JPH07191237A - Optical transmission / reception module - Google Patents
Optical transmission / reception moduleInfo
- Publication number
- JPH07191237A JPH07191237A JP5331791A JP33179193A JPH07191237A JP H07191237 A JPH07191237 A JP H07191237A JP 5331791 A JP5331791 A JP 5331791A JP 33179193 A JP33179193 A JP 33179193A JP H07191237 A JPH07191237 A JP H07191237A
- Authority
- JP
- Japan
- Prior art keywords
- light
- light receiving
- receiving element
- signal light
- optical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Semiconductor Lasers (AREA)
- Optical Couplings Of Light Guides (AREA)
Abstract
(57)【要約】
【目的】 光通信用受発信モジュールにおいて、ハーフ
ミラーなどの光分離機構を用いないで、ノイズの少ない
送信、受信を行うことができる小型で安価な受発信モジ
ュールを提供する。
【構成】 送信信号光を発生させる発光素子１と、該発
光素子１からの送信信号光を光伝送路に結合させるカッ
プリングレンズ３と、前記光伝送路からの受信信号光を
受信する受光素子２とからなる光通信用受発光モジュー
ルであって、前記受光素子２の表面で前記発光素子１か
らの送信信号光を反射させて前記カップリングレンズを
経て光伝送路に結合せしめると共に該受光素子２により
光伝送路からの受信信号光が受信せしめられてなるもの
である。
(57) [Summary] [Object] To provide a small and inexpensive transceiver module for optical communication that can perform transmission and reception with less noise without using an optical separation mechanism such as a half mirror. . A light emitting element 1 for generating transmission signal light, a coupling lens 3 for coupling the transmission signal light from the light emitting element 1 to an optical transmission line, and a light receiving element for receiving the reception signal light from the optical transmission line. 2. A light receiving and emitting module for optical communication, comprising: 2), wherein the transmission signal light from the light emitting element 1 is reflected on the surface of the light receiving element 2 to be coupled to an optical transmission line through the coupling lens and the light receiving element. 2, the signal light received from the optical transmission line is received.
Description
【０００１】[0001]
【産業上の利用分野】本発明は光通信用受発信モジュー
ルに関する。さらに詳しくは、光ファイバーを用いた加
入者系通信、センシングヘッドなどに好適な光通信用受
発信モジュールに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting / receiving module for optical communication. More specifically, the present invention relates to an optical communication transmitting / receiving module suitable for subscriber communication using an optical fiber, a sensing head, and the like.
【０００２】[0002]
【従来の技術】光通信用受発信モジュールの基本的構成
は図９に示されるように、送信信号光を発生する半導体
レーザなどの発光素子１と、受信信号光をハーフミラー
８を介して受光するフォトダイオード、フォトトランジ
スタ、光電池などからなる受光素子２と、送信信号光を
光ファイバなどの光伝送路（図示せず）に結合させるカ
ップリングレンズ３と、発光素子１の発光量をモニタす
るモニタ用受光素子６とからなっている。2. Description of the Related Art As shown in FIG. 9, a basic structure of an optical communication receiving / transmitting module is to receive a light emitting element 1 such as a semiconductor laser for generating a transmission signal light and a reception signal light via a half mirror 8. A light receiving element 2 including a photodiode, a phototransistor, a photocell, and the like, a coupling lens 3 that couples transmission signal light to an optical transmission path (not shown) such as an optical fiber, and the light emission amount of the light emitting element 1 is monitored. The monitor light receiving element 6 is included.
【０００３】ところで、送信信号光を発生させる発光素
子１からの発光ビームの軸線に沿って発光素子１部から
カップリングレンズ３までの距離Ｌを短くするため、た
とえば特開平５−１２９７１１号公報に示されているよ
うに、発光素子１からの光を垂直方向に反射させる半導
体レーザ装置が考えられている。その構造を図10に示
す。By the way, in order to shorten the distance L from the light emitting element 1 part to the coupling lens 3 along the axis of the light emitting beam from the light emitting element 1 for generating the transmission signal light, for example, Japanese Patent Laid-Open No. 5-129711. As shown, a semiconductor laser device that reflects light from the light emitting element 1 in the vertical direction is considered. Its structure is shown in FIG.
【０００４】図10において、71は放熱板で、炭素鋼板、
銅板、あるいはアルミニウム板などの熱伝導性のよい金
属板などの表面に金などの金属メッキを施したものから
なり、放熱板71の上面にはサブマウント73が固着され、
このサブマウント73の上面に、半導体レーザチップ74
を、当該半導体レーザチップ74における前方劈開面から
のレーザ光線が前記放熱板の上面とほぼ平行の方向に発
射するように横向きに固着されている。In FIG. 10, reference numeral 71 denotes a heat dissipation plate, which is a carbon steel plate,
It is made of a metal plate such as a copper plate or a metal plate having good heat conductivity such as an aluminum plate plated with metal such as gold.A submount 73 is fixed to the upper surface of the heat dissipation plate 71.
On the top surface of this submount 73, the semiconductor laser chip 74
Is laterally fixed so that the laser beam from the front cleavage surface of the semiconductor laser chip 74 is emitted in a direction substantially parallel to the upper surface of the heat dissipation plate.
【０００５】半導体レーザチップ74における後方劈開面
は反射膜にて完全に塞がれ、レーザ光線のすべてが前方
劈開面から発射されるようにする一方、キャップ体72の
枠本体内における反射部装着部76に、モニター用のフォ
トダイオード77を装着し、このフォトダイオード77の表
面で、前記半導体レーザチップ74における前方劈開面か
ら発射されるレーザ光線の大部分をキャップ体72に取り
付けられたガラス板７８に向かって反射させ、残りのレ
ーザ光線をフォトダイオード７７で受光することによ
り、レーザ光の反射部とモニター用受光素子とを兼用し
ている。このフォトダイオード77の出力により、半導体
レーザ装置の駆動電流を制御し、半導体レーザ装置から
出力されるレーザ光線の安定化を図っている。The rear cleaved surface of the semiconductor laser chip 74 is completely covered with a reflective film so that all of the laser beam is emitted from the front cleaved surface, while the reflective portion is mounted inside the frame body of the cap body 72. A photodiode 77 for monitoring is attached to the portion 76, and on the surface of the photodiode 77, most of the laser beam emitted from the front cleavage surface of the semiconductor laser chip 74 is attached to the cap body 72. The laser light is reflected toward 78, and the remaining laser beam is received by the photodiode 77, so that it serves as both the laser light reflecting portion and the monitor light receiving element. The output of the photodiode 77 controls the drive current of the semiconductor laser device to stabilize the laser beam output from the semiconductor laser device.
【０００６】この構成の半導体レーザ装置を用いて光通
信用受発信モジュールを構成するばあいも、図９で示し
たように、光伝送路から送られてくる受信信号光は光フ
ァイバなどの光伝送路と反射部とのあいだ（通常はカッ
プリングレンズと光伝送路とのあいだ）に配置されるハ
ーフミラーにより反射させて別途設けられた受光素子で
受光できるように構成されている。When a semiconductor laser device of this structure is used to form a receiver / transmitter module for optical communication, as shown in FIG. 9, the received signal light sent from the optical transmission line is an optical fiber or the like. It is configured so that it is reflected by a half mirror arranged between the transmission path and the reflection section (usually between the coupling lens and the optical transmission path) and can be received by a separately provided light receiving element.
【０００７】[0007]
【発明が解決しようとする課題】従来の光通信用受発信
モジュールは前述のように、受光素子部が発光素子部か
らの光路と別の光路を形成するように、光伝送路の前で
ハーフミラーなどにより分離している。そのため、部品
点数が多くなり、組立て工数の増加につながると共に、
装置が大型化するという問題がある。As described above, the conventional optical transmission / reception module for optical communication is arranged such that the light receiving element section forms a light path different from the light path from the light emitting element section in the half way in front of the optical transmission path. Separated by a mirror. Therefore, the number of parts increases, leading to an increase in the number of assembling steps, and
There is a problem that the device becomes large.
【０００８】本発明はこのような問題を解決するために
なされたものであり、発光素子からの送信信号光を反射
させる反射部が設けられると共に、光伝送路からの受信
信号光を受信する受光素子が送受信光ビームの光路に設
けられることにより、ハーフミラーなどの分離光学系を
使用しない簡単な構成の光通信用受発信モジュールを提
供することを目的とする。The present invention has been made in order to solve such a problem, and is provided with a reflecting portion for reflecting the transmission signal light from the light emitting element and for receiving the reception signal light from the optical transmission line. It is an object of the present invention to provide a light transmitting / receiving module for optical communication, which has a simple structure without using a separation optical system such as a half mirror by providing an element in the optical path of a transmission / reception light beam.
【０００９】本発明の他の目的は発光素子からの発光ビ
ームの反射部と受信信号光の受光素子とを兼用するばあ
いに、反射部で反射した受信信号光が再度発光素子およ
び反射部で反射して光伝送路に結合され、受信信号光を
発した発信部に戻ってノイズを発生するのを防止するこ
とにある。Another object of the present invention is to use the light emitting element and the reflecting portion to re-receive the receiving signal light reflected by the reflecting portion when the light emitting beam from the light emitting element is also used as the reflecting portion and the receiving signal light receiving element. It is intended to prevent the noise from being generated by returning to the transmitting portion that emitted the received signal light by being reflected and coupled to the optical transmission line.
【００１０】本発明のさらに他の目的は、発光素子から
の発光ビームの反射部と受信信号光の受光素子とを兼用
するばあいに、受信信号光が受光素子に対して斜めに入
射することに伴う、偏光依存性をできるだけ小さくする
ことにある。とくに、光ファイバを用いた加入者通信網
では、光ファイバ内で偏波面が回転するため、偏光方向
に依存しない受信特性が必要となる。Still another object of the present invention is that the reception signal light is obliquely incident on the light receiving element when the reflection part of the emission beam from the light emitting element is also used as the light receiving element of the reception signal light. The purpose is to reduce the polarization dependence as much as possible. Particularly, in the subscriber communication network using the optical fiber, the polarization plane rotates in the optical fiber, and therefore the reception characteristic that does not depend on the polarization direction is required.
【００１１】本発明のさらに他の目的は、発光素子から
の発光ビームの反射部と受信信号光の受光素子とを兼用
するばあいに、受信信号光の偏光依存性をなくすると共
に、発光素子に半導体レーザを用いたばあいに生じやす
い半導体レーザの非点隔差による非点収差をも補正する
ことにある。Still another object of the present invention is to eliminate the polarization dependency of the received signal light when the reflection part of the emitted light beam from the light emitting element is also used as the light receiving element of the received signal light, and to make the light emitting element. The purpose is to correct astigmatism due to the astigmatic difference of the semiconductor laser, which is likely to occur when the semiconductor laser is used.
【００１２】[0012]
【課題を解決するための手段】本発明の光通信用受発信
モジュールは、送信信号光を発生させる発光素子と、該
発光素子からの送信信号光を光伝送路に結合させるカッ
プリングレンズと、前記光伝送路からの受信信号光を受
信する受光素子とからなる光通信用受発信モジュールで
あって、前記受光素子の表面で前記発光素子からの送信
信号光を反射させて前記カップリングレンズを経て光伝
送路に結合せしめるものである。An optical communication receiving / transmitting module of the present invention comprises a light emitting element for generating a transmission signal light, and a coupling lens for coupling the transmission signal light from the light emitting element to an optical transmission line. A receiving / transmitting module for optical communication, comprising a light receiving element for receiving a signal light received from the optical transmission line, wherein the coupling lens is formed by reflecting the signal light transmitted from the light emitting element on the surface of the light receiving element. After that, it is coupled to the optical transmission line.
