 10 on the circular light receiving surface 7i becomes smaller. FIG. 10C shows a case where the reduction ratio of the lens is large, and the beam spot 10 is condensed on the side where the distance between the beam spots 10 on the circular light receiving surface 7i becomes larger. As shown in FIGS. 10B and 10C, since the beam spot 10 is positioned near the end of the circular light receiving surface 7i, the tolerance of the beam spot 10 on the circular light receiving surface 7i is reduced. I understand. In both figures, since the reduction ratio of the optical system (lens) is different between the case where the interval between the beam spots 10 is large and the case where the interval is small, the beam spot diameter is also slightly different. Further, as shown in FIG. 10 (d), if the compression ratio of the lens deviates further than that shown in FIG. 10 (c), all of the incident light 1 cannot be condensed on the circular light receiving surface 7i. Loss occurs.

上記のことから、レンズの縮小率を所定の範囲内となるように調整するためには、２芯フェルールとレンズとの間隔、および、レンズと受光素子との間隔の各々を許容公差の範囲内に調整する必要がある。そのためには、最初に調整を行うレンズと受光素子との間隔を許容公差の範囲内に調整しなければならない。また、レンズと受光素子との間隔が許容公差の範囲内となるように位置調整できれば、その後に行う２芯フェルールの位置調整は、受光部６ｂにて受光された光の検出光量が最大となるように、フェルールの回転と３軸（ｘ軸、ｙ軸、ｚ軸）方向の微動による通常の調芯方法によって調整することができる。従来では、レンズと受光素子との間隔を正しく位置調整することが最も難しく、そのため当該調整時における公差の増大（許容公差の範囲の拡大）が求められている。本実施形態では、公差を増大させることを目的としており、以下に本実施形態１の特徴について説明する。 From the above, in order to adjust the reduction ratio of the lens to be within a predetermined range, the distance between the two-core ferrule and the lens and the distance between the lens and the light receiving element are each within the allowable tolerance range. It is necessary to adjust to. For this purpose, the distance between the lens to be adjusted first and the light receiving element must be adjusted within the allowable tolerance range. Further, if the position can be adjusted so that the distance between the lens and the light receiving element is within the allowable tolerance range, then the position adjustment of the two-core ferrule performed thereafter will maximize the amount of light detected by the light receiving unit 6b. As described above, it can be adjusted by a normal alignment method based on the rotation of the ferrule and the fine movement in the three-axis (x-axis, y-axis, z-axis) directions. Conventionally, it is most difficult to correctly adjust the distance between the lens and the light receiving element, and therefore, an increase in tolerance (expansion of the allowable tolerance range) is required at the time of the adjustment. The present embodiment aims to increase the tolerance, and the features of the first embodiment will be described below.

図２は、本発明の実施形態１による受光面の形状を示す図である。図２に示すように、受光面の形状は、レンズ４の中心軸に対応する中心点１１と、受光部６ｂの中点とを結ぶ直線に沿って延伸した方向を長手方向とし、長手方向に対して垂直方向を短手方向とした対称トラック型受光面７ａ（トラック形状）である。このように、受光面は、レンズ４の中心軸に対応する中心点１１を中心として１軸方向に配列されている。なお、本実施形態１において、受光部６ｂと受光面との形状は同じ形状であるとする。また、受光面の形状は、受光素子を製造するウエハプロセスにて用いられる露光用マスクによって、容易に所望の形状とすることができる。 FIG. 2 is a diagram showing the shape of the light receiving surface according to the first embodiment of the present invention. As shown in FIG. 2, the shape of the light receiving surface is such that the direction extending along a straight line connecting the center point 11 corresponding to the central axis of the lens 4 and the midpoint of the light receiving portion 6b is the longitudinal direction, On the other hand, it is a symmetrical track type light receiving surface 7a (track shape) in which the vertical direction is the short direction. As described above, the light receiving surfaces are arranged in one axis direction around the center point 11 corresponding to the center axis of the lens 4. In the first embodiment, it is assumed that the light receiving portion 6b and the light receiving surface have the same shape. Further, the shape of the light receiving surface can be easily set to a desired shape by an exposure mask used in a wafer process for manufacturing a light receiving element.

対称トラック型受光面７ａの形状は、例えば、同面積の円形の受光面と比較すると、長手方向の大きさが約１．５倍（３３μｍ）、短手方向の大きさが約０．５倍（１０μｍ）である。また、各対称トラック型受光面７ａの中心の間隔は、従来の円形の受光面と同じ１２５μｍである。 The shape of the symmetric track type light receiving surface 7a is, for example, about 1.5 times longer (33 μm) in the longitudinal direction and about 0.5 times shorter than the circular light receiving surface of the same area. (10 μm). Further, the distance between the centers of the symmetrical track type light receiving surfaces 7a is 125 μm, which is the same as that of the conventional circular light receiving surface.

