JP2597358B2 - Y-branch waveguide - Google Patents
Y-branch waveguideInfo
- Publication number
- JP2597358B2 JP2597358B2 JP61220862A JP22086286A JP2597358B2 JP 2597358 B2 JP2597358 B2 JP 2597358B2 JP 61220862 A JP61220862 A JP 61220862A JP 22086286 A JP22086286 A JP 22086286A JP 2597358 B2 JP2597358 B2 JP 2597358B2
- Authority
- JP
- Japan
- Prior art keywords
- branch
- waveguide
- refractive index
- substrate
- loss
- 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 - Fee Related
Links
Landscapes
- Optical Integrated Circuits (AREA)
Description
【発明の詳細な説明】 〔概要〕 本発明は、Ｙ分岐導波路において、その分岐部に直線
導波路と基板との中間の屈折率を持たせることにより、
分岐損失の一層の低減化を可能にしたものである。DETAILED DESCRIPTION OF THE INVENTION [Overview] The present invention provides a Y-branch waveguide in which a branch portion has an intermediate refractive index between a straight waveguide and a substrate.
This makes it possible to further reduce the branch loss.
本発明は、Ｙ字形の導波路を持つＹ分岐導波路に関す
る。The present invention relates to a Y-branch waveguide having a Y-shaped waveguide.
Ｙ分岐導波路は、光回路における種々のデバイスの文
意、合波回路等として重要であり、その低損失化が望ま
れている。The Y-branch waveguide is important as the meaning of various devices in an optical circuit, a multiplexing circuit, and the like, and it is desired to reduce its loss.
従来のＹ分岐導波路の構成を第３図に示す。これは、
屈折率n1を持つ基板１内に、屈折率n2（＞n1）を持ち互
いにＹ字形状をなす３本の直線導波路2,3,4を形成した
ものである。なお、これらが互いに交わる部分を分岐部
５とした。上記構成において、直線導波路２を伝播され
てきた光は、分岐部５で分岐され、２本の直線導波路3,
4内に導かれる。FIG. 3 shows the configuration of a conventional Y-branch waveguide. this is,
In the substrate 1 having a refractive index n 1, it is obtained by forming a refractive index n 2 (> n 1) 3 straight line waveguides 2, 3 and 4 forming the Y-shapes have. Note that a portion where these cross each other is referred to as a branch portion 5. In the above configuration, the light that has propagated through the linear waveguide 2 is branched at the branching section 5 and the two linear waveguides 3,
Guided within 4.
上記従来のＹ分岐導波路では、光が分岐部５で分岐さ
れるときに生じる損失（すなわち分岐損失）を抑えるた
めに、分岐角θを２〔deg〕以下に設定するようにして
いる。しかし、このようにした場合であっても、分岐損
失を十分に小さな値に抑えることはできなかった。In the above-described conventional Y-branch waveguide, the branch angle θ is set to 2 [deg] or less in order to suppress a loss (that is, a branch loss) that occurs when light is branched at the branch section 5. However, even in this case, the branch loss cannot be suppressed to a sufficiently small value.
本発明は、上記問題点に鑑み、より一段と低損失な光
の分岐を可能にするＹ分岐導波路を提供することを目的
とする。The present invention has been made in view of the above problems, and has as its object to provide a Y-branch waveguide capable of branching light with even lower loss.
本発明のＹ分岐導波路は、分岐部の分岐開始位置から
分岐終了位置までのほぼ全領域の屈折率を直線導波路の
屈折率よりも小さく、かつ基板の屈折率よりも大きな値
としたものである。In the Y-branch waveguide of the present invention, the refractive index of almost the entire region from the branch start position to the branch end position of the branch part is smaller than the refractive index of the linear waveguide and larger than the refractive index of the substrate. It is.