【００１３】前記受光素子は、前記発光素子の発光量を
モニタするモニタ用受光素子の機能が兼用されることが
装置の小型化の点から好ましい。It is preferable that the light receiving element also has the function of a monitor light receiving element for monitoring the amount of light emitted from the light emitting element from the viewpoint of downsizing of the device.
【００１４】前記受光素子は同一基板上に前記モニタ用
受光部と前記光伝送路からの受信信号光を受光する受光
部とが隣接して別々に設けられていることがモニタ用受
光部の受光感度と受信信号光の受信感度を調整する点か
ら好ましい。The light receiving element of the monitor light receiving unit is that the light receiving unit for monitoring and the light receiving unit for receiving the signal light received from the optical transmission line are separately provided adjacent to each other on the same substrate. It is preferable from the viewpoint of adjusting the sensitivity and the receiving sensitivity of the received signal light.
【００１５】前記発光素子の発光ビームの前記受光素子
による反射後のビームの中心軸と前記カップリングレン
ズの光軸とが、該カップリングレンズの開口数をＮＡと
してｓｉｎ-1ＮＡ以上ずれるように前記受光素子の表面
が傾斜されていることが、受信信号光の戻りによるノイ
ズを防止する点から好ましい。The central axis of the light beam emitted from the light emitting element after being reflected by the light receiving element and the optical axis of the coupling lens are deviated from each other by sin -1 NA or more, where NA is the numerical aperture of the coupling lens. It is preferable that the surface of the light receiving element is inclined in order to prevent noise due to return of the received signal light.
【００１６】前記兼用受光素子の表面で反射させるた
め、前記受光素子の少なくとも受信信号光の受信部表面
に網目状の孔が設けられた反射膜または複数の点状の反
射膜が設けられていることが送信信号光を効率よく反射
させる点から好ましい。In order to reflect the light on the surface of the dual-purpose light receiving element, at least the surface of the light receiving element for receiving the received signal light is provided with a reflective film having mesh holes or a plurality of dot-like reflective films. It is preferable that the transmitted signal light is reflected efficiently.
【００１７】さらに偏光依存性を少なくするため、前記
受光素子の少なくとも受信信号光の受光部表面に反射防
止膜が設けられ、該反射防止膜上に前記網目状の孔が設
けられた反射膜または複数の点状の反射膜が設けられる
ことが反射による偏光依存性を減らす点から好ましい。In order to further reduce the polarization dependence, an antireflection film is provided on at least the surface of the light receiving portion of the light receiving element for receiving the received signal light, and the reflection film provided with the mesh holes on the antireflection film, or It is preferable to provide a plurality of dot-shaped reflective films in order to reduce the polarization dependence due to reflection.
【００１８】前記受信信号光の受光部表面に設けられた
網目状の孔または点状の反射膜は受信信号の波長の１／
２から５倍の範囲の直径を有することが、ファイバカッ
プリング効率を高くすると共に、フォトダイオードへの
透過率を向上させる点から好ましい。The mesh-like holes or the dot-shaped reflection film provided on the surface of the light receiving portion of the received signal light is 1/1 of the wavelength of the received signal.
It is preferable to have a diameter in the range of 2 to 5 times from the viewpoint of increasing the fiber coupling efficiency and improving the transmittance to the photodiode.
【００１９】前記網目状の孔が設けられた反射膜の孔ま
たは前記複数の点状の反射膜が不規則に設けられている
ことが回折作用による光伝送路へのカップリング効率の
低下を減らす点から好ましい。Since the holes of the reflection film provided with the mesh-like holes or the plurality of dot-shaped reflection films are irregularly provided, the reduction of the coupling efficiency to the optical transmission line due to the diffraction effect is reduced. It is preferable from the point.
【００２０】前記反射防止膜が送受信光の波長λに対し
てλ／４より５〜１０％厚く形成されることが、偏光依
存性を減らす点からさらに好ましい。It is more preferable that the antireflection film is formed 5 to 10% thicker than λ / 4 with respect to the wavelength λ of transmitted and received light in order to reduce the polarization dependence.
【００２１】偏光依存性をなくする他の手段として前記
受光素子の表面と光伝送路とのあいだにカバーガラスが
設けられ、該カバーガラスの透過による受信信号光の偏
光と前記受光素子表面での透過による受信信号光の偏光
が打ち消されるように前記カバーガラスが傾けられるこ
とが好ましい。As another means for eliminating the polarization dependence, a cover glass is provided between the surface of the light receiving element and the optical transmission line, and the polarization of the received signal light due to the transmission of the cover glass and the surface of the light receiving element. The cover glass is preferably tilted so that the polarization of the received signal light due to the transmission is canceled.
【００２２】また、前記発光素子と光伝送路とのあいだ
に前記発光素子の非点隔差を打ち消すようにカバーガラ
スが傾けて設けられていることが発光素子の非点隔差に
基づく非点収差を除去するのに好ましい。Further, the cover glass is inclined between the light emitting element and the optical transmission line so as to cancel the astigmatism of the light emitting element. It is preferable to remove.
【００２３】前記受光素子の表面と光伝送路とのあいだ
にカバーガラスが設けられ、該カバーガラスの透過によ
る受信信号光の偏光と前記受光素子表面での反射による
受信信号光の偏光とが打ち消され、かつ、前記発光素子
の非点隔差と前記カバーガラスの透過による発信信号光
の偏光とが打ち消されるように前記カバーガラスが傾け
られてなることが、斜面の反射、透過による偏光と発光
素子の非点隔差に基づく非点収差を補正できて好まし
い。A cover glass is provided between the surface of the light receiving element and the optical transmission line, and the polarization of the received signal light due to the transmission of the cover glass and the polarization of the received signal light due to the reflection on the surface of the light receiving element are canceled. And that the cover glass is tilted so that the astigmatic difference of the light emitting element and the polarization of the transmitted signal light due to the transmission of the cover glass are canceled out. It is preferable since the astigmatism based on the astigmatism of can be corrected.
【００２４】さらに、前記カバーガラスの一方の表面に
送受信光の波長λに対して高屈折率の材料が（送受信光
の波長λにおける屈折率をｎとして）該波長λの１／
（４ｎ）の厚さだけコーティングされ、他方の表面に反
射防止膜がコーティングされていることが、屈折率の小
さいガラスからなるカバーガラスを使用しても大きな偏
光依存性を生じさせることができ、斜面での反射により
生じる偏光を相殺するのに好ましい。Further, a material having a high refractive index with respect to the wavelength λ of the transmitted / received light is provided on one surface of the cover glass (where the refractive index at the wavelength λ of the transmitted / received light is n).
The coating of a thickness of (4n) and the coating of the antireflection film on the other surface can cause a large polarization dependency even when a cover glass made of glass having a small refractive index is used. It is preferable to cancel the polarized light caused by the reflection on the inclined surface.
【００２５】[0025]
【作用】本発明によれば、発光素子から発した発光ビー
ムを受光素子の表面側で反射させ、該反射光をカップリ
ングレンズを介して光ファイバなどの光伝送路に結合さ
せているため、発光素子載置面と光伝送路との距離を短
くでき、小型の光通信用受発信モジュールがえられると
共に、発光ビームを効率よく光伝送路に結合することが
できる。その結果、受信信号光を受信するための別の受
光素子やハーフミラーを必要とせず、小型で簡素な構成
になる。According to the present invention, since the light emitting beam emitted from the light emitting element is reflected on the surface side of the light receiving element and the reflected light is coupled to the optical transmission path such as an optical fiber through the coupling lens, The distance between the light emitting element mounting surface and the optical transmission line can be shortened, a small-sized optical communication transmitting / receiving module can be obtained, and the emission beam can be efficiently coupled to the optical transmission line. As a result, a separate light receiving element or a half mirror for receiving the received signal light is not required, and the structure is small and simple.
【００２６】しかも、光通信においては送信と受信を時
間的に交互に行う時分割方向制御方式が用いられてお
り、前記受光素子で発光素子の発光出力をモニタし、出
力を制御するモニタ用受光素子の機能を兼用することも
でき、一層装置の小型化を達成することができる。Moreover, in the optical communication, a time division direction control system in which transmission and reception are alternately performed in time is used. The light receiving element for monitoring monitors the light emission output of the light emitting element and controls the output. The device can also serve as the element, and the device can be further downsized.
【００２７】前記受光素子のモニタ用受光部と受信用受
光部とが別々に形成されることにより、送信信号光と受
信信号光のパワーが1000倍程度異なっていても、増幅器
の増幅率を変えることなどにより信号処理をすることが
できる。By forming the monitor light receiving portion and the reception light receiving portion of the light receiving element separately, the amplification factor of the amplifier is changed even if the powers of the transmission signal light and the reception signal light are different by about 1000 times. Signal processing can be performed by such things.
【００２８】また、受光素子の表面側の反射部を反射後
の発光ビームの軸とカップリングレンズの光軸とが、カ
ップリングレンズの開口数ＮＡに対しｓｉｎ-1ＮＡ以上
傾くように傾斜させることにより、受信信号光が反射部
で反射し、発光素子でさらに反射して反射部に戻った光
は、カップリングレンズの外側へ向くため、反射光が光
伝送路に戻らず、ノイズを防止することができる。すな
わち、カップリングレンズの一番端部側を通る受信信号
光の反射部による反射、発光素子での反射および再度の
反射部での反射による光が丁度カップリングレンズの外
側を通るようになり、カップリングレンズの反対側の端
部を通る受信信号光は反射部および発光素子での反射光
が大きくそれてカップリングレンズには入射されない。
したがって受信信号光が反射により光伝送路に戻ること
がない。一方反射部の傾きを光軸に沿う角度から１／２
ｓｉｎ-1ＮＡより余り大きく傾けると発信用の発光ビー
ムとカップリングレンズとの結合が小さくなり好ましく
ないが、発光ビームのビーム角にも依存し、通常発光ビ
ームの40％程度を採り込めればよい。Further, the reflecting portion on the surface side of the light receiving element is tilted so that the axis of the emitted light beam after reflection and the optical axis of the coupling lens are inclined by sin -1 NA or more with respect to the numerical aperture NA of the coupling lens. As a result, the received signal light is reflected by the reflection part, further reflected by the light emitting element and returned to the reflection part, and is directed to the outside of the coupling lens, so that the reflected light does not return to the optical transmission path and noise is prevented. can do. That is, the light reflected by the reflection part of the received signal light passing through the endmost side of the coupling lens, the light reflected by the light emitting element, and the light reflected by the reflection part again comes to pass just outside the coupling lens. The received signal light passing through the opposite end of the coupling lens is not incident on the coupling lens because the reflected light from the reflecting portion and the light emitting element is large.
Therefore, the received signal light does not return to the optical transmission line due to reflection. On the other hand, make the inclination of the reflection part 1/2 from the angle along the optical axis.
If it is tilted much more than sin -1 NA, the coupling between the emission beam for transmission and the coupling lens becomes small, which is not preferable, but it depends on the beam angle of the emission beam and if about 40% of the normal emission beam can be taken in. Good.
【００２９】また、受光素子の表面に反射防止膜が設け
られ、さらにその上に網状に反射膜または複数の点状の
反射膜が設けられることにより、受信信号光が反射膜上
ではほぼ100 ％近くが反射し、反射膜がない部分では10
0 ％近くが透過する。その結果斜面に受信信号光が斜め
に入射しても、Ｓ偏光とＰ偏光の反射率や透過率の差が
小さく、斜面への入射による偏光の影響を殆ど受けな
い。Further, an antireflection film is provided on the surface of the light receiving element, and a reflection film or a plurality of dot-like reflection films is provided on the antireflection film, so that the received signal light is almost 100% on the reflection film. 10 near the area where there is no reflection film
Nearly 0% is transparent. As a result, even if the received signal light is obliquely incident on the slope, the difference between the reflectance and the transmittance of the S-polarized light and the P-polarized light is small, and there is almost no influence of the polarization on the slope.
