WO2012026523A1 - Optical tap module - Google Patents

Optical tap module Download PDF

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Publication number
WO2012026523A1
WO2012026523A1 PCT/JP2011/069170 JP2011069170W WO2012026523A1 WO 2012026523 A1 WO2012026523 A1 WO 2012026523A1 JP 2011069170 W JP2011069170 W JP 2011069170W WO 2012026523 A1 WO2012026523 A1 WO 2012026523A1
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Prior art keywords
optical
lens
optical tap
light
tap
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PCT/JP2011/069170
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French (fr)
Japanese (ja)
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尚史 稲村
大生 峰
哲郎 石塚
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株式会社ケンコー・トキナー
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Publication of WO2012026523A1 publication Critical patent/WO2012026523A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features

Definitions

  • the present invention relates to an optical tap module used when monitoring signal light propagating in an optical fiber used as a transmission line in the fields of optical communication and optical measurement.
  • a conventional technique for monitoring signal light by branching a part of signal light from an optical fiber using a branching means having a predetermined branching ratio and detecting the branched signal light with a photodetector is known. Yes. Specifically, when the signal light propagating in the optical fiber is branched, a part of the signal light propagating in the optical fiber is set as leakage light by bending the optical fiber with a small curvature or providing a cutting groove in the cladding. It can be taken out. Further, when branching the signal light propagating through the optical waveguide including the optical fiber, a branching waveguide obtained by branching the optical waveguide at a predetermined branching ratio can be used.
  • Patent Document 1 discloses, as a conventional technique related to this optical tap module, an optical fiber on the emission side, a lens that collects light emitted from the optical fiber, and an incident side in which an end face is disposed at the condensing point of the lens.
  • a technique for reducing the number of components and facilitating assembly work by providing an optical fiber and a transmissive semiconductor light-receiving element disposed between the lens and the incident-side optical fiber.
  • FIG. 4 is a longitudinal sectional view of a conventional optical tap lens represented by Patent Document 1 described above.
  • the light is incident on an optical tap lens 12 having an end surface that is obliquely polished from the light emitting fiber 11, is transmitted through a predetermined amount by the optical filter 14, and the rest is reflected to return to the light incident fiber 13 as return light.
  • the light transmitted through the optical filter 14 is collected by the condenser lens 15 and detected by the photodiode 16. This makes it possible to detect the presence / absence of an optical signal and its intensity.
  • the optical tap lens 12 a gradient index GRIN lens is generally used.
  • the optical tap lens 12 is used.
  • the insertion loss on the return side of the lens 12 becomes large. That is, not all of the light reflected by the optical filter 14 returns to the light incident fiber 13, and not a little light loss occurs. Therefore, it cannot be said that the coupling efficiency is sufficient.
  • the coupling efficiency is increased at the optical coupling point by using an aspherical rod lens that is easy to adjust the optical axis without being affected by aberrations and that has good collimation and condensing properties of the light beam.
  • the optical tapping lens 12 formed of an aspherical rod lens is used, the signal light emitted from the light emitting fiber 11 is partially reflected by the incident surface of the optical tapping lens 12, and the light emitting fiber 11 is used. The phenomenon of returning to
  • a technique for avoiding a phenomenon in which a part of the reflected light returns to the light emitting fiber 11 by performing oblique polishing on the end face of the optical tap lens 12 is known.
  • the transmitted light A is directly incident on the optical tap lens 12
  • the reflected light B also has a light incident surface so that the light is deflected sideways. Incident to the outgoing fiber 11 can be avoided.
  • the oblique polishing on the end face of the optical tap lens 12 there arises a problem that a process requiring considerable accuracy is required.
  • the optical tap lens 12 can efficiently suppress the phenomenon in which the light emitted from the light emitting fiber 11 is partially reflected by the incident surface of the optical tap lens 12 and returns to the light emitting fiber 11. How to achieve this is an important issue.
  • the present invention was made to solve the above-described problems of the prior art, and efficiently suppresses a phenomenon in which the signal light emitted from the light emitting fiber partially reflects on the incident surface and returns to the light emitting fiber.
  • An object of the present invention is to provide an inexpensive optical tap module that can be used.
  • an optical tap module comprising: an optical fiber for incident light; an optical tap lens comprising a rod lens having a spherical or aspherical incident end surface; an optical tap filter; and a photodiode.
  • the lens for use is characterized in that the normal line at the center of the spherical surface or aspheric surface of the incident side end surface is formed in a shape inclined at a predetermined angle with respect to the optical axis of the optical tap module.
  • the present invention provides the optical tap lens according to the above-mentioned invention, wherein the normal line at the center position of the spherical surface or aspherical surface of the incident side end surface is at an angle of 5 ° to 10 ° with respect to the optical axis of the optical tap module. It is formed in the shape inclined by.
  • the present invention provides the optical tap lens according to the above invention, wherein the position of the spherical or aspherical optical axis of the incident side end surface is shifted by 0.1 mm to 0.3 mm with respect to the optical axis of the optical tap module. It is formed in a different shape.
