JPS62191803A - Asymmetrical spherical working focusing rod lens - Google Patents
Asymmetrical spherical working focusing rod lensInfo
- Publication number
- JPS62191803A JPS62191803A JP3453386A JP3453386A JPS62191803A JP S62191803 A JPS62191803 A JP S62191803A JP 3453386 A JP3453386 A JP 3453386A JP 3453386 A JP3453386 A JP 3453386A JP S62191803 A JPS62191803 A JP S62191803A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- curvature
- spherical surface
- rod lens
- coupling efficiency
- 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.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 claims abstract description 13
- 230000008878 coupling Effects 0.000 abstract description 24
- 238000010168 coupling process Methods 0.000 abstract description 24
- 238000005859 coupling reaction Methods 0.000 abstract description 24
- 239000013307 optical fiber Substances 0.000 abstract description 11
- 239000000835 fiber Substances 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 230000004075 alteration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
Landscapes
- Lenses (AREA)
- Optical Couplings Of Light Guides (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は光線断面の形状が互いに相似でない光源と受光
側との光結合用のロッドレンズに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rod lens for optical coupling between a light source and a light-receiving side, in which the cross-sectional shapes of light rays are dissimilar to each other.
従来の技術
光線断面の形状が互いに相似でない光源と受光側との光
結合の一例として、例えば半導体レーザ(以後、LDと
称す。)と光ファイバとの結合が考えられる。多くの場
合、LDを出射した光は、その面内で非対称に分布して
おり、LDの活性層に対して垂直方向の放射全角は、L
Dの活性層に封1.−7”+平古面めi射仝糸のつ〜悶
泣1−1μ甑又よのもある。一方、光ファイバは、多く
の場合、コアは真円で光軸に対し面内で対称である。BACKGROUND ART As an example of optical coupling between a light source and a light receiving side whose cross-sectional shapes of light rays are not similar to each other, for example, coupling between a semiconductor laser (hereinafter referred to as LD) and an optical fiber can be considered. In many cases, the light emitted from the LD is distributed asymmetrically within its plane, and the total radiation angle perpendicular to the active layer of the LD is L
Seal in the active layer of D1. -7"+Hirakomenmei firing thread ~ 1-1μKoshikimatayo. On the other hand, in most optical fibers, the core is a perfect circle and is symmetrical in the plane with respect to the optical axis. It is.
このLDからの出力光を光ファイバに結合させるのに、
集束性ロッドレンズの入射端を半球状に加工したレンズ
を用いて光を小さく集束させることがよく行なわれる。To couple the output light from this LD to an optical fiber,
It is often done to focus light into a small size using a converging rod lens whose input end is processed into a hemispherical shape.
この方法は、光源、レンズ。This method uses a light source and a lens.
光ファイバそれぞれの間を多少離せるので、光源の気密
パッケージ化が容易であり、レンズが大きいのでレンズ
のトレランスが緩い等の利点がある。Since the optical fibers can be spaced apart from each other to some extent, the light source can be easily packaged in an airtight manner, and since the lens is large, the tolerance of the lens is relaxed.
また、集束性ロッドレンズの入射端を半球状に加工して
、レンズのNAを増大し、低収差化を図ったもので、入
射端が平面の集束性ロッドレンズを用いる場合に比較し
て結合効率の向上を達成しており、4〜edBの結合効
率を得ている。In addition, the input end of the convergent rod lens is processed into a hemispherical shape to increase the NA of the lens and reduce aberrations, making it possible to combine better than when using a convergent rod lens with a flat input end. An improvement in efficiency has been achieved, with a coupling efficiency of 4 to edB.
発明が解決しようとする問題点
この様な従来の方法では、LDの偏平な出力光を偏平な
ままで円形断面のファイバに結合させているためにモー
ド整合がとりにくく、結合効率の向上に限界があった。Problems to be Solved by the Invention In such conventional methods, since the flat output light of the LD is coupled to the circular cross-section fiber while remaining flat, mode matching is difficult to achieve, and there is a limit to the improvement of coupling efficiency. was there.