【００３０】さらに、前記反射膜が不規則に設けられる
ことにより、回折による送信信号光のスポットの分裂を
防ぐことができ、光伝送路へのカップリング効率を向上
させることができる。Further, since the reflecting film is irregularly provided, it is possible to prevent the spot of the transmitted signal light from being split by diffraction and improve the coupling efficiency to the optical transmission line.
【００３１】さらに、受光素子表面に反射防止膜などを
設けなくても、その表面側に設けられるカバーガラスの
角度を調整することにより、カバーガラスに斜めに受信
信号光が入射し、Ｓ偏光とＰ偏光のあいだで透過率が異
なって偏光依存性を生じる。このカバーガラスによるＳ
偏光とＰ偏光のあいだの透過率の変化が、受光素子表面
への斜め入射に伴なうＳ偏光とＰ偏光の透過率の変化を
相殺する向きに傾けることにより、受光素子への受信信
号光の斜め入射に伴う偏光依存性を防止することができ
る。Further, even if an antireflection film or the like is not provided on the surface of the light receiving element, by adjusting the angle of the cover glass provided on the surface side, the received signal light is obliquely incident on the cover glass and the S-polarized light is generated. The transmittance is different between the P-polarized light and polarization dependency is generated. S by this cover glass
By tilting the change in the transmittance between the polarized light and the P-polarized light so as to cancel the change in the transmittance of the S-polarized light and the P-polarized light due to the oblique incidence on the surface of the light receiving element, the signal light received by the light receiving element is received. It is possible to prevent the polarization dependence due to the oblique incidence of light.
【００３２】さらに、カバーガラスの傾きは、傾ける方
向をｘｙ平面内で変えることにより、発光素子として使
用する半導体レーザの非点隔差から生じる非点収差を補
正することもできる。Further, as for the inclination of the cover glass, the astigmatism caused by the astigmatic difference of the semiconductor laser used as the light emitting element can be corrected by changing the inclination direction within the xy plane.
【００３３】前記カバーガラスの一面に送受信信号光の
波長λに対して高屈折率の材料を該波長λにおける屈折
率をｎとして１／（４ｎ）の厚さだけコーティングする
ことにより、低い屈折率のカバーガラスであっても大き
な偏光依存性をもたせることができ、その偏光依存性を
受光素子表面の偏光依存性と相殺させることができる。By coating one surface of the cover glass with a material having a high refractive index with respect to the wavelength λ of transmitted / received signal light by a thickness of 1 / (4n) where n is the refractive index at the wavelength λ, a low refractive index is obtained. Even the cover glass of 1 can have a large polarization dependence, and the polarization dependence can be offset with the polarization dependence of the surface of the light receiving element.
【００３４】[0034]
【実施例】つぎに図面を参照しながら本発明について詳
細に説明する。図１は本発明の光通信用受発信モジュー
ルの一実施例を示す概略説明図、図２は受信信号光の反
射光の光路を説明する図、図３は受光素子の一例の平面
図、図４はその断面説明図、図５は受光素子とがカップ
リングレンズのあいだに設けられたカバーガラスの傾き
を説明する図である。The present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing an embodiment of an optical communication receiving / transmitting module of the present invention, FIG. 2 is a view explaining an optical path of reflected light of received signal light, and FIG. 3 is a plan view of an example of a light receiving element. 4 is a cross-sectional explanatory view thereof, and FIG. 5 is a view for explaining an inclination of a cover glass provided between the light receiving element and the coupling lens.
【００３５】図１において、１はたとえばサブマウント
14に固定された半導体レーザチップなどからなる発光素
子で、２はフォトダイオード、フォトトランジスタなど
からなる受光素子、３は発光ビームを収束して光ファイ
バなどの光伝送路に送信信号光を結合させるカップリン
グレンズである。受光素子２の表面側では発光素子１か
ら発した発光ビームを反射させて上方に反射させるよう
にし、カップリングレンズ３により集光された送信信号
光を光ファイバなどの光伝送路（図示せず）に結合させ
ている。また光伝送路を伝わってきた受信信号光はカッ
プリグレンズ３を介して受光素子２により受信され、電
気信号に変換された光信号を電気的に処理したり、さら
に音声などに変換して光通信として利用されている。In FIG. 1, reference numeral 1 denotes a submount, for example.
A light emitting element composed of a semiconductor laser chip or the like fixed to 14, 2 is a light receiving element composed of a photodiode, a phototransistor, etc., 3 is a light emitting element for converging an emission beam and coupling a transmission signal light to an optical transmission path such as an optical fiber. It is a coupling lens. On the surface side of the light receiving element 2, the emission beam emitted from the light emitting element 1 is reflected and reflected upward, and the transmission signal light condensed by the coupling lens 3 is transmitted through an optical transmission line (not shown) such as an optical fiber. ). Further, the received signal light transmitted through the optical transmission path is received by the light receiving element 2 via the coupling lens 3, and the optical signal converted into an electric signal is electrically processed, or further converted into a sound or the like to be converted into an optical signal. It is used for communication.
【００３６】本発明の光通信用受発信モジュールは、受
信信号光を受信する受光素子２を送信信号光および受信
信号光の光路におき、その表面側に送信信号光を反射さ
せる反射部21が設けられているところに特徴がある。そ
の結果、発光ビームの方向に沿っての発光素子１部とカ
ップリングレンズ３との距離を短くでき、小型化が達成
されると共に、ハーフミラーなどの他の光学素子を使用
しない簡単な構成としたものである。図１を参照しなが
ら具体的な実施例でさらに詳細に説明する。In the optical communication receiving / transmitting module of the present invention, the light receiving element 2 for receiving the received signal light is placed in the optical paths of the transmitted signal light and the received signal light, and the reflecting portion 21 for reflecting the transmitted signal light is provided on the surface side thereof. The feature is that it is provided. As a result, the distance between the light emitting element 1 part and the coupling lens 3 along the direction of the emission beam can be shortened, downsizing can be achieved, and a simple configuration without using other optical elements such as a half mirror can be achieved. It was done. A specific embodiment will be described in more detail with reference to FIG.
【００３７】発光素子１として半導体レーザチップを用
い、本実施例では半導体レーザチップの後方劈開面11は
反射膜12で塞がれている。このためレーザ光線はすべて
前方剪開面13から発射されることになる。このレーザ光
線は製造プロセスにもよるが、その発光ビームの中心軸
Ａを中心に周囲20〜45゜の角度（図１のβ）、通常は30
゜程度の角度で放射される。このレーザ光線は送信信号
でパルス変調され断続的なパルスとして発射されたり、
またアナログ変調され発光強度が変化する光線として発
射されたりするが、光通信用では通常パルス変調させて
使用される。A semiconductor laser chip is used as the light emitting element 1. In this embodiment, the rear cleavage surface 11 of the semiconductor laser chip is covered with a reflection film 12. Therefore, all the laser beams are emitted from the front cleaved surface 13. Depending on the manufacturing process, this laser beam has an angle of 20 to 45 ° around the central axis A of the emission beam (β in FIG. 1), usually 30.
It is emitted at an angle of about °. This laser beam is pulse modulated by the transmitted signal and emitted as intermittent pulses,
Further, although it is emitted as a light beam which is analog-modulated and whose emission intensity changes, it is usually pulse-modulated for use in optical communication.
【００３８】本実施例では発光ビームがパルス変調さ
れ、送信と受信を時分割することにより、発光ビームの
強さをモニタするモニタ用受光素子と受信信号光の受信
用受光素子とを兼用している。そのため、レーザ光線は
受光素子２の表面21で反射されてカップリングレンズ３
の方向に進行すると共に、一部は受光素子２の内部へ透
過する。In the present embodiment, the emission beam is pulse-modulated, and transmission and reception are time-divided, so that the light-receiving element for monitoring monitors the intensity of the emission beam and the light-receiving element for receiving the received signal light. There is. Therefore, the laser beam is reflected by the surface 21 of the light receiving element 2 and the coupling lens 3
While advancing in the direction of, a part of the light penetrates into the light receiving element 2.
【００３９】本実施例では発光ビームの中心軸Ａとカッ
プリングレンズ３の光軸とがほぼ垂直方向になるよう
に、配置されているが、受光素子の反射面21を発光ビー
ムの反射後のビーム軸（中心軸）Ｃに対してカップリン
グレンズ３の光軸Ｂが重ならないようにしている。すな
わち、カップリングレンズ３の開口数をＮＡとして反射
後の発光ビームの軸Ｃとカップリングレンズの光軸Ｂと
のなす角がｓｉｎ-1ＮＡ以上の角度をなすように、反射
面21の傾斜角度が設定されている。すなわち、反射面21
の発光ビームの中心軸Ａに対する角度βは45゜−１／２
ｓｉｎ-1ＮＡ以下になるように傾ける。その理由は後述
するように、受信信号光が反射面21およびさらに発光素
子１の正面劈開面13で反射して再度光伝送路に戻りノイ
ズが発生するのを防止するためである。In this embodiment, the central axis A of the emitted light beam and the optical axis of the coupling lens 3 are arranged so as to be substantially perpendicular to each other. The optical axis B of the coupling lens 3 does not overlap the beam axis (center axis) C. That is, with the numerical aperture of the coupling lens 3 being NA, the inclination of the reflecting surface 21 is such that the angle between the axis C of the emitted light beam after reflection and the optical axis B of the coupling lens is at least sin −1 NA. The angle is set. That is, the reflective surface 21
The angle β of the emission beam with respect to the central axis A is 45 ° -1 / 2
Tilt it to be less than sin -1 NA. The reason is to prevent the received signal light from being reflected by the reflection surface 21 and further the front cleavage surface 13 of the light emitting element 1 and returning to the optical transmission line again to generate noise, as will be described later.
【００４０】たとえばカップリングレンズ３の開口数Ｎ
Ａが0.25のレンズを採用すると１／２ｓｉｎ-10.25＝7.
25゜となり、反射面21の水平面に対する傾斜角度θを45
゜−7.3 ゜＝37.7゜程度になるように設定されている。
その結果、発光ビームの中心軸の光線Ｃは丁度カップリ
ングレンズ３の一端部31を透過し、ビーム角29゜の光線
がカップリングレンズ３の他端部32を透過し、ビームの
中心軸から下側のこの範囲の光ビームがカップリングレ
ンズ３を介して光伝送路に結合される。そのため、発光
ビームの中心軸Ａより上部に発射された光線および29゜
のビーム角より下側に放射された光はカップリングレン
ズ３に入射されず、送信信号光として寄与しないことに
なるが、実際には発光素子のパワーの１／６〜１／10程
度を光ファイバに結合できれば支障はなく、送信信号光
としては発光ビームの１／３〜１／５程度をカップリン
グレンズ３にとり入れられればよい。For example, the numerical aperture N of the coupling lens 3
If you use a lens with A of 0.25, 1/2 sin -1 0.25 = 7.
25 °, and the inclination angle θ of the reflecting surface 21 with respect to the horizontal plane is 45
It is set so that ゜ -7.3 ゜ = 37.7 ゜.
As a result, the light ray C on the central axis of the emission beam is exactly transmitted through one end 31 of the coupling lens 3, and the light ray having a beam angle of 29 ° is transmitted through the other end 32 of the coupling lens 3 from the central axis of the beam. The light beam in this lower range is coupled into the optical transmission line via the coupling lens 3. Therefore, the light rays emitted above the central axis A of the emission beam and the light emitted below the beam angle of 29 ° are not incident on the coupling lens 3 and do not contribute as transmission signal light. Actually, there is no problem if about 1/6 to 1/10 of the power of the light emitting element can be coupled to the optical fiber, and about 1/3 to 1/5 of the emitted light beam is transmitted to the coupling lens 3 as the transmission signal light. Good.
