JPH0638128B2 - Optical coupling lens - Google Patents
Optical coupling lensInfo
- Publication number
- JPH0638128B2 JPH0638128B2 JP22193585A JP22193585A JPH0638128B2 JP H0638128 B2 JPH0638128 B2 JP H0638128B2 JP 22193585 A JP22193585 A JP 22193585A JP 22193585 A JP22193585 A JP 22193585A JP H0638128 B2 JPH0638128 B2 JP H0638128B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- refracting surface
- light beam
- laser diode
- optical fiber
- 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.)
- Expired - Lifetime
Links
Landscapes
- Lenses (AREA)
- Optical Couplings Of Light Guides (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は光源と光回路間に配設され、光源と光回路を
光学的に結合する光結合用レンズに関する。The present invention relates to an optical coupling lens which is arranged between a light source and an optical circuit and optically couples the light source and the optical circuit.
従来、この種の光結合用レンズとしては、種々のものが
実施化され、例えば、IEEE/OSA LT-2NO.3、PP305-311に
記載された第１従来例が知られている。Conventionally, various types of optical coupling lenses have been put into practice, for example, a first conventional example described in IEEE / OSA LT-2NO.3, PP305-311 is known.
第１実施例は第２図に示すように、レーザダイオード１
からのレーザビームを単一モード光フアイバ２に集束さ
せる光結合器としてレーザダイオード１と単一モード光
フアイバ２との間に配設した単一のレンズ３がある。In the first embodiment, as shown in FIG.
There is a single lens 3 disposed between the laser diode 1 and the single-mode optical fiber 2 as an optical coupler for focusing the laser beam from the single-mode optical fiber 2 onto the single-mode optical fiber 2.
レーザダイオード１の射出面とレンズ３の主面間の距離
をＡ、レンズ３の主面と単一モード光フアイバ２の入射
面との間の距離をＢ、レンズ３の焦点距離をＦとする
と、以下の結合公式を満たすようにレーザダイオード
１、レンズ３および単一モード光フアイバ２が配設され
ている。Let A be the distance between the emission surface of the laser diode 1 and the principal surface of the lens 3, B be the distance between the principal surface of the lens 3 and the incident surface of the single-mode optical fiber 2, and F be the focal length of the lens 3. , A laser diode 1, a lens 3 and a single mode optical fiber 2 are arranged so as to satisfy the following coupling formula.
また、電子通信学会論文誌(B)，J65-B，NO.４，第374〜
381頁に記載された第２従来例が知られている。 Also, IEICE Transactions (B), J65-B, NO.4, No. 374-
A second conventional example described on page 381 is known.
第２従来例は第３図に示すように、レーザダイオード１
の射出面と単一モード光フアイバ２の入射面との間に第
１レンズ４および第２レンズ５を同一光軸上に配設した
ものである。The second conventional example is a laser diode 1 as shown in FIG.
The first lens 4 and the second lens 5 are arranged on the same optical axis between the exit surface of the first lens and the entrance surface of the single mode optical fiber 2.
第１従来例の単一のレンズ３および第２従来例の第１レ
ンズ４として球レンズが用いられているので、加工が容
易である、近軸近似による設計が容易である、レンズパ
ラメータの再現性が極めて高い、などの長所が得られ
る。Since spherical lenses are used as the single lens 3 of the first conventional example and the first lens 4 of the second conventional example, processing is easy, design by paraxial approximation is easy, and reproduction of lens parameters is performed. It has advantages such as extremely high performance.
