JP2006201298A - Optical waveguide and optical communication component using the same - Google Patents

Optical waveguide and optical communication component using the same Download PDF

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JP2006201298A
JP2006201298A JP2005010822A JP2005010822A JP2006201298A JP 2006201298 A JP2006201298 A JP 2006201298A JP 2005010822 A JP2005010822 A JP 2005010822A JP 2005010822 A JP2005010822 A JP 2005010822A JP 2006201298 A JP2006201298 A JP 2006201298A
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curvature
waveguide
radius
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optical waveguide
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Norihiro Tajima
典拓 田嶋
Fumio Takahashi
文雄 高橋
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NHK Spring Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide in which generation of a changed point of a curvature can be avoided in a flexural waveguide and in which bending loss can be reduced. <P>SOLUTION: The optical waveguide 10 has a linear part 11 and a curved part 12, with the curved part 12 having a maximum curvature part 12a. The curved part 12 varies in a manner that a radius of curvature gradually becomes smaller from the linear part 11 to the maximum curvature part 12a and larger from the maximum curvature part 12a to a connecting part 13. This curved part 12 has a shape along the curve expressed by the equation 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

この発明は、光通信あるいは光信号処理等の分野において使用される曲り導波路を有する光導波路と、それを用いた光通信部品に関する。   The present invention relates to an optical waveguide having a curved waveguide used in the field of optical communication or optical signal processing, and an optical communication component using the optical waveguide.

光導波路内を伝播する光を分岐あるいは合波させるための導波路デバイスとして、Ｙ分岐導波路や光方向性結合器等が知られている。この種の光導波路においては、光の伝播方向の一部に、湾曲部を備えた曲り導波路が必要となる。また、Ｙ分岐導波路や光方向性結合器以外の導波路デバイスにおいても、曲り導波路が必要になることがある。   As a waveguide device for branching or multiplexing light propagating in an optical waveguide, a Y-branch waveguide, an optical directional coupler, and the like are known. In this type of optical waveguide, a bent waveguide having a curved portion is required in a part of the light propagation direction. Also, a waveguide waveguide other than the Y-branch waveguide and the optical directional coupler may be required.

例えば図１０に示す従来の光導波回路１では、互いに逆方向に曲がる２つの円弧状導波路２，３を連ねることにより、曲り導波路を構成している。従来の曲り導波路において、それぞれの円弧状導波路２，３は、曲率が一定の単一の円弧からなる。図１０中のＡ，Ｂは、各円弧状導波路２，３の円弧の曲率半径を示している。このような２つの円弧の接続部５が曲率の変化点となり、接続部５においてリーキー（leaky）なモードが発生する。   For example, in the conventional optical waveguide circuit 1 shown in FIG. 10, a curved waveguide is formed by connecting two arc-shaped waveguides 2 and 3 that are bent in opposite directions. In the conventional curved waveguide, each of the arc-shaped waveguides 2 and 3 is formed of a single arc having a constant curvature. A and B in FIG. 10 indicate the radii of curvature of the arcs of the arcuate waveguides 2 and 3, respectively. The connecting portion 5 having such two circular arcs becomes a curvature changing point, and a leaky mode is generated in the connecting portion 5.

従来、上記のような単一の円弧を用いた曲り導波路において、リーキーなモードの発生や損失を低減させるために、あるいは光のパワーのピーク位置を調節するために、曲率変化点となる接続部に軸ずらし部を形成することが提案されている。（例えば下記特許文献１参照）
特開平４−２１３４０７号公報 Conventionally, in a curved waveguide using a single arc as described above, a connection that becomes a curvature change point in order to reduce the occurrence or loss of a leaky mode or to adjust the peak position of light power It has been proposed to form an off-axis portion in the portion. (For example, see Patent Document 1 below)
JP-A-4-213407

特許文献１のように、２つの円弧の接続部に軸ずらし部を設けた導波路は、狭帯域な波長領域においては、リーキーなモードの発生を押さえることができる。しかし広帯域な波長領域では、円弧と直線との接続部、または円弧と円弧との接続部などのように曲率が不連続となる箇所においてリーキーなモードが発生する。このため、光学特性に波長依存性が発生するなどの問題があった。   As in Patent Document 1, a waveguide in which an axis shift portion is provided at a connection portion between two arcs can suppress the occurrence of a leaky mode in a narrow wavelength region. However, in a broad wavelength region, a leaky mode is generated at a location where the curvature is discontinuous, such as a connecting portion between an arc and a straight line, or a connecting portion between an arc and an arc. For this reason, there existed problems, such as a wavelength dependence generating in an optical characteristic.

しかも従来の導波路では、曲率が不連続な変化点において光のピーク位置のずれが多重に発生し、光軸ずれが収束しないまま、曲り導波路内を伝播していた。また、従来の曲り導波路においては、円弧と直線との接続部、または円弧と円弧の接続部などの曲率が不連続となる箇所でモード不整合による損失が発生していた。   In addition, in the conventional waveguide, the shift of the light peak position occurs at multiple points where the curvature is discontinuous, and the optical axis shift does not converge and propagates through the bent waveguide. Further, in the conventional bent waveguide, a loss due to mode mismatch occurs at a portion where the curvature is discontinuous, such as a connection portion between the arc and the straight line, or a connection portion between the arc and the arc.

従って本発明の目的は、曲り導波路に曲率の変化点が生じることを抑制でき、曲り損失を低減できるような光導波路と、それを用いた光通信部品を提供することにある。   Accordingly, an object of the present invention is to provide an optical waveguide that can suppress the occurrence of a curvature change point in a bending waveguide and reduce bending loss, and an optical communication component using the optical waveguide.

本発明は、コアとクラッド層によって構成され光の伝播方向の少なくとも一部に湾曲部を有する光導波路であって、前記湾曲部が光の伝播方向に連なる複数の微小部分からなり、前記湾曲部が、曲率半径が最大の曲率最小部と、曲率半径が最小の曲率最大部とを含み、前記各微小部分の曲率半径が、前記曲率最小部から曲率最大部に向かって順次小さくなる形状であり、かつ、前記湾曲部が、次式

Figure 2006201298
The present invention is an optical waveguide that includes a core and a clad layer and has a curved portion in at least a part of the light propagation direction, wherein the curved portion is composed of a plurality of minute portions continuous in the light propagation direction, and the curved portion Includes a curvature minimum portion with the largest curvature radius and a curvature maximum portion with the smallest curvature radius, and the curvature radius of each minute portion is a shape that gradually decreases from the curvature smallest portion toward the curvature maximum portion. And, the bending portion has the following formula
Figure 2006201298

で表される曲線に沿う形状である。   It is a shape along the curve represented by.

本発明に係る光通信部品は、前記光導波路が形成された曲り導波路パーツと、前記光導波路の一端に光学的に接続される第１の接続相手パーツと、前記光導波路の他端に光学的に接続される第２の接続相手パーツとを具備し、前記曲り導波路パーツの光導波路の前記一端の曲率半径および角度が前記第１の接続相手パーツの曲率半径および角度と等しく、前記曲り導波路パーツの光導波路の前記他端の曲率半径および角度が前記第２の接続相手パーツの曲率半径および角度と等しい。   An optical communication component according to the present invention includes a bent waveguide part in which the optical waveguide is formed, a first connection partner part optically connected to one end of the optical waveguide, and an optical at the other end of the optical waveguide. A second connecting mating part connected to each other, the radius of curvature and the angle of the one end of the optical waveguide of the bent waveguide part being equal to the radius of curvature and the angle of the first connecting mating part, The radius of curvature and the angle of the other end of the optical waveguide of the waveguide part are equal to the radius of curvature and the angle of the second connection counterpart part.

本発明の光通信部品では、好ましくは、前記湾曲部が光の伝播方向に連なる長さ１００μｍ以下の直線形状の多数の微小部分からなり、該湾曲部における曲率半径がこれら微小部分ごとに段階的に変化する形状にするとよい。あるいは、前記湾曲部が光の伝播方向に連なる多数の円弧状の微小部分からなり、該湾曲部における曲率半径が連続的に変化するものでもよい。   In the optical communication component of the present invention, preferably, the curved portion is composed of a large number of linear microscopic portions having a length of 100 μm or less continuous in the light propagation direction, and the curvature radius of the curved portion is stepwise for each of the microscopic portions. A shape that changes to Alternatively, the curved portion may be composed of a large number of arc-shaped minute portions that are continuous in the light propagation direction, and the curvature radius of the curved portion may change continuously.

本発明によれば、曲り導波路に曲率の変化点が生じることを回避でき、曲り損失を低減することができる。本発明では、リーキーなモードを湾曲部の一部の曲率最大部で放射させ、それ以外の部位ではリーキーなモードを発生させにくい曲り導波路を得ることが可能である。また、曲り導波路内に入力した光のピークの光軸ずれ量を、曲り導波路の終点に近付くにしたがい小さくすることが可能となる。   According to the present invention, it is possible to avoid the occurrence of a curvature change point in a curved waveguide and to reduce the bending loss. According to the present invention, it is possible to obtain a curved waveguide in which a leaky mode is radiated at a part of the curvature maximum portion of the curved portion and a leaky mode is hardly generated at other portions. Further, it is possible to reduce the optical axis deviation amount of the peak of the light input into the bent waveguide as it approaches the end point of the bent waveguide.

以下に本発明の一実施形態について、図１〜図９を参照して説明する。
図１は、本実施形態の光導波路１０を示している。この光導波路１０は、光の伝播方向に第１の直線部１１と、この直線部１１に連なる第１の湾曲部１２と、接続部１３を介して第１の湾曲部１２に連なる第２の湾曲部１４と、第２の湾曲部１４に連なる第２の直線部１５を備えている。第１の湾曲部１２と接続部１３および第２の湾曲部１４によって、Ｓ形の曲り導波路１６が構成されている。第１および第２の直線部１１，１５は曲率半径が無限大、すなわち実質的に曲率半径が最大となる部位（曲率最小部）である。 Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows an optical waveguide 10 of this embodiment. The optical waveguide 10 includes a first linear portion 11 in the light propagation direction, a first curved portion 12 that is continuous with the linear portion 11, and a second linear portion that is continuous with the first curved portion 12 via the connection portion 13. A bending portion 14 and a second straight portion 15 connected to the second bending portion 14 are provided. The first curved portion 12, the connecting portion 13, and the second curved portion 14 constitute an S-shaped curved waveguide 16. The first and second straight portions 11 and 15 are portions where the radius of curvature is infinite, that is, the radius of curvature is substantially maximized (the minimum curvature portion).

図２に示すように光導波路１０は、下部クラッド層２０と、コア２１と、上部クラッド層２２によって構成され、コア２１の内部を光が伝播するようになっている。クラッド層２０，２２はコア２１の全周を被っている。コア２１の屈折率はクラッド層２０，２２よりも高く、比屈折率差は例えば０．４５％である。コア２１の断面形状は例えば一辺が６μｍの正方形である。   As shown in FIG. 2, the optical waveguide 10 includes a lower clad layer 20, a core 21, and an upper clad layer 22, and light propagates through the core 21. The clad layers 20 and 22 cover the entire circumference of the core 21. The refractive index of the core 21 is higher than that of the cladding layers 20 and 22, and the relative refractive index difference is, for example, 0.45%. The cross-sectional shape of the core 21 is, for example, a square having a side of 6 μm.

第１の湾曲部１２は、第１の直線部（曲率最小部）１１から曲率最大部１２ａに向かって曲率半径が次第に小さくなり、かつ、曲率最大部１２ａから接続部（曲率最小部）１３に向かって曲率半径が次第に大きくなる曲線に沿う曲り導波路である。この