【００４１】受光素子２の反射面とする表面は、たとえ
ば図３に示すようにＡｕまたはＡｌなどの金属膜などか
らなる反射膜22の部分と、反射防止膜23が露出した部分
とに分けられ、反射膜の割合は適宜調整できるが通常は
50％程度の割合が反射部分とされる。このように反射率
の高い反射膜22と反射が殆ど生じない反射防止膜に分離
する理由はあとで詳述するが、受信信号光が受光素子２
に斜め入射しても偏光依存が生じないようにするためで
ある。受光素子２の表面がこのように処理されているた
め、発光素子１の発光ビームは反射膜22部に当った部分
が反射して前述のように発光ビームの１／４程度の光が
カップリングレンズ３に結合し、光伝送路に進む。一
方、発光素子１から反射防止膜23に入射された光は受光
素子内部に進み電流に変換されて発光素子１の発光の強
さをモニタすることができ、駆動電流の調整などにより
発光出力を一定に制御することができる。The reflection surface of the light receiving element 2 is divided into a reflection film 22 made of a metal film such as Au or Al and an exposed antireflection film 23 as shown in FIG. , The ratio of the reflective film can be adjusted appropriately, but usually
About 50% of the light is reflected. The reason why the reflective film 22 having a high reflectance and the antireflection film that hardly causes reflection are separated will be described later in detail.
This is to prevent polarization dependence from occurring even when the light is obliquely incident on. Since the surface of the light receiving element 2 is treated in this way, the light emitting beam of the light emitting element 1 is reflected at the portion hitting the reflection film 22 and as described above, about 1/4 of the light emitting beam is coupled. It is connected to the lens 3 and proceeds to the optical transmission line. On the other hand, the light incident on the antireflection film 23 from the light emitting element 1 travels inside the light receiving element and is converted into a current so that the intensity of light emission of the light emitting element 1 can be monitored. It can be controlled to be constant.
【００４２】一方、光伝送路からの受信信号光はカップ
リングレンズ３により集光される。受信信号光の中心軸
とカップリングレンズ３の光軸とは一致させてあるの
で、受信信号光はカップリングレンズ３の焦点に集光さ
れる。カップリングレンズ３により集光された受信信号
光は受光素子２により受信されるが、受光素子２の表面
は前述のように、表面積の半分程度が反射膜22になって
いるため、受信信号光の半分程度は発光素子１の方に反
射し、発光素子１の発光面で再度反射して受光素子表面
に戻る。しかし受光素子１の表面の斜面は前述のよう
に、発光ビームの反射後のビームの中心軸Ｃとカップリ
ングレンズ３の光軸Ｂとがｓｉｎ-1ＮＡだけずれるよう
に傾けられているため、発光素子１により反射した受信
信号が再度受光素子２の表面で反射すると図２に示すよ
うに、すべての反射光がカップリングレンズ３の外側に
反射し、光伝送路に戻ることがない。また、受光素子２
の内部へ透過した受信信号光は受光素子２で電気信号に
変換され、信号処理されて出力される。On the other hand, the received signal light from the optical transmission line is condensed by the coupling lens 3. Since the central axis of the received signal light and the optical axis of the coupling lens 3 are aligned with each other, the received signal light is condensed at the focal point of the coupling lens 3. The received signal light collected by the coupling lens 3 is received by the light receiving element 2. However, since the surface of the light receiving element 2 has the reflective film 22 in about half of the surface area as described above, the received signal light is received. About half of the light is reflected toward the light emitting element 1, and is reflected again on the light emitting surface of the light emitting element 1 to return to the surface of the light receiving element. However, as described above, the slope of the surface of the light receiving element 1 is tilted so that the center axis C of the beam after the emission beam is reflected and the optical axis B of the coupling lens 3 are displaced by sin −1 NA. When the received signal reflected by the light emitting element 1 is reflected again on the surface of the light receiving element 2, all the reflected light is reflected to the outside of the coupling lens 3 and does not return to the optical transmission path, as shown in FIG. In addition, the light receiving element 2
The received signal light that has been transmitted into the inside of the is converted into an electric signal by the light receiving element 2, is subjected to signal processing, and is output.
【００４３】ところで受信信号光は受光素子２の表面に
斜め入射により受光される。たとえば半導体レーザチッ
プから発せられる光は常に図１の紙面に垂直な電気ベク
トルをもつ直線偏光のみであるため、斜面で反射しても
反射率は一定であるが、受信信号光は光ファイバなどの
光伝送路内を伝播する際に偏波面が回転しているため、
受信光学系に偏光依存性が生じると偏波面の回転により
受信信号が変動する。そのため、正確な受信をするため
には、偏光依存性が生じないようにする必要がある。そ
こで、本発明の実施例では図４に受光素子２の断面説明
図を示すように、受光素子２の表面にはチッ化ケイ素な
どからなる反射防止膜23が設けられ、その表面に網目状
の開口部25がもうけられた反射膜22が設けられ、反射膜
22は送信信号光を反射すると共に受光素子２であるフォ
トダイオードのｐ電極24と連結されている。すなわち、
フォトダイオードはたとえばｎ型ＩｎＰ基板26上にｎ型
ＩｎＰバッファ層27が設けられ、その上に厚さが３μｍ
程度のｎ- 型ＩｎＧａＡｓ層28、厚さが0.7 μｍ程度の
ｎ- 型Ｉｎ1-x Ｇａx Ａｓy Ｐ1-y （０≦ｘ≦0.25、０
≦ｙ≦0.55）ウィンドウ層29からなり、ｐ+ 型拡散層41
が設けられ、ｐｎ接合42が形成されている。また基板26
の裏面側にはｎ電極43が形成されている。The received signal light is received by the surface of the light receiving element 2 by oblique incidence. For example, since the light emitted from the semiconductor laser chip is always only linearly polarized light having an electric vector perpendicular to the paper surface of FIG. 1, the reflectance is constant even if reflected on an inclined surface, but the received signal light is transmitted by an optical fiber or the like. Since the plane of polarization is rotating when propagating in the optical transmission line,
When polarization dependency occurs in the receiving optical system, the received signal fluctuates due to rotation of the plane of polarization. Therefore, in order to perform accurate reception, it is necessary to prevent polarization dependence from occurring. Therefore, in the embodiment of the present invention, as shown in the sectional view of the light receiving element 2 in FIG. 4, an antireflection film 23 made of silicon nitride or the like is provided on the surface of the light receiving element 2, and the surface of the light receiving element 2 has a mesh shape. A reflective film 22 having an opening 25 is provided,
Reference numeral 22 reflects the transmitted signal light and is connected to the p electrode 24 of the photodiode, which is the light receiving element 2. That is,
The photodiode has, for example, an n-type InP buffer layer 27 provided on an n-type InP substrate 26 and has a thickness of 3 μm on the n-type InP buffer layer 27.
N − -type InGaAs layer 28 having a thickness of about 0.7 μm and n − -type In 1-x Ga x As y P 1-y (0 ≦ x ≦ 0.25, 0
≦ y ≦ 0.55) consisting of window layer 29 and p + type diffusion layer 41
Is provided and a pn junction 42 is formed. Also the substrate 26
An n electrode 43 is formed on the back surface side of the.
【００４４】受光素子２の構成はこの例に限らず、他の
材料からなるフォトダイオードでもよく、またｎ型とｐ
型は逆でもよく、さらにはフォトトランジスタなどでも
よい。本発明の受光素子はその表面に反射防止膜23が設
けられ、その表面にさらに網目状の開口部（パターン）
25が設けられた反射膜22が設けられていることにある。
反射膜22は、反射防止膜23上に蒸着やスパッタリングな
どにより設けられ、パターニングにより開口部25が設け
られてもよいし、網目状のパターンが設けられた反射膜
22を反射防止膜23の表面に重ねる形状で設けられてもよ
い。また、反射膜が点状に設けられる構造でもよい。反
射膜22としては、反射率の高いＡｕ（98％）やＡｌ（92
％）などの金属が好ましく、反射防止膜23は殆ど反射が
生じないように１／４波長の厚さの誘導体膜や屈折率の
異なる２層の誘電体の積層体などからなることが望まし
い。すなわち、反射防止膜を完全な反射膜とすることに
より、斜め入射に対しても偏光の影響を殆ど防止できる
ものである。The configuration of the light-receiving element 2 is not limited to this example, and a photodiode made of another material may be used, and the n-type and the p-type may be used.
The molds may be reversed, and a phototransistor or the like may be used. An antireflection film 23 is provided on the surface of the light receiving element of the present invention, and a mesh-shaped opening (pattern) is further formed on the surface.
The reflection film 22 provided with 25 is provided.
The reflection film 22 is provided on the antireflection film 23 by vapor deposition, sputtering, or the like, and the opening 25 may be provided by patterning, or the reflection film provided with a mesh pattern.
22 may be provided in a shape that overlaps the surface of the antireflection film 23. Alternatively, the reflective film may be provided in a dot shape. As the reflection film 22, Au (98%) or Al (92%) having high reflectance is used.
%), And the antireflection film 23 is preferably made of a dielectric film having a thickness of 1/4 wavelength or a laminated body of two dielectric layers having different refractive indexes so that almost no reflection occurs. That is, when the antireflection film is a perfect reflection film, the influence of polarized light can be almost prevented even when obliquely incident.
【００４５】絶縁膜11の光学的厚さｎｄ＝327.5 ｎｍ
（ｎは屈折率、ｄは機械的厚さ）にすると、この光学的
厚さは1310ｎｍの波長のレーザ光線に対して１／４波長
に相当する。したがって、入射角30゜に対するフォトダ
イオード表面での反射率および透過率は波長1310ｎｍの
レーザ光線に対して Ｓ偏光 反射率＝1.6 ％ 透過率（Ｔｓ）＝9
8.4％ Ｐ偏光 反射率＝0.2 ％ 透過率（Ｔｐ）＝9
9.8％ となる。Optical thickness of insulating film 11 nd = 327.5 nm
If (n is a refractive index and d is a mechanical thickness), this optical thickness corresponds to a quarter wavelength for a laser beam having a wavelength of 1310 nm. Therefore, the reflectance and transmittance at the photodiode surface for an incident angle of 30 ° are as follows: S-polarized reflectance = 1.6% Transmittance (Ts) = 9 for a laser beam with a wavelength of 1310 nm.
8.4% P-polarized reflectance = 0.2% Transmittance (Tp) = 9
It will be 9.8%.
【００４６】無偏光度は２×Ｔｐ／（Ｔｓ＋Ｔｐ）で計
算できるので、この実施例の無偏光度は２×Ｔｐ／（Ｔ
ｓ＋Ｔｐ）＝２×0.998 ／（0.984 ＋0.997 ）＝1.0076
すなわち0.03dBとなる。Since the degree of non-polarization can be calculated by 2 × Tp / (Ts + Tp), the degree of non-polarization of this embodiment is 2 × Tp / (T
s + Tp) = 2 × 0.998 / (0.984 + 0.997) = 1.0076
That is 0.03 dB.
【００４７】一方、反射防止膜が設けられていないばあ
いは、上記と同様に入射角30゜に対するフォトダイオー
ド表面での反射率および透過率は波長1310ｎｍのレーザ
光線に対して Ｓ偏光 反射率＝31％ 透過率（Ｔｓ）＝69％ Ｐ偏光 反射率＝21％ 透過率（Ｔｐ）＝79％ となる。On the other hand, when the antireflection film is not provided, the reflectance and the transmittance on the surface of the photodiode with respect to the incident angle of 30 ° are S-polarized reflectance = 13 31% transmittance (Ts) = 69% P polarized light reflectance = 21% Transmittance (Tp) = 79%.