本発明はかかる点に鑑みてなされたもので、簡単な構成
で、縦・横で収束の強さを異ならせ、光源側と受光側と
の光線断面の形状を互いに相似になる様に変形してモー
ド整合を良くし結合効率を向上することを目的としてい
る。The present invention has been made in view of the above points, and has a simple configuration that changes the strength of convergence vertically and horizontally and deforms the shapes of the cross sections of the light rays on the light source side and the light receiving side so that they are similar to each other. The purpose is to improve mode matching and improve coupling efficiency.
問題点を解決するだめの手段
本発明は上記した例の様に、光線断面の形状が互いに相
似でないものの間で光結合を行なう場合に出てくる問題
点を解決するために、集束性ロッドレンズの光軸に対し
て垂直に、少なくとも一面の非対称な球面を加工するこ
とを時機とする非対称球面加工集束性ロンドレンズを提
供するものである。Means for Solving the Problems The present invention provides a converging rod lens in order to solve the problems that occur when optical coupling is performed between objects whose cross-sectional shapes of light rays are not similar to each other, as in the above-mentioned example. The object of the present invention is to provide an asymmetric spherically processed focusing Rondo lens in which at least one asymmetric spherical surface is processed perpendicularly to the optical axis of the lens.
作 用
本発明は、光結合しようとする一対の光線断面の形状に
対応させて、集束性ロッドレンズの入射面あるいは出射
面の少なくとも一方を非対称に球面加工することにより
、集束の強さを異ならせ、結合効率を高めるものである
。Function The present invention makes it possible to vary the strength of focusing by asymmetrically processing at least one of the entrance surface or the exit surface of the focusing rod lens into a spherical surface in accordance with the shape of the cross section of a pair of light rays to be optically coupled. This increases the coupling efficiency.
実施例
本発明の一実施例として、出力光の偏平なLDとシング
ルモード光ファイバ(以下、SMFと称す。)との結合
を述べる。Embodiment As an embodiment of the present invention, coupling of output light between a flat LD and a single mode optical fiber (hereinafter referred to as SMF) will be described.
本実施例のLDはDHレーザで、出力光の波長は1.3
μm、LDからの出力光の放射全角は、活ア径が10μ
mで、N、A、は8.5°である。この両者の結合のた
めに用いる集束性ロンドレンズの屈折率分布定数は0.
4121. 中心屈折率は1.636である。レンズ長
は、加工の容易さを考慮して、3mmとした。また、L
D=レンズ間距離は、レンズ端面からのLDへの近端反
射を考慮して、0.8mmとした。また、レンズエフ1
4フ間距離は、パッケージ等の問題から、5m以上離す
ことにした。The LD in this example is a DH laser, and the wavelength of the output light is 1.3
μm, the total radiation angle of the output light from the LD is 10μm when the active diameter is 10μm.
m, N, A, is 8.5°. The refractive index distribution constant of the converging Rondo lens used to combine these two is 0.
4121. The center refractive index is 1.636. The lens length was set to 3 mm in consideration of ease of processing. Also, L
D = inter-lens distance was set to 0.8 mm in consideration of near-end reflection from the lens end face to the LD. Also, Lens F 1
The distance between the four frames was decided to be at least 5 meters apart due to issues such as packaging.
以上の条件で、本A明の非対称球面加工集束性ロッドレ
ンズを用いて最高の結合効率を得ることを試みた。Under the above conditions, an attempt was made to obtain the highest coupling efficiency using the asymmetric spherically processed focusing rod lens of the present invention.