しかしながら、このような従来の構成では、屈折面の球
面形状は一点から発した発散光束を一点に集束させた
り、光軸に平行な光束に変換したり、あるいは平行光束
を一点に集束させるのに最も適したものではなく、光軸
から離れた屈折面の部分を通過する近軸領域外の光線に
対しては、大きな収差が生ずる。このため、レーザビー
ムの広がり角の大きいレーザダイオード１を光源として
用いた場合、球レンズでは十分高い結合効率が得られな
い。However, in such a conventional configuration, the spherical shape of the refracting surface is used for converging a divergent light beam emitted from one point into one point, converting it into a light beam parallel to the optical axis, or converging a parallel light beam into one point. It is not the most suitable, and a large aberration occurs for a ray outside the paraxial region that passes through the portion of the refracting surface away from the optical axis. Therefore, when the laser diode 1 having a large divergence angle of the laser beam is used as the light source, the spherical lens cannot obtain a sufficiently high coupling efficiency.
一点から放射状に発する発散光束を平行光束に変換する
理想的な屈折面は光線の理論およびSnellの法則によ
り、双曲面形状となる。An ideal refracting surface for converting a divergent light beam emitted radially from one point into a parallel light beam has a hyperboloidal shape according to the theory of light rays and Snell's law.
第４図において、レンズ６は光軸Ｚを軸とする回転対称
の形状を有し、回転半径をｒ、屈折率をｎ、レーザダイ
オード１の射出面と後側屈折面７の頂点との間の距離を
ｌ、レーザダイオード１からのレーザビームの広がり角
をθ0とすれば、双曲面形状は以下の式で表される。In FIG. 4, the lens 6 has a rotationally symmetric shape with the optical axis Z as an axis, the radius of rotation is r, the refractive index is n, and the distance between the emission surface of the laser diode 1 and the apex of the rear refractive surface 7 is large. If the distance is 1 and the divergence angle of the laser beam from the laser diode 1 is θ 0 , the hyperboloid shape is expressed by the following equation.
ここで、θ0は遠方放射界が中心最大値の1/eとなる角，
ｗ0は平行ビームの界が中心最大値の１／ｅとなる幅で
ある。 Where θ 0 is the angle at which the far field is 1 / e of the central maximum,
w 0 is the width at which the field of the parallel beam is 1 / e of the central maximum value.
双曲面形状の後側屈折面７を有するレンズ６を用いれ
ば、高い結合効率が得られる反面、レンズ６の後側屈折
面７を双曲面形状に加工することが面倒であり、しか
も、レンズパラメータの再現性が低下するという問題点
があつた。If the lens 6 having the hyperboloidal rear refracting surface 7 is used, high coupling efficiency can be obtained, but it is troublesome to process the rear refracting surface 7 of the lens 6 into a hyperboloidal shape, and lens parameters There was a problem that the reproducibility of was decreased.
そこで、この発明は前記問題点に着目してなされたもの
で、その目的とするところは、収差特性を向上させ、加
工性を良好にし、レンズパラメータの再現性の向上を図
つた光結合用レンズを提供することにある。Therefore, the present invention has been made in view of the above problems, and an object thereof is to improve the aberration characteristics, improve the processability, and improve the reproducibility of lens parameters. To provide.
前記目的を達成するこの発明の構成は近軸領域を球面と
し、近軸領域外を、球面と連接し、連接箇所における接
線と同一の傾きを有する円錐面とした屈折面を備えたこ
とを要旨とする。The configuration of the present invention that achieves the above object is provided with a refractive surface that is a conical surface having a paraxial region as a spherical surface, and the outside of the paraxial region is connected to the spherical surface and has a conical surface having the same inclination as the tangent line at the connection point. And
前記構成において、レンズの屈折面は中心部の球面と、
これと連接する円錐面とで理想的な双曲面形状に近いも
のとしたので、光源からの広がり角の大きい発散光束で
あつても屈折面に入射すると、平行光束に変換され、ま
た、平行光束が逆向きに屈折面に入射すると、光回路の
入射面に集束する光束となる。In the above configuration, the refracting surface of the lens is a central spherical surface,
The conical surface connected to this is close to the ideal hyperboloid shape, so even a divergent light beam with a large divergence angle from the light source is converted into a parallel light beam when it enters the refracting surface, and a parallel light beam When is incident on the refracting surface in the opposite direction, it becomes a light beam that is focused on the incident surface of the optical circuit.