上記の条件の場合において、出射部６ａから出射される入射光１のビーム径を約１０μｍとすると、縮小率が１／２のレンズ４（集光光学系）を介して受光部６ｂに集光された光のビームスポットは、直径約５μｍの円形となる。当該ビームスポットが対称トラック型受光面７ａの中央に調芯することができた場合は、対称トラック型受光面７ａの短手方向に±２．５μｍ、長手方向に±１４．０μｍの位置調整の公差を確保できる。一方、従来の円形（直径２０μｍ）の受光面の場合は、何れの方向にも±７．５μｍの等方的な位置調整の公差となる。 Under the above conditions, if the beam diameter of the incident light 1 emitted from the emitting part 6a is about 10 μm, the light is condensed on the light receiving part 6b via the lens 4 (condensing optical system) having a reduction ratio of 1/2. The light beam spot thus formed is a circle having a diameter of about 5 μm. When the beam spot can be aligned with the center of the symmetric track type light receiving surface 7a, the position of the symmetric track type light receiving surface 7a is adjusted to ± 2.5 μm in the short direction and ± 14.0 μm in the long direction. Tolerance can be secured. On the other hand, in the case of a conventional circular (diameter 20 μm) light-receiving surface, an isotropic position adjustment tolerance of ± 7.5 μm in any direction.

従来より、受光素子およびレンズを固定した後、受光部にて受光された光の検出量が最大（受光強度が最大）となるように２芯フェルール（多芯フェルール）によって調芯されるが、２芯フェルールによって受光強度が最大となる位置±１μｍ以内の精度で調芯して固定することができる。 Conventionally, after fixing the light receiving element and the lens, it is aligned by a two-core ferrule (multi-core ferrule) so that the detected amount of light received by the light receiving unit is maximized (the received light intensity is maximum). The two-core ferrule can be aligned and fixed with an accuracy within ± 1 μm of the position where the received light intensity becomes maximum.

上記のことから、対称トラック型受光面７ａの短手方向については、位置調整公差が従来の±７．５μｍから±２．５μｍに減少しても、レンズの固定位置によらず正しく調整（調芯）することができる。また、対称トラック型受光面７ａの長手方向については、２芯フェルールの調芯による精度（±１μｍ）を考慮しても、±１３μｍ程度の公差がある。当該公差は、光学系の縮小率の変動に伴う各受光面の中心の間隔（ビームスポット間隔）の変動に換算すると、±１３μｍ／１２５μｍ＝±１０．４％の変動に相当し、当該変動をレンズと受光素子との間隔に換算すると概ね１／２の±５％の変動に相当する。 From the above, regarding the short direction of the symmetrical track type light receiving surface 7a, even if the position adjustment tolerance is reduced from ± 7.5 μm to ± 2.5 μm, it can be adjusted correctly regardless of the fixed position of the lens. Core). Further, the longitudinal direction of the symmetrical track type light receiving surface 7a has a tolerance of about ± 13 μm even in consideration of accuracy (± 1 μm) due to alignment of the two-core ferrule. The tolerance corresponds to a variation of ± 13 μm / 125 μm = ± 10.4% when converted to a variation in the center interval (beam spot interval) of each light receiving surface due to a variation in the reduction ratio of the optical system. When converted to the distance between the lens and the light receiving element, this corresponds to a fluctuation of approximately ½ of ± 5%.

従って、レンズと受光素子との間隔が上記の変動範囲内であれば、レンズの固定位置のばらつきによって光学系の縮小率が変動しても２芯フェルールの調芯によって正しく調整することができる。例えば、レンズと受光素子との間隔を６６０μｍ程度とした場合、レンズの固定位置の公差は６６０μｍの±５％＝±３３μｍとなる。一方、受光面が従来の円形で、かつ受光面積が対称トラック型受光面７ａと同じである場合、受光面での位置調整の公差は±７．５μｍとなる。当該公差は、光学系の縮小率の変動に伴う各受光面の中心の間隔（ビームスポット間隔）の変動に換算すると、±７．５μｍ／１２５μｍ＝±約６％の変動に相当し、当該変動をレンズと受光素子との間隔に換算すると概ね１／２の±３％の変動に相当する。例えば、レンズと受光素子との間隔を６６０μｍ程度とした場合、レンズの固定位置の公差は６６０μｍの±３％＝±２０μｍとなる。 Therefore, if the distance between the lens and the light receiving element is within the above fluctuation range, even if the reduction ratio of the optical system fluctuates due to variations in the fixed position of the lens, it can be correctly adjusted by the alignment of the two-core ferrule. For example, when the distance between the lens and the light receiving element is about 660 μm, the tolerance of the fixed position of the lens is ± 5% of 660 μm = ± 33 μm. On the other hand, when the light receiving surface is a conventional circle and the light receiving area is the same as that of the symmetrical track type light receiving surface 7a, the positional adjustment tolerance on the light receiving surface is ± 7.5 μm. The tolerance corresponds to a fluctuation of ± 7.5 μm / 125 μm = ± about 6% when converted into a fluctuation of the center interval (beam spot interval) of each light receiving surface due to the fluctuation of the reduction ratio of the optical system. Is converted to an interval between the lens and the light receiving element, which corresponds to a fluctuation of approximately ½ of ± 3%. For example, when the distance between the lens and the light receiving element is about 660 μm, the tolerance of the fixed position of the lens is ± 3% of 660 μm = ± 20 μm.

以上のことから、レンズの固定位置の公差は、受光面の形状を異方性形状（対称トラック型受光面７ａ）とした方が従来と比べて１３μｍ以上大きくなることが分かる。従って、レンズの固定位置の公差が大きくなることによって光受光部とレンズとの距離のばらつきや多芯フェルールのコア間隔のばらつきによって光学系の倍率がばらついても高効率で光受光部に集光させることが可能となるとともに、レンズの調芯に要する時間を短縮することができ、受光モジュールを歩留まり良く製造することができる。 From the above, it can be seen that the tolerance of the fixed position of the lens is larger by 13 μm or more when the shape of the light receiving surface is an anisotropic shape (symmetrical track type light receiving surface 7a) than in the prior art. Therefore, even if the magnification of the optical system varies due to the variation in the distance between the light receiving unit and the lens and the variation in the core interval of the multi-core ferrule due to the increased tolerance of the fixed position of the lens, the light is collected on the light receiving unit with high efficiency. It is possible to reduce the time required for lens alignment, and the light receiving module can be manufactured with high yield.

