JPH0477882B2 - - Google Patents
Info
- Publication number
- JPH0477882B2 JPH0477882B2 JP59064012A JP6401284A JPH0477882B2 JP H0477882 B2 JPH0477882 B2 JP H0477882B2 JP 59064012 A JP59064012 A JP 59064012A JP 6401284 A JP6401284 A JP 6401284A JP H0477882 B2 JPH0477882 B2 JP H0477882B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- light
- fiber
- wavelength
- 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
- 239000013307 optical fiber Substances 0.000 claims description 27
- 230000003287 optical effect Effects 0.000 claims description 17
- 238000013459 approach Methods 0.000 claims description 2
- 239000000835 fiber Substances 0.000 description 27
- 230000004075 alteration Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 239000011521 glass Substances 0.000 description 4
- 239000010453 quartz Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 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
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
- G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
-
- 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
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
- G02B6/29361—Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
- G02B6/2937—In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
Description
【発明の詳細な説明】
産業上の利用分野
本発明は光通信に用いる光分波器に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical demultiplexer used in optical communications.
従来例の構成とその問題点
従来、光分波器として種々の構成が提案されて
いる。なかでも、集束ロツドレンズを１個だけ用
い、干渉膜フイルタの組み合わせによつて分波も
しくは合波する光分波合波器は構成の容易性、低
価格の面で有効であつた。しかしながら、分波、
合波する波長の組み合わせにおいて、短波長帯
（700nｍ〜900nｍ）と長波長帯（1.2μｍ〜1.6μｍ
の組み合わせを用いると、集束性ロツドレンズの
色収差により、光フアイバ間の結合損失が大きく
たる欠点がある。そのための対策として、従来、
第１図に示すような構成が用いられていた。この
構成はレンズ端から長波長側の入力もしくは出力
フアイバの端面を、端波長側の入力もしくは出力
フアイバ端面より、離すことによつて色収差の補
正を施したものである。例えば、短波長側の波長
λ1、λ2をそれぞれ810nｍ、890nｍを用い、長波
長側の波長λ3を1.3μｍを用いて構成した場合を考
えると、第１図のように構成できる。Conventional configurations and their problems Conventionally, various configurations have been proposed as optical demultiplexers. Among these, an optical demultiplexer/multiplexer that uses only one focusing rod lens and performs demultiplexing or multiplexing using a combination of interference film filters has been effective in terms of ease of construction and low cost. However, demultiplexing,
In the combination of wavelengths to be combined, there is a short wavelength band (700nm to 900nm) and a long wavelength band (1.2μm to 1.6μm).
If a combination of the above is used, there is a drawback that the coupling loss between the optical fibers is large due to the chromatic aberration of the converging rod lens. As a countermeasure for this, conventionally,
A configuration as shown in FIG. 1 was used. In this configuration, chromatic aberration is corrected by separating the end face of the input or output fiber on the long wavelength side from the lens end from the end face of the input or output fiber on the end wavelength side. For example, if we consider a case in which the short wavelengths λ 1 and λ 2 are 810 nm and 890 nm, respectively, and the long wavelength λ 3 is 1.3 μm, the structure can be constructed as shown in FIG. 1.
第１図において、１〜４は入出力フアイバであ
り、１は短波、長波両者の共通フアイバ、２は波
長λ1の出力フアイバ、３は波長λ2の入力フアイ
バ、４は波長λ3の出力フアイバである。５短波長
側のλ1、λ2の光の分離度をよくするために、波長
λ2の短波側の裾の部分をカツトする特性Ａの干渉
膜フイルタ５′を一部に形成したガラス板である。
６は集束性ロツドレンズ、７〜９は、それぞれ波
長λ1〜λ3を順次分離する前面に干渉膜フイルタを
施したガラス板であり、第２図中のＡ、Ｂ、Ｃで
示した特性のものである。１０は、それぞれの干
渉膜フイルタを接着する透明な光学接着剤であ
る。ここで入出力フアイバ１〜４は、図のよう
に、短波長側と共通フアイバを同一端面上に配
し、長波長側のフアイバ４をl2だけレンズ端より
遠ざけて取りつけている。 In Figure 1, 1 to 4 are input and output fibers, 1 is a common fiber for both shortwave and longwave, 2 is an output fiber with wavelength λ 1 , 3 is an input fiber with wavelength λ 2 , and 4 is an output fiber with wavelength λ 3 . It's fiber. 5. A glass plate on which an interference film filter 5' having characteristic A is partially formed to cut off the tail portion on the short wavelength side of wavelength λ 2 in order to improve the separation of light of λ 1 and λ 2 on the short wavelength side. It is.
