JP3112115B2 - Manufacturing method of optical waveguide - Google Patents
Manufacturing method of optical waveguideInfo
- Publication number
- JP3112115B2 JP3112115B2 JP5497892A JP5497892A JP3112115B2 JP 3112115 B2 JP3112115 B2 JP 3112115B2 JP 5497892 A JP5497892 A JP 5497892A JP 5497892 A JP5497892 A JP 5497892A JP 3112115 B2 JP3112115 B2 JP 3112115B2
- Authority
- JP
- Japan
- Prior art keywords
- cladding layer
- tapered
- upper cladding
- optical waveguide
- waveguide
- 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
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
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体あるいは誘電体
基板上の光導波路に属するものであり、さらに具体的に
は上部クラッド層の厚さが導波路面内で徐々に変化した
構成を有する光導波路の製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to an optical waveguide on a semiconductor or dielectric substrate, and more specifically, has a structure in which the thickness of an upper cladding layer is gradually changed in the plane of the waveguide. it relates manufacturing method of the optical waveguide.
【０００２】[0002]
【従来の技術】レーザ、変調器、方向性結合器、受光器
などの光素子を一つの結晶基板上に形成し、各素子間を
光導波路で光学的に結合した半導体光集積回路は、各素
子間を光ファイバなどで結合するハイブリッド光回路に
比べて、素子間の光軸合わせが不必要でかつ回路全体の
面積が極めて小さいという利点を有している。しかし各
素子の構造は互いに異なるため、光導波路による効率的
な光結合は困難であり、また半導体光集積回路への光入
力端あるいはここからの光出力端では光ファイバとの結
合による光損失が生じる。この問題を回避するため、コ
ア層の厚さを除々に変化させたテーパー導波路が用いら
れて提案されている（Ｇ．Ｍｕｌｌｅｒ他、Ｅｌｅｃｔ
ｒｏｎｉｃｓ Ｌｅｔｔｅｒｓ， Ｖｏｌ．２７，Ｎ
ｏ．２０，ｐ１８３６（１９９１年）参照）。2. Description of the Related Art A semiconductor optical integrated circuit in which optical elements such as a laser, a modulator, a directional coupler, and a light receiver are formed on a single crystal substrate and each element is optically coupled by an optical waveguide, Compared with a hybrid optical circuit in which elements are coupled by an optical fiber or the like, there is an advantage that optical axis alignment between elements is unnecessary and the area of the entire circuit is extremely small. However, since the structure of each element is different from each other, it is difficult to efficiently couple the light with an optical waveguide.At the optical input end to the semiconductor optical integrated circuit or the optical output end therefrom, optical loss due to coupling with the optical fiber is reduced. Occurs. To avoid this problem, it has been proposed to use a tapered waveguide in which the thickness of the core layer is gradually changed (G. Muller et al., Elect).
ronics Letters, Vol. 27, N
o. 20, p 1836 (1991)).
【０００３】この従来技術に係るコア層の厚さを徐々に
変化させたテーパー導波路の一例を図４に示す。同図に
示すように、従来のテーパ導波路はＩｎＰ基板である下
部クラッド層１１の上部にエッチングによって長手方向
の一端が他端より厚みを有し且つ導波方向に沿ってその
厚さが漸大するテーパ形状のＩｎＧａＡｓＰコア１２が
形成されており、さらにこのコア１２の上面にはＩｎＰ
上部クラッド層１３を均一に再成長させている。FIG. 4 shows an example of a tapered waveguide in which the thickness of a core layer according to the prior art is gradually changed. As shown in the figure, in the conventional tapered waveguide, one end in the longitudinal direction has a thickness greater than the other end by etching on the upper part of the lower cladding layer 11 which is an InP substrate, and the thickness gradually increases along the waveguide direction. An InGaAsP core 12 having a large taper shape is formed.
The upper cladding layer 13 is uniformly regrown.
【０００４】このテーパー導波路の入射端に入射された
光ビームは、導波路のコア層厚さの変化とともにその広
がりが変化して出射端より出射される。The light beam incident on the incident end of the tapered waveguide changes its spread as the core layer thickness of the waveguide changes, and is emitted from the output end.