図３は、本発明の実施形態１による受光面の他の形状を示す図である。図３に示す非対称トラック型受光面７ｂは、図２に示す対称トラック型受光面７ａに対して、短手方向の長さがレンズ４の中心軸に対応する中心点１１から長手方向に向かって徐々に長くなる形状となっている。 FIG. 3 is a diagram illustrating another shape of the light receiving surface according to the first embodiment of the present invention. The asymmetric track type light receiving surface 7b shown in FIG. 3 has a length in the short direction from the center point 11 corresponding to the central axis of the lens 4 in the longitudinal direction with respect to the symmetrical track type light receiving surface 7a shown in FIG. The shape becomes gradually longer.

本発明の実施形態における受光モジュールでは、例えば受光部６ｂが２つ設けられている場合において、それぞれの受光部６ｂにて対称となる位置で受光するように調整されると、最も出射部６ａの位置調整の公差を大きくすることができる。ビームスポットの間隔が小さい状態で受光する場合（図４（ａ））と、ビームスポットの間隔が大きい状態で受光する場合（図４（ｂ））とでは、ビームスポットの大きい状態で受光した方が光学系の倍率が大きくなるため、集光されたビームスポットが大きくなる。従って、図２に示す対称トラック型受光面７ａにて受光すると、ビームスポットの間隔が大きくなるほどビームスポット径も大きくなるため、その分だけ位置調整の公差が減少してしまう。一方、図３に示す非対称トラック型受光面７ｂにて受光すると、ビームスポットの間隔が大きくなっても位置調整の公差を確保できるという利点がある。 In the light receiving module according to the embodiment of the present invention, for example, when two light receiving portions 6b are provided, when the light receiving portions 6b are adjusted so as to receive light at symmetrical positions, the light emitting portions 6a Position adjustment tolerances can be increased. When light is received with a small beam spot interval (FIG. 4A) and when light is received with a large beam spot interval (FIG. 4B), the light beam is received with a large beam spot. However, since the magnification of the optical system is increased, the focused beam spot is increased. Accordingly, when light is received by the symmetrical track type light receiving surface 7a shown in FIG. 2, the beam spot diameter increases as the interval between the beam spots increases, and the positional adjustment tolerance decreases accordingly. On the other hand, when light is received by the asymmetric track type light receiving surface 7b shown in FIG. 3, there is an advantage that a tolerance for position adjustment can be ensured even if the interval between the beam spots is increased.

図３において点線で示される受光エリア８は、光学系のばらつきを考慮した場合に受光する可能性のあるエリアを示しており、非対称トラック形状となる。なお、非対称トラック型受光面７ｂは、受光エリア８に対して所定の位置調整公差分だけ同じ幅で広がった（相似の）非対称トラック状にすることが望ましい。 A light receiving area 8 indicated by a dotted line in FIG. 3 indicates an area that may receive light in consideration of variations in the optical system, and has an asymmetric track shape. The asymmetric track type light receiving surface 7b is preferably formed in an asymmetric track shape having a similar width with respect to the light receiving area 8 by a predetermined positional adjustment tolerance (similar).

また、受光面の形状は、本実施形態１の図２および図３に示した形状だけではなく、受光面積を同一としたままで、短手方向をさらに短くして長手方向をさらに長くすることによって、レンズの固定位置の公差をさらに大きくすることが可能となる。例えば、短手方向の長さを９μｍとすると、長手方向の長さは４５μｍとすることができる。その結果、レンズの固定位置の公差を±２０μｍと大きくすることが可能となる。短手方向の長さは、出射部６ａから出射される出射ビームのビーム径と集光光学系の縮小率で決まる集光ビームのスポット径に対して、±１μｍ程度の固定精度公差を加えた大きさまで小さくすることが可能であり、本実施形態の場合では約７μｍ程度まで低減可能であると推考される。 In addition, the shape of the light receiving surface is not limited to the shape shown in FIGS. 2 and 3 of the first embodiment, but with the same light receiving area, the short side direction is further shortened and the longitudinal direction is further lengthened. This makes it possible to further increase the tolerance of the fixed position of the lens. For example, if the length in the short direction is 9 μm, the length in the long direction can be 45 μm. As a result, the tolerance of the lens fixing position can be increased to ± 20 μm. For the length in the short direction, a fixed accuracy tolerance of about ± 1 μm is added to the spot diameter of the condensed beam determined by the beam diameter of the emitted beam emitted from the emitting portion 6a and the reduction ratio of the condensing optical system. It can be reduced to a size, and in the case of the present embodiment, it can be estimated that the size can be reduced to about 7 μm.