  • the optical tap lens is a rod lens whose reflection side end surface is a spherical surface or an aspherical surface.
  • the present invention is characterized in that, in the above-mentioned invention, the optical tap lens has a tap filter film directly coated on a reflection side end face.
  • the present invention is characterized in that, in the above-mentioned invention, the optical tap lens is an integrally molded glass lens.
  • the optical tap lens is configured such that the normal line at the center position of the spherical surface or aspherical surface of the incident side end surface is inclined at a predetermined angle with respect to the optical axis of the optical tap module. Therefore, it is possible to efficiently suppress the phenomenon that the signal light emitted from the light emitting fiber is partially reflected on the incident surface and returns to the light emitting fiber. In particular, it is possible to provide an efficient and inexpensive optical tab module because a process or the like that requires the accuracy of performing oblique polishing on the end face of the optical tap lens is not required.
  • the tap filter film is directly coated on the reflection side end face of the optical tap lens, the manufacturing process and the mounting process of the optical filter can be omitted, and a cheaper and more efficient optical tap module is provided. be able to.
  • FIG. 1 is a longitudinal sectional view of a tap lens for explaining an embodiment of the invention.
  • FIG. 2 is an enlarged longitudinal sectional view of a lens portion of a tap lens for explaining an embodiment of the present invention.
  • FIG. 3 shows data comparing the coupling efficiency in the case of using the optical tap lens with the conventional GRIN lens and the coupling efficiency in the case of using the optical tap lens according to the present invention.
  • FIG. 4 is a longitudinal sectional view of a conventional tap lens.
  • FIG. 5 is an enlarged vertical sectional view of a portion where light enters and exits from the fiber of the conventional tap lens for explaining the necessity of oblique polishing.
  • the optical tap module shown in FIG. 1 includes a light emitting fiber 1, a light tap lens 2, a light incident fiber 3, an optical filter 4, a condenser lens 5, and a photodiode 6.
  • the light emitting fiber 1 is an optical fiber that emits signal light to the optical tap lens 2, and is located at a position shifted by a predetermined distance from the optical axis of the optical tap module.
  • the light incident fiber 3 is an optical fiber for receiving signal light, and is located at a position symmetrical to the outgoing light fiber 1 via the optical axis of the optical tap module.
  • the condensing lens 5 is a lens for condensing the signal light transmitted through the optical filter 4, and the photodiode 6 is an element that detects the intensity of the signal light collected by the condensing lens 5.
  • the optical tap lens 2 is not a GRIN lens used in the prior art, but a rod lens having an incident side end surface formed into a spherical surface. As shown in FIG. 2, the incident-side end face is formed in a shape in which the normal line AB at the center position is inclined at an angle of 8 ° with respect to the optical axis CD of the optical tap module. The reason for this is to suppress a phenomenon in which the signal light emitted from the light emitting fiber 1 is partially reflected on the incident side end face and returns to the light emitting fiber 1.
  • the incident-side end surface of the optical tap lens 2 can be an aspherical surface that means a curved surface that is not a flat surface or a spherical surface.
  • the inclination angle is not limited to 8 °, and may be 5 ° to 10 °.
  • the coupling efficiency when the signal light incident on the optical tap lens 2 and reflected by the optical filter 4 enters the light incident fiber 3 decreases. For this reason, the reflected light does not return to the light emitting fiber 1, and an angle of 5 ° to 10 ° is effective as an angle at which good coupling efficiency is obtained.
  • the optical filter 4 is a filter that transmits part of the signal light incident on the optical tap lens 2 and reflects the remaining signal light.
  • the optical filter 4 can be realized by directly coating the reflection side end face of the optical tap lens 2 with a tap filter film.
  • the reflection side end surface of the optical tap lens 2 is formed into a spherical surface or an aspherical surface.
  • the optical tap module having the above-described configuration, a predetermined amount of signal light transmitted through the optical filter 4 out of the signal light incident on the optical tap lens 2 from the light emitting fiber 1 is transmitted by the condenser lens 5 to the photodiode. 6, the remaining signal light reflected by the optical filter 4 is incident on the light incident fiber 3.
  • the incident-side end surface of the optical tap lens 2 is a spherical surface or an aspherical surface, and the normal line at the center position is inclined at an angle of 8 ° with respect to the optical axis of the optical tap module. It is possible to suppress a phenomenon in which the signal light emitted from the light emitting fiber 1 is partially reflected on the incident side end face and returns to the light emitting fiber 1. Moreover, since this angle is 8 °, good coupling efficiency can be obtained.
  • optical filter 4 is incident on the optical tap lens 2 and is directly coated with the tap filter film on the reflection side end face, the manufacturing process and the mounting process of the optical filter 4 can be omitted, and the optical filter 4 is more inexpensive.
  • An efficient optical tap module can be provided.