【００４８】無偏光度は、２×Ｔｐ／（Ｔｓ＋Ｔｐ）＝
２×0.79／（0.69＋0.79）＝1.07すなわち0.3dB とな
る。したがって、反射防止膜を設けたばあいの受信信号
光の無偏光度は反射防止膜を設けないばあいに対して11
％となり、充分低い値となる。The degree of non-polarization is 2 × Tp / (Ts + Tp) =
2 × 0.79 / (0.69 + 0.79) = 1.07, or 0.3 dB. Therefore, the non-polarization degree of the received signal light when the antireflection film is provided is 11 times that when the antireflection film is not provided.
%, Which is a sufficiently low value.
【００４９】なお、本発明者らが鋭意検討を重ねた結
果、光の入射方向に対し斜めに傾いたフォトダイオード
では、入射光は反射防止膜中を斜めに進み、さらに透明
なウィンドウ層29の影響もあり、反射防止膜の光学的厚
さはレーザ光線の波長λの１／４ではなく、その波長λ
の１／４の厚さの５〜10％増程度の厚さが最も偏光度が
小さくなることを見出した。As a result of earnest studies by the present inventors, in a photodiode that is obliquely inclined with respect to the incident direction of light, the incident light travels obliquely through the antireflection film and the transparent window layer 29 Due to the influence, the optical thickness of the antireflection film is not ¼ of the wavelength λ of the laser beam, but the wavelength λ.
It was found that the degree of polarization becomes the smallest when the thickness is increased by 5 to 10% of the thickness of 1/4.
【００５０】すなわち、１／４波長の厚さの反射防止膜
を設けたときの反射率は1.4 ％であるのに対し、1.04倍
の厚さにしたときの反射率は1.1 ％、1.08倍の厚さにし
たときの反射率は1.0 ％、1.12倍の厚さにしたときの反
射率は1.3 ％で８％増の厚さで設けたときが一番反射率
が低くなり、その前後の５〜10％程度厚くする方が好ま
しいことを見出した。That is, the reflectance when the antireflection film having a thickness of ¼ wavelength is 1.4%, while the reflectance when the thickness is 1.04 times is 1.1% and 1.08 times. The reflectance when the thickness is 1.0%, the reflectance when 1.12 times thicker is 1.3%, and the reflectance is the lowest when the thickness is increased by 8%. It has been found that it is preferable to increase the thickness to about 10%.
【００５１】一方、受光素子２の受光面21の表面に網目
状の開口部25を有する反射膜22は網目状開口部の有孔率
を変化させることによって、受光素子２の表面の反射率
をあらかじめ任意に設定することができる。金属膜22と
してたとえばＡｕを用い、有孔率が50％の網目状パター
ンの反射率Ｒは、60゜の入射角に対するレーザビームの
Ａｕによる反射率が98％、反射防止膜付きの受光素子２
の表面でのＳ偏光に対する反射率が12％なので、反射率
ＲはＲ＝（98＋12）／２＝55％となり、充分高い反射率
となる。On the other hand, the reflection film 22 having the mesh-shaped openings 25 on the surface of the light-receiving surface 21 of the light-receiving element 2 changes the porosity of the mesh-shaped openings to change the reflectance of the surface of the light-receiving element 2. It can be arbitrarily set in advance. For example, Au is used as the metal film 22, and the reflectance R of the mesh pattern having a porosity of 50% is 98% with respect to the incident angle of 60 ° by the Au of the laser beam, and the light receiving element 2 with the antireflection film is provided.
Since the reflectance for S-polarized light on the surface of is 12%, the reflectance R is R = (98 + 12) / 2 = 55%, which is a sufficiently high reflectance.
【００５２】図５に受光素子２の他の実施例の説明図を
示す。本実施例では受信信号光の受光部44と送信信号光
の強さをモニタするモニタ受光部45とを同一基板上では
あるが別々に形成することにより、受信信号光とモニタ
光の受光を兼用すると共に、送信信号光の光の強さと受
信信号光の強さの差に基づく受光感度の違いをキャンセ
ルできるようにしたものである。FIG. 5 shows an explanatory view of another embodiment of the light receiving element 2. In this embodiment, the light receiving section 44 for the received signal light and the monitor light receiving section 45 for monitoring the intensity of the transmitted signal light are formed on the same substrate, but separately, so that the received signal light and the monitor light can both be received. In addition, it is possible to cancel the difference in the light receiving sensitivity based on the difference between the intensity of the transmitted signal light and the intensity of the received signal light.
【００５３】受信信号光の受光部44の表面はカップリン
グレンズ３の開口絞り内にあるため、発光素子１からの
発光ビームを反射させてカップリングレンズ３と結合さ
せる必要があり、前述のようにＳｉＮｘなどからなる反
射防止膜46と開口部が設けられたＡｕやＡｌなどからな
る反射膜47が設けられ、送信信号光の半分程度はカップ
リングレンズ３の方向に反射されると共に、受信信号光
については偏光依存性がなくなるように構成されてい
る。一方モニタ用受光部45は発光素子１からの発光ビー
ムの反射光が、カップリングレンズ３の開口絞りの外側
になる部分に設けられているため、とくに反射膜が設け
られる必要はなく、また受信信号光も入射しないため、
偏光に関係がなく無反射防止膜も必要ではないが、図５
には無反射防止膜46が設けられた例が示されている。ま
た各々のｐ側電極48、49は別々に形成されている。Since the surface of the light receiving portion 44 for receiving the received signal light is inside the aperture stop of the coupling lens 3, it is necessary to reflect the emitted light beam from the light emitting element 1 and combine it with the coupling lens 3, as described above. Is provided with an antireflection film 46 made of SiNx or the like and a reflection film 47 made of Au or Al having an opening, and about half of the transmitted signal light is reflected toward the coupling lens 3 and the received signal is received. The light is configured to have no polarization dependence. On the other hand, since the monitor light-receiving unit 45 is provided in a portion where the reflected light of the light-emission beam from the light-emitting element 1 is located outside the aperture stop of the coupling lens 3, it is not necessary to provide a reflective film and the reception is not required. Since no signal light is incident,
It is not related to the polarized light, and an antireflection film is not necessary.
Shows an example in which an antireflection film 46 is provided. Further, each p-side electrode 48, 49 is formed separately.
【００５４】このような構成にすることにより、発光素
子１からの送信信号光のパワーはｍＷ台と強いのに対
し、光伝送路から受信する受信信号光はμＷ台と非常に
弱い光量で1000倍程度の差があるが、別々に設けられる
増幅器の増幅率を変えることにより、モニタ光と受信信
号光を同様に信号処理することができる。With such a configuration, the power of the transmission signal light from the light emitting element 1 is as high as mW, while the reception signal light received from the optical transmission line is in the μW range, which is a very weak light quantity of 1000. Although there is a difference of about double, the monitor light and the received signal light can be similarly processed by changing the amplification factors of the amplifiers provided separately.
【００５５】さらに図５に示した反射膜47の開口部は図
３に示したような規則的には形成されていないで、その
間隔を不規則に形成された例を示している。開口部を不
規則に形成することにより、回折作用の影響をなくして
光伝送路へのカップリング効率の向上を図ったものであ
る。Furthermore, the openings of the reflection film 47 shown in FIG. 5 are not formed regularly as shown in FIG. 3, but the intervals are irregularly formed. By irregularly forming the openings, the effect of the diffraction effect is eliminated and the coupling efficiency to the optical transmission line is improved.
【００５６】すなわち、開口部のパターンが周期的に形
成されていると回折作用が働き、送信信号光の光伝送路
でのスポットが多くの点に分裂する。たとえば20μｍの
幅の縞がピッチ40μｍで設けられたパターンのばあいに
は図６（ａ）に示すように、光伝送路でのスポットが39
μｍづつ離れた３個のスポットに分裂し、ファイバなど
の光伝送路にカップリングするのはこの３個のスポット
のうち、真中のスポットのみとなる。その結果、レンズ
入射光を100 ％としたばあい、光伝送路へカップリング
する効率は24％に下がる。また、縞の幅を細くしたばあ
いは３個のスポットの間隔が広がり中心のスポット光が
強くなるが、それでも光伝送路へのカップリング効率は
30％である。なお、図６において80％、50％、‥‥‥は
ピークの光の強度を100 としたときの光強度を示す。That is, when the pattern of the openings is formed periodically, the diffracting action works and the spot of the transmission signal light on the optical transmission line is split into many points. For example, in the case of a pattern in which stripes with a width of 20 μm are provided with a pitch of 40 μm, as shown in FIG. 6 (a), there are 39 spots on the optical transmission line.
Of these three spots, only the middle spot is split into three spots separated by μm and coupled to an optical transmission line such as a fiber. As a result, if the light incident on the lens is 100%, the efficiency of coupling to the optical transmission line drops to 24%. In addition, if the width of the stripe is made narrower, the distance between the three spots will increase and the central spot light will become stronger, but the coupling efficiency to the optical transmission line will still be high.
30%. In FIG. 6, 80%, 50%, ... Show the light intensity when the peak light intensity is 100.
【００５７】一方図５に示したような反射膜47に不規則
な開口部のパターンを施したものはたとえば、反射膜の
開口部の口径が３μｍで5000個（0.24mm×0.3mm の受光
面）のパターンの例を図６（ｂ）に示すように、スポッ
トの分裂を防ぐことができ、単一で強度が大きいスポッ
トがえられる。不規則なパターンを施すには、開口部の
径を変えることもできるが、たとえば開口部の径を一定
にし、開口部の位置をランダムに決めることによりえら
れる。開口部の位置をランダムに決めるには、たとえば
コンピュータを使用し、開口部の位置を乱数で求めるソ
フトを使用することにより簡単に決められる。On the other hand, as shown in FIG. 5, the reflection film 47 having an irregular opening pattern is, for example, 5000 pieces (a light receiving surface of 0.24 mm × 0.3 mm) when the opening of the reflection film has a diameter of 3 μm. As shown in FIG. 6 (b), an example of the pattern of (1) can prevent the splitting of spots, and a single spot with high intensity can be obtained. The diameter of the opening can be changed to give an irregular pattern, but it can be obtained by, for example, making the diameter of the opening constant and randomly determining the position of the opening. To randomly determine the position of the opening, for example, a computer is used, and the position of the opening is easily determined by using software for obtaining the position by random numbers.
【００５８】この方法で0.24mm×0.3mm の受光面に直径
21.4μｍの開口部を100 個設けたばあい、光伝送路への
カップリング効率は35％、フォトダイオードへの透過率
は50％になった。また、開口部の直径13μｍで270 個の
開口部を設けたばあいは光伝送路へのカップリング効率
は40％、フォトダイオードへの透過率は50％になった。
開口部の直径３μｍで5000個の開口部をランダムに設け
たばあいはカップリング効率が50％まで向上し、フォト
ダイオードへの透過率は50％になった。開口部の直径が
0.7μｍで94000 個のばあいはカップリング効率が52％
になり、完全に平坦な面からのカップリング効率55％に
近づいた。しかし、フォトダイオードへの透過率が30％
になった。この結果を図７に示す。なお、図７で一点鎖
線はフォトダイオードへの透過率を示す。With this method, a diameter of 0.24 mm × 0.3 mm light receiving surface is obtained.