一般に、導波路内に光を閉じ込める作用は、導波路の
屈折率が大きいほど、また導波路の幅が大きいほど大き
い。このことを考慮すれば、Ｙ分岐導波路の分岐部で
は、その幅が直線導波路の幅よりも大きくなっているの
で、光を閉じ込める作用が強く、上述したように屈折率
をある程度小さくしたとしても光を十分に閉じ込めるこ
とができる。しかも、分岐部のほぼ全領域の屈折率を小
さくすれば、基板の屈折率との差が小さくなるので、分
岐部での導波路内から基板への光のしみ出しが大きくな
り、その結果、光の分岐が長い距離で徐々に行われるこ
とになり、よって分岐損失が一段と低減される。Generally, the effect of confining light in a waveguide increases as the refractive index of the waveguide increases and as the width of the waveguide increases. In consideration of this, at the branch portion of the Y-branch waveguide, since the width is larger than the width of the linear waveguide, the effect of confining light is strong, and as described above, the refractive index is reduced to some extent. Can sufficiently confine the light. Moreover, if the refractive index of almost the entire region of the branch portion is reduced, the difference from the refractive index of the substrate is reduced, so that light seeping from the waveguide at the branch portion to the substrate increases, and as a result, Light branching is performed gradually over a long distance, so that branch loss is further reduced.
以下、本発明の実施例について、図面を参照しながら
説明する。Hereinafter, embodiments of the present invention will be described with reference to the drawings.
第１図は、本発明の一実施例を示す構成図である。本
実施例は、屈折率n1の基板１内に、屈折率n2（＞n1）の
三本の直線導波路2,3,4を、屈折率n3（n2＞n3＞n1）の
分岐部10を介してＹ字形状に形成したものである。同図
では、分岐が開始する位置から、完全に分岐される位置
までを分岐部10としている。FIG. 1 is a configuration diagram showing one embodiment of the present invention. In this embodiment, three straight waveguides 2, 3, and 4 having a refractive index of n 2 (> n 1 ) are formed in a substrate 1 having a refractive index of n 1 by a refractive index of n 3 (n 2 > n 3 > n). It is formed in a Y-shape via the branch portion 10 of 1 ). In the figure, a portion from the position where the branch starts to the position where the branch is completely made is defined as the branch portion 10.
このようなＹ分岐導波路の製造は、たとえばLiNbO3の
基板１に対してTiの２重蒸着等を行って、上記直線導波
路２〜４、分岐部10となるべき領域の屈折率をそれぞれ
n2,n3となるようにすることにより実現することができ
る。To manufacture such a Y-branch waveguide, for example, double vapor deposition of Ti or the like is performed on the substrate 1 of LiNbO 3 , and the refractive indices of the linear waveguides 2 to 4 and the region to become the branch portion 10 are respectively adjusted.
This can be realized by setting n 2 and n 3 .
上記構成において、分岐部10では、その幅が大きくな
っているので、光を閉じ込める作用が強い。そのため、
屈折率がn3（n2＞n3＞n1）として小さくても、光を十分
に閉じ込めることができる。しかも、分岐部10の屈折率
をn3と小さくしたことにより、基板１の屈折率n1との差
が小さくなり、よって分岐損失を一段と低減させること
ができる。In the above configuration, since the width of the branch portion 10 is large, the effect of confining light is strong. for that reason,
Even if the refractive index is small as n 3 (n 2 > n 3 > n 1 ), light can be sufficiently confined. Moreover, the refractive index of the branch portion 10 by the small as n 3, the difference between the refractive index n 1 of the substrate 1 is reduced, thus branching loss can further be reduced.
そこで、本実施例の効果を確認するために、分岐損失 の分岐角θへの依存性を求めてみた。この結果を、従来
の理想的なＹ分岐導波路（第３図）の場合と対比して第
２図に示す。なお、同図では屈折率差n2−n1＝0.004,n3
−n1＝0.002とした。すると同図により、分岐角が1.8
〔deg〕以下では両者に顕著な差が生じ、本実施例の方
が従来よりも一段と低損失となっていのがわかる。この
ことから、本実施例のＹ分岐導波路を実際に使用する場
合は、分岐角θを1.8〔deg〕以下に設定することが望ま
しいと言える。Therefore, in order to confirm the effect of the present embodiment, the branch loss I tried to find the dependence on the branch angle θ. The result is shown in FIG. 2 in comparison with the case of a conventional ideal Y branch waveguide (FIG. 3). In the figure, the refractive index difference n 2 −n 1 = 0.004, n 3
−n 1 = 0.002. Then, according to the figure, the branch angle is 1.8
Below [deg], a remarkable difference occurs between the two, and it can be seen that the loss of the present embodiment is much lower than that of the prior art. From this, when the Y-branch waveguide of the present embodiment is actually used, it can be said that it is desirable to set the branch angle θ to 1.8 [deg] or less.