以上のことから、例えば、初めに受光部６ｂを位置固定した後に、レンズ４を光受光強度をモニタすることなく通常の光モジュールよりも大きな位置公差で固定（無調芯固定）し、その後に２芯フェルール３ａの出射部６ａを光受光強度をモニタし調芯しながら位置固定するため、レンズの調芯が簡便になって受光モジュールを容易に製造することが可能となる。このとき、受光部６ｂとレンズ４との間隔、または、レンズ４と出射部６ａとの間隔のうちのいずれか一方の間隔を無調芯で設定すればよい。また、光出射部６ａによる調芯時の位置調整の公差を大きくできるため、調芯工程における歩留まりを良好にできる。すなわち、光受光部とレンズとの距離のばらつきや多芯フェルールのコア間隔のばらつきによって光学系の倍率がばらついても高効率で光受光部に集光させることが可能となる。 From the above, for example, after first fixing the position of the light receiving portion 6b, the lens 4 is fixed with a position tolerance larger than that of a normal optical module without monitoring the light receiving intensity (fixed with no alignment), and thereafter Since the position of the emitting part 6a of the two-core ferrule 3a is fixed while monitoring the light receiving intensity, the lens is easily aligned and the light receiving module can be easily manufactured. At this time, the interval between the light receiving unit 6b and the lens 4 or the interval between the lens 4 and the emitting unit 6a may be set with no alignment. Moreover, since the tolerance of the position adjustment at the time of alignment by the light emitting part 6a can be increased, the yield in the alignment process can be improved. That is, even if the magnification of the optical system varies due to the variation in the distance between the light receiving unit and the lens and the variation in the core interval of the multi-core ferrule, the light receiving unit can be condensed with high efficiency.

〈実施形態２〉
図５は、本発明の実施形態２による出射部および受光面の形状を示す図である。図５に示すように、本実施形態２による光モジュールは、出射部６ａおよび受光面は４個ずつあり、それぞれが正方形状に配列されている。その他の構成は、実施形態１と同様であるため、ここでは説明を省略する。 <Embodiment 2>
FIG. 5 is a diagram showing the shapes of the emitting part and the light receiving surface according to Embodiment 2 of the present invention. As shown in FIG. 5, the optical module according to the second embodiment has four emitting portions 6a and four light receiving surfaces, each of which is arranged in a square shape. Other configurations are the same as those of the first embodiment, and thus the description thereof is omitted here.

図５に示す非対称トラック型ＰＤアレイ受光面は、正方形状の中心から延伸された非対称トラック形状となっている。すなわち、レンズ４の中心軸に対応する中心点１１を中心として２軸方向に配列されている。 The light receiving surface of the asymmetric track type PD array shown in FIG. 5 has an asymmetric track shape extending from a square center. That is, they are arranged in the biaxial direction around the center point 11 corresponding to the center axis of the lens 4.

なお、受光面は、受光する可能性のあるエリアに対して所望の位置調整の公差分だけ広がった非対称トラック形状にすることが好ましい。また、出射部６ａおよび受光面は、３個以上であればよく、配列状態は正方形状だけではなく長方形状など所望の形状であってもよい。 It is preferable that the light receiving surface has an asymmetric track shape that is widened by a desired positional adjustment tolerance with respect to an area that may receive light. Further, the number of the emitting portions 6a and the light receiving surfaces may be three or more, and the arrangement state may be a desired shape such as a rectangular shape as well as a square shape.

以上のことから、光学系の倍率がばらついた場合であっても、出射部６ａの位置調整の公差を大きくすることができる。 From the above, even when the magnification of the optical system varies, the positional adjustment tolerance of the emitting portion 6a can be increased.

〈実施形態３〉
図６は、本発明の実施形態３による出射部および受光面の形状を示す図である。図６に示すように、本実施形態３による光モジュールは、出射部６ａおよび受光面は２個ずつあり、各受光面は円弧状に延伸された形状となっている。すなわち、２つ（複数）の受光面６ｂ（光受光部）の形状は、レンズ４の中心軸に対応する中心点１１から所定の距離を半径とし、中心点１１を中心として所定の角度だけ回転して描かれた円弧に沿った形状であることを特徴としている。その他の構成は、実施形態１と同様であるため、ここでは説明を省略する。 <Embodiment 3>
FIG. 6 is a diagram showing the shapes of the emitting part and the light receiving surface according to Embodiment 3 of the present invention. As shown in FIG. 6, the optical module according to the third embodiment has two emitting portions 6a and two light receiving surfaces, and each light receiving surface has a shape extending in an arc shape. That is, the shape of the two (plurality) of light receiving surfaces 6b (light receiving portions) is a predetermined distance from the center point 11 corresponding to the central axis of the lens 4 and is rotated by a predetermined angle around the center point 11. It is characterized by the shape along the arc drawn. Other configurations are the same as those of the first embodiment, and thus the description thereof is omitted here.

光学系の調整において、受光部６ｂとレンズ４との距離、レンズ４と出射部６ａとの距離を正確に調整する他に、出射部６ａにおける各光ファイバ２のファイバコアの配列方向の角度と、受光部６ｂの受光面の配列方向の角度とを正確に合わせる必要がある。 In the adjustment of the optical system, in addition to accurately adjusting the distance between the light receiving unit 6b and the lens 4 and the distance between the lens 4 and the emitting unit 6a, the angle in the arrangement direction of the fiber cores of the optical fibers 2 in the emitting unit 6a Therefore, it is necessary to accurately match the angle of the light receiving surface of the light receiving unit 6b in the arrangement direction.