When 100 openings of 21.4 μm were provided, the coupling efficiency to the optical transmission line was 35% and the transmittance to the photodiode was 50%. When 270 openings with a diameter of 13 μm were provided, the coupling efficiency to the optical transmission line was 40% and the transmittance to the photodiode was 50%.
When 5000 openings were randomly provided with an opening diameter of 3 μm, the coupling efficiency was improved to 50% and the transmittance to the photodiode was 50%. The diameter of the opening is
Coupling efficiency is 52% when using 94,000 with 0.7 μm
And the coupling efficiency from a completely flat surface approached 55%. However, the transmittance to the photodiode is 30%
Became. The result is shown in FIG. 7. In FIG. 7, the alternate long and short dash line shows the transmittance of the photodiode.
【００５９】すなわち、開口部の直径を小さくし、開口
部の個数を増やす程カップリング効率が向上する。しか
し、開口部の直径を受信信号光の波長以下に小さくする
と、フォトダイオードへの透過率が減少する。ファイバ
カップリング効率は45％以上あることが好ましく、孔径
は約７μｍ以下、すなわち受信信号光の波長の５倍以下
であることが好ましく、一方フォトダイオードへの透過
率は30％以上であることが好ましく、孔径は0.75μｍ以
上、すなわち受信信号光の波長の１／２以上であること
が好ましい。したがって開口部の直径は受信信号光の波
長の１／２〜５倍であることが好ましい。また、この開
口部は円形状の反射膜が設けられた間隙部を利用したも
のでもよく、反射と透過の割合は50％程度にすることが
好ましく、このばあいも同じ理由から反射膜の直径が受
信信号光の波長の１／２〜５倍であることが好ましい。
なお開口部を孔でなく、縞状にしたときの縞の幅を変え
てカップリング効率を調べた結果を図７に同様に破線で
示した。That is, the coupling efficiency is improved as the diameter of the openings is reduced and the number of openings is increased. However, if the diameter of the opening is made smaller than the wavelength of the received signal light, the transmittance of the photodiode decreases. The fiber coupling efficiency is preferably 45% or more, the hole diameter is preferably about 7 μm or less, that is, 5 times or less of the wavelength of the received signal light, while the transmittance to the photodiode is 30% or more. The hole diameter is preferably 0.75 μm or more, that is, ½ or more of the wavelength of the received signal light. Therefore, the diameter of the opening is preferably 1/2 to 5 times the wavelength of the received signal light. The opening may be a gap provided with a circular reflection film, and the ratio of reflection and transmission is preferably about 50%. In this case, the diameter of the reflection film is also the same. Is preferably 1/2 to 5 times the wavelength of the received signal light.
Note that the results of investigating the coupling efficiency by changing the width of the stripes when the openings are formed as stripes instead of holes are shown by broken lines in FIG.
【００６０】つぎに、受信信号光の偏光依存性をなくす
る他の実施例について説明する。図８はその説明図で、
１は発光素子、２は受光素子、３はカップリングレン
ズ、５は受発光素子１、２の前面に配置されるカバーガ
ラスである。本実施例ではカバーガラス５を受信信号光
に対して斜めになるように配置し、受光素子２への斜め
入射に伴う偏光依存性をカバーガラス５に斜め入射させ
ることによる偏光依存性により相殺するようにしたもの
である。すなわち、図８に示すように、受光素子２の表
面がｘｙ平面でｙ軸に対して30゜傾いているばあい、カ
バーガラス５をｘｙ表面でｘ軸に対して30゜傾けること
により偏光依存性が相殺される。傾ける方向は受光素子
２のｙ軸に対する傾きに対して、カバーガラス５をｘ軸
に対して傾けることによりｘ方向の偏光に対してはカバ
ーガラスに対しＰ偏光であり、透過率が高く、受光素子
に対してはＳ偏光であり、透過率が低い。他方ｙ方向の
偏光に対してはカバーガラスに対しＳ偏光であり透過率
が低く、受光素子に対してはＰ偏光であり透過率が高
い。このような理由で偏光依存性が相殺される。Next, another embodiment for eliminating the polarization dependence of the received signal light will be described. FIG. 8 is an explanatory diagram of that.
Reference numeral 1 is a light emitting element, 2 is a light receiving element, 3 is a coupling lens, and 5 is a cover glass arranged in front of the light receiving and emitting elements 1 and 2. In this embodiment, the cover glass 5 is arranged so as to be oblique to the received signal light, and the polarization dependence due to the oblique incidence on the light receiving element 2 is canceled by the polarization dependence due to the oblique incidence on the cover glass 5. It was done like this. That is, as shown in FIG. 8, when the surface of the light receiving element 2 is tilted by 30 ° with respect to the y-axis in the xy plane, the cover glass 5 is tilted by 30 ° with respect to the x-axis on the xy surface, and the polarization dependence Sex is offset. With respect to the inclination of the light-receiving element 2 with respect to the y-axis, the cover glass 5 is inclined with respect to the x-axis so that the polarized light in the x-direction is P-polarized with respect to the cover glass and has a high transmittance. The element is S-polarized and has a low transmittance. On the other hand, with respect to polarized light in the y direction, the cover glass is S-polarized and has a low transmittance, and the light receiving element is P-polarized and has a high transmittance. For this reason, the polarization dependence is canceled out.
【００６１】さらにカバーガラス５を傾けることにより
発光素子１として半導体レーザを用いたばあいに生じや
すい非点隔差に伴う非点収差を補正することができる。
前述のように半導体レーザから発せられるビームは直線
偏光のみであるため、受光素子２の表面に斜めに入射し
ても反射率は一定である。半導体レーザーに非点隔差が
生じていれば収束スポットに非点収差が生じるように進
行する。この送信信号光がカバーガラス５に対して斜め
に入射する。Further, by tilting the cover glass 5, it is possible to correct the astigmatism associated with the astigmatic difference that tends to occur when a semiconductor laser is used as the light emitting element 1.
Since the beam emitted from the semiconductor laser is only linearly polarized light as described above, the reflectance is constant even if the beam is obliquely incident on the surface of the light receiving element 2. If there is an astigmatic difference in the semiconductor laser, the process proceeds so that astigmatism occurs in the converging spot. This transmission signal light is obliquely incident on the cover glass 5.
【００６２】たとえば、カバーガラス５をレーザ光線の
直線偏光方向に対し垂直な方向を軸として傾けることに
より、発散光のレーザビームは斜めのカバーガラス５を
透過する際にｘ方向およびｙ方向に非対称に屈折する。
その結果、ｘ軸断面内の光線はｙ軸断面内の光線よりも
前方で発光したかのように進む。しかし、非点隔差が生
じている半導体レーザチップから発するレーザ光線は、
ｙ軸断面内の光線がｘ軸断面内の光線よりも前方で発光
しているような非点収差をもっている。これにより、カ
バーガラス５を傾けることにより半導体レーザチップに
生じる非点隔差が補正されることになる。For example, by tilting the cover glass 5 about a direction perpendicular to the linear polarization direction of the laser beam, the divergent laser beam is asymmetrical in the x and y directions when passing through the oblique cover glass 5. Refract to.
As a result, the light ray in the x-axis cross section proceeds as if it emitted in front of the light ray in the y-axis cross section. However, the laser beam emitted from the semiconductor laser chip with the astigmatic difference is
The light rays in the y-axis cross section have astigmatism such that they are emitted in front of the light rays in the x-axis cross section. As a result, the astigmatic difference generated in the semiconductor laser chip by tilting the cover glass 5 is corrected.
【００６３】さらに詳述すると、カバーガラスの屈折率
をｎ2 、カバーガラスの厚さをｄ2、カバーガラスの傾
きをδとすると、補正できる非点隔差はΔｚは Δｚ＝−ｄ2 ×［（ｎ2 2 −１）ｓｉｎ2 δ］ ÷（ｎ2 2 −ｓｉｎ2 δ）3/2 (1) で表わされる。たとえば、カバーガラスの屈折率ｎ2 ＝
1.5 、カバーガラスの厚さｄ2 ＝0.2mm 、カバーガラス
の傾きδ＝30゜としてこの値を式(1) に代入すると、補
正できるΔｚはΔｚ＝22μｍとなる。More specifically, assuming that the refractive index of the cover glass is n 2 , the thickness of the cover glass is d 2 , and the inclination of the cover glass is δ, the astigmatic difference Δz that can be corrected is Δz = −d 2 × [ It is represented by (n 2 2 −1) sin 2 δ] ÷ (n 2 2 −sin 2 δ) 3/2 (1). For example, the refractive index of the cover glass n 2 =
Substituting this value into the equation (1) assuming that the cover glass has a thickness d 2 = 0.2 mm and the cover glass has an inclination δ = 30 °, the correctable Δz is Δz = 22 μm.
【００６４】したがって、カバーガラスの屈折率ｎ2 、
カバーガラスの厚さｄ2 、カバーガラスの傾きδを半導
体レーザダイオードの非点隔差に応じて変化させること
によって、その有する非点隔差を補正することができ
る。なお、カバーガラスの表面の反射率を高め偏光依存
性を高めるためには前述のように、カバーガラス５の片
面に高屈折率材料をコーティングすることにより調整で
き、高屈折率材料としてはたとえば、ＴｉＯ2 、Ｔａ2
Ｏ5 、ＺｒＯ2 （ｎ＝1.9 〜2.2 ）などを使用すること
ができる。このばあい多重反射を防ぐため、カバーガラ
スの反対面は反射防止膜がコーティングされることが望
ましい。Therefore, the refractive index n 2 of the cover glass,
By changing the thickness d 2 of the cover glass and the inclination δ of the cover glass according to the astigmatic difference of the semiconductor laser diode, the astigmatic difference of the semiconductor laser diode can be corrected. In addition, in order to increase the reflectance of the surface of the cover glass and increase the polarization dependence, it can be adjusted by coating a high refractive index material on one surface of the cover glass 5 as described above, and as the high refractive index material, for example, TiO 2 , Ta 2
O 5 , ZrO 2 (n = 1.9 to 2.2) and the like can be used. In this case, in order to prevent multiple reflection, it is desirable that the opposite surface of the cover glass be coated with an antireflection film.
【００６５】半導体レーザの非点隔差を補正するには、
前述のようにカバーガラスをレーザー光線の直線偏光方
向に対し、垂直な方向を軸として傾くようにすればよ
く、この条件を満たすと共に、前述の受信信号光の偏光
依存性を補正するように傾けることができる。たとえば
図８に示すように、受光素子２がｘｙ平面のｙ軸に対し
て30゜傾けられ、カバーガラス５がｘｙ平面のｘ軸に対
し30゜傾けられることにより、送信信号光の非点収差を
生じさせなくすると共に、受信信号光の偏光依存性をも
防止することができる。To correct the astigmatic difference of the semiconductor laser,
As described above, the cover glass may be tilted with respect to the linear polarization direction of the laser beam about a direction perpendicular to the linear polarization direction. In addition to satisfying this condition, the cover glass should be tilted so as to correct the polarization dependence of the received signal light. You can For example, as shown in FIG. 8, the light receiving element 2 is tilted by 30 ° with respect to the y axis of the xy plane, and the cover glass 5 is tilted by 30 ° with respect to the x axis of the xy plane. It is possible to prevent the occurrence of the above and prevent the polarization dependency of the received signal light.
【００６６】[0066]
【発明の効果】本発明によれば、発光素子からの発光ビ
ームの光路に発光ビームを反射させるように受信信号光
を受信する受光素子を配設しているため、ハーフミラー
などの分光装置を設ける必要がなく部品点数が減り、安
価な受発信モジュールがえられる。しかも受光素子の表
面側で反射させているため、発光素子部とカップリング
レンズとの距離も短くすることができ、小型の受発信モ
ジュールがえられる。According to the present invention, since the light receiving element for receiving the received signal light is arranged in the optical path of the light emitting beam from the light emitting element so as to reflect the light emitting beam, a spectroscopic device such as a half mirror is provided. Since it is not necessary to provide the components, the number of parts is reduced, and an inexpensive transmitting / receiving module can be obtained. Moreover, since the light is reflected on the front surface side of the light receiving element, the distance between the light emitting element portion and the coupling lens can be shortened, and a small transmitting / receiving module can be obtained.