本発明のＹ分岐導波路によれば、分岐部の屈折率を直
線導波路の屈折率よりも小さく基板の屈折率よりも大き
くしたことにより、光を導波路中に十分に閉じ込めなが
ら、しかも分岐損失を一段と低減させることが出来るよ
うになった。According to the Y-branch waveguide of the present invention, the refractive index of the branch portion is smaller than the refractive index of the linear waveguide and larger than the refractive index of the substrate. The loss can be further reduced.
第１図は本発明の一実施例を示す構成図、 第２図は上記実施例及び従来例における、分岐損失と分
岐角との関係を示す図、 第３図は従来のＹ分岐導波路を示す構成図である。 １……基板、 2,3,4……直線導波路、 10……分岐部．FIG. 1 is a configuration diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the branch loss and the branch angle in the above embodiment and the conventional example, and FIG. 3 is a diagram showing a conventional Y-branch waveguide. FIG. 1 ... substrate, 2,3,4 ... linear waveguide, 10 ... branch.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭56−126809（ＪＰ，Ａ) 特開 昭54−161350（ＪＰ，Ａ) 特開 昭61−55612（ＪＰ，Ａ) 特開 昭52−134453（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-126809 (JP, A) JP-A-54-161350 (JP, A) JP-A-61-55612 (JP, A) JP-A Sho 52- 134453 (JP, A)
Claims (2)
導波路（２、３、４）をＹ字形に構成してなるＹ分岐導
波路において、 前記分岐部の分岐開始位置から分岐終了位置までにおけ
る導波路のほぼ全領域の屈折率を、前記直線導波路の屈
折率よりも小さく前記基板の屈折率よりも大きくしたこ
とを特徴とするＹ分岐導波路。1. A Y-branch waveguide in which straight waveguides (2, 3, 4) are formed in a Y-shape in a substrate (1) via a branch (10), wherein a branching start position of the branch is provided. A Y-branch waveguide, wherein the refractive index of almost the entire region of the waveguide from the point to the branch end position is smaller than the refractive index of the linear waveguide and larger than the refractive index of the substrate.
したことを特徴とする特許請求の範囲第１項記載のＹ分
岐導波路。2. The Y-branch waveguide according to claim 1, wherein a branch angle of said branch portion is set to 0.8 ° [deg] or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61220862A JP2597358B2 (en) | 1986-09-20 | 1986-09-20 | Y-branch waveguide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61220862A JP2597358B2 (en) | 1986-09-20 | 1986-09-20 | Y-branch waveguide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6377009A JPS6377009A (en) | 1988-04-07 |
| JP2597358B2 true JP2597358B2 (en) | 1997-04-02 |
Family
ID=16757710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61220862A Expired - Fee Related JP2597358B2 (en) | 1986-09-20 | 1986-09-20 | Y-branch waveguide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2597358B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2903543B2 (en) * | 1989-05-26 | 1999-06-07 | 日本電気株式会社 | Optical branch circuit |
| JP2742466B2 (en) * | 1990-05-12 | 1998-04-22 | 株式会社日立製作所 | Resin optical circuit board and method for producing the same |
| KR19990038490A (en) | 1997-11-05 | 1999-06-05 | 윤종용 | Optical power divider and its manufacturing method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52134453A (en) * | 1976-05-06 | 1977-11-10 | Nippon Telegr & Teleph Corp <Ntt> | Optical wave dividing device |
| JPS5810721B2 (en) * | 1978-06-10 | 1983-02-26 | 日本電信電話株式会社 | Manufacturing method of thin film optical device |
| JPS56126809A (en) * | 1980-03-10 | 1981-10-05 | Nippon Telegr & Teleph Corp <Ntt> | Light branching circuit |
| JPH0731285B2 (en) * | 1984-08-25 | 1995-04-10 | 彰二郎 川上 | Three-dimensional optical splitter |
-
1986
- 1986-09-20 JP JP61220862A patent/JP2597358B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6377009A (en) | 1988-04-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |