JP2012118380A

JP2012118380A - Optical coupling structure

Info

Publication number: JP2012118380A
Application number: JP2010269254A
Authority: JP
Inventors: Naoki Kitamura; 直樹北村
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2010-12-02
Filing date: 2010-12-02
Publication date: 2012-06-21

Abstract

PROBLEM TO BE SOLVED: To provide an optical coupling structure which achieves high coupling efficiency between a light-emitting element and an optical waveguide.SOLUTION: An optical coupling structure includes a substrate, a pedestal and an optical waveguide provided on the substrate, a light-emitting element mounted on the pedestal, and a holding member connected to a face of the light-emitting element which is on the opposite side to a face facing the substrate, and the holding member is joined to the substrate.

Description

本発明は発光素子等の光部品と光導波路の結合構造に関する。 The present invention relates to a coupling structure of an optical component such as a light emitting element and an optical waveguide.

近年、技術の発展に伴い光通信システムは飛躍的な伸びを見せている。特にファイバは、利用効率を高めるため、光信号の高速化・多波長化といった技術が進展している。しかし、このような技術進展に伴い、ファイバを使用する部品への要求は増々厳しくなっている。 In recent years, with the development of technology, optical communication systems have grown dramatically. In particular, in order to increase the utilization efficiency of the fiber, technologies such as speeding up of the optical signal and increase in wavelength are progressing. However, with such technological progress, the demand for components using fibers has become increasingly severe.

一方、特にＦＴＴＨ（Fiber To The Home）の進展に伴い、ファイバは低コスト化が重要な問題となっている。またファイバの高速化の要求は増えており、当初１００Ｍｂｐｓ程度の伝送速度だったものが、近年では２．４Ｇｂｐｓが出回り始めており、今後１０Ｇｂｐｓも検討され始めている。更に伝送距離についても２０ｋｍ以上の長距離の通信が求められている。 On the other hand, especially with the progress of FTTH (Fiber To The Home), cost reduction of the fiber has become an important issue. In addition, there is an increasing demand for high-speed fibers, and 2.4 Gbps has started to be available in recent years, although transmission speeds of about 100 Mbps have been on the market. Further, regarding the transmission distance, communication over a long distance of 20 km or more is required.

このような状況下において発光素子は、マルチモードで発振するファブリペローレーザーからシングルモードで発振するＤＦＢ−ＬＤ（Distributed Feedback Laser Diode）素子の使用が必須となっている。 Under such circumstances, it is essential to use a DFB-LD (Distributed Feedback Laser Diode) element that oscillates in a single mode from a Fabry-Perot laser that oscillates in a multimode.

光部品の実装は、高い結合効率を維持するために、サブミクロンレベルの位置調整が必要であり、調芯に掛かるコストが低コスト化を阻害していた。 In order to maintain high coupling efficiency, the mounting of optical components requires sub-micron level position adjustment, and the cost for alignment has hindered cost reduction.

これを解決するために、基板上に形成された光導波路と光部品とを高精度に結合する技術など、光導波路を用いて光部品の機械的な位置決めを行う研究が進められてきた。例えば特許文献１には、サブミクロンレベルでの発光素子と光導波路の位置合わせを簡単に実現する方法が記載されている。 In order to solve this problem, researches for mechanically positioning an optical component using an optical waveguide have been advanced, such as a technique for coupling an optical waveguide formed on a substrate and an optical component with high accuracy. For example, Patent Document 1 describes a method for easily realizing alignment between a light emitting element and an optical waveguide at a submicron level.

特許文献１に記載されている発明は、発光素子と光導波路とが搭載される基板表面と発光素子の活性層部分との距離を、基板表面と光導波路の中心間の距離と一致させる構造にすることによって高い結合効率を簡単に得る構造である。 The invention described in Patent Document 1 has a structure in which the distance between the surface of the substrate on which the light emitting element and the optical waveguide are mounted and the active layer portion of the light emitting element coincides with the distance between the substrate surface and the center of the optical waveguide. By doing so, the structure can easily obtain high coupling efficiency.

特開平９−３０４６６３JP-A-9-304663

発光素子は、活性層部分と光導波路とを高い結合効率を維持する構造とする必要がある。特許文献１では、発光素子と基板とが高融点の半田材料を介して固着して、光導波路と結合した構造が記載されている。しかし、特許文献１に記載された上記構造では、発光素子と基板との間に設けられた半田材料の応力が発光素子の活性層に影響を与えることで発振特性が変化してしまい、マルチモードで発振してしまうという問題点があった。 The light emitting element needs to have a structure that maintains high coupling efficiency between the active layer portion and the optical waveguide. Patent Document 1 describes a structure in which a light emitting element and a substrate are fixed via a high melting point solder material and coupled to an optical waveguide. However, in the above structure described in Patent Document 1, the oscillation characteristics are changed due to the stress of the solder material provided between the light emitting element and the substrate affecting the active layer of the light emitting element, and the multimode is changed. There was a problem of oscillation.

本発明の目的は、上記課題を解決する光結合構造を提供することにある。 The objective of this invention is providing the optical coupling structure which solves the said subject.

本発明における光結合構造は、基板と、基板上に設けられた台座と光導波路と、台座上に搭載された発光素子と、発光素子の前記基板と対向する面とは反対側の面と接続する保持部材とを備え、保持部材は基板と接合していることを特徴とする。 The optical coupling structure according to the present invention includes a substrate, a pedestal and an optical waveguide provided on the substrate, a light emitting element mounted on the pedestal, and a surface of the light emitting element opposite to the surface facing the substrate. And a holding member that is bonded to the substrate.

本発明の効果は、発光素子と光導波路との高い結合効率を実現することができる。 The effect of the present invention can realize high coupling efficiency between the light emitting element and the optical waveguide.

第１の実施形態における光結合構造の側面図である。It is a side view of the optical coupling structure in 1st Embodiment. 第１の実施形態における光結合構造の断面図である。It is sectional drawing of the optical coupling structure in 1st Embodiment. 第２の実施形態における光結合構造の断面図である。It is sectional drawing of the optical coupling structure in 2nd Embodiment. 特許文献１における光結合構造の側面図である。It is a side view of the optical coupling structure in patent document 1. FIG. 特許文献１における光結合構造の断面図である。It is sectional drawing of the optical coupling structure in patent document 1. FIG.

〔第１の実施形態〕以下に、本発明を実施するための好ましい形態について図面を用いて説明する。但し、以下に述べる実施形態には、本発明を実施するために技術的に好ましい限定がされているが、発明の範囲を以下に限定するものではない。 [First Embodiment] A preferred embodiment for carrying out the present invention will be described below with reference to the drawings. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following.

〔構造の説明〕図１は本実施形態の光結合構造１０の側面図であり、図２は図１におけるA−A´の断面図である。図１、および図２に示すように、本実施形態における光結合構造１０は、発光素子１と、基板２と、光導波路３と、台座４とを少なくとも備えている。 [Description of Structure] FIG. 1 is a side view of the optical coupling structure 10 of this embodiment, and FIG. 2 is a cross-sectional view taken along the line AA 'in FIG. As shown in FIGS. 1 and 2, the optical coupling structure 10 in this embodiment includes at least a light emitting element 1, a substrate 2, an optical waveguide 3, and a pedestal 4.

発光素子１は、平板形状であり、少なくとも２つの対向する主面をもつ。発光素子１の一方の主面には、表面電極１−１が形成されている。また反対側の主面には、裏面電極１−２が形成されている。なお発光素子１は、表面電極１−１近傍に発光中心である活性層１−３を形成している。言い換えると活性層１−３は、発光素子１の内部に形成されており、表面電極１−１と活性層１−３との距離は数ミクロンと近いのに対し、裏面電極１−２と活性層１−３との距離は数百ミクロンと離れている。 The light emitting element 1 has a flat plate shape and has at least two opposing main surfaces. A surface electrode 1-1 is formed on one main surface of the light emitting element 1. A back electrode 1-2 is formed on the opposite main surface. In the light emitting element 1, an active layer 1-3 which is a light emission center is formed in the vicinity of the surface electrode 1-1. In other words, the active layer 1-3 is formed inside the light emitting element 1, and the distance between the surface electrode 1-1 and the active layer 1-3 is close to several microns, whereas the active layer 1-3 is active with the back electrode 1-2. The distance from the layer 1-3 is several hundred microns.

基板２は、発光素子１を搭載している同じ面に光導波路３を設けている。光導波路３は、基板２上にクラッド層を形成した後に、クラッド層の屈折率よりも高い屈折率を有するコア層３１を形成する。そして光導波路３は、上記コア層３１を所望のパタンになるようにエッチングし、その上に再度クラッド層を形成している。 The substrate 2 is provided with an optical waveguide 3 on the same surface on which the light emitting element 1 is mounted. In the optical waveguide 3, after forming a cladding layer on the substrate 2, a core layer 31 having a refractive index higher than that of the cladding layer is formed. In the optical waveguide 3, the core layer 31 is etched so as to have a desired pattern, and a clad layer is formed thereon again.

基板２は、発光素子１を配置している面に、台座４を設けている。そして、発光素子１は、台座４上に搭載されており、発光素子１と基板２とは直接に接していない。なお図１において、台座４は発光素子１の延伸方向（活性層１−３と光導波路３のコア層３１とが結合する方向）における両端部に対応する位置に２つ設けられているが、台座４の個数はこれに限定されない。例えば、発光素子１の四隅に対応する位置に４つ設けてもよい。 The substrate 2 is provided with a pedestal 4 on the surface on which the light emitting element 1 is disposed. The light emitting element 1 is mounted on the pedestal 4, and the light emitting element 1 and the substrate 2 are not in direct contact with each other. In FIG. 1, two pedestals 4 are provided at positions corresponding to both ends in the extending direction of the light emitting element 1 (the direction in which the active layer 1-3 and the core layer 31 of the optical waveguide 3 are coupled). The number of pedestals 4 is not limited to this. For example, four light emitting elements 1 may be provided at positions corresponding to the four corners.

台座４の高さは、台座４上に発光素子１を搭載した際に、活性層１−３と光導波路３との高さ方向を一致するように形成している。つまり台座４は、基板２上における活性素子１−３と光導波路３のコア層３１との高さが一致するように形成している。 The height of the pedestal 4 is formed so that the height directions of the active layer 1-3 and the optical waveguide 3 coincide with each other when the light emitting element 1 is mounted on the pedestal 4. That is, the pedestal 4 is formed so that the active element 1-3 on the substrate 2 and the core layer 31 of the optical waveguide 3 have the same height.

発光素子１は、表面電極１−１が形成された面とは反対側に形成された裏面電極１−２において、第２接続部６を介して保持部材７と接合している。なお、発光素子１と保持部材７とを接続する第２接続部６の材質は、発光素子１の裏面側電極１−２との電気的に接続する必要があるため、例えばＡｕＳｎの半田を用いることができるが、これに限定されない。 The light emitting element 1 is joined to the holding member 7 via the second connection portion 6 in the back electrode 1-2 formed on the side opposite to the surface on which the front electrode 1-1 is formed. In addition, since the material of the 2nd connection part 6 which connects the light emitting element 1 and the holding member 7 needs to electrically connect with the back surface side electrode 1-2 of the light emitting element 1, the solder of AuSn is used, for example. However, the present invention is not limited to this.

保持部材７は、図１に示すようにコの字型の形状であり、凹部である中央部付近において発光素子１の裏面側電極１−２と接続している。そして保持部材７は、両端部において光導波路３が形成された基板２と接続している。基板２と保持部材７とは、第１接続部５を介して接続している。第１接続部５は、例えばＳｎＳｂの半田などを用いることができるが、これに限定されない。 As shown in FIG. 1, the holding member 7 has a U-shape, and is connected to the back surface side electrode 1-2 of the light emitting element 1 in the vicinity of the central portion which is a recess. The holding member 7 is connected to the substrate 2 on which the optical waveguide 3 is formed at both ends. The substrate 2 and the holding member 7 are connected via the first connection portion 5. For example, SnSb solder or the like can be used for the first connection portion 5, but is not limited thereto.

保持部材７は、基板２と接続することで発光素子１を固定するとともに、発光素子１と基板２とを電気的に接続することで、基板２から発光素子１に対して電力供給を行う。そのため保持部材７は、発光素子１の裏面電極１−２との電気的接続をする必要があり、導電性の材料を用いるか、もしくは表面を導電性の金属などでコーティングする。 The holding member 7 is connected to the substrate 2 to fix the light emitting element 1 and electrically connects the light emitting element 1 and the substrate 2 to supply power from the substrate 2 to the light emitting element 1. Therefore, it is necessary for the holding member 7 to be electrically connected to the back electrode 1-2 of the light emitting element 1, and a conductive material is used or the surface is coated with a conductive metal or the like.

また保持部材７は、金属、半導体、セラミック等の材料で構成されており高い剛性を有する。そのため保持部材７に外力などが加わったとしても、保持部材７のたわみや位置ずれの発生を防止することができる。その結果、保持部材７と接続する発光素子１の位置ずれについても防止することができるため、発光素子１と光導波路３との高い結合効率を維持することができる。 The holding member 7 is made of a material such as metal, semiconductor, or ceramic and has high rigidity. Therefore, even if an external force is applied to the holding member 7, it is possible to prevent the holding member 7 from being bent or displaced. As a result, since it is possible to prevent the positional deviation of the light emitting element 1 connected to the holding member 7, high coupling efficiency between the light emitting element 1 and the optical waveguide 3 can be maintained.

〔作用の説明〕次に、本実施形態における作用について説明を行う。 [Explanation of Action] Next, the action in this embodiment will be described.

図４は特許文献１の光結合構造１０の側面図、図５は図４のＢ−Ｂ´の断面図である。図４のように発光素子１の基板２と対向した面に形成されている表面電極１−１と基板２とが半田接合する特許文献１に記載の構造の場合、半田（図５の第１接続部５）の応力が表面電極１−１の近傍（数ミクロン程度）に形成されている活性層１−３に影響を与えてしまう。そのため、発光素子１の発振特性が変化してしまうという問題があった。 4 is a side view of the optical coupling structure 10 of Patent Document 1, and FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG. In the case of the structure described in Patent Document 1 in which the surface electrode 1-1 formed on the surface of the light emitting element 1 facing the substrate 2 and the substrate 2 are joined by soldering as shown in FIG. The stress of the connecting portion 5) affects the active layer 1-3 formed in the vicinity of the surface electrode 1-1 (about several microns). Therefore, there is a problem that the oscillation characteristics of the light emitting element 1 are changed.

そこで本実施形態では、図１および図２に示すように、発光素子１と基板２との間に半田を設けずに、裏面電極１−２と保持部材７との間に第２接続部６を設けて、発光素子１と保持部材７とを接続している。また保持部材７の両端部は、第１接続部５を介して基板２と接続している。上記構造により、発光素子１は、直接に基板２とは接続せずに、保持部材７を介して固定接続している。 Therefore, in the present embodiment, as shown in FIGS. 1 and 2, the second connection portion 6 is provided between the back electrode 1-2 and the holding member 7 without providing solder between the light emitting element 1 and the substrate 2. The light emitting element 1 and the holding member 7 are connected. Further, both end portions of the holding member 7 are connected to the substrate 2 through the first connection portion 5. With the above structure, the light emitting element 1 is fixedly connected through the holding member 7 without being directly connected to the substrate 2.

〔効果の説明〕次に、本実施形態における効果について説明を行う。 [Explanation of Effects] Next, effects of the present embodiment will be described.

本実施形態における発光素子１は、基板２上に設けられた台座４に搭載されている。なお発光素子１は、表面電極１−１が形成された面で台座４と接続している。また発光素子１は、表面電極１−１が形成された面とは反対側に形成された裏面電極１−２において、保持部材７と固定して接続している。そして、台座４の高さは、台座４上に発光素子１を搭載した際に、活性層１−３と光導波路３の高さ方向を一致するように形成されている。詳細には、台座４は基板２上における活性素子１−３と光導波路３のコア層３１との高さが一致するように形成している。 The light emitting element 1 in the present embodiment is mounted on a pedestal 4 provided on a substrate 2. The light emitting element 1 is connected to the pedestal 4 on the surface on which the surface electrode 1-1 is formed. The light emitting element 1 is fixedly connected to the holding member 7 on the back electrode 1-2 formed on the side opposite to the surface on which the front electrode 1-1 is formed. And the height of the base 4 is formed so that the height direction of the active layer 1-3 and the optical waveguide 3 may correspond when the light emitting element 1 is mounted on the base 4. Specifically, the pedestal 4 is formed so that the heights of the active element 1-3 on the substrate 2 and the core layer 31 of the optical waveguide 3 coincide.

上記の構成により、発光素子１の表面電極１−１側には基板２と接続する半田を設けていないため、表面電極１−１から数ミクロンと近くに設けられた活性層１−３に掛かる応力を抑制することができ、発光素子１の発振特性の低下を抑えることができる。 With the above configuration, since the solder for connecting to the substrate 2 is not provided on the surface electrode 1-1 side of the light emitting element 1, the light is applied to the active layer 1-3 provided near several microns from the surface electrode 1-1. Stress can be suppressed, and a decrease in oscillation characteristics of the light-emitting element 1 can be suppressed.