以下、この発明の実施例を図面に基づいて詳細に説明す
る。Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
第１図はこの発明の光結合用レンズに係る第１実施例を
示す構成図である。FIG. 1 is a constitutional view showing a first embodiment according to the optical coupling lens of the present invention.
図面において、１１はレンズで、レーザダイオード１２
からの発散光束を平行光束に変換できるようにしたもの
である。発散光束から平行光束への変換はレンズ１１の
後側屈折面１３によつて行われる。レンズ１１の後側屈
折面１３は広がり角の小さい近軸領域の部分では、近軸
近似に基づく曲率半径Ｒの球面をなし、広がり角の大き
い近軸領域外の部分では、双曲線の漸近線に従う円錐面
をなし、これら２つの面を組合せたものである。In the drawing, 11 is a lens, which is a laser diode 12
The divergent light flux from is converted into a parallel light flux. The conversion of the divergent light beam into the parallel light beam is performed by the rear refracting surface 13 of the lens 11. The rear refracting surface 13 of the lens 11 is a spherical surface having a radius of curvature R based on the paraxial approximation in the paraxial region where the divergence angle is small, and follows the asymptote of the hyperbola in the portion outside the paraxial region where the divergence angle is large. It is a conical surface and is a combination of these two surfaces.
レンズ１１は光軸Ｚを軸とする回転対称の形状を有し、
回転半径をｒ、屈折率をｎ、レーザダイオード１２の射
出面と後側屈折面１３の頂点との間の距離をｌとすれ
ば、曲率半径Ｒおよび双曲線は以下の式で表される。The lens 11 has a rotationally symmetrical shape about the optical axis Z,
If the radius of gyration is r, the refractive index is n, and the distance between the exit surface of the laser diode 12 and the apex of the rear refractive surface 13 is l, the radius of curvature R and the hyperbola are expressed by the following equations.
Ｒ＝(n-1)ｌ 双曲線の漸近線及びその傾きαは以下の式で与えられ
る。R = (n-1) l The asymptote of the hyperbola and its slope α are given by the following equation.
レンズ１１の前側屈折面１４はこれに平行光束が入射す
るので、Ｚ軸に直交する平面形状に形成されている。ま
た、レンズ１１のＺ軸方向の長さも任意である。 The front refracting surface 14 of the lens 11 is formed in a plane shape orthogonal to the Z axis, because a parallel light beam is incident on the front refracting surface 14. Further, the length of the lens 11 in the Z-axis direction is also arbitrary.
次に加工方法を説明する。Next, the processing method will be described.
まず、透明体の後側を漸近線に基づく円錐形に削り、次
いで、円錐形の先端を曲率半径Ｒをもつ球面に削つて研
磨する。First, the rear side of the transparent body is ground into a conical shape based on the asymptote, and then the tip of the conical shape is ground into a spherical surface having a radius of curvature R and polished.
あるいは透明体の後側を漸近線に基づく円錐台に削り、
これに曲率半径Ｒの球レンズを割切したものを接着して
研磨する。Or scraping the rear side of the transparent body into a truncated cone based on the asymptote,
A spherical lens having a radius of curvature R is cut and bonded to this, and the resultant is ground.
また、結合作用を説明すれば、レーザダイオード１２か
らの発散光束を図示しない光フアイバに収束させて両者
を結合するには、レーザダイオード１２側のレンズ１１
に加えて、これと同様の屈折面形状を有する図示しない
レンズを逆向きに対向させて図示省略の光フアイバ側に
配設した構成において、レーザダイオード１２の射出面
からレーザビームを放射すると、レンズ１１の後側屈折
面１３はほぼ双曲面形状であるので、光源１２からの発
散光束は広がり角θ0の大小に関係なく平行光束に変換
されて光フアイバ側のレンズに入射する。そして、光フ
アイバ側のレンズでは、ビーム幅ｗ0の大きい平行光束
であつても、双曲面形状に近い前側屈折面によつて光フ
アイバの入射面に集束する。Further, to explain the coupling action, in order to converge the divergent light flux from the laser diode 12 to an optical fiber (not shown) and couple the two, the lens 11 on the laser diode 12 side is used.