  • FIG. 3 shows data comparing the coupling efficiency when the optical tap lens using the conventional GRIN lens is used and the coupling efficiency when the optical tap lens according to the present invention is used.
  • the light amount of the return side insertion loss IN is X1
  • the light amount of OUT (reflected and enters the OUT side fiber) is X2
  • the values measured as the logarithm of X2 / X1 are shown in FIG. Show.
  • the average value of the insertion loss on the return side when the optical tap lens using the conventional GRIN lens is “0.1198 dB”, whereas the optical tap lens according to the present invention is used.
  • the average value of the return side insertion loss is “0.1054 dB”, which indicates that the coupling efficiency is improved.
  • the optical tap module according to the present invention is suitable for efficiently suppressing the phenomenon that the signal light emitted from the light emitting fiber partially reflects on the incident surface and returns to the light emitting fiber.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

Among signal light inputted to an optical tap lens (2) from a light-outputting fiber (1), signal light of a predetermined quantity that passed through an optical filter (4) is detected by a photodiode (6) using a light collecting lens (5), and the rest of the signal light reflected by the optical filter (4) is inputted to a light-inputting fiber (3). The input-side end surface of the optical tap lens (2) has a spherical or aspherical shape, with a normal line at the center position tilted at an angle of 8° with respect to the optical axis of the optical tap module. Excellent coupling efficiency can be obtained, while suppressing a phenomenon of having the reflected light from the input-side end surface returned to the light-outputting fiber (1).

Description

光タップモジュールOptical tap module
　本発明は、光通信や光計測の分野で伝送路として用いられる光ファイバー内を伝搬する信号光を監視する際に利用される光タップモジュールに関する。 The present invention relates to an optical tap module used when monitoring signal light propagating in an optical fiber used as a transmission line in the fields of optical communication and optical measurement.
　光通信システムや光計測システムなどの分野では、システムを監視する観点から光ファイバー内を伝搬する信号光の有無やその強度を検知する必要がある。また、増幅器や変調器などの信号光に作用を及ぼす装置を用いる場合には、その作用の結果を把握するために信号光を監視する必要がある。 In the fields of optical communication systems and optical measurement systems, it is necessary to detect the presence and intensity of signal light propagating in the optical fiber from the viewpoint of monitoring the system. Further, when using a device that acts on signal light such as an amplifier or a modulator, it is necessary to monitor the signal light in order to grasp the result of the action.
　このため、所定の分岐比を有する分岐手段を用いて光ファイバーから信号光の一部を分岐し、分岐した信号光を光検出器で検知することで、信号光を監視する従来技術が知られている。具体的には、光ファイバー内を伝搬する信号光を分岐する場合には、光ファイバーを小さな曲率で曲げたり、クラッドに切削溝を設けることにより、光ファイバー内を伝搬する信号光の一部を漏れ光として取り出すことができる。また、光ファイバーを含む光導波路を伝搬する信号光を分岐する場合には、光導波路を所定の分岐比で分岐した分岐導波路を利用することもできる。 For this reason, a conventional technique for monitoring signal light by branching a part of signal light from an optical fiber using a branching means having a predetermined branching ratio and detecting the branched signal light with a photodetector is known. Yes. Specifically, when the signal light propagating in the optical fiber is branched, a part of the signal light propagating in the optical fiber is set as leakage light by bending the optical fiber with a small curvature or providing a cutting groove in the cladding. It can be taken out. Further, when branching the signal light propagating through the optical waveguide including the optical fiber, a branching waveguide obtained by branching the optical waveguide at a predetermined branching ratio can be used.
　一方、光ファイバー内を伝搬する光信号の一部を分岐するのではなく、該光ファイバーから出力されて空間を伝搬する信号光からその一部の信号光を分岐する従来技術も知られている。具体的には、空間を伝播する信号光を分岐する場合には、光学フィルターを用いて信号光の一部を透過させることにより、一部の信号光のみを取り出すことができる。かかる光学フィルターとして波長依存性を持たないニュートラルデンシティーフィルターを用いると、信号光から一定の比率で光を取り出すことができ、しかもその比率は波長によらず一定となる。このような分岐器が光タップと呼ばれ、これを構成する光学部品を一体化したものが光タップモジュールと呼ばれる。また光タップに用いられる光学フィルターはタップフィルターと呼ばれる。 On the other hand, there is also known a prior art in which a part of an optical signal propagating in an optical fiber is not branched, but a part of the signal light is branched from the signal light output from the optical fiber and propagating in space. Specifically, when the signal light propagating in the space is branched, only a part of the signal light can be extracted by transmitting a part of the signal light using an optical filter. When a neutral density filter having no wavelength dependency is used as such an optical filter, light can be extracted from the signal light at a constant ratio, and the ratio is constant regardless of the wavelength. Such a branching device is called an optical tap, and an integrated optical component constituting the branching device is called an optical tap module. An optical filter used for an optical tap is called a tap filter.