6 is a focusing rod lens, and 7 to 9 are glass plates each having an interference film filter on the front surface that sequentially separates wavelengths λ 1 to λ 3 . It is something. 10 is a transparent optical adhesive that adheres each interference film filter. Here, as shown in the figure, the input/output fibers 1 to 4 are arranged such that the short wavelength side fiber and the common fiber are arranged on the same end face, and the long wavelength side fiber 4 is attached at a distance l 2 from the lens end.
このようなフアイバ束の構成では、製作時に、
まず、レンズ端より遠ざけるフアイバの先端をあ
らかじめフラツトな鏡面にしておき、他のフアイ
バ端を研磨する際に、フアイバ端の側面より顕微
鏡で確認しながら研磨しなければならない。又、
このようなフラツトな端面にカツトフイルタを挿
入すると、数％の反射が生じるために、LD等の
光源を用いると、反射光がLD（半導体レーザー）
端面に再注入され、LDの発振波長の変化や、雑
音の増大、直線性が劣化するなどの現象が生じ
る。 In this fiber bundle configuration, during fabrication,
First, the tip of the fiber that is placed away from the lens edge must be made into a flat, mirror-like surface in advance, and when polishing the other fiber ends, it is necessary to polish the ends while checking the side surface of the fiber using a microscope. or,
When a cut filter is inserted into such a flat end face, a few percent of reflection will occur, so if a light source such as an LD is used, the reflected light will be reflected from an LD (semiconductor laser).
It is re-injected into the end face, causing phenomena such as a change in the LD's oscillation wavelength, an increase in noise, and a deterioration in linearity.
発明の目的
本発明は、LDを光源として用いた時のフイル
タ面での３〜５％程度の反射光がLDに再注入す
るのを防ぐと共に、長波長と端波長を組み合わせ
た時の色収差による損失増加を低減する光分波器
を提供するものである。Purpose of the Invention The present invention prevents about 3 to 5% of reflected light from the filter surface when an LD is used as a light source from being re-injected into the LD, and also prevents chromatic aberration caused by combining long wavelengths and edge wavelengths. The present invention provides an optical demultiplexer that reduces increase in loss.
発明の構成
本発明は、ロツドレンズの一端に光フアイバ、
他端に光学フイルタを設けてなる光分波合波器に
おいて、光フアイバの端面を光フアイバの臨界角
近傍もしくは大きい角になる面を持ち、レンズ端
より最も離れた位置に端面を有する光フアイバを
一番波長の長い光の入力、もしくは出力端子と
し、順次レンズ端に近づくに従がい、波長が短く
なるような光の入力、もしくは出力端子用光フア
イバとすることにより、色収差による損失増加を
低減すると共に光源にLDを用いた時、カツトフ
イルタの挿入等による反射戻り光を低減しLDへ
の影響をなくすものである。Structure of the Invention The present invention includes an optical fiber at one end of the rod lens.
In an optical demultiplexing/combining device with an optical filter provided at the other end, the optical fiber has an end face near or at a large critical angle of the optical fiber, and has an end face at a position farthest from the lens end. By using it as the input or output terminal for light with the longest wavelength, and using it as the input or output terminal for light whose wavelength becomes shorter as it approaches the lens edge, it is possible to reduce the increase in loss due to chromatic aberration. In addition, when an LD is used as a light source, it reduces the reflected return light due to insertion of a cut filter, etc., and eliminates the effect on the LD.
実施例の説明
以下、本発明の一実施例について、図面を参照
しながら説明する。DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
第３図、第４図は本発明の一実施例の光分波合
波器の構成を示すものである。図は３波長の双方
向用分波器で、波長λ1に0.81μｍ、波長λ2に0.89μ
ｍ、波長λ3に1.3μｍのLDを用いている。１１〜
１４は光フアイバであり、１１は波長λ3の出力フ
アイバ、１２は波長λ1の出力フアイバ、１４は波
長λ2の入力フアイバである。 FIGS. 3 and 4 show the configuration of an optical demultiplexer/multiplexer according to an embodiment of the present invention. The figure shows a 3-wavelength bidirectional demultiplexer, 0.81 μm for wavelength λ 1 and 0.89 μm for wavelength λ 2 .
m, a 1.3 μm LD is used for the wavelength λ 3 . 11~
14 is an optical fiber, 11 is an output fiber with wavelength λ 3 , 12 is an output fiber with wavelength λ 1 , and 14 is an input fiber with wavelength λ 2 .
各々の光フアイバ１１〜１４は石英板１５，１
５′によつてサンドイツチ構造に固着されている。
また、各々の光フアイバ１１〜１４は石英板１
５，１５′と同時に斜めに研磨されている。研磨
された光フアイバ１１〜１４は、波長の一番長い
光の出力端を集束性ロツドレンズ１６（以下単に
レンズとよぶ）端より遠くなる位置にし、波長が
短かいほうをレンズ端に近づくように配置してい
る。１７はレンズ１６と、石英板１５，１５′で
挾まれた光フアイバ１１〜１４を一体形成した光
フアイバ束との間隙を埋めるためのくさび状のガ
ラスブロツクであり、一部に誘電体多層膜フイル
タ１８を有している。このフイルタ１８は、光フ
アイバ１３より入射されるλ2光スペクトルの裾を
カツトするもので、波長間隔の狭い光源を用いて
分波器を構成する場合に、他の受光部へ漏れるの
を防ぐためのものである。 Each optical fiber 11 to 14 is connected to a quartz plate 15, 1
5' to the sanderch structure.
Further, each optical fiber 11 to 14 is connected to a quartz plate 1.
5 and 15' are polished diagonally at the same time. The polished optical fibers 11 to 14 are arranged such that the output end of the light with the longest wavelength is located further away from the end of the focusing rod lens 16 (hereinafter simply referred to as the lens), and the end with the shorter wavelength is located closer to the lens end. It is placed. Reference numeral 17 designates a wedge-shaped glass block for filling the gap between the lens 16 and the optical fiber bundle integrally formed with optical fibers 11 to 14 sandwiched between quartz plates 15 and 15'. It has a filter 18. This filter 18 cuts the tail of the λ 2 light spectrum incident from the optical fiber 13, and prevents it from leaking to other light receiving sections when a demultiplexer is configured using a light source with a narrow wavelength interval. It is for.
１９は波長λ1の光を反射し、λ2、λ3光を透過す
る誘電体多層膜フイルタ（以下フイルタとよぶ）
で、第２図Ａの特性で示されるものである。光路
は図中実線で示す。同様に２０は波長λ2の光を反
射し、λ3光を透過するフイルタで、第２図Ｂで示
されるものである。光路は図中破線で示す。２１
は波長λ3の光を反射するフイルタで第２図Ｃで示
されるものである。光路は図中一点鎖線で示す。
各々のフイルタ１９〜２１は、共通端子の光フア
イバ１４と結合するように、傾きをもつて透明エ
ポキシ等の光学接着剤２２で取り付けられてい
る。 19 is a dielectric multilayer film filter (hereinafter referred to as a filter) that reflects light with a wavelength of λ 1 and transmits light with wavelengths of λ 2 and λ 3 .