【００６７】また受信信号光用の受光部と発光出力モニ
タ用の受光部とを兼用することができ、素子の簡素化を
図れる。このばあい、受信用受光部とモニタ用受光部と
を同一基板上に別々に形成することにより、送信信号光
と受信信号光のパワーに差があっても、増幅器などで調
整できる。Further, the light receiving portion for the received signal light and the light receiving portion for the emission output monitor can be used in common, and the element can be simplified. In this case, by separately forming the receiving light receiving portion and the monitoring light receiving portion on the same substrate, even if there is a difference in power between the transmission signal light and the reception signal light, it can be adjusted by an amplifier or the like.
【００６８】また受光素子の反射面の角度を調整し、反
射後の発光ビームの中心軸とカップリングレンズの光軸
とをｓｉｎ-1ＮＡ以上ずらせることにより受信信号光が
反射して再度光伝送路に戻るのを防止することができ
る。Further, by adjusting the angle of the reflecting surface of the light receiving element and shifting the center axis of the emitted light beam after reflection and the optical axis of the coupling lens by sin −1 NA or more, the received signal light is reflected and re-lighted. It is possible to prevent returning to the transmission path.
【００６９】また受光素子の表面に反射防止膜を設け、
その上に網目状に開口部が設けられた反射膜を設けるこ
とにより、またはカバーガラスの傾斜角を適当に設定す
ることにより、受信信号光が受光素子に斜めに入射して
も偏光依存性が生じなく、受光素子を受信信号光に対し
て斜めに配置しても偏光角の回転により受信信号光の変
動ノイズを防げ、正確に受信することができる。Further, an antireflection film is provided on the surface of the light receiving element,
Even if the received signal light is incident on the light receiving element at an angle, the polarization dependence can be obtained by providing a reflective film with a mesh-like opening on it or setting the inclination angle of the cover glass appropriately. Even if the light receiving element is obliquely arranged with respect to the received signal light, the fluctuation noise of the received signal light can be prevented by the rotation of the polarization angle and accurate reception can be achieved.
【図１】本発明の光通信用受発信モジュールの一実施例
の概略説明図である。FIG. 1 is a schematic explanatory diagram of an embodiment of an optical communication receiver / transmitter module of the present invention.
【図２】本発明の光通信用受発信モジュールの一実施例
の受信信号光の反射の様子を説明する図である。FIG. 2 is a diagram for explaining how the received signal light is reflected in an embodiment of the optical communication receiving / transmitting module of the present invention.
【図３】本発明の光通信用受発信モジュールの一実施例
に用いる受光素子の平面説明図である。FIG. 3 is a plan view of a light receiving element used in an embodiment of the optical communication receiving and transmitting module of the present invention.
【図４】図３に示す受光素子の断面説明図である。4 is a cross-sectional explanatory view of the light receiving element shown in FIG.
【図５】本発明の光通信用受発信モジュールの他の実施
例で受光素子部を変えた説明図である。FIG. 5 is an explanatory view in which a light receiving element section is changed in another embodiment of the optical communication receiving / transmitting module of the present invention.
【図６】反射膜のパターンによる回析作用により生じる
スポットの説明図である。FIG. 6 is an explanatory diagram of spots generated by a diffracting action due to a pattern of a reflective film.
【図７】反射膜に設けられた開口部の大きさと光伝送路
へのカップリングの関係を示す図である。FIG. 7 is a diagram showing the relationship between the size of the opening provided in the reflective film and the coupling to the optical transmission line.
【図８】本発明の光通信用受発信モジュールの他の実施
例の説明図である。FIG. 8 is an explanatory diagram of another embodiment of the optical communication receiving / transmitting module of the present invention.
【図９】従来の光通信用受発信モジュールの概略説明図
である。FIG. 9 is a schematic explanatory view of a conventional optical communication receiving / transmitting module.
【図１０】従来の光通信用受発信モジュールの発光素子
部の一例の説明図である。FIG. 10 is an explanatory diagram of an example of a light emitting element portion of a conventional optical communication receiving / transmitting module.
１ 発光素子 ２ 受光素子 ３ カップリングレンズ Ａ、Ｃ 発光ビームの中心軸 Ｂ カップリングレンズの光軸 1 Light emitting element 2 Light receiving element 3 Coupling lens A, C Central axis of emitted light beam B Optical axis of coupling lens
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成６年１月１７日[Submission date] January 17, 1994
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Name of item to be amended] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【特許請求の範囲】[Claims]
【請求項３】 前記受光素子は、前記発光素子の発光量
をモニタするモニタ用受光部と、前記光伝送路からの受
信信号光を受光する受光部とが同一受光面に兼用して形
成されてなる請求項２記載の光通信用受発信モジュー
ル。 3. The light receiving element is a light emitting amount of the light emitting element.
The light receiving part for monitoring that monitors the
The light receiving part that receives the signal light also serves as the same light receiving surface.
A transmitting / receiving module for optical communication according to claim 2, wherein
Le.
【請求項４】 前記受光素子は同一基板上に前記発光素
子の発光量をモニタするモニタ用受光部と前記光伝送路
からの受信信号光を受光する受光部とが隣接して別々に
設けられてなる請求項２記載の光通信用受発信モジュー
ル。 Wherein said light emitting element to the light receiving element on the same substrate
3. The optical communication receiver / transmitter module according to claim 2 , wherein a monitor light receiver for monitoring the light emission amount of the child and a light receiver for receiving the signal light received from the optical transmission line are provided separately adjacent to each other.
【請求項５】 前記発光素子の発光ビームの前記受光素
子による反射後のビームの中心軸と前記カップリングレ
ンズの光軸とが、該カップリングレンズの開口数をＮＡ
としてｓｉｎ-1ＮＡ以上ずれるように前記受光素子の表
面が傾斜されてなる請求項１記載の光通信用受発信モジ
ュール。 5. the center axis of the beam after reflection by the light receiving elements of the light emitting beam of the light emitting element and the optical axis of the coupling lens, the numerical aperture of the coupling lens NA
The optical communication receiver / transmitter module according to claim 1, wherein the surface of the light receiving element is inclined so as to deviate by not less than sin −1 NA.
【請求項６】 前記受光素子の少なくとも受信信号光の
受光部表面に網目状の孔が設けられた反射膜または複数
の点状の反射膜が設けられてなる請求項１記載の光通信
用受発信モジュール。 6. At least a mesh-shaped reflecting layer or a plurality of point-like reflection membrane pores is provided is provided on the light-receiving portion surface of the reception signal light comprising optical communication received according to claim 1, wherein said light receiving element Outgoing module.
【請求項７】 前記受光素子の少なくとも受信信号光の
受光部表面に反射防止膜が設けられ、該反射防止膜上に
前記網目状の孔が設けられた反射膜または複数の点状の
反射膜が設けられてなる請求項１、３、４または６記載
の光通信用受発信モジュール。 7. A reflection film or a plurality of dot-shaped reflection films in which an antireflection film is provided on at least the light receiving surface of the light receiving element of the light receiving element, and the mesh holes are provided on the antireflection film. The optical communication receiver / transmitter module according to claim 1, 3 , 4, or 6 .
【請求項８】 前記受光素子の少なくとも受信信号光の
受光部表面に設けられた前記網目状の孔は受信信号光の
波長の１／２から５倍の範囲の孔径を有してなる請求項
６または７記載の光通信用受発信モジュール。 8. At least claim wherein mesh holes provided on the light-receiving portion surface of the received signal light is made with a pore size in the range of 1/2 to 5 times the wavelength of the received signal light of the light receiving element
The optical transmission / reception module according to 6 or 7 .
【請求項９】 前記受光素子の少なくとも受信信号光の
受光部表面に設けられた前記点状の反射膜は受信信号光
の波長の１／２から５倍の範囲の直径を有してなる請求
項６または７記載の受発信モジュール。 Wherein said said point-like reflection film provided on the light-receiving portion surface of the at least the received signal light of the light receiving element is a diameter in the range of 1/2 to 5 times the wavelength of the received optical signal according The transmitting / receiving module according to item 6 or 7 .
【請求項１０】 前記網目状の孔が設けられた反射膜の
孔または前記複数の点状の反射膜が不規則に設けられて
なる請求項６または７記載の光通信用受発信モジュー
ル。 10. A optical communication transceiving module of the mesh holes hole or said plurality of point-like reflective film reflective film provided is provided irregularly according to claim 6 or 7.
【請求項１１】 前記反射防止膜が送受信信号光の波長
λに対してλ／４より５〜10％厚く形成されてなる請求
項７記載の光通信用受発信モジュール。 11. optical communication transceiving module of the antireflection film is formed by 5-10% thicker than lambda / 4 relative to the wavelength lambda of the reception signal light according to claim 7 wherein.
【請求項１２】 前記受光素子の表面と光伝送路とのあ
いだにカバーガラスが設けられ、該カバーガラスの透過
による受信信号光の偏光依存性と前記受光素子表面での
透過による受信信号光の偏光依存性が打ち消されるよう
に前記カバーガラスが傾けられてなる請求項１記載の光
通信用受発信モジュール。 12. cover glass provided between the surface and the optical transmission path of the light receiving element, the received signal light due to transmission at the polarization dependence and the light receiving element surface of the reception signal light by transmission of the cover glass The optical transmission / reception module for optical communication according to claim 1, wherein the cover glass is tilted so as to cancel the polarization dependency.
【請求項１３】 前記発光素子と光伝送路とのあいだに
前記発光素子の非点隔差を打ち消すようにカバーガラス
が傾けて設けられてなる請求項１記載の光通信用受発信
モジュール。 Wherein said light emitting element and the optical communication transceiving module according to claim 1, wherein the cover glass so as to cancel out the astigmatism is provided tilted in the light emitting element between the optical transmission path.
【請求項１４】 前記受光素子の表面と光伝送路とのあ
いだにカバーガラスが設けられ、該カバーガラスの透過
による受信信号光の偏光依存性と前記受光素子表面での
反射による受信信号光の偏光依存性とが打ち消され、か
つ、前記発光素子の非点隔差と前記カバーガラスの屈折
による発信信号光の偏光とが打ち消されるように前記カ
バーガラスが傾けられてなる請求項１記載の光通信用受
発信モジュール。 14. A cover glass is provided between the surface of the light receiving element and an optical transmission line, and the polarization dependency of the received signal light due to the transmission of the cover glass and the received signal light due to the reflection on the surface of the light receiving element. The optical communication according to claim 1, wherein the polarization dependency is canceled out, and the cover glass is tilted so as to cancel out the astigmatic difference of the light emitting element and the polarization of the transmitted signal light due to the refraction of the cover glass. Reception / transmission module.
