JPH0151803B2 - - Google Patents
Info
- Publication number
- JPH0151803B2 JPH0151803B2 JP13745079A JP13745079A JPH0151803B2 JP H0151803 B2 JPH0151803 B2 JP H0151803B2 JP 13745079 A JP13745079 A JP 13745079A JP 13745079 A JP13745079 A JP 13745079A JP H0151803 B2 JPH0151803 B2 JP H0151803B2
- Authority
- JP
- Japan
- Prior art keywords
- central axis
- light
- radius
- refractive index
- index distribution
- 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
Links
- 239000013307 optical fiber Substances 0.000 claims description 16
- 230000005540 biological transmission Effects 0.000 claims description 11
- 230000008878 coupling Effects 0.000 claims description 9
- 238000010168 coupling process Methods 0.000 claims description 9
- 238000005859 coupling reaction Methods 0.000 claims description 9
- 230000003247 decreasing effect Effects 0.000 claims description 3
- 230000003287 optical effect Effects 0.000 description 25
- 230000004075 alteration Effects 0.000 description 8
- 239000004065 semiconductor Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
Classifications
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Optical Couplings Of Light Guides (AREA)
Description
【発明の詳細な説明】
この発明は、光デバイス用部品、特に光ビーム
変換用レンズ作用素子及びそれを用いた光源・光
フアイバ結合装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to parts for optical devices, particularly to a lens effecting element for converting a light beam, and a light source/optical fiber coupling device using the same.
光フアイバ通信の有用性が実証されるにつれ
て、各種の機能を有する光デバイスの開発への要
求が高まつている。これらの光デバイスでは、光
ビームを集束したりビーム径を変えたりするいわ
ゆる光ビーム変換作用を行なわせる素子が必要に
なることが多い。このような作用が可能な光部品
の中で、中心軸に垂直な断面内の屈折率が中心軸
からの距離の２乗にほぼ比例して減少している集
束性光伝送体は、きわめて小形にできることか
ら、光デバイスの小形化に対して特に効果的な光
部品として注目され、開発が進められている。 As the usefulness of optical fiber communications has been demonstrated, there has been an increasing demand for the development of optical devices with various functions. These optical devices often require an element that performs a so-called light beam conversion function that focuses the light beam or changes the beam diameter. Among optical components capable of this kind of action, convergent optical transmitters, whose refractive index in a cross section perpendicular to the central axis decreases approximately in proportion to the square of the distance from the central axis, are extremely compact. Because of this, it has attracted attention as an especially effective optical component for miniaturizing optical devices, and its development is progressing.
光フアイバ通信の主要な光源として考えられて
いる半導体レーザや発光ダイオードの出射光ビー
ムは大きな拡がり角を持つので、これらの光ビー
ムを変換する集束性光伝送体はかなり大きな受光
角を持つことが望ましい。一方、低挿入損失の光
デバイスを実現するためには、光ビーム変換素子
により光ビームが歪みを受けないことが必要で、
そのために集束性光伝送体においては屈折率分布
の精密な制御が要求される。従来、集束性光伝送
体は、ガラス材へのイオン交換や、プラスチツク
材の重合拡散等により実現されてきたが、実質的
に受光角が大きく、しかも収差の小さいものは製
作が困難であつた。すなわち、中心軸附近ではか
なり収差の小さい屈折率分布が実現できるが、周
辺部では分布を良く制御できないので、集束性光
伝送体の周辺部まで光ビームが通るような使い方
をすると、周辺部での望ましくない屈折率分布に
より光ビームが歪んでしまう。したがつて、集束
性光伝送体の実質的に有効な受光角はかなり小さ
いことになり、そのために、放射角の大きな半導
体レーザや発光ダイオードからの出射ビームのビ
ーム変換の効率低下が著しく、効率の良い光源・
光フアイバ結合装置の実現は困難であつた。 The light beams emitted from semiconductor lasers and light emitting diodes, which are considered as the main light sources for optical fiber communications, have a large divergence angle, so the convergent optical transmitter that converts these light beams can have a fairly large acceptance angle. desirable. On the other hand, in order to realize an optical device with low insertion loss, it is necessary that the optical beam is not distorted by the optical beam conversion element.
For this reason, precise control of the refractive index distribution is required in the convergent light transmission body. Conventionally, focusing optical transmitters have been realized by ion exchange with glass materials, polymerization diffusion of plastic materials, etc., but it has been difficult to produce materials with substantially large acceptance angles and small aberrations. . In other words, although it is possible to achieve a refractive index distribution with fairly small aberrations near the central axis, it is not possible to control the distribution well at the periphery. The optical beam is distorted due to the undesirable refractive index distribution. Therefore, the effective acceptance angle of the convergent optical transmitter is quite small, and as a result, the efficiency of beam conversion of the emitted beam from a semiconductor laser or light emitting diode with a large emission angle is significantly reduced. A good light source
It has been difficult to realize an optical fiber coupling device.