本実施形態１および２では、受光部６ｂとレンズ４との距離のばらつきに対して調整公差を大きくする受光モジュールについて説明したが、本実施形態３では、各受光面が円弧状に延伸して形成されているため、上述の角度がばらついた場合であっても良好に受光することができ、出射部６ａの角度調整の公差を大きくすることが可能となる。 In the first and second embodiments, the light receiving module that increases the adjustment tolerance with respect to the variation in the distance between the light receiving unit 6b and the lens 4 has been described. However, in the third embodiment, each light receiving surface extends in an arc shape. Since it is formed, it is possible to receive light well even when the above-mentioned angle varies, and it is possible to increase the tolerance of angle adjustment of the emitting portion 6a.

なお、角度の公差としては、例えば±１度〜±５度とすることによって、出射部６ａの角度調整の工程なしで光学系を調整することができる。また、受光面は、受光する可能性のあるエリア（受光エリア８）に対して、所望の位置調整の公差分だけ広がった円弧形状にすることが好ましい。さらに、出射部６ａおよび受光面は３個以上でもよく、出射部６ａおよび受光面の配列状態は１軸方向であっても２軸方向であってもよい。 Note that the angle tolerance is, for example, ± 1 ° to ± 5 °, so that the optical system can be adjusted without the step of adjusting the angle of the emitting portion 6a. Moreover, it is preferable that the light receiving surface has an arc shape that is widened by a desired positional adjustment tolerance with respect to an area (light receiving area 8) that may receive light. Furthermore, the number of the emitting portions 6a and the light receiving surfaces may be three or more, and the arrangement state of the emitting portions 6a and the light receiving surfaces may be uniaxial or biaxial.

以上のことから、出射部６ａにおける各光ファイバ２のファイバコアの配列方向の角度と、受光部６ｂの受光面の配列方向の角度とがばらついた場合であっても良好に受光することができ、出射部６ａの角度調整の公差を大きくすることが可能となる。 From the above, even if the angle in the arrangement direction of the fiber cores of the respective optical fibers 2 in the emission part 6a and the angle in the arrangement direction of the light receiving surface of the light receiving part 6b vary, it can receive light well. Thus, it becomes possible to increase the tolerance of the angle adjustment of the emitting portion 6a.

〈実施形態４〉
図７は、本発明の実施形態４による受光面の形状を示す図である。図７（ａ）および（ｂ）に示すように、本実施形態４による受光モジュールは、出射部６ａおよび受光面は１個ずつであり、受光部６ｂは、受光面と非受光面とを混在させ受光面が広範囲に存在することを特徴としている。また、受光面の形状は、受光部６ｂ（光受光部）の各々に照射される入力光の直径よりも小さい幅のパターン形状である。 <Embodiment 4>
FIG. 7 is a diagram showing the shape of the light receiving surface according to the fourth embodiment of the present invention. As shown in FIGS. 7A and 7B, the light receiving module according to the fourth embodiment has one emitting portion 6a and one light receiving surface, and the light receiving portion 6b has both a light receiving surface and a non-light receiving surface. The light receiving surface is present in a wide range. The shape of the light receiving surface is a pattern shape having a width smaller than the diameter of the input light irradiated on each of the light receiving portions 6b (light receiving portions).

図７（ａ）に示す受光面のパターン形状は渦巻き形状（渦巻き型受光面７ｅ）であり、図７（ｂ）に示す受光面のパターン形状は蛇行型形状（蛇行型受光面７ｆ）である。渦巻き型受光面７ｅ（または、蛇行型受光面７ｆ）の総面積は、応答周波数帯域によって変わるが、例えば１０ＧＨｚの帯域の場合には１００μｍ²以下にする。また、非受光面は上部電極を設けない構造とし、渦巻き型受光面７ｅ（または、蛇行型受光面７ｆ）以外の領域に光が入射しないように金属膜などの遮光膜を設けることが望ましい。 The pattern shape of the light receiving surface shown in FIG. 7A is a spiral shape (spiral light receiving surface 7e), and the pattern shape of the light receiving surface shown in FIG. 7B is a meandering shape (meandering light receiving surface 7f). . The total area of the spiral light receiving surface 7e (or the meandering light receiving surface 7f) varies depending on the response frequency band, but is, for example, 100 μm ² or less in the case of a 10 GHz band. Further, it is desirable that the non-light-receiving surface has a structure in which no upper electrode is provided, and a light-shielding film such as a metal film is provided so that light does not enter a region other than the spiral light-receiving surface 7e (or the meandering light-receiving surface 7f).

上記の構造では、受光感度が（集光スポット内の受光部面積／集光スポットの面積）の割合だけ減少するが、入射光１の信号を渦巻き型受光面７ｅ（または、蛇行型受光面７ｆ）の受光面が存在する広い面積にわたって高い応答周波数帯域で受信することが可能となる。また、本実施形態４における受光面の面積と非受光面の面積との総和が、実施形態１における受光面の面積と同一である場合において、受光面の面積と非受光面の面積との総和を小さくすると実施形態１よりも高い応答周波数帯域の信号を受信することが可能となる。 In the above structure, the light receiving sensitivity is reduced by a ratio of (light receiving portion area in the condensing spot / area of the condensing spot), but the signal of the incident light 1 is converted into the spiral light receiving surface 7e (or the meandering light receiving surface 7f). ) In a high response frequency band over a wide area where the light receiving surface exists. Further, when the sum of the areas of the light receiving surface and the non-light receiving surface in the fourth embodiment is the same as the area of the light receiving surface in the first embodiment, the sum of the area of the light receiving surface and the area of the non-light receiving surface. If it is made smaller, it becomes possible to receive a signal in a higher response frequency band than in the first embodiment.

なお、出射部６ａおよび受光面は複数でもよく、出射部６ａおよび受光面の配列状態は１軸方向であっても２軸方向であってもよい。また、受光面および非受光面は、受光面上に集光された場合に想定されるビーム径の１／２の幅、あるいは偶数分の１の幅の受光面のパターン形状で混在することが望ましい。当該パターンとすることによって、受光面および非受光面が混在する受光部６ｂの如何なる箇所でも同じ感度で受光することができる。 Note that there may be a plurality of emitting portions 6a and light receiving surfaces, and the arrangement state of the emitting portions 6a and the light receiving surfaces may be uniaxial or biaxial. In addition, the light receiving surface and the non-light receiving surface may be mixed in a pattern shape of the light receiving surface having a width that is 1/2 of the beam diameter assumed when the light is collected on the light receiving surface or an even-numbered width. desirable. With this pattern, light can be received with the same sensitivity at any location of the light receiving portion 6b in which the light receiving surface and the non-light receiving surface are mixed.

以上のことから、受光面が存在する面積を広くすることによって、受光部６ｂとレンズ４との距離のばらつきによる位置調整の公差を大きくすることができ、受光モジュール製造時の調芯工程を容易にすることが可能となる。また、受光面の面積を小さくすることによって、さらに高い応答周波数帯域の信号を受信することが可能となる。 From the above, by widening the area where the light receiving surface exists, the tolerance of position adjustment due to the variation in the distance between the light receiving unit 6b and the lens 4 can be increased, and the alignment process at the time of manufacturing the light receiving module is facilitated. It becomes possible to. Further, by reducing the area of the light receiving surface, it is possible to receive a signal in a higher response frequency band.

〈実施形態５〉
図８は、本発明の実施形態５による出射部および受光面の形状を示す図である。図８（ａ）は出射部６ａの形状（多芯フェルール３ｂの断面）を示し、図８（ｂ）はＰＤアレイ６ｂの受光面の形状を示している。図８に示すように、本実施形態５による受光モジュールでは、出射部６ａおよび受光面は２個ずつであり、受光部６ｂは実施形態４と同様、受光面と非受光面とを混在させ受光面が広範囲に存在することを特徴としている。本実施形態５は、図８に示す受光面の形状に特徴を有しており、その他の構成は実施形態４と同様であるため、ここでは説明を省略する。 <Embodiment 5>
FIG. 8 is a view showing the shapes of the emitting part and the light receiving surface according to Embodiment 5 of the present invention. FIG. 8A shows the shape of the emitting portion 6a (cross section of the multi-core ferrule 3b), and FIG. 8B shows the shape of the light receiving surface of the PD array 6b. As shown in FIG. 8, in the light receiving module according to the fifth embodiment, there are two light emitting portions 6a and two light receiving surfaces, and the light receiving portion 6b receives light by mixing light receiving surfaces and non-light receiving surfaces as in the fourth embodiment. It is characterized by a wide range of surfaces. The fifth embodiment has a feature in the shape of the light receiving surface shown in FIG. 8, and the other configuration is the same as that of the fourth embodiment. Therefore, the description thereof is omitted here.

図８（ｂ）に示す受光面は、非対称トラック型蛇行型受光面７ｇである。非対称トラック型蛇行型受光面７ｇの総面積は、応答周波数帯域によって変わるが、例えば１０ＧＨｚの帯域の場合には１００μｍ²以下にする。また、さらに高い応答周波数帯域の信号を受信する必要がある場合は、非対称トラック型蛇行型受光面７ｇの総面積を減少させる。非受光面は上部電極を設けない構造とし、非対称トラック型蛇行型受光面７ｇ以外の領域に光が入射しないように金属膜などの遮光膜を設けることが望ましい。さらに、実施形態１にて説明したように、受光面および非受光面が混在した形状を、光学系の倍率のばらつきを考慮した場合において受光する可能性があるエリア（受光エリア８）に対して、所望の位置調整の公差分だけ広がった非対称トラック形状にすることが好ましい。すなわち、受光面および非受光面が混在した形状は図３に示す非対称トラック型受光面７ｂと同様であり、トラック形状の短手方向の長さがレンズ４の中心軸に対応する中心点１１から長手方向に向かって徐々に長くなる形状となっている。 The light receiving surface shown in FIG. 8B is an asymmetric track type meandering light receiving surface 7g. The total area of the asymmetric track type meandering type light receiving surface 7g varies depending on the response frequency band, but is, for example, 100 μm ² or less in the case of a 10 GHz band. Further, when it is necessary to receive a signal in a higher response frequency band, the total area of the asymmetric track type meandering light receiving surface 7g is reduced. It is desirable that the non-light receiving surface has a structure in which the upper electrode is not provided, and a light shielding film such as a metal film is provided so that light does not enter a region other than the asymmetric track type meandering light receiving surface 7g. Further, as described in the first embodiment, the shape in which the light receiving surface and the non-light receiving surface are mixed is compared with an area (light receiving area 8) that may receive light when variation in magnification of the optical system is taken into consideration. Preferably, the asymmetric track shape is widened by a desired positional adjustment tolerance. That is, the shape in which the light receiving surface and the non-light receiving surface are mixed is the same as the asymmetric track type light receiving surface 7 b shown in FIG. 3, and the length in the short direction of the track shape is from the center point 11 corresponding to the central axis of the lens 4. The shape gradually becomes longer in the longitudinal direction.

上記の構造では、受光感度が（集光スポット内の受光部面積／集光スポットの面積）の割合だけ減少するが、入射光１の信号を非対称トラック型蛇行型受光面７ｇの受光面が存在する広い面積にわたって高い応答周波数帯域で受信することが可能となる。 In the above structure, the light receiving sensitivity decreases by a ratio of (light receiving portion area / light collecting spot area in the light collecting spot), but there is a light receiving surface of the asymmetric track type meandering light receiving surface 7g. It is possible to receive in a high response frequency band over a wide area.

また、本実施形態４における受光面の面積と非受光面の面積との総和が、実施形態１における受光面の面積と同一である場合において、受光面の面積と非受光面の面積との総和を小さくすると実施形態１よりも高い応答周波数帯域の信号を受信することが可能となる。 Further, when the sum of the areas of the light receiving surface and the non-light receiving surface in the fourth embodiment is the same as the area of the light receiving surface in the first embodiment, the sum of the area of the light receiving surface and the area of the non-light receiving surface. If it is made smaller, it becomes possible to receive a signal in a higher response frequency band than in the first embodiment.

なお、出射部６ａおよび受光面は３個以上でもよく、出射部６ａおよび受光面の配列状態は１軸方向であっても２軸方向であってもよい。 Note that the number of the emitting portions 6a and the light receiving surfaces may be three or more, and the arrangement state of the emitting portions 6a and the light receiving surfaces may be uniaxial or biaxial.

また、受光面および非受光面が混在した形状は、レンズ４の中心軸に対応する中心点１１と、受光部６ｂの中点とを結ぶ直線に沿って延伸した方向を長手方向とし、長手方向に対して垂直方向を短手方向とした対称トラック型受光面（図２参照）としてもよい。 In addition, the shape in which the light receiving surface and the non-light receiving surface are mixed is defined by a direction extending along a straight line connecting the center point 11 corresponding to the center axis of the lens 4 and the midpoint of the light receiving unit 6b as a longitudinal direction. Alternatively, a symmetrical track-type light receiving surface (see FIG. 2) with the perpendicular direction as the short direction may be used.

また、本実施形態５では、受光面の形状を非対称トラック型蛇行型受光面７ｇとして説明したが、受光面および非受光面が混在した形状が対称トラック型受光面および非対称トラック型受光面である場合において、受光面のパターン形状を渦巻き形状としてもよい。 In the fifth embodiment, the shape of the light receiving surface is described as the asymmetric track type meandering type light receiving surface 7g. However, the shape in which the light receiving surface and the non-light receiving surface are mixed is the symmetric track type light receiving surface and the asymmetric track type light receiving surface. In some cases, the pattern shape of the light receiving surface may be a spiral shape.

〈実施形態６〉
図９は、本発明の実施形態６による出射部および受光面の形状を示す図である。図９（ａ）は出射部６ａの形状（多芯フェルールの断面）を示し、図８（ｂ）はＰＤアレイ６ｂの受光面の形状を示している。図９に示すように、本実施形態６による受光モジュールでは、出射部６ａおよび受光面は２個ずつであり、受光部６ｂは実施形態４と同様、受光面と非受光面とを混在させ受光面が広範囲に存在することを特徴としている。本実施形態６は、図９に示す受光面の形状に特徴を有しており、その他の構成は実施形態４と同様であるため、ここでは説明を省略する。 <Embodiment 6>
FIG. 9 is a diagram showing the shapes of the emitting part and the light receiving surface according to Embodiment 6 of the present invention. FIG. 9A shows the shape of the emitting portion 6a (cross section of the multi-core ferrule), and FIG. 8B shows the shape of the light receiving surface of the PD array 6b. As shown in FIG. 9, in the light receiving module according to the sixth embodiment, there are two light emitting portions 6a and two light receiving surfaces, and the light receiving portion 6b has a light receiving surface and a non-light receiving surface mixed as in the fourth embodiment. It is characterized by a wide range of surfaces. The sixth embodiment has a feature in the shape of the light receiving surface shown in FIG. 9, and the other configuration is the same as that of the fourth embodiment. Therefore, the description thereof is omitted here.

図９（ｂ）に示す受光面は、円弧型蛇行型受光面７ｈである。円弧型蛇行型受光面７ｈの総面積は、応答周波数帯域によって変わるが、例えば１０ＧＨｚの帯域の場合には１００μｍ²以下にする。また、さらに高い応答周波数帯域の信号を受信する必要がある場合は、円弧型蛇行型受光面７ｈの総面積を減少させる。非受光面は上部電極を設けない構造とし、円弧型蛇行型受光面７ｈ以外の領域に光が入射しないように金属膜などの遮光膜を設けることが望ましい。さらに、受光面および非受光面が混在した形状は、受光する可能性のあるエリア（受光エリア８）に対して、所望の位置調整の公差分だけ広がった円弧形状にすることが好ましい。すなわち、すなわち、受光面および非受光面が混在した形状は、レンズ４の中心軸に対応する中心点１１から所定の距離を半径とし、中心点１１を中心として所定の角度だけ回転して描かれた円弧に沿った形状となっている。 The light receiving surface shown in FIG. 9B is an arcuate meandering light receiving surface 7h. The total area of the arc-shaped meandering light-receiving surface 7h varies depending on the response frequency band, but is, for example, 100 μm ² or less in the case of a 10 GHz band. Further, when it is necessary to receive a signal in a higher response frequency band, the total area of the arc-shaped meandering light-receiving surface 7h is reduced. It is desirable that the non-light-receiving surface has a structure in which no upper electrode is provided, and a light-shielding film such as a metal film is provided so that light does not enter a region other than the arc-shaped meandering light-receiving surface 7h. Furthermore, the shape in which the light receiving surface and the non-light receiving surface are mixed is preferably an arc shape that is widened by a tolerance of a desired position adjustment with respect to an area (light receiving area 8) that may receive light. In other words, the shape in which the light receiving surface and the non-light receiving surface are mixed is drawn by rotating a predetermined distance from the center point 11 corresponding to the central axis of the lens 4 and rotating by a predetermined angle around the center point 11. The shape is along a circular arc.