　例えば、特許文献１には、この光タップモジュールに関する従来技術として、出射側の光ファイバーと、光ファイバーより出射される光を集光するレンズと、レンズの集光点に端面が配置された入射側の光ファイバーと、レンズと入射側の光ファイバーとの間に配置された透過型の半導体受光素子とを設けることで、部品点数を少なくするとともに組立作業を容易にする技術が開示されている。 For example, Patent Document 1 discloses, as a conventional technique related to this optical tap module, an optical fiber on the emission side, a lens that collects light emitted from the optical fiber, and an incident side in which an end face is disposed at the condensing point of the lens. There has been disclosed a technique for reducing the number of components and facilitating assembly work by providing an optical fiber and a transmissive semiconductor light-receiving element disposed between the lens and the incident-side optical fiber.
　図４は、上記特許文献１に代表される従来の光タップ用レンズの縦断面図である。光出射用ファイバー１１から斜め研磨された端面を持つ光タップ用レンズ１２に入射し光学フィルター１４により所定の量透過して、残りは反射して戻り光として光入射用ファイバー１３に戻る。光学フィルター１４を透過した光は集光レンズ１５によって集光され、フォトダイオード１６により検知される。これにより、光信号の有無やその強度の検知を行うことが可能となる。 FIG. 4 is a longitudinal sectional view of a conventional optical tap lens represented by Patent Document 1 described above. The light is incident on an optical tap lens 12 having an end surface that is obliquely polished from the light emitting fiber 11, is transmitted through a predetermined amount by the optical filter 14, and the rest is reflected to return to the light incident fiber 13 as return light. The light transmitted through the optical filter 14 is collected by the condenser lens 15 and detected by the photodiode 16. This makes it possible to detect the presence / absence of an optical signal and its intensity.
　ここで、この光タップ用レンズ１２としては、従来屈折率分布型のＧＲＩＮレンズが用いられるのが一般的であるが、上記ＧＲＩＮレンズを光タップ用レンズ１２として用いた場合には、光タップ用レンズ１２の戻り側挿入損失が大きくなってしまう。つまり、光学フィルター１４で反射された光が全て光入射用ファイバー１３に全て戻るわけではなく、少なからず光損失が生じてしまうため、結合効率が十分とは言えなくなる。このため、特許文献２には、収差の影響を受けず光軸調整が容易で光ビームのコリメーションや集光性が良好な非球面ロッドレンズを用いることで、光結合点において結合効率を高くする技術が開示されている。 Here, as the optical tap lens 12, a gradient index GRIN lens is generally used. However, when the GRIN lens is used as the optical tap lens 12, the optical tap lens 12 is used. The insertion loss on the return side of the lens 12 becomes large. That is, not all of the light reflected by the optical filter 14 returns to the light incident fiber 13, and not a little light loss occurs. Therefore, it cannot be said that the coupling efficiency is sufficient. For this reason, in Patent Document 2, the coupling efficiency is increased at the optical coupling point by using an aspherical rod lens that is easy to adjust the optical axis without being affected by aberrations and that has good collimation and condensing properties of the light beam. Technology is disclosed.
特開２００５－４１２３号公報Japanese Patent Laid-Open No. 2005-4123 特開２００３－１９５０１２号公報JP 2003-195012 A
　しかしながら、非球面ロッドレンズからなる光タップ用レンズ１２を用いたとしても、光出射用ファイバー１１から出た信号光がこの光タップ用レンズ１２の入射面で一部反射して光出射用ファイバー１１に戻る現象が生ずる。 However, even if the optical tapping lens 12 formed of an aspherical rod lens is used, the signal light emitted from the light emitting fiber 11 is partially reflected by the incident surface of the optical tapping lens 12, and the light emitting fiber 11 is used. The phenomenon of returning to
　このため、図５に示すように、光タップ用レンズ１２の端面に斜め研磨を施すことで、反射光の一部が光出射用ファイバー１１に戻る現象を避ける技術が知られている。具体的には、光出射用ファイバー１１から出射された光のうち透過光Ａがそのまま光タップ用レンズ１２に入射され、反射した光Ｂも入射面が傾斜しているため、横へそれて光出射用ファイバー１１への入射を避けることができる。しかし、この光タップ用レンズ１２の端面に斜め研磨を行うには、かなりの精度が要求される工程が必要になるという問題が生ずる。 For this reason, as shown in FIG. 5, a technique for avoiding a phenomenon in which a part of the reflected light returns to the light emitting fiber 11 by performing oblique polishing on the end face of the optical tap lens 12 is known. Specifically, among the light emitted from the light emitting fiber 11, the transmitted light A is directly incident on the optical tap lens 12, and the reflected light B also has a light incident surface so that the light is deflected sideways. Incident to the outgoing fiber 11 can be avoided. However, in order to perform the oblique polishing on the end face of the optical tap lens 12, there arises a problem that a process requiring considerable accuracy is required.
　これらのことから、光出射用ファイバー１１から出た光が光タップ用レンズ１２の入射面で一部反射して光出射用ファイバー１１に戻る現象を効率良く抑制することができる光タップ用レンズ１２をいかに実現するかが重要な課題となっている。 For these reasons, the optical tap lens 12 can efficiently suppress the phenomenon in which the light emitted from the light emitting fiber 11 is partially reflected by the incident surface of the optical tap lens 12 and returns to the light emitting fiber 11. How to achieve this is an important issue.
　本発明は、上記従来技術の課題を解決するためになされたものであって、光出射用ファイバーから出た信号光が入射面で一部反射して光出射用ファイバーに戻る現象を効率良く抑制することができる安価な光タップモジュールを提供することを目的とする。 The present invention was made to solve the above-described problems of the prior art, and efficiently suppresses a phenomenon in which the signal light emitted from the light emitting fiber partially reflects on the incident surface and returns to the light emitting fiber. An object of the present invention is to provide an inexpensive optical tap module that can be used.
　上記従来技術の課題を解決するため、本発明は、光タップモジュールの光軸にずらして位置した出射光用ファイバーと、該光タップモジュールの光軸を介して前記出射光用ファイバーと対称の位置にある入射光用ファイバーと、入射側端面が球面もしくは非球面に形成されたロッドレンズからなる光タップ用レンズと、光タップフィルターと、フォトダイオードとからなる光タップモジュールであって、前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の中心位置における法線が該光タップモジュールの光軸に対して所定の角度で傾斜した形状で形成されることを特徴とする。 In order to solve the above-described problems of the prior art, the present invention provides an output light fiber that is shifted from the optical axis of the optical tap module, and a position symmetrical to the output light fiber via the optical axis of the optical tap module. An optical tap module comprising: an optical fiber for incident light; an optical tap lens comprising a rod lens having a spherical or aspherical incident end surface; an optical tap filter; and a photodiode. The lens for use is characterized in that the normal line at the center of the spherical surface or aspheric surface of the incident side end surface is formed in a shape inclined at a predetermined angle with respect to the optical axis of the optical tap module.
　また、本発明は、上記発明において、前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の中心位置における法線が該光タップモジュールの光軸に対して５°～１０゜の角度で傾斜した形状で形成されることを特徴とする。 Further, the present invention provides the optical tap lens according to the above-mentioned invention, wherein the normal line at the center position of the spherical surface or aspherical surface of the incident side end surface is at an angle of 5 ° to 10 ° with respect to the optical axis of the optical tap module. It is formed in the shape inclined by.
　また、本発明は、上記発明において、前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の光軸が光タップモジュールの光軸に対してその位置が０．１ｍｍ～０．３ｍｍずらした形状で形成されることを特徴とする。 Further, the present invention provides the optical tap lens according to the above invention, wherein the position of the spherical or aspherical optical axis of the incident side end surface is shifted by 0.1 mm to 0.3 mm with respect to the optical axis of the optical tap module. It is formed in a different shape.
　また、本発明は、上記発明において、前記光タップ用レンズは、反射側端面が球面もしくは非球面からなるロッドレンズであることを特徴とする。 Further, the present invention is characterized in that, in the above invention, the optical tap lens is a rod lens whose reflection side end surface is a spherical surface or an aspherical surface.
　また、本発明は、上記発明において、前記光タップ用レンズは、反射側端面に直接タップフィルター膜をコーティングしたことを特徴とする。 Further, the present invention is characterized in that, in the above-mentioned invention, the optical tap lens has a tap filter film directly coated on a reflection side end face.
　　また、本発明は、上記発明において、前記光タップ用レンズは、一体成型されたガラスレンズであることを特徴とする。 Also, the present invention is characterized in that, in the above-mentioned invention, the optical tap lens is an integrally molded glass lens.
　本発明によれば、光タップ用レンズが、入射側端面の球面もしくは非球面の中心位置における法線が該光タップモジュールの光軸に対して所定の角度で傾斜した形状で形成されるよう構成したので、光出射用ファイバーから出た信号光が入射面で一部反射して光出射用ファイバーに戻る現象を効率良く抑制することができる。特に、光タップ用レンズの端面に斜め研磨を行う精度が要求される工程等が不要となるので、効率的かつ安価な光タッブモジュールを提供することが可能となる。 According to the present invention, the optical tap lens is configured such that the normal line at the center position of the spherical surface or aspherical surface of the incident side end surface is inclined at a predetermined angle with respect to the optical axis of the optical tap module. Therefore, it is possible to efficiently suppress the phenomenon that the signal light emitted from the light emitting fiber is partially reflected on the incident surface and returns to the light emitting fiber. In particular, it is possible to provide an efficient and inexpensive optical tab module because a process or the like that requires the accuracy of performing oblique polishing on the end face of the optical tap lens is not required.