【０００５】[0005]
【発明が解決しようとする課題】しかし、従来のテーパ
ー導波路は、コア層をテーパー形状にエッチングするこ
とが困難であるのみならず、上部クラッド層を再成長に
より形成するため、上部クラッド層の結晶性あるいは再
成長界面の平滑性が劣化しやすく、テーパー導波路内で
の導波損失が大きいという問題があった。However, in the conventional tapered waveguide, not only is it difficult to etch the core layer into a tapered shape, but also because the upper cladding layer is formed by regrowth, the upper cladding layer is not formed. There is a problem that the crystallinity or the smoothness of the regrowth interface is easily deteriorated, and the waveguide loss in the tapered waveguide is large.
【０００６】本発明は、上記従来技術の問題点を解消
し、製作が容易でかつ導波損失の小さいテーパー状の光
導波路の製造方法を提供することを目的とする。[0006] The present invention is to solve the problems of the prior art, fabrication and has an object to provide an easy and small tapered manufacturing method of the optical waveguide path of the waveguide loss.
【０００７】[0007]
【０００８】[0008]
【課題を解決するための手段】 前記目的を達成する本発
明に係る光導波路の製造方法は、 半導体あるいは誘電体
基板上に下部クラッド層、コア層及び上部クラッド層を
順次積層し、次いで、導波方向に亙って漸次その幅が変
化してなるテーパ状のエッチングマスクを用い、前記上
部クラッド層を選択エッチングし、当該上部クラッド層
の一部を上記エッチングマスクと同形のテーパ状リッジ
部に加工した後、該エッチングマスクを除去し、その
後、当該リッジ形状部を有する上部クラッド層を無選択
的にエッチング加工することを特徴とする。 In order to achieve the object of the present onset to achieve the above purpose
According to the method for manufacturing an optical waveguide according to the present invention , a lower clad layer, a core layer, and an upper clad layer are sequentially laminated on a semiconductor or dielectric substrate, and then the taper whose width gradually changes in the waveguide direction is obtained. The upper cladding layer is selectively etched by using an etching mask having a shape, a part of the upper cladding layer is processed into a tapered ridge portion having the same shape as the etching mask, and then the etching mask is removed. An upper clad layer having a shape portion is non-selectively etched.
【０００９】[0009]
【作用】基板上に下部クラッド層、コア層、上部クラッ
ド層を順次エピタキシャル成長する。次に、ＣＶＤ法を
用いて上部クラッド層上部全面に窒化硅素膜を推積し、
その後テーパー状のエッチングマスクとしての窒化硅素
膜を形成する。さらにテーパ状エッチングマスクと同形
の、テーパ状リッジ部を有する上部クラッド層を形成す
る。その後、窒化硅素マスクを除去し、テーパ状リッジ
部を有する上部クラッド層の全面をエッチングし、リッ
ジの上面だけでなく側面からもエッチングを施し、リッ
ジの幅が狭い場所ほどエッチング量が増える結果、テー
パー状に厚さが変化する上部クラッド層を形成する。The lower clad layer, the core layer, and the upper clad layer are sequentially grown on the substrate by epitaxial growth. Next, a silicon nitride film is deposited on the entire upper surface of the upper cladding layer using a CVD method,
Thereafter, a silicon nitride film is formed as a tapered etching mask. Further, an upper clad layer having a tapered ridge portion having the same shape as the tapered etching mask is formed. After that, the silicon nitride mask was removed, the entire surface of the upper cladding layer having the tapered ridge was etched, and the etching was performed not only on the upper surface but also on the side surfaces. An upper cladding layer having a tapered thickness is formed.
【００１０】[0010]
【実施例】以下、本発明に係る光導波路の好適な一実施
例を図面を参照して説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the optical waveguide according to the present invention will be described below with reference to the drawings.
【００１１】図１及び図２は本実施例に係る光導波路の
形成過程を示す概略図を各々示す。図２に示すように、
本実施例に係る光導波路１００は、ＩｎＰ半導体基板１
０１上にＩｎＰ下部クラッド層１０２、ＩｎＧａＡｓＰ
コア層１０３及びＩｎＰ上部クラッド層１０４が順次積
層されてなる光導波路において、ＩｎＰ上部クラッド層
１０４の一部を導波方向に沿ってその幅及び高さが漸次
増大したテーパ状リッジ部１０６に形成してなるもので
ある。FIGS. 1 and 2 are schematic views showing a process of forming an optical waveguide according to this embodiment. As shown in FIG.
The optical waveguide 100 according to the present embodiment includes the InP semiconductor substrate 1
01, an InP lower cladding layer 102, InGaAsP
In an optical waveguide in which a core layer 103 and an InP upper cladding layer 104 are sequentially laminated, a part of the InP upper cladding layer 104 is formed in a tapered ridge portion 106 whose width and height gradually increase along the waveguide direction. It is made.
【００１２】よって、ＩｎＰ上部クラッド層１０４の一
部を導波方向に沿ったテーパ状リッジ部１０６とするこ
とにより、導波路の両端（Ａ端及びＢ端）における導波
光の基板垂直方向の強度分布が大小異なるものとしてい
る。この結果、テーパ状に厚さが変化するテーパ状リッ
ジ部１０６を有するＩｎＰ上部クラッド層１０４に光を
導波させることで、基板垂直方向に導波光が漸次増大又
は減少する導波光分布を形成することができ、高効率な
光結合を可能としている。Accordingly, by forming a part of the InP upper cladding layer 104 as the tapered ridge portion 106 along the waveguide direction, the intensity of the guided light at both ends (A end and B end) of the waveguide in the direction perpendicular to the substrate. The distribution is assumed to be different in size. As a result, by guiding the light to the InP upper cladding layer 104 having the tapered ridge portion 106 having a tapered thickness, a guided light distribution is formed in which the guided light gradually increases or decreases in the direction perpendicular to the substrate. This enables highly efficient optical coupling.
【００１３】以下、本実施例に係る光導波路の形成方法
を説明する。Hereinafter, a method for forming an optical waveguide according to this embodiment will be described.
【００１４】工程１ 図１（Ａ）に示すように、ＩｎＰ基板１０１上にＭＯＶ
ＰＥ（有機金属気相エピタキシャル法）法を用いて厚さ
０．５μｍのＩｎＰからなる下部クラッド層１０２、厚
さ０．１μｍのＩｎＧａＡｓＰからなるコア層１０３、
厚さ５μｍのＩｎＰからなる上部クラッド層１０４を順
次エピタキシャル成長する。 Step 1 As shown in FIG. 1A, an MOV is formed on an InP substrate 101.
A lower cladding layer 102 made of InP having a thickness of 0.5 μm, a core layer 103 made of InGaAsP having a thickness of 0.1 μm,
An upper cladding layer 104 of InP having a thickness of 5 μm is sequentially epitaxially grown.
【００１５】工程２ 図１（Ｂ）に示すように、ＣＶＤ法を用いて上部クラッ
ド層１０４の上部全面に厚さ０．２μｍの窒化硅素膜１
０５を推積し、その後のフォトプロセスおよびフッ素系
ＲＩＥ法により、長さ（Ｌ）５００μｍ，一方の端（Ａ
端）での幅（Ｄ 1)１０μｍ、他方の端（Ｂ端）での幅
（Ｄ2)２μｍのテーパー状のエッチングマスクとしての
窒化硅素膜１０５を形成する。さらに図１（Ｃ）に示す
ように、塩素系ＲＩＥ法を用いてＩｎＰ上部クラッド層
１０４をエッチングし、テーパ状エッチングマスク１０
５と同形の、テーパ状リッジ部１０６を有するＩｎＰ上
部クラッド層１０４を形成する。[0015]Step 2 As shown in FIG. 1B, the upper cladding is formed by using the CVD method.
Silicon nitride film 1 having a thickness of 0.2 μm
05 and then photo process and fluorine system
According to the RIE method, the length (L) is 500 μm, and one end (A
Width at end (D 1) 10 μm, width at the other end (end B)
(DTwo) 2 μm tapered etching mask
A silicon nitride film 105 is formed. Further shown in FIG.
As described above, an InP upper cladding layer is formed by using a chlorine-based RIE method.
104 is etched to form a tapered etching mask 10
5 on InP having a tapered ridge 106 having the same shape as
A partial cladding layer 104 is formed.
【００１６】工程３ 図２（Ａ）に示すように、緩衝フッ酸により窒化硅素マ
スクを除去した後、塩素系ＲＩＥ法を用いてテーパ状リ
ッジ部１０６を有する上部クラッド層１０４の全面をエ
ッチングする。上記工程（３）におけるエッチングで
は、工程（２）のエッチングと異なりエッチングマスク
を用いないため、リッジの上面だけでなく側面からのエ
ッチングが顕著になる。したがってリッジの幅が狭い場
所（図中Ｂ端側）ほどエッチング量が増えるため、テー
パー状に厚さが変化する（リッジ部の高さが漸次変化す
ると共に、リッジ部上面１０６ｂが屋根型で且つ傾斜が
変化する）テーパ状リッジ部１０６を有する上部クラッ
ド層が形成される。 Step 3 As shown in FIG. 2A, after the silicon nitride mask is removed with buffered hydrofluoric acid, the entire surface of the upper cladding layer 104 having the tapered ridge portion 106 is etched by chlorine-based RIE. . In the etching in the step (3), unlike the etching in the step (2), an etching mask is not used, so that not only the upper surface but also the side surface of the ridge becomes remarkable. Therefore, the etching amount increases as the width of the ridge becomes narrower (the end B in the figure), so that the thickness changes in a tapered shape (the height of the ridge portion gradually changes, and the upper surface 106b of the ridge portion has a roof-like shape). An upper cladding layer having a tapered ridge 106 (with varying slope) is formed.
【００１７】この結果、導波路のＡ点のリッジ部の高さ
（Ｈ1 ）が３μｍでＢ点のリッジ部の高さ（Ｈ2 ）が
０．１μｍとなる幅及び高さ並びにそのリッジ部上面１
０６ｂがＢ端からＡ端に向って漸次増大したテーパ状リ
ッジ部１０６が形成される。As a result, the height and height of the ridge at point A (H 1 ) of the waveguide are 3 μm and the height (H 2 ) of the ridge at point B is 0.1 μm and the ridge. Top 1
The tapered ridge portion 106b gradually increases from the B end to the A end.
【００１８】この光導波路の端部Ａ端とＢ端における導
波光の基板垂直方向の強度分布を図２に示す。端面Ａで
は上部クラッド層が厚いため導波光が上部クラッド層側
に広く分布しているのに対して、端面Ｂでは上部クラッ
ド層が薄いため導波光の分布は狭くなっており、この導
波路ＡからＢへあるいはＢからＡへ光を導波させること
で基板垂直方向に導波光の分布の分布を大小させる機能
を有している。FIG. 2 shows the intensity distribution of the guided light at the ends A and B of the optical waveguide in the direction perpendicular to the substrate. On the end face A, the guided light is widely distributed on the upper clad layer side because the upper clad layer is thick, whereas on the end face B, the distribution of the guided light is narrow because the upper clad layer is thin. Has a function of increasing or decreasing the distribution of the guided light in the direction perpendicular to the substrate by guiding the light from the substrate to B or from B to A.
【００１９】このように本実施例に係る光導波路は、光
の導波方向に沿って厚さがテーパ状に変化した上部クラ
ッド層を有する光導波路の構成を特徴とするものであ
り、従来の厚さがテーパ状に変化したコア層を有する光
導波路と比べて、上部クラッド層を再成長する必要がな
いため、製作が容易でかつ導波損失が小さいという利点
がある。As described above, the optical waveguide according to the present embodiment is characterized by the configuration of the optical waveguide having the upper clad layer whose thickness changes in a tapered shape along the light guiding direction. Compared with an optical waveguide having a core layer having a tapered thickness, there is no need to regrow the upper cladding layer, so that there is an advantage that the fabrication is easy and the waveguide loss is small.
【００２０】本実施例においては、上部クラッド層の加
工に二回のエッチングを用いた例を示したが、これを、
サイドエッチング効果、あるいは結晶方位に依存したエ
ッチングの異方性を利用した一回のエッチングで行なう
ことも可能である。またマスクとしては窒化硅素以外に
も例えば酸化硅素やレジストなどを用いることができ
る。In this embodiment, an example in which the etching of the upper cladding layer is performed twice is shown.
It is also possible to carry out a single etching utilizing the side etching effect or the anisotropy of etching depending on the crystal orientation. In addition to the silicon nitride, for example, silicon oxide or resist can be used as the mask.