上記の構造では、受光感度が（集光スポット内の受光部面積／集光スポットの面積）の割合だけ減少するが、入射光１の信号を円弧型蛇行型受光面７ｈの受光面が存在する広い面積にわたって高い応答周波数帯域で受信することが可能となる。 In the above structure, the light receiving sensitivity decreases by a ratio of (light receiving portion area / light collecting spot area in the light collecting spot), but there is a light receiving surface of the arc-shaped meandering light receiving surface 7h for the incident light 1 signal. It is possible to receive in a high response frequency band over a wide area.

以上のことから、出射部６ａにおける各光ファイバ２のファイバコアの配列方向の角度と、受光部６ｂの受光面の配列方向の角度とがばらついた場合であっても出射部６ａの角度調整の公差を大きくすることができ、受光モジュール製造時の調芯工程を容易にすることが可能となる。また、受光面の面積を小さくすることによって、さらに高い応答周波数帯域の信号を受信することが可能となる。 From the above, even if the angle in the arrangement direction of the fiber cores of the respective optical fibers 2 in the emission section 6a and the angle in the arrangement direction of the light receiving surface of the light receiving section 6b vary, the angle adjustment of the emission section 6a can be performed. The tolerance can be increased, and the alignment process at the time of manufacturing the light receiving module can be facilitated. Further, by reducing the area of the light receiving surface, it is possible to receive a signal in a higher response frequency band.

また、本実施形態６では、受光面の形状を円弧型蛇行型受光面７ｈとして説明したが、受光面のパターン形状を渦巻き形状としてもよい。 In the sixth embodiment, the shape of the light receiving surface is described as the arc-shaped meandering light receiving surface 7h. However, the pattern shape of the light receiving surface may be a spiral shape.

１入射光、２光ファイバ、３ａ２芯フェルール、３ｂ多芯フェルール、４レンズ、５ａツインＰＤ、５ｂＰＤアレイ、６ａ出射部、６ｂ受光部、７ａ対称トラック型受光面、７ｂ非対称トラック型受光面、７ｃ非対称トラック型ＰＤアレイ受光部、７ｄ円弧型受光面、７ｅ渦巻き型受光面、７ｆ蛇行型受光面、７ｇ非対称トラック型蛇行型受光面、７ｈ円弧型蛇行型受光面、７ｉ円形受光面、８受光エリア、９非受光部、１０集光スポット、１１中心点。 DESCRIPTION OF SYMBOLS 1 Incident light, 2 Optical fiber, 3a 2 core ferrule, 3b Multi-core ferrule, 4 Lens, 5a Twin PD, 5b PD array, 6a Output part, 6b Light receiving part, 7a Symmetric track type light receiving surface, 7b Asymmetric track type light receiving surface 7c Asymmetric track type PD array light receiving portion, 7d Arc type light receiving surface, 7e Spiral type light receiving surface, 7f Serpentine type light receiving surface, 7g Asymmetric track type serpentine type light receiving surface, 7h Arc type serpentine type light receiving surface, 7i Circular light receiving surface, 8 Light-receiving area, 9 Non-light-receiving part, 10 Condensing spot, 11 Center point.

Claims

In a light receiving module that receives multiple input lights,
A plurality of light emitting sections for emitting each of the incident plurality of input lights to the next stage;
A plurality of light receiving units arranged corresponding to each of the plurality of light emitting units, and receiving the plurality of input lights emitted from each of the plurality of light emitting units;
The plurality of input lights emitted from each of the plurality of light emitting units are condensed on each of the plurality of light receiving units, arranged between the plurality of light emitting units and the plurality of light receiving units. One convex lens,
With
The interval between the respective light collecting spots collected on each of the plurality of light receiving units varies depending on the interval between the plurality of light receiving units and the lens,
Each of the plurality of light receiving portions has a longitudinal direction in a direction along a straight line connecting a center point corresponding to a central axis of the lens and a midpoint of each of the light receiving portions, with respect to the longitudinal direction. Track shape with the vertical direction as the short direction,
The plurality of light receiving units are arranged in one axis direction around the center point ,
Each of the plurality of light receiving portions has a shape in which the length of the track shape in the short direction gradually increases as the distance from the center point along the longitudinal direction increases . Light receiving module.

Each of the plurality of light receiving parts has a light receiving surface and a non-light receiving surface,
Each of the plurality of light receiving portions having the light receiving surface and the non-light receiving surface has a shape along a straight line connecting a center point corresponding to the center axis of the lens and a midpoint of the light receiving portion. A track shape having a longitudinal direction and a short direction perpendicular to the longitudinal direction,
2. The light receiving module according to claim 1, wherein the shape of the light receiving surface is a pattern shape having a width smaller than a diameter of the plurality of input lights irradiated to each of the plurality of light receiving portions.

The light receiving module according to claim 2, wherein the pattern shape of the light receiving surface is a spiral shape or a meandering shape.