この発明の目的は、受光角が大きく収差の小さ
い集束性光伝送体及びそれを用いた高効率な光
源・光フアイバ結合装置を提供することにある。 An object of the present invention is to provide a convergent light transmitter with a large acceptance angle and small aberrations, and a highly efficient light source/optical fiber coupling device using the same.
この発明によれば、半径がｒで、中心軸に垂直
な断面内で前記中心軸から距離の２乗にほぼ比例
して減少する屈折率分布と、少なくとも光入射側
の端面に形成した前記中心軸に対してほぼ対称な
凸曲面とを有し、前記凸曲面が曲率半径をＲとす
るとき
ｒ＜Ｒ＜3r
を満たす球面である先球集束性光伝送体が得られ
る。 According to this invention, the refractive index distribution has a radius r and decreases in a cross section perpendicular to the central axis in approximately proportion to the square of the distance from the central axis, and the center formed at least on the end surface on the light incidence side. A convex curved surface that is substantially symmetrical with respect to the axis is obtained, and the convex curved surface is a spherical surface satisfying r<R<3r when the radius of curvature is R.
また、この発明によれば、半径がｒで中心軸に
垂直な断面内で前記中心軸からの距離の２乗にほ
ぼ比例して減少する屈折率分布と、少なくとも光
入射側の端面に形成した前記中心軸に対してほぼ
対称な凸曲面とを有し、前記凸曲面が曲率半径を
Ｒとするとき
ｒ＜Ｒ＜3r
を満たす球面である先球集束性光伝送体と、前記
先球集束性光伝送体の凸曲面に近接して配置した
光源と、前記先球集束性光伝送体の他方の端面に
対向して配置した光フアイバとを含む光源と光フ
アイバとの結合装置が得られる。 Further, according to the present invention, a refractive index distribution having a radius r and decreasing approximately in proportion to the square of the distance from the central axis within a cross section perpendicular to the central axis, and a refractive index distribution formed at least on the end face on the light incidence side. a convex curved surface that is substantially symmetrical with respect to the central axis, and the convex curved surface is a spherical surface satisfying r<R<3r when the radius of curvature is R; A coupling device for a light source and an optical fiber is obtained, which includes a light source disposed close to a convex curved surface of a converging light transmitting body, and an optical fiber disposed facing the other end surface of the converging light transmitting body. .
この発明では、集束性光伝送体の少なくとも一
方の端面を中心軸にほぼ対称な曲面にして、放射
角の大きな光ビームがこの曲面で屈折され、小さ
な角度で集束性光伝送体に入射し、その中心軸附
近を通るようにすることにより、実質的に受光角
が大きく、しかも収差の小さい集束性光伝送体を
実現している。すなわち、集束性光伝送体の中心
軸附近の屈折率分布は比較的良く制御することが
できるので、放射角の大きな光ビームも中心軸附
近を通るようにすることにより実質的に低収差の
素子が実現できる。これまでに、集束性光伝送体
の端面を中心軸に対称でなく、一方向のみ曲面に
したいわゆる一次元的な曲面をつけたものが考案
されているが、これでは曲面の方向とそれと直角
な方向とでレンズの焦点距離が異なり、そのため
例えば半導体レーザからの光ビームが集束される
位置が異なるために、光フアイバとの良好な結合
が不可能であつた。また、製造された集束性光伝
送体の屈折率分布を精密に測定し、その分布の理
想分布からのずれを補正するような曲率半径の球
面を集束性光伝送体の端面に形成することが考案
されているが、この方法は、屈折率分布を精度良
く測定することが困難なことと、それに合わせた
曲率半径の球面の研磨が必ずしも容易でないため
に、実用的ではない。 In this invention, at least one end surface of the convergent light transmission body is made into a curved surface that is substantially symmetrical about the central axis, and a light beam with a large radiation angle is refracted by this curved surface and enters the convergence light transmission body at a small angle, By passing near the central axis, a convergent light transmitter with a substantially large acceptance angle and small aberrations is realized. In other words, since the refractive index distribution near the central axis of the convergent light transmitter can be controlled relatively well, by allowing the light beam with a large radiation angle to pass near the central axis, it is possible to create an element with substantially low aberrations. can be realized. So far, so-called one-dimensional curved surfaces have been devised, in which the end surfaces of focusing optical transmitters are not symmetrical about the central axis, but are curved only in one direction. Since the focal length of the lens differs in each direction, and therefore the position at which the light beam from, for example, a semiconductor laser is focused differs, good coupling with the optical fiber has not been possible. In addition, it is possible to precisely measure the refractive index distribution of the manufactured convergent light transmitting body and form a spherical surface with a radius of curvature that corrects the deviation of the distribution from the ideal distribution on the end face of the convergent light transmitting body. Although this method has been devised, it is not practical because it is difficult to accurately measure the refractive index distribution and it is not necessarily easy to polish a spherical surface with a radius of curvature that matches the distribution.
以下、図面を参照してこの発明を詳しく説明す
る。 Hereinafter, the present invention will be explained in detail with reference to the drawings.
第１図はこの発明の実施例の光結合装置で、主
要構成光部品の断面図をあらわす。これは、直径
が約1.5mmのガラス丸棒に良く知られたイオン交
換法により中心軸５０に垂直な断面内で中心軸１
０からの距離の２乗にほぼ比例して減少する屈折
率分布を形成した後に、中心軸１０にほぼ垂直な
出射面３と半径が約1.2mmの球面の入射面２を研
磨により形成した先球集束性光伝送体１を、半導
体レーザ２０に近接して設置し、その出射光３０
を光フアイバ５０へ結合しようとするものであ
る。半導体レーザ２０の活性層２１に垂直な方向
に大きなひろがり角を持つ出射光３０は、先球集
束性光伝送体１へ入射するとき、曲面の入射面２
により屈折されて小さなひろがり角を持つ光ビー
ム４０になつて先球集束性光伝送体１中を伝搬す
る。したがつてこの光ビーム４０は入射側の端面
が平面の場合に較べて中心軸１０附近を通過する
割合が大きくなる。すなわち、集束性光伝送体１
の屈折率分布制御が不十分な周辺部の影響を余り
受けなくてすむために、出射光３０を余り歪まさ
ずに光フアイバ５０に結合することができ、従来
の平面端面の集束性光伝送体を用いた場合に較べ
て結合効率を約２倍以上上げることができた。こ
のように、この発明によりひろがり角の大きな光
ビームを効率良く光フアイバへ結合させることの
できる光部品が得られた。つまり、実質的に受光
角が大きく、かつ収差の小さい集束性光伝送体が
得られた。また、これを用いることにより、高効
率で構成の単純な光源・光フアイバの光結合装置
が得られた。球面の曲率半径の大きさは、集束性
光伝送体の半径の１倍程度から３倍程度が望まし
いことが試作検討により明らかになつている。こ
れは、曲線半径が集束性光伝送体の半径よりもす
つと小さいと球面の収差が大きくなるために、ま
た曲率半径が集束性光伝送体の半径の３倍程度よ
りもずつと大きくなると球面のレンズ作用が小さ
くなつて集束性光伝送体の周辺部を光ビームが多
く通過するようになるために、先球集束性光伝送
体の収差が大きくなるためである。このように、
この発明は球面の曲率半径のかなり広い範囲にわ
たつて効果がある上に、集束性光伝送体の屈折率
分布の精密な測定等は必要ないので、きわめて実
用的である。 FIG. 1 shows an optical coupling device according to an embodiment of the present invention, and shows a sectional view of the main constituent optical components. This is done by using the well-known ion exchange method on a glass round rod with a diameter of about 1.5 mm, in a cross section perpendicular to the central axis 50.
After forming a refractive index distribution that decreases approximately in proportion to the square of the distance from zero, an exit surface 3 approximately perpendicular to the central axis 10 and a spherical entrance surface 2 with a radius of approximately 1.2 mm are formed by polishing. The spherical focusing light transmitting body 1 is installed close to the semiconductor laser 20, and the emitted light 30
It is intended to couple the optical fiber 50 to the optical fiber 50. When the emitted light 30 having a large spread angle in the direction perpendicular to the active layer 21 of the semiconductor laser 20 enters the spherical convergent light transmitting body 1, it enters the curved incident surface 2.
The light beam 40 is refracted by the beam 40 and propagates through the spherical convergent light transmission body 1. Therefore, this light beam 40 passes through the vicinity of the central axis 10 more often than when the end face on the incident side is flat. That is, the focusing optical transmission body 1
Since the refractive index distribution of the refractive index distribution is not so affected by the insufficient peripheral region, the emitted light 30 can be coupled to the optical fiber 50 without being distorted too much, compared to the conventional converging light transmission body with a flat end face. It was possible to increase the binding efficiency by more than twice compared to the case where the method was used. As described above, the present invention provides an optical component that can efficiently couple a light beam with a large spread angle to an optical fiber. In other words, a convergent optical transmission body with a substantially large light receiving angle and small aberrations was obtained. Moreover, by using this, a light source/optical fiber optical coupling device with high efficiency and a simple configuration was obtained. Prototype studies have revealed that the radius of curvature of the spherical surface is preferably about 1 to 3 times the radius of the convergent light transmission body. This is because the aberration of the spherical surface increases if the radius of the curve is much smaller than the radius of the convergent light transmitter, and if the radius of curvature becomes larger than about three times the radius of the convergent light transmitter, the spherical surface This is because the lens action of the lens becomes smaller and more of the light beam passes through the periphery of the convergent light transmitter, which increases the aberration of the spherical convergent light transmitter. in this way,
This invention is effective over a fairly wide range of radius of curvature of the spherical surface, and is extremely practical because it does not require precise measurement of the refractive index distribution of the convergent light transmitter.