【００２１】[0021]
【発明の効果】以上説明したように本発明によれば、半
導体基板上あるいは誘電体基板上に、テーパ状に上部ク
ラッド層の厚さが変化する光導波路を形成することによ
り、製作が容易でかつ高性能な光集積回路を実現できる
という利点がある。As described above, according to the present invention, an optical waveguide in which the thickness of an upper cladding layer changes in a tapered shape is formed on a semiconductor substrate or a dielectric substrate, thereby facilitating the fabrication. In addition, there is an advantage that a high-performance optical integrated circuit can be realized.
【図１】本実施例に係る光導波路の形成過程を示す概略
図である。FIG. 1 is a schematic view illustrating a process of forming an optical waveguide according to an embodiment.
【図２】本実施例に係る光導波路の形成過程を示す概略
図である。FIG. 2 is a schematic view illustrating a process of forming an optical waveguide according to the present embodiment.
【図３】本実施例に係る光導波路の導波光分布図であ
る。FIG. 3 is a waveguide light distribution diagram of the optical waveguide according to the present embodiment.
【図４】従来技術に係る光導波路の斜視図である。FIG. 4 is a perspective view of an optical waveguide according to the related art.
１００ 光導波路 １０１ ＩｎＰ半導体基板 １０２ ＩｎＰ下部クラッド層 １０３ ＩｎＧａＡｓＰコア層 １０４ ＩｎＰ上部クラッド層 １０５ 窒化硅素膜 １０６ テーパ状リッジ部 REFERENCE SIGNS LIST 100 Optical waveguide 101 InP semiconductor substrate 102 InP lower cladding layer 103 InGaAsP core layer 104 InP upper cladding layer 105 Silicon nitride film 106 Tapered ridge portion
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平３−10207（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G02B 6/12 - 6/14 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-10207 (JP, A) (58) Field surveyed (Int. Cl. 7 , DB name) G02B 6/12-6/14
Claims (1)
ッド層、コア層及び上部クラッド層を順次積層し、次い
で、導波方向に亙って漸次その幅が変化してなるテーパ
状のエッチングマスクを用い、前記上部クラッド層を選
択エッチングし、当該上部クラッド層の一部を上記エッ
チングマスクと同形のテーパ状リッジ部に加工した後、
該エッチングマスクを除去し、その後、当該テーパ状リ
ッジ部を有する上部クラッド層を無選択的にエッチング
加工することを特徴とする光導波路の製造方法。1. A tapered etching mask in which a lower cladding layer, a core layer and an upper cladding layer are sequentially laminated on a semiconductor or dielectric substrate, and the width thereof gradually changes in the waveguide direction. Using, selective etching of the upper cladding layer, after processing a part of the upper cladding layer into a tapered ridge having the same shape as the etching mask,
A method for manufacturing an optical waveguide, comprising: removing the etching mask; and thereafter, non-selectively etching the upper cladding layer having the tapered ridge portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5497892A JP3112115B2 (en) | 1992-03-13 | 1992-03-13 | Manufacturing method of optical waveguide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5497892A JP3112115B2 (en) | 1992-03-13 | 1992-03-13 | Manufacturing method of optical waveguide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05257018A JPH05257018A (en) | 1993-10-08 |
| JP3112115B2 true JP3112115B2 (en) | 2000-11-27 |
Family
ID=12985742
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5497892A Expired - Fee Related JP3112115B2 (en) | 1992-03-13 | 1992-03-13 | Manufacturing method of optical waveguide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3112115B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9939582B2 (en) | 2011-04-21 | 2018-04-10 | Lionix International Bv | Layer having a non-linear taper and method of fabrication |
| EP2942652B1 (en) * | 2014-05-05 | 2018-10-10 | LioniX International B.V. | Layer having a non-linear taper and method of fabrication |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3758258B2 (en) * | 1996-11-29 | 2006-03-22 | 富士通株式会社 | Optical coupling device |
| JP3682367B2 (en) | 1998-01-28 | 2005-08-10 | パイオニア株式会社 | Distributed feedback laser diode |
| JP4066670B2 (en) | 2002-02-19 | 2008-03-26 | オムロン株式会社 | Light switch |
-
1992
- 1992-03-13 JP JP5497892A patent/JP3112115B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9939582B2 (en) | 2011-04-21 | 2018-04-10 | Lionix International Bv | Layer having a non-linear taper and method of fabrication |
| EP2942652B1 (en) * | 2014-05-05 | 2018-10-10 | LioniX International B.V. | Layer having a non-linear taper and method of fabrication |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05257018A (en) | 1993-10-08 |
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