This is shown by the characteristics shown in FIG. 2A. The optical path is shown by a solid line in the figure. Similarly, 20 is a filter that reflects light of wavelength λ 2 and transmits light of wavelength λ 3 , as shown in FIG. 2B. The optical path is indicated by a broken line in the figure. 21
is a filter that reflects light of wavelength λ 3 and is shown in FIG. 2C. The optical path is indicated by a chain line in the figure.
Each of the filters 19 to 21 is attached at an angle with an optical adhesive 22 such as transparent epoxy so as to be coupled to the optical fiber 14 of the common terminal.
このような構成にすることにより、従来の短波
長と長波長の色収差による損失増加を低減する光
フアイバの位置調整を同時研磨でほぼ同様に補え
る。 With such a configuration, the position adjustment of the optical fiber, which reduces the increase in loss due to chromatic aberration of short and long wavelengths, can be compensated for in almost the same way by simultaneous polishing.
又、第５図で示すように、例えば波長λ2のLD
光源より出射した光が光フアイバ１３に最大伝搬
角で入射した場合を考えると、LDのスペクトル
の透過しない裾の光と、フイルタ１５の特性によ
る３〜10％の反射光は、角度θだけ傾いたフイル
タ１８面で反射し、光源側へ行く。しかし、これ
らの反射光は光フアイバの伝搬できる臨界角より
大きくなるために、再び光フアイバ内を伝搬でき
ずに、光フアイバ外へ放射モードとなつて抜けて
いく。一方、フイルタ１８を透過した光は、所定
の光路を通つて共通フアイバ１４に結合される。 Moreover, as shown in FIG. 5, for example, an LD with wavelength λ 2
Considering the case where the light emitted from the light source enters the optical fiber 13 at the maximum propagation angle, the light at the bottom of the LD spectrum that is not transmitted and the 3 to 10% reflected light due to the characteristics of the filter 15 are tilted by the angle θ. The light is reflected by the filter 18 and goes to the light source. However, since these reflected lights are larger than the critical angle at which the optical fiber can propagate, they cannot propagate within the optical fiber again and escape outside the optical fiber as a radiation mode. On the other hand, the light transmitted through the filter 18 is coupled to the common fiber 14 through a predetermined optical path.
なお、受光フアイバのコア径を共通フアイバの
コア径よりも大きくしたり、発光フアイバのコア
径を共通フアイバのコア径よりも小さくするとい
うように、本発明の色収差補正と併用することに
より一層の損失低減につながるのは言うまでもな
い。 Further, by using the chromatic aberration correction of the present invention in combination, such as by making the core diameter of the light-receiving fiber larger than the core diameter of the common fiber or by making the core diameter of the light-emitting fiber smaller than the core diameter of the common fiber. Needless to say, this leads to loss reduction.
また本実施例のように、カツトフイルタを入れ
ない場合でも接着層での屈折率不等合によつて生
じる反射光を、取り除くことができる。 Further, as in this embodiment, even if a cut filter is not used, reflected light caused by refractive index mismatch in the adhesive layer can be removed.
発明の効果
以上述べたように本発明によれば、短波長、長
波長の組み合わせによる分波器での色収差による
損失増加を小さくできる。又、本発明の構成によ
ると、フアイバ束の製作が、短波長のみ、及び長
波長のみの分波・合波器を作製する場合と同様に
できるため、量産性がよくなる。さらに光フアイ
バ端面傾斜が光フアイバの臨界角以上になつてい
るために、LDを光源として用いた場合のカツト
フイルタ面での反射光が（約−15dB）、再びLD
チツプに戻るのを防ぐことができる。Effects of the Invention As described above, according to the present invention, it is possible to reduce the increase in loss due to chromatic aberration in a demultiplexer due to a combination of short wavelength and long wavelength. Furthermore, according to the configuration of the present invention, the fiber bundle can be manufactured in the same way as the demultiplexer/multiplexer for only short wavelengths and only for long wavelengths, which improves mass productivity. Furthermore, since the slope of the end face of the optical fiber is greater than the critical angle of the optical fiber, when an LD is used as a light source, the reflected light at the cut filter surface (approximately -15 dB) is reflected back to the LD.
You can prevent it from returning to chips.
第１図は従来の分波・合波器の構成図、第２図
は第１図における干渉膜フイルタの特性図、第３
図は本発明の一実施例における分波器の構成図、
第４図は第３図におけるフアイバ束端面の斜視
図、第５図は第３図におけるフアイバ端とフイル
タ面での反射光の状態を示した図である。
１１〜１４……光フアイバ、１６……集束性ロ
ツドレンズ、１７……ガラスブロツク、１８〜２
１……誘電体多層膜フイルタ。
Figure 1 is a configuration diagram of a conventional demultiplexer/multiplexer, Figure 2 is a characteristic diagram of the interference film filter in Figure 1, and Figure 3 is a diagram of the characteristics of the interference film filter in Figure 1.
The figure is a configuration diagram of a duplexer in an embodiment of the present invention.
4 is a perspective view of the end face of the fiber bundle in FIG. 3, and FIG. 5 is a diagram showing the state of reflected light at the fiber end and the filter surface in FIG. 3. 11-14... Optical fiber, 16... Focusing rod lens, 17... Glass block, 18-2
1...Dielectric multilayer film filter.
Claims (1)
介して複数の波長の光を入出力させ、波長の長い
光を入力あるいは出力する光フアイバを前記ロツ
ドレンズ端より最も遠くなる位置に配し、波長が
短くなるにしたがい対応する光フアイバを順次前
記ロツドレンズ端に近づくように配列するととも
に、前記複数の光フアイバが、光フアイバの臨界
角近傍あるいは臨界角以上の端面を有するように
形成され、前記ロツドレンズと光フアイバ間に一
部に光学フイルタを設けたくさび状の光透過体を
設け、前記異なる波長の光を選択的に反射する複
数の光干渉膜フイルタを前記ロツドレンズの他端
に設け、かつ前記複数の光干渉膜フイルタは、前
記異なる波長の光を反射させて所定の光フアイバ
に戻るように傾きをもたせて配置したことを特徴
とする光分波器。1 Input and output light of multiple wavelengths from multiple optical fibers via a common rod lens, and place the optical fiber that inputs or outputs light with a long wavelength at a position farthest from the end of the rod lens, so that the wavelength becomes shorter. The corresponding optical fibers are arranged so as to approach the end of the rod lens in sequence, and the plurality of optical fibers are formed to have an end face near or at a critical angle of the optical fiber, and the rod lens and the optical fiber a wedge-shaped light transmitting body with an optical filter partially provided therebetween; a plurality of optical interference film filters that selectively reflect the light of different wavelengths are provided at the other end of the rod lens; An optical demultiplexer characterized in that the interference film filter is arranged with an inclination so as to reflect the light of the different wavelengths and return it to a predetermined optical fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6401284A JPS60205510A (en) | 1984-03-30 | 1984-03-30 | Optical demultiplexer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6401284A JPS60205510A (en) | 1984-03-30 | 1984-03-30 | Optical demultiplexer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60205510A JPS60205510A (en) | 1985-10-17 |
| JPH0477882B2 true JPH0477882B2 (en) | 1992-12-09 |
Family
ID=13245835
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6401284A Granted JPS60205510A (en) | 1984-03-30 | 1984-03-30 | Optical demultiplexer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60205510A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6400862B1 (en) * | 2000-05-23 | 2002-06-04 | Alliance Fiber Optics Products, Inc. | Retro-reflective multi-port filter device with triple-fiber ferrule |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59140416A (en) * | 1982-12-08 | 1984-08-11 | アンストルマン・ソシエテ・アノニム | Optical element having dividing function for remote transmission of light signal |
-
1984
- 1984-03-30 JP JP6401284A patent/JPS60205510A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59140416A (en) * | 1982-12-08 | 1984-08-11 | アンストルマン・ソシエテ・アノニム | Optical element having dividing function for remote transmission of light signal |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60205510A (en) | 1985-10-17 |
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