なお、曲面の形成は、研磨によらなくても可能
で、例えば、バーナやヒータ等による加熱熔融に
よつても形成することができる。また、光結合装
置の光源としては、実施例に示した半導体レーザ
の他に、発光ダイオード等も有効である。さら
に、第１の実施例において、光フアイバは、半導
体レーザと集束性光伝送体とともに一体化して固
定しても良いし、光コネクタ等で着脱できるよう
にしても良い。 Note that the curved surface can be formed without polishing, and can also be formed, for example, by heating and melting using a burner, a heater, or the like. In addition to the semiconductor laser shown in the embodiment, a light emitting diode or the like is also effective as a light source for the optical coupling device. Further, in the first embodiment, the optical fiber may be fixed integrally with the semiconductor laser and the focusing optical transmission body, or may be detachable using an optical connector or the like.
第１図はこの発明の実施例の断面図をあらわ
す。
図において、１……先球集束性光伝送体、１０
……中心軸、２……入射面をそれぞれあらわす。
FIG. 1 shows a sectional view of an embodiment of the invention. In the figure, 1... a spherical convergent optical transmission body, 10
. . . central axis, 2 . . . represent the incident plane, respectively.
Claims (1)
心軸から距離の２乗にほぼ比例して減少する屈折
率分布と、少なくとも光入射側の端面に形成した
前記中心軸に対してほぼ対称な凸曲面とを有し、
前記凸曲面が曲率半径をＲとするとき ｒ＜Ｒ＜3r を満たす球面である先球集束性光伝送体。 ２ 半径がｒで中心軸に垂直な断面内で前記中心
軸からの距離の２乗にほぼ比例して減少する屈折
率分布と、少なくとも光入射側の端面に形成した
前記中心軸に対してほぼ対称な凸曲面とを有し、
前記凸曲面が曲率半径をＲとするとき ｒ＜Ｒ＜3r を満たす球面である先球集束性光伝送体と、前記
先球集束性光伝送体の凸曲面に近接して配置した
光源と、前記先球集束性光伝送体の他方の端面に
対向して配置した光フアイバとを含む光源と光フ
アイバとの結合装置。[Scope of Claims] 1. A refractive index distribution having a radius r and decreasing approximately in proportion to the square of the distance from the central axis in a cross section perpendicular to the central axis, and the refractive index distribution formed at least on the end surface on the light incidence side. It has a convex curved surface that is almost symmetrical about the central axis,
The convex curved surface is a spherical surface satisfying r<R<3r when the radius of curvature is R. 2. A refractive index distribution having a radius r and decreasing approximately in proportion to the square of the distance from the central axis within a cross section perpendicular to the central axis, and a refractive index distribution approximately proportional to the square of the distance from the central axis formed at least on the end surface on the light incidence side. It has a symmetrical convex curved surface,
a spherical convergent light transmitting body that is a spherical surface satisfying r<R<3r when the convex curved surface has a radius of curvature R; a light source disposed close to the convex curved surface of the convex convergent light transmitting body; A coupling device for a light source and an optical fiber, including an optical fiber disposed opposite to the other end surface of the spherical converging light transmission body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13745079A JPS5662211A (en) | 1979-10-24 | 1979-10-24 | Tip spherical focusing type optical transmission body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13745079A JPS5662211A (en) | 1979-10-24 | 1979-10-24 | Tip spherical focusing type optical transmission body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5662211A JPS5662211A (en) | 1981-05-28 |
| JPH0151803B2 true JPH0151803B2 (en) | 1989-11-06 |
Family
ID=15198886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13745079A Granted JPS5662211A (en) | 1979-10-24 | 1979-10-24 | Tip spherical focusing type optical transmission body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5662211A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3101378C2 (en) * | 1981-01-17 | 1985-01-10 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Optics for coupling a fiber optic light wave guide |
| JPS6258210A (en) * | 1985-09-09 | 1987-03-13 | Fujitsu Ltd | Optical coupling structure for semiconductor laser module |
-
1979
- 1979-10-24 JP JP13745079A patent/JPS5662211A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5662211A (en) | 1981-05-28 |
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