　また、光タップ用レンズの反射側端面に直接タップフィルター膜をコーティングするよう構成したので、光フィルターの製造工程及び装着工程を省略することができ、より安価で効率的な光タップモジュールを提供することができる。 In addition, since the tap filter film is directly coated on the reflection side end face of the optical tap lens, the manufacturing process and the mounting process of the optical filter can be omitted, and a cheaper and more efficient optical tap module is provided. be able to.
図１は、発明の実施例を説明するためのタップレンズの縦断面図である。FIG. 1 is a longitudinal sectional view of a tap lens for explaining an embodiment of the invention. 図２は、本発明の実施例を説明するためのタップレンズのレンズ部分の拡大縦断面図である。FIG. 2 is an enlarged longitudinal sectional view of a lens portion of a tap lens for explaining an embodiment of the present invention. 図３は、従来のＧＲＩＮレンズによる光タップ用レンズを用いた場合の結合効率と本発明に係る光タップ用レンズを用いた場合の結合効率とを対比したデータである。FIG. 3 shows data comparing the coupling efficiency in the case of using the optical tap lens with the conventional GRIN lens and the coupling efficiency in the case of using the optical tap lens according to the present invention. 図４は、従来のタップレンズの縦断面図である。FIG. 4 is a longitudinal sectional view of a conventional tap lens. 図５は、斜め研磨の必要性を説明するための従来のタップレンズのファイバーからタップレンズに光が入発射する部分の拡大縦断面図である。FIG. 5 is an enlarged vertical sectional view of a portion where light enters and exits from the fiber of the conventional tap lens for explaining the necessity of oblique polishing.
　以下に、添付図面を参照して、本発明に係る光タップモジュールの好適な実施例について説明する。 Hereinafter, preferred embodiments of an optical tap module according to the present invention will be described with reference to the accompanying drawings.
　図１に示す光タップモジュールは、光出射用ファイバー１と、光タップ用レンズ２と、光入射用ファイバー３と、光学フィルター４と、集光レンズ５と、フォトダイオード６とを有する。 The optical tap module shown in FIG. 1 includes a light emitting fiber 1, a light tap lens 2, a light incident fiber 3, an optical filter 4, a condenser lens 5, and a photodiode 6.
　光出射用ファイバー１は、光タップ用レンズ２に信号光を出射する光ファイバーであり、光タップモジュールの光軸から所定の距離だけずらした位置に所在する。光入射用ファイバー３は、信号光を入射する光ファイバーであり、光タップモジュールの光軸を介して出射光用ファイバー１と対称の位置に所在する。 The light emitting fiber 1 is an optical fiber that emits signal light to the optical tap lens 2, and is located at a position shifted by a predetermined distance from the optical axis of the optical tap module. The light incident fiber 3 is an optical fiber for receiving signal light, and is located at a position symmetrical to the outgoing light fiber 1 via the optical axis of the optical tap module.
　集光レンズ５は、光学フィルター４を透過した信号光を集光するためのレンズであり、フォトダイオード６は、集光レンズ５によって集光された信号光の強度を検知する素子である。 The condensing lens 5 is a lens for condensing the signal light transmitted through the optical filter 4, and the photodiode 6 is an element that detects the intensity of the signal light collected by the condensing lens 5.
　光タップ用レンズ２は、従来技術で用いられるＧＲＩＮレンズではなく、入射側端面が球面に形成されたロッドレンズである。この入射側端面は、図２に示すように、中心位置における法線ＡＢが該光タップモジュールの光軸ＣＤに対して８°の角度で傾斜した形状で形成されている。このようにした理由は、光出射用ファイバー１から出た信号光が入射側端面で一部反射して光出射用ファイバー１に戻る現象を抑制するためである。 The optical tap lens 2 is not a GRIN lens used in the prior art, but a rod lens having an incident side end surface formed into a spherical surface. As shown in FIG. 2, the incident-side end face is formed in a shape in which the normal line AB at the center position is inclined at an angle of 8 ° with respect to the optical axis CD of the optical tap module. The reason for this is to suppress a phenomenon in which the signal light emitted from the light emitting fiber 1 is partially reflected on the incident side end face and returns to the light emitting fiber 1.
　この光タップ用レンズ２の入射側端面は、平面及び球面ではない曲面を意味する非球面とすることもできる。また、傾斜角は、８°に限定されるものではなく、５°～１０゜にすることもできる。光出射用ファイバー１から出た信号光が入射側端面で一部反射して光出射用ファイバー１に戻る現象を抑制するためには、かかる傾斜角を大きくすることが望まれる。その一方で、この傾斜角を過度に大きくすると、光タップ用レンズ２に入射し、光学フィルター４で反射した信号光が光入射用ファイバー３に入射する際の結合効率が低下する。このため、反射光が光出射用ファイバー１に戻らず、良好な結合効率が得られる角度として５°～１０°が有効となる。 The incident-side end surface of the optical tap lens 2 can be an aspherical surface that means a curved surface that is not a flat surface or a spherical surface. Further, the inclination angle is not limited to 8 °, and may be 5 ° to 10 °. In order to suppress a phenomenon in which the signal light emitted from the light emitting fiber 1 is partially reflected by the incident-side end face and returns to the light emitting fiber 1, it is desirable to increase the inclination angle. On the other hand, if the inclination angle is excessively increased, the coupling efficiency when the signal light incident on the optical tap lens 2 and reflected by the optical filter 4 enters the light incident fiber 3 decreases. For this reason, the reflected light does not return to the light emitting fiber 1, and an angle of 5 ° to 10 ° is effective as an angle at which good coupling efficiency is obtained.