【請求項１５】 前記カバーガラスの一方の表面に送受
信信号光の波長λに対して高屈折率の材料（送受信信号
光の波長λにおける屈折率ｎ）が該波長λの１／（４
ｎ）の厚さだけコーティングされ、他方の表面に反射防
止膜がコーティングされてなる請求項１２、１３または
１４記載の光通信用受発信モジュール。 15. a high refractive index for the wavelength λ of the transmission and reception signal light on one surface of said cover glass material (transmission and reception signals
The refractive index n) at the wavelength λ of light is 1 / (4
is only the thickness of the coating of n), the anti-reflection film on the other surface is coated claim 12, 13 or
14. The optical transmission / reception module for optical communication according to 14 .
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１４[Correction target item name] 0014
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１４】前記受光素子は兼用して前記発光素子の発
光量をモニタするモニタ用受光部と前記光伝送路からの
受信信号光を受光する受光部とが同一受光面に形成され
ていれば素子の小形化の点から好ましく、また同一基板
上に隣接して別々に設けられていればモニタ用受光部の
受光感度と受信信号光の受信感度を調整する点から好ま
しい。The light-receiving element also serves as the light-emitting element.
A monitor light-receiving part for monitoring the amount of light and a light-receiving part for receiving the received signal light from the optical transmission line are formed on the same light-receiving surface.
Is preferable from the viewpoint of miniaturization of the device, and the same substrate
If it provided separately adjacent the top from the viewpoint of adjusting the reception sensitivity of the light receiving sensitivity and the received signal light of the monitoring light receiving unit.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２０[Correction target item name] 0020
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２０】前記反射防止膜が送受信信号光の波長λに
対してλ／４より５〜１０％厚く形成されることが、偏
光依存性を減らす点からさらに好ましい。It is more preferable that the antireflection film is formed 5 to 10% thicker than λ / 4 with respect to the wavelength λ of the transmitted / received signal light in order to reduce the polarization dependence.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２４[Name of item to be corrected] 0024
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２４】さらに、前記カバーガラスの一方の表面に
送受信信号光の波長λに対して高屈折率の材料が（送受
信信号光の波長λにおける屈折率をｎとして）該波長λ
の１／（４ｎ）の厚さだけコーティングされ、他方の表
面に反射防止膜がコーティングされていることが、屈折
率の小さいガラスからなるカバーガラスを使用しても大
きな偏光依存性を生じさせることができ、斜面での反射
により生じる偏光を相殺するのに好ましい。Further, a material having a high refractive index with respect to the wavelength λ of the transmitted / received signal light is provided on one surface of the cover glass (where the refractive index at the wavelength λ of the transmitted / received signal light is n).
1 / (4n) of the thickness and the other surface coated with an anti-reflection film causes a large polarization dependence even when a cover glass made of glass with a small refractive index is used. This is preferable for canceling the polarized light generated by the reflection on the slope.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 青木 直史 京都市右京区西院溝崎町21番地 ローム株 式会社内 (72)発明者 岡田 賢治 東京都千代田区内幸町１丁目１番６号 日 本電信電話株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Naoshi Aoki, 21 Naomi, Saiin Mizozaki-cho, Ukyo-ku, Kyoto ROHM Co., Ltd. In the company
Claims (14)
発光素子からの送信信号光を光伝送路に結合させるカッ
プリングレンズと、前記光伝送路からの受信信号光を受
信する受光素子とからなる光通信用受発信モジュールで
あって、前記受光素子の表面で前記発光素子からの送信
信号光を反射させて前記カップリングレンズを経て光伝
送路に結合せしめると共に該受光素子により光伝送路か
らの受信信号光が受信せしめられてなる光通信用受発信
モジュール。1. A light emitting element for generating transmission signal light, a coupling lens for coupling the transmission signal light from the light emitting element to an optical transmission line, and a light receiving element for receiving the reception signal light from the optical transmission line. And a transmission signal light from the light emitting element is reflected on the surface of the light receiving element to be coupled to an optical transmission path through the coupling lens and the optical transmission path by the light receiving element. Optical transmission / reception module for receiving received signal light from.
をモニタするモニタ用受光素子の機能が兼用されてなる
請求項１記載の光通信用受発信モジュール。2. The light transmitting / receiving module for optical communication according to claim 1, wherein the light receiving element also has a function of a monitor light receiving element for monitoring a light emission amount of the light emitting element.
用受光部と前記光伝送路からの受信信号光を受光する受
光部とが隣接して別々に設けられてなる請求項１または
２記載の光通信用受発信モジュール。3. The light receiving element according to claim 1, wherein the monitor light receiving section and the light receiving section for receiving the signal light received from the optical transmission path are separately provided adjacent to each other on the same substrate. Optical communication module for optical communication.
子による反射後のビームの中心軸と前記カップリングレ
ンズの光軸とが、該カップリングレンズの開口数をＮＡ
としてｓｉｎ-1ＮＡ以上ずれるように前記受光素子の表
面が傾斜されてなる請求項１記載の光通信用受発信モジ
ュール。4. The numerical aperture of the coupling lens is determined by the central axis of the beam emitted from the light emitting element after reflection by the light receiving element and the optical axis of the coupling lens.
The optical communication receiver / transmitter module according to claim 1, wherein the surface of the light receiving element is inclined so as to deviate by not less than sin −1 NA.
受光部表面に網目状の孔が設けられた反射膜または複数
の点状の反射膜が設けられてなる請求項１記載の光通信
用受発信モジュール。5. The optical communication receiver according to claim 1, wherein a reflective film having a mesh-shaped hole or a plurality of dot-shaped reflective films is provided on at least a surface of the light receiving portion of the light receiving element for receiving the received signal light. Outgoing module.
受光部表面に反射防止膜が設けられ、該反射防止膜上に
前記網目状の孔が設けられた反射膜または複数の点状の
反射膜が設けられてなる請求項１、３または５記載の光
通信用受発信モジュール。6. A reflection film, or a plurality of dot-shaped reflection films, wherein an antireflection film is provided on at least a surface of a light receiving portion for receiving signal light of the light receiving element, and the mesh holes are provided on the antireflection film. The optical communication receiver / transmitter module according to claim 1, 3 or 5, further comprising:
受光部表面に設けられた前記網目状の孔は受信信号光の
波長の１／２から５倍の範囲の孔径を有してなる請求項
５または６記載の光通信用受発信モジュール。7. The mesh holes provided on at least the surface of the light receiving portion of the received signal light of the light receiving element have a hole diameter in the range of 1/2 to 5 times the wavelength of the received signal light. 5. The optical communication receiving / transmitting module according to 5 or 6.
受光部表面に設けられた前記点状の反射膜は受信信号光
の波長の１／２から５倍の範囲の直径を有してなる請求
項５または６記載の受発信モジュール。8. The point-like reflection film provided on at least the surface of the light receiving portion of the light receiving element for receiving the received signal light has a diameter in the range of 1/2 to 5 times the wavelength of the received signal light. Item 5. The transmitting / receiving module according to item 5 or 6.
または前記複数の点状の反射膜が不規則に設けられてな
る請求項５または６記載の光通信用受発信モジュール。9. The transmission / reception module for optical communication according to claim 5, wherein the holes of the reflection film provided with the mesh-like holes or the plurality of dot-shaped reflection films are provided irregularly.
対してλ／４より５〜10％厚く形成されてなる請求項６
記載の光通信用受発信モジュール。10. The antireflection film is formed 5 to 10% thicker than λ / 4 with respect to the wavelength λ of transmitted and received light.
The transmitting / receiving module for optical communication described.
いだにカバーガラスが設けられ、該カバーガラスの透過
による受信信号光の偏光依存性と前記受光素子表面での
透過による受信信号光の偏光依存性が打ち消されるよう
に前記カバーガラスが傾けられてなる請求項１記載の光
通信用受発信モジュール。11. A cover glass is provided between the surface of the light receiving element and the optical transmission path, and the polarization dependence of the received signal light due to the transmission of the cover glass and the received signal light due to the transmission on the surface of the light receiving element. The optical transmission / reception module for optical communication according to claim 1, wherein the cover glass is tilted so as to cancel the polarization dependency.
前記発光素子の非点隔差を打ち消すようにカバーガラス
が傾けて設けられてなる請求項１記載の光通信用受発信
モジュール。12. The transmission / reception module for optical communication according to claim 1, wherein a cover glass is tilted between the light emitting element and the optical transmission line so as to cancel the astigmatic difference of the light emitting element.
いだにカバーガラスが設けられ、該カバーガラスの透過
による受信信号光の偏光依存性と前記受光素子表面での
反射による受信信号光の偏光依存性とが打ち消され、か
つ、前記発光素子の非点隔差と前記カバーガラスの屈折
による発信信号光の偏光とが打ち消されるように前記カ
バーガラスが傾けられてなる請求項１記載の光通信用受
発信モジュール。13. A cover glass is provided between the surface of the light receiving element and an optical transmission line, and the polarization dependency of the received signal light due to the transmission of the cover glass and the received signal light due to the reflection on the surface of the light receiving element. The optical communication according to claim 1, wherein the polarization dependency is canceled out, and the cover glass is tilted so as to cancel out the astigmatic difference of the light emitting element and the polarization of the transmitted signal light due to the refraction of the cover glass. Reception / transmission module.
信光の波長λに対して高屈折率の材料（送受信の波長λ
における屈折率ｎ）が該波長λの１／（４ｎ）の厚さだ
けコーティングされ、他方の表面に反射防止膜がコーテ
ィングされてなる請求項１１、１２または１３記載の光
通信用受発信モジュール。14. A material having a high refractive index with respect to the wavelength λ of transmitted / received light on one surface of the cover glass (wavelength of transmitted / received λ
The optical communication receiver / transmitter module according to claim 11, 12 or 13, wherein the refractive index n) in 1) is coated by a thickness of 1 / (4n) of the wavelength λ, and the other surface is coated with an antireflection film.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33179193A JP2912536B2 (en) | 1993-12-27 | 1993-12-27 | Receiver / transmitter module for optical communication |
| GB9708554A GB2310507B (en) | 1993-12-27 | 1994-12-22 | Transceiver module for optical communication |
| GB9425992A GB2285320B (en) | 1993-12-27 | 1994-12-22 | Transceiver module for optical communication |
| US08/363,278 US5528407A (en) | 1993-12-27 | 1994-12-22 | Transceiver module for optical communication |
| DE4446328A DE4446328C2 (en) | 1993-12-27 | 1994-12-23 | Transceiver module for optical communication |
| CA002139032A CA2139032C (en) | 1993-12-27 | 1994-12-23 | Transceiver module for optical communication |
| DE4447700A DE4447700C2 (en) | 1993-12-27 | 1994-12-23 | Optical transceiver module for subscriber communications, e.g. telephone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33179193A JP2912536B2 (en) | 1993-12-27 | 1993-12-27 | Receiver / transmitter module for optical communication |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07191237A true JPH07191237A (en) | 1995-07-28 |
| JP2912536B2 JP2912536B2 (en) | 1999-06-28 |
Family
ID=18247686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33179193A Expired - Fee Related JP2912536B2 (en) | 1993-12-27 | 1993-12-27 | Receiver / transmitter module for optical communication |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2912536B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9341788B2 (en) | 2010-07-27 | 2016-05-17 | Mitsubishi Electric Corporation | Optical module |
| WO2021106127A1 (en) * | 2019-11-28 | 2021-06-03 | 三菱電機株式会社 | Semiconductor laser device |
| JPWO2021171545A1 (en) * | 2020-02-28 | 2021-09-02 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110085767A1 (en) * | 2009-10-09 | 2011-04-14 | Emcore Corporation | Cooled Laser Module |
-
1993
- 1993-12-27 JP JP33179193A patent/JP2912536B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9341788B2 (en) | 2010-07-27 | 2016-05-17 | Mitsubishi Electric Corporation | Optical module |
| WO2021106127A1 (en) * | 2019-11-28 | 2021-06-03 | 三菱電機株式会社 | Semiconductor laser device |
| JPWO2021106127A1 (en) * | 2019-11-28 | 2021-06-03 | ||
| JPWO2021171545A1 (en) * | 2020-02-28 | 2021-09-02 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2912536B2 (en) | 1999-06-28 |
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