つまり、発光素子１は裏面電極１−２において第２接続部６を介して保持部材７と固定接続することで、裏面電極１−２と活性層１−３は数百ミクロンと離れているため、第２接続部６が活性層１−３に与える応力を抑えることができる。その結果、本実施形態の構造は、発振特性を低下しないため、活性層１−３と光導波路３との高い結合効率と良好な接合状態を維持することができる。 That is, since the light emitting element 1 is fixedly connected to the holding member 7 via the second connection portion 6 in the back electrode 1-2, the back electrode 1-2 and the active layer 1-3 are separated by several hundred microns. The stress applied to the active layer 1-3 by the second connection portion 6 can be suppressed. As a result, since the structure of this embodiment does not deteriorate the oscillation characteristics, it is possible to maintain a high coupling efficiency and a good bonding state between the active layer 1-3 and the optical waveguide 3.

〔第２の実施形態〕次に第２の実施形態について説明をする。図３は本実施形態における光結合構造１０を示す断面図である。 [Second Embodiment] Next, a second embodiment will be described. FIG. 3 is a cross-sectional view showing the optical coupling structure 10 in the present embodiment.

〔構造の説明〕本実施形態の光結合構造１０は、図３に示すように、第１の実施形態と異なる点は、保持部材７の形状がコの字型でなく、Ｌ字型である点である。それ以外の構成・接続関係は、第１の実施形態と同様である。つまり、第２の実施形態の光結合構造１０は、発光素子１と、基板２と、光導波路３と、台座４とを少なくとも備えている。 [Description of Structure] As shown in FIG. 3, the optical coupling structure 10 of the present embodiment is different from the first embodiment in that the shape of the holding member 7 is not U-shaped but L-shaped. Is a point. Other configurations and connection relationships are the same as those in the first embodiment. That is, the optical coupling structure 10 of the second embodiment includes at least the light emitting element 1, the substrate 2, the optical waveguide 3, and the pedestal 4.

本実施形態における保持部材７は、L字型の形状である。そのため、保持部材７の一方の端部は、第２接続部６を介して発光素子１の裏面電極１−２と接続している。また保持部材７の他方の端部が、第１接続部５を介して基板２と接続している。 The holding member 7 in the present embodiment has an L shape. Therefore, one end portion of the holding member 7 is connected to the back electrode 1-2 of the light emitting element 1 through the second connection portion 6. The other end of the holding member 7 is connected to the substrate 2 via the first connection portion 5.

第１の実施形態と同様に、発光素子１の裏面電極１−２と保持部材７とを接合する第２接続部６の材質は、ＡｕＳｎの半田を用いる。保持部材７と基板２とを接続する第１接続部５の材質は、例えばＳｎＳｂの半田などを用いる。 As in the first embodiment, AuSn solder is used as the material of the second connection portion 6 that joins the back electrode 1-2 of the light emitting element 1 and the holding member 7. For example, SnSb solder or the like is used as the material of the first connection portion 5 that connects the holding member 7 and the substrate 2.

保持部材７は、基板２と接続することで発光素子１を固定するとともに、発光素子１と基板２とを電気的に接続することで、基板２から発光素子１に対して電力供給を行う。そのため保持部材７は、発光素子１の裏面電極１−２との電気的接続をする必要があり、導電性の材料を用いるか、もしくは表面が導電性の金属などでコーティングする。 The holding member 7 is connected to the substrate 2 to fix the light emitting element 1 and electrically connects the light emitting element 1 and the substrate 2 to supply power from the substrate 2 to the light emitting element 1. For this reason, the holding member 7 needs to be electrically connected to the back electrode 1-2 of the light emitting element 1, and is made of a conductive material or coated with a conductive metal on the surface.

保持部材７は、金属、半導体、セラミック等の材料で構成されており高い剛性を有する。そのため保持部材７に外力などが加わったとしても、保持部材７のたわみや位置ずれが発生を防止することができる。その結果、保持部材７と接続する発光素子１の位置ずれについても防止することができるため、発光素子１と光導波路３との高い結合効率を維持することができる。 The holding member 7 is made of a material such as metal, semiconductor, or ceramic and has high rigidity. Therefore, even when an external force is applied to the holding member 7, it is possible to prevent the holding member 7 from being bent or displaced. As a result, since it is possible to prevent the positional deviation of the light emitting element 1 connected to the holding member 7, high coupling efficiency between the light emitting element 1 and the optical waveguide 3 can be maintained.