　光学フィルター４は、光タップ用レンズ２に入射した信号光のうちの一部を透過させ、残余の信号光を反射させるフィルターである。この光学フィルター４は、光タップ用レンズ２の反射側端面に直接タップフィルター膜をコーティングすることにより実現することができる。この場合には、光タップ用レンズ２の反射側端面が球面もしくは非球面に形成される。 The optical filter 4 is a filter that transmits part of the signal light incident on the optical tap lens 2 and reflects the remaining signal light. The optical filter 4 can be realized by directly coating the reflection side end face of the optical tap lens 2 with a tap filter film. In this case, the reflection side end surface of the optical tap lens 2 is formed into a spherical surface or an aspherical surface.
　上記構成を有する光タップモジュールを用いることにより、光出射用ファイバー１から光タップ用レンズ２に入射した信号光のうち、光学フィルター４を透過した所定量の信号光が集光レンズ５によりフォトダイオード６に検知され、光学フィルター４で反射した残りの信号光が光入射用ファイバー３に入射されることになる。 By using the optical tap module having the above-described configuration, a predetermined amount of signal light transmitted through the optical filter 4 out of the signal light incident on the optical tap lens 2 from the light emitting fiber 1 is transmitted by the condenser lens 5 to the photodiode. 6, the remaining signal light reflected by the optical filter 4 is incident on the light incident fiber 3.
　ここで、光タップ用レンズ２の入射側端面は、球面もしくは非球面であり、中心位置における法線が該光タップモジュールの光軸に対して８°の角度で傾斜した形状とされているため、光出射用ファイバー１から出た信号光が入射側端面で一部反射して光出射用ファイバー１に戻る現象を抑制することができる。また、かかる角度が８°であるため、良好な結合効率が得られる。 Here, the incident-side end surface of the optical tap lens 2 is a spherical surface or an aspherical surface, and the normal line at the center position is inclined at an angle of 8 ° with respect to the optical axis of the optical tap module. It is possible to suppress a phenomenon in which the signal light emitted from the light emitting fiber 1 is partially reflected on the incident side end face and returns to the light emitting fiber 1. Moreover, since this angle is 8 °, good coupling efficiency can be obtained.
　また、光学フィルター４は、光タップ用レンズ２に入射し反射側端面に直接タップフィルター膜をコーティングすることとしたので、光学フィルター４の製造工程及び装着工程を省略することができ、より安価で効率的な光タップモジュールを提供することが可能となる。 In addition, since the optical filter 4 is incident on the optical tap lens 2 and is directly coated with the tap filter film on the reflection side end face, the manufacturing process and the mounting process of the optical filter 4 can be omitted, and the optical filter 4 is more inexpensive. An efficient optical tap module can be provided.
　図３は、従来のＧＲＩＮレンズによる光タップ用レンズを用いた場合の結合効率と本発明に係る光タップ用レンズを用いた場合の結合効率とを対比したデータである。結合効率を示す指標として、戻り側挿入損失ＩＮの光量をＸ１とし、ＯＵＴ（反射して戻ってＯＵＴ側ファイバに入る）の光量をＸ２とし、Ｘ２／Ｘ１の対数として測定した値を図３に示している。 FIG. 3 shows data comparing the coupling efficiency when the optical tap lens using the conventional GRIN lens is used and the coupling efficiency when the optical tap lens according to the present invention is used. As an index indicating the coupling efficiency, the light amount of the return side insertion loss IN is X1, the light amount of OUT (reflected and enters the OUT side fiber) is X2, and the values measured as the logarithm of X2 / X1 are shown in FIG. Show.
　図３に示すように、従来のＧＲＩＮレンズによる光タップ用レンズを用いた場合の戻り側挿入損失の平均値が「０．１１９８ｄＢ」であるのに対し、本発明に係る光タップ用レンズを用いた場合の戻り側挿入損失の平均値は「０．１０５４ｄＢ」となり、その結合効率が改善されていることが分かる。 As shown in FIG. 3, the average value of the insertion loss on the return side when the optical tap lens using the conventional GRIN lens is “0.1198 dB”, whereas the optical tap lens according to the present invention is used. In this case, the average value of the return side insertion loss is “0.1054 dB”, which indicates that the coupling efficiency is improved.
　以上のように、本発明に係る光タップモジュールは、光出射用ファイバーから出た信号光が入射面で一部反射して光出射用ファイバーに戻る現象を効率良く抑制する場合に適している。 As described above, the optical tap module according to the present invention is suitable for efficiently suppressing the phenomenon that the signal light emitted from the light emitting fiber partially reflects on the incident surface and returns to the light emitting fiber.
　　１　光出射用ファイバー
　　２　光タップ用レンズ
　　３　光入射用ファイバー
　　４　光学フィルター
　　５　集光レンズ
　　６　フォトダイオード
　１１　光出射用ファイバー
　１２　光タップ用レンズ
　１３　光入射用ファイバー
　１４　光学フィルター
　１５　集光レンズ
　１６　フォトダイオード DESCRIPTION OF SYMBOLS 1 Light emission fiber 2 Optical tap lens 3 Light incident fiber 4 Optical filter 5 Condensing lens 6 Photodiode 11 Light emitting fiber 12 Optical tap lens 13 Light incident fiber 14 Optical filter 15 Condensing lens 16 Photodiode

Claims (6)

  1. 　光タップモジュールの光軸にずらして位置した出射光用ファイバーと、該光タップモジュールの光軸を介して前記出射光用ファイバーと対称の位置にある入射光用ファイバーと、入射側端面が球面もしくは非球面に形成されたロッドレンズからなる光タップ用レンズと、光タップフィルターと、フォトダイオードとからなる光タップモジュールであって、
    　前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の中心位置における法線が該光タップモジュールの光軸に対して所定の角度で傾斜した形状で形成される
    　ことを特徴とする光タップモジュール。     An outgoing light fiber that is shifted from the optical axis of the optical tap module, an incident light fiber that is symmetrical to the outgoing light fiber via the optical axis of the optical tap module, and an incident side end face that is spherical or An optical tap module comprising an optical tap lens formed of an aspherical rod lens, an optical tap filter, and a photodiode,
    The optical tap lens is formed such that a normal line at the center position of the spherical surface or the aspherical surface of the incident side end surface is inclined at a predetermined angle with respect to the optical axis of the optical tap module. Tap module.
  2. 　前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の中心位置における法線が該光タップモジュールの光軸に対して５°～１０゜の角度で傾斜した形状で形成されることを特徴とする請求項１に記載の光タップモジュール。 The optical tap lens is formed such that the normal line at the center of the spherical surface or aspherical surface of the incident side end surface is inclined at an angle of 5 ° to 10 ° with respect to the optical axis of the optical tap module. The optical tap module according to claim 1.
  3. 　前記光タップ用レンズは、前記入射側端面の球面もしくは非球面の光軸が光タップモジュールの光軸に対してその位置が０．１ｍｍ～０．３ｍｍずらした形状で形成されることを特徴とする請求項１に記載の光タップモジュール。 The optical tap lens is characterized in that a spherical or aspherical optical axis of the incident side end face is formed in a shape whose position is shifted by 0.1 mm to 0.3 mm with respect to the optical axis of the optical tap module. The optical tap module according to claim 1.
  4. 　前記光タップ用レンズは、反射側端面が球面もしくは非球面からなるロッドレンズであることを特徴とする請求項１、２又は３に記載の光タップモジュール。 4. The optical tap module according to claim 1, wherein the optical tap lens is a rod lens whose reflection side end surface is a spherical surface or an aspherical surface.
  5. 　前記光タップ用レンズは、反射側端面に直接タップフィルター膜をコーティングしたことを特徴とする請求項１、２又は３に記載の光タップモジュール。 The optical tap module according to claim 1, 2 or 3, wherein the optical tap lens is obtained by coating a tap filter film directly on a reflection side end face.
  6. 　前記光タップ用レンズは、一体成型されたガラスレンズであることを特徴とする請求項１に記載の光タップモジュール。 The optical tap module according to claim 1, wherein the optical tap lens is an integrally molded glass lens.
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WO2020000775A1 (en) * 2018-06-29 2020-01-02 昂纳信息技术（深圳）有限公司 Compact tap pd

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JP2007219514A (en) * 2006-02-16 2007-08-30 Nippon Sheet Glass Co Ltd Optical tap module

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JP2003195012A (en) * 2001-09-27 2003-07-09 Matsushita Electric Ind Co Ltd Aspherical rod lens and its manufacturing method
JP2004006638A (en) * 2002-03-15 2004-01-08 Pactonix Inc High performance high reliability small optical power monitor and its manufacturing method
JP2005123778A (en) * 2003-10-15 2005-05-12 Matsushita Electric Ind Co Ltd Optical composite component and optical transmission system employing the same
WO2006080143A1 (en) * 2005-01-31 2006-08-03 Hitachi Metals, Ltd. Optical power monitor and its manufacturing method
JP2007219514A (en) * 2006-02-16 2007-08-30 Nippon Sheet Glass Co Ltd Optical tap module

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020000775A1 (en) * 2018-06-29 2020-01-02 昂纳信息技术（深圳）有限公司 Compact tap pd

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