本発明の非対称球面加工集束性ロッドレンズの最もシン
プルな形として、本実施例では、レンズの入射面に、縦
方向と横方向で曲率半径の異なる非対称球面を加工した
。まず、LDの活性層に対して垂直方向に拡がる出力光
の放射全角は500であるから、対応するレンズの曲率
半径を3.58閣とした。この時、レンズからの光の出
射角度は了0であり、使用したSMFのN、A、 よ
りも小さく、また、集束位置は、レンズから6.2瓢の
位置である。一方、LDの活性層に対して水平方向に拡
がる出力光の放射全期は1o0であるから、対応するレ
ンズの曲率半径を2.23m+とじた。この時、レンズ
からの光の出射角度は1.3°であり、使用したSMF
のN、A、より小さく、また、集束位置は、レンズから
6.2簡の位置で、前記、LDの垂直方向の光の集束位
置と一致する。この実施例での結合効率は、2〜3dB
が達成できた。As the simplest form of the asymmetric spherically machined converging rod lens of the present invention, in this example, an asymmetric spherical surface with different radii of curvature in the vertical and horizontal directions was machined on the entrance surface of the lens. First, since the total radiation angle of the output light that spreads in the direction perpendicular to the active layer of the LD is 500, the radius of curvature of the corresponding lens was set to 3.58 mm. At this time, the exit angle of the light from the lens is 0, which is smaller than N, A, of the SMF used, and the focusing position is 6.2 degrees from the lens. On the other hand, since the total radiation period of the output light that spreads in the horizontal direction with respect to the active layer of the LD is 1o0, the radius of curvature of the corresponding lens was set to 2.23 m+. At this time, the angle of light emission from the lens was 1.3°, and the SMF used
N and A are smaller, and the focusing position is 6.2 meters from the lens, which coincides with the vertical focusing position of the LD. The coupling efficiency in this example is 2-3 dB
was achieved.
なお、従来と同様に、曲率半径3.58mmで対称な球
面を加工した場合には、結合効率は4〜sdBであった
。この時の、活性層に対して水平方向の出力光の集束位
置は、6.38mであり、垂直方向のものと1.2膿程
ずれており、円形断面のファイバとモード整合がとりに
くく、結合効率の向上に限界があったものと考えられる
。Note that when a symmetrical spherical surface with a radius of curvature of 3.58 mm was processed as in the conventional case, the coupling efficiency was 4 to sdB. At this time, the focal position of the output light in the horizontal direction with respect to the active layer was 6.38 m, which was 1.2 m apart from the vertical one, making it difficult to achieve mode matching with the fiber with a circular cross section. It is thought that there was a limit to the improvement of coupling efficiency.
第1図、第2図に、本実施例の非対称球面加工集束性ロ
ッドレンズ3により、LD(半導体レーザ)1とファイ
バ2との光結合の様子を示す。第1図がレーザの活性層
に対して垂直方向の出射光の場合第2図は活性層に対し
て水平方向の出射光の場合である。本発明のレンズを用
いることにより、1〜4dBの結合効率の向上を図った
。1 and 2 show optical coupling between an LD (semiconductor laser) 1 and a fiber 2 using the asymmetric spherically processed focusing rod lens 3 of this embodiment. FIG. 1 shows the case of emitted light in a direction perpendicular to the active layer of the laser, and FIG. 2 shows the case of emitted light in the horizontal direction with respect to the active layer. By using the lens of the present invention, the coupling efficiency was improved by 1 to 4 dB.
なお、本実施例では、集束性ロッドレンズの入射面に縦
方向と横方向とで曲率半径の異なる球面を加工したが、
入射面は対称的な球面であり、出射面に曲率半径の異な
る球面を加工したものでも良い。In this example, a spherical surface with different radii of curvature in the vertical and horizontal directions was machined on the entrance surface of the focusing rod lens.
The entrance surface is a symmetrical spherical surface, and the exit surface may be machined with spherical surfaces having different radii of curvature.
なお、球面加工する場合の球面の中心軸は何本であって
も良く、また、その交わり方は、光結合をしようとする
ものの一対の形状に対応するものである。Note that when processing a spherical surface, there may be any number of central axes of the spherical surface, and the way in which they intersect corresponds to the shape of the pair of objects to be optically coupled.
なお、以上で述べた球面の曲率半径は、無限大の場合(
平面)をも含むものである。Note that the radius of curvature of the spherical surface described above is in the case of infinity (
It also includes planes.
なお、実施例では、−例としてLDと光ファイバの結合
について述べたが、例えばLDと光導波路、LDと光フ
アイバアレイ、光ファイバと光フグイバアレイ等どの様
な組合せでも良く、広く、光線断面の形状が互いに相似
でない光源と受光側との光結合に適用できるものである
。In the embodiment, the coupling of an LD and an optical fiber was described as an example, but any combination may be used, such as an LD and an optical waveguide, an LD and an optical fiber array, an optical fiber and an optical fiber array, etc. This can be applied to optical coupling between a light source and a light receiving side whose shapes are not similar to each other.
発明の効果
以上述べてきたように、本発明によれば、きわめて簡単
な構成で、高い結合効率を達成でき、実用的にきわめて
有用な光結合が可能となる。Effects of the Invention As described above, according to the present invention, high coupling efficiency can be achieved with an extremely simple configuration, and optical coupling that is extremely useful in practice becomes possible.
第1図、第2図は本発明の一実施例におけるLDと光フ
ァイバとの結合の様子を示す断面図で、第1図は活性層
に対して垂直方向の出射光の場合、第2図は活性層に対
して水平方向の出射光の場合を示す図である。
1・・・・・・半導体レーザ、2・・・・・・シングル
モードファイバ、3・・・・・・非対称球面加工集束性
ロッドレンズ。1 and 2 are cross-sectional views showing how an LD and an optical fiber are coupled in an embodiment of the present invention. FIG. 3 is a diagram showing a case where light is emitted in a horizontal direction with respect to the active layer. 1...Semiconductor laser, 2...Single mode fiber, 3...Asymmetric spherical processing focusing rod lens.
Claims (1)
1面が非対称な球面を有してなることを特徴とする非対
称球面加工集束性ロッドレンズ。An asymmetric spherically processed focusing rod lens, characterized in that at least one surface has an asymmetric spherical surface perpendicular to the optical axis of the focusing rod lens.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3453386A JPS62191803A (en) | 1986-02-18 | 1986-02-18 | Asymmetrical spherical working focusing rod lens |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3453386A JPS62191803A (en) | 1986-02-18 | 1986-02-18 | Asymmetrical spherical working focusing rod lens |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS62191803A true JPS62191803A (en) | 1987-08-22 |
Family
ID=12416912
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3453386A Pending JPS62191803A (en) | 1986-02-18 | 1986-02-18 | Asymmetrical spherical working focusing rod lens |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS62191803A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0587914A1 (en) * | 1992-04-06 | 1994-03-23 | The Furukawa Electric Co., Ltd. | Asymmetric lens |
KR100488337B1 (en) * | 2002-01-21 | 2005-05-11 | 주식회사 포엠 | Rotational asymmetric aspheric lens |
KR100583651B1 (en) | 2003-12-24 | 2006-05-26 | 한국전자통신연구원 | Method for packaging light transmission module |
-
1986
- 1986-02-18 JP JP3453386A patent/JPS62191803A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0587914A1 (en) * | 1992-04-06 | 1994-03-23 | The Furukawa Electric Co., Ltd. | Asymmetric lens |
EP0587914A4 (en) * | 1992-04-06 | 1994-09-14 | Furukawa Electric Co Ltd | Asymmetric lens |
KR100488337B1 (en) * | 2002-01-21 | 2005-05-11 | 주식회사 포엠 | Rotational asymmetric aspheric lens |
KR100583651B1 (en) | 2003-12-24 | 2006-05-26 | 한국전자통신연구원 | Method for packaging light transmission module |
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