In addition, in a configuration in which a lens (not shown) having a similar refracting surface shape is oppositely arranged and disposed on the optical fiber side (not shown), when a laser beam is emitted from the emission surface of the laser diode 12, the lens Since the rear refracting surface 13 has a substantially hyperboloidal shape, the divergent light beam from the light source 12 is converted into a parallel light beam regardless of the divergence angle θ 0 and enters the lens on the optical fiber side. Then, in the lens on the optical fiber side, even a parallel light beam having a large beam width w 0 is focused on the incident surface of the optical fiber by the front refracting surface which is close to the hyperboloid shape.
第５図はこの発明の第２実施例を示す構成図である。FIG. 5 is a block diagram showing a second embodiment of the present invention.
この第２実施例はレーザダイオード１２と光フアイバ１
５間に単一のレンズ１６を配設して両者を結合できるよ
うにしたものである。The second embodiment is a laser diode 12 and an optical fiber 1.
A single lens 16 is arranged between the five lenses so that the two can be combined.
この単一のレンズ１６は前側屈折面１７にも後側屈折面
１８と同様中心部の球面と、これに連接する円錐面とか
らなるほぼ双曲面形状をなしている。The single lens 16 has a substantially hyperboloidal shape in which the front refracting surface 17 has a central spherical surface and a conical surface which is connected to the front refracting surface 17 as well as the rear refracting surface 18.
設計に際しては、平行光束のビーム幅ｗ0を適当に選
び、広がり角θ1、ビーム幅ｗ0、屈折率ｎから後側屈折
面１８を、入射角θ2、ビーム幅ｗ0、屈折率ｎから前側
屈折面１７を前記した曲率半径の式と漸近線の式を用い
て夫々決定する。In designing, the beam width w 0 of the parallel light beam is appropriately selected, and the divergence angle θ 1 , the beam width w 0 , and the refractive index n are used to determine the rear refracting surface 18, the incident angle θ 2 , the beam width w 0 , and the refractive index n. From the above, the front refracting surface 17 is determined by using the above-described equation of the radius of curvature and the equation of the asymptote.
但し、光フアイバ１５のように入射角θ2が小さい場合
は前側屈折面１７を曲率半径の式に基づく球面とするこ
とができる。However, when the incident angle θ 2 is small like the optical fiber 15, the front refracting surface 17 can be a spherical surface based on the expression of the radius of curvature.
この実施例の加工方法，結合作用については第１実施例
とほぼ同様であるので、その説明を省略する。Since the processing method and the connecting action of this embodiment are almost the same as those of the first embodiment, the description thereof will be omitted.
以上の説明から明らかなように、この発明によれば、近
軸領域内を球面とし、近軸領域外を、球面と連接し、連
接箇所における接線と同一の傾きを有する円錐面とした
屈折面を備えた構成としたので、理想的な双曲面形状の
屈折面を有するレンズに比べて収差特性は少し低下する
ものの従来の球レンズに比べれば、かなり高い結合効率
が得られる。しかも、屈折面を容易に加工できるばかり
でなく、レンズパラメータの再現性を向上させることが
できる。As is apparent from the above description, according to the present invention, the inside of the paraxial region is a spherical surface, the outside of the paraxial region is a conical surface that is connected to the spherical surface and has the same inclination as the tangent line at the connection point. Since the configuration is provided with, the aberration characteristic is slightly reduced as compared with a lens having an ideal hyperbolic refracting surface, but a considerably higher coupling efficiency can be obtained as compared with a conventional spherical lens. Moreover, not only the refracting surface can be easily processed, but also the reproducibility of lens parameters can be improved.