〔作用・効果の説明〕本実施形態における発光素子１は、基板２上に設けられた台座４に搭載されている。なお発光素子１は表面電極１−１が形成された面で、台座４と接続している。また保持部材７の一方の端部は裏面電極１−２と第２接続部６を介して固定して接続しており、保持部材７の他方の端部は、第１接続部５を介して基板２と固定して接続している。そして、台座４の高さは、台座４上に発光素子１を搭載した際に、活性層１−３と光導波路３の高さ方向を一致するように形成されている。詳細には、台座４は基板２上における活性素子１−３と光導波路３のコア層３１との高さが一致するように形成している。 [Explanation of Functions and Effects] The light emitting device 1 in this embodiment is mounted on a base 4 provided on a substrate 2. The light emitting element 1 is connected to the pedestal 4 on the surface on which the surface electrode 1-1 is formed. One end of the holding member 7 is fixedly connected to the back electrode 1-2 via the second connection portion 6, and the other end of the holding member 7 is connected via the first connection portion 5. The substrate 2 is fixedly connected. And the height of the base 4 is formed so that the height direction of the active layer 1-3 and the optical waveguide 3 may correspond when the light emitting element 1 is mounted on the base 4. Specifically, the pedestal 4 is formed so that the heights of the active element 1-3 on the substrate 2 and the core layer 31 of the optical waveguide 3 coincide.

上記の構成により、発光素子１の表面電極１−１側には半田が接触していないため、活性層１−３に掛かる応力を抑圧できると共に、発光素子１の発振特性の低下を抑えることができる。その結果、発振特性を低下させる応力が発生しないため、活性層１−３と光導波路３との高い結合効率と良好な接合状態を維持することができる。 With the above configuration, since the solder is not in contact with the surface electrode 1-1 side of the light emitting element 1, it is possible to suppress the stress applied to the active layer 1-3 and to suppress the deterioration of the oscillation characteristics of the light emitting element 1. it can. As a result, since no stress that lowers the oscillation characteristics is generated, a high coupling efficiency between the active layer 1-3 and the optical waveguide 3 and a good bonding state can be maintained.

本実施形態では、必ずしも保持部材７はコの字型形状で基板２と２箇所で接続していなくてもよいことを示している。つまり保持部材７は、高い剛性を有する材料である場合、本実施形態のようにL字型の形状で、基板２と１箇所で接続していてもよい。上記構成により、本実施形態におけるL字型の保持部材７は、コの字型形状に比べて、さらなる小型化・低コスト化を実現することができる。 In the present embodiment, it is indicated that the holding member 7 is not necessarily connected to the substrate 2 at two locations in a U shape. That is, when the holding member 7 is a material having high rigidity, the holding member 7 may be connected to the substrate 2 at one place in an L-shape as in this embodiment. With the above configuration, the L-shaped holding member 7 in the present embodiment can realize further downsizing and cost reduction compared to the U-shaped shape.

〔第３の実施形態〕次に第３の実施形態について説明をする。 [Third Embodiment] Next, a third embodiment will be described.

〔構造の説明〕本実施形態の光結合構造１０は、第１の実施形態と異なる点は、第２接続部６は第１接続部５より高い融点を有する材料である点である。それ以外の構成・接続関係は、第１の実施形態と同様である。つまり、第２の実施形態の光結合構造１０は、発光素子１と、基板２と、光導波路３と、台座４と、接続部５を少なくとも備えている。 [Description of Structure] The optical coupling structure 10 of the present embodiment is different from the first embodiment in that the second connecting portion 6 is a material having a higher melting point than the first connecting portion 5. Other configurations and connection relationships are the same as those in the first embodiment. That is, the optical coupling structure 10 of the second embodiment includes at least the light emitting element 1, the substrate 2, the optical waveguide 3, the pedestal 4, and the connection portion 5.

本実施形態における、発光素子１と保持部材７とを固定して接続する第２接続部６は、保持部材７と基板２とを固定して接続する第１接続部５より融点が高い。 In the present embodiment, the second connection portion 6 that fixes and connects the light emitting element 1 and the holding member 7 has a higher melting point than the first connection portion 5 that fixes and connects the holding member 7 and the substrate 2.

〔作用・効果の説明〕本実施形態における光結合構造１０は、第２接続部６を第１接続部５より融点の高い材料を用いている。例えば、第２接続部６の材料としてはＡｕＳｎを用いることができ、第１接続５としては、ＳｎＳｂを用いることができる。なお、第２接続部６の融点が、第1接続部５の融点より高い材料であれば、これに限定されない。 [Description of Functions and Effects] In the optical coupling structure 10 in this embodiment, the second connection portion 6 is made of a material having a melting point higher than that of the first connection portion 5. For example, AuSn can be used as the material of the second connection portion 6, and SnSb can be used as the first connection 5. In addition, if the melting | fusing point of the 2nd connection part 6 is a material higher than the melting | fusing point of the 1st connection part 5, it will not be limited to this.

本実施形態では発光素子１の裏面電極１−２と保持部材７とを第２接続部６で接合した後に、保持部材７と基板２とを第１接続部５で接合する。そのため、もし保持部材７と基板２とを接続する工程で用いる第１接続部５の融点が第２接続部６より高いと、上記工程において第２接続部６が再溶融してしまい、保持部材７と発光素子１とが位置ずれを生じてしまう可能性があった。 In the present embodiment, after the back electrode 1-2 of the light emitting element 1 and the holding member 7 are joined by the second connecting portion 6, the holding member 7 and the substrate 2 are joined by the first connecting portion 5. Therefore, if the melting point of the first connecting part 5 used in the process of connecting the holding member 7 and the substrate 2 is higher than that of the second connecting part 6, the second connecting part 6 is remelted in the above process, and the holding member 7 and the light emitting element 1 may be misaligned.

本実施形態の第２接続部６は、融点が第１接続部５より高いため、保持部材７と基板２とを接続する上記の工程において、発光素子１と保持部材７とを接続する第２接続部６が再度溶融し、位置ズレが発生することを抑えることができる。 Since the second connection portion 6 of this embodiment has a melting point higher than that of the first connection portion 5, the second connection portion that connects the light emitting element 1 and the holding member 7 in the above-described step of connecting the holding member 7 and the substrate 2. It can suppress that the connection part 6 fuse | melts again and position shift generate | occur | produces.

１発光素子
１−１表面電極
１−２裏面電極
１−３活性層
２基板
３光導波路
３１コア層
４台座
５第１接続部
６第２接続部
７保持部材
１０光結合構造 DESCRIPTION OF SYMBOLS 1 Light emitting element 1-1 Front surface electrode 1-2 Back surface electrode 1-3 Active layer 2 Board | substrate 3 Optical waveguide 31 Core layer 4 Base 5 1st connection part 6 2nd connection part 7 Holding member 10 Optical coupling structure

Claims

A substrate, a pedestal and an optical waveguide provided on the substrate,
A light emitting device mounted on the pedestal;
A holding member connected to the surface of the light emitting element opposite to the surface facing the substrate;
The optical coupling structure, wherein the holding member is bonded to a substrate.

The optical coupling structure according to claim 1, wherein the height of the active layer formed in the light emitting element with respect to the substrate is the same as the height of the optical waveguide with respect to the substrate.

The active layer is
The optical coupling structure according to claim 2, wherein the optical coupling structure is provided in the vicinity of a surface of the light emitting element facing the substrate.

The holding member is U-shaped,
The optical coupling structure according to claim 3, wherein the holding member is bonded to the light emitting element at a central portion and bonded to the substrate at both end portions.

The holding member is L-shaped,
The optical coupling structure according to claim 3, wherein the holding member is bonded to the light emitting element at one end and is bonded to the substrate at the other end.

The melting point of the second connection part connecting the holding member and the light emitting element is:
The optical coupling structure according to claim 4, wherein the optical coupling structure has a melting point higher than a melting point of a first connection portion that connects the holding member and the substrate.

6. The optical coupling structure according to claim 4, wherein the holding member is made of a conductive material.

6. The optical coupling structure according to claim 4, wherein a surface of the holding member is coated with a conductive material.

The optical coupling structure according to claim 4, wherein the holding member is made of a metal, a semiconductor, or a ceramic material.

The second connection part connecting the holding member and the light emitting element is AuSn solder,
10. The optical coupling structure according to claim 5, wherein the first connection portion that connects the holding member and the substrate is SnSb solder. 11.