第１図はこの発明の結合用レンズに係る第１実施例を示
す構成図、第２図は第１従来例を示す構成図、第３図は
第２従来例を示す構成図、第４図は理想的な後側屈折面
を有するレンズを示す構成図、第５図は第２実施例を示
す構成図である。 １１…レンズ、１２…レーザダイオード、１３…後側屈
折面、１５…光フアイバ、１６…レンズ、１７…前側屈
折面、１８…後側屈折面、Ｒ…曲率半径。FIG. 1 is a block diagram showing a first embodiment of a coupling lens of the present invention, FIG. 2 is a block diagram showing a first conventional example, FIG. 3 is a block diagram showing a second conventional example, and FIG. Is a block diagram showing a lens having an ideal rear refracting surface, and FIG. 5 is a block diagram showing a second embodiment. 11 ... Lens, 12 ... Laser diode, 13 ... Rear refraction surface, 15 ... Optical fiber, 16 ... Lens, 17 ... Front refraction surface, 18 ... Rear refraction surface, R ... Radius of curvature.
Claims (1)
を光学的に結合する光結合用レンズにおいて、 近軸領域を球面とし、近軸領域外を球面と連接し、連接
箇所における接線と同一の傾きを有する円錐面とした屈
折面を備えたことを特徴とする光結合用レンズ。1. An optical coupling lens arranged between a light source and an optical circuit for optically coupling the light source and the optical circuit, wherein the paraxial region is a spherical surface, and the outside of the paraxial region is connected to the spherical surface, and the connecting point An optical coupling lens having a refracting surface that is a conical surface having the same inclination as the tangent line in FIG.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22193585A JPH0638128B2 (en) | 1985-10-07 | 1985-10-07 | Optical coupling lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22193585A JPH0638128B2 (en) | 1985-10-07 | 1985-10-07 | Optical coupling lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6281615A JPS6281615A (en) | 1987-04-15 |
| JPH0638128B2 true JPH0638128B2 (en) | 1994-05-18 |
Family
ID=16774462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22193585A Expired - Lifetime JPH0638128B2 (en) | 1985-10-07 | 1985-10-07 | Optical coupling lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0638128B2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0650888Y2 (en) * | 1988-10-07 | 1994-12-21 | 株式会社小糸製作所 | Lighting equipment |
| JPH0736042B2 (en) * | 1989-12-15 | 1995-04-19 | 松下電工株式会社 | Condensing lens for infrared detector |
| JPH0734041B2 (en) * | 1989-12-15 | 1995-04-12 | 松下電工株式会社 | Condensing lens for infrared detector |
| JPH0736041B2 (en) * | 1989-12-15 | 1995-04-19 | 松下電工株式会社 | Condensing lens for infrared detector |
| JPH03100801U (en) * | 1990-01-31 | 1991-10-22 | ||
| JP2769078B2 (en) * | 1992-12-28 | 1998-06-25 | エイチイー・ホールディングス・インコーポレーテッド・ディービーエー・ヒューズ・エレクトロニクス | Optical fiber built-in power divider / combiner |
| JP3067968B2 (en) | 1994-11-11 | 2000-07-24 | 株式会社精工技研 | Optical fiber interface for coupling light source and method of manufacturing the same |
| US6349159B1 (en) * | 1999-09-02 | 2002-02-19 | Agilent Technologies, Inc. | Lenses that launch high bandwidth modes into a fiber optic cable while eliminating feedback to a laser |
| JP3979168B2 (en) * | 2002-04-26 | 2007-09-19 | ヤマハ株式会社 | Light emitting part structure in a key depression detection device for a keyboard instrument |
| JP2006195097A (en) * | 2005-01-12 | 2006-07-27 | Moritex Corp | Fiber with lens and method for forming aspheric lens therein |
| JP5919530B2 (en) * | 2010-12-21 | 2016-05-18 | パナソニックＩｐマネジメント株式会社 | Optical detection device and apparatus using the same |
-
1985
- 1985-10-07 JP JP22193585A patent/JPH0638128B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6281615A (en) | 1987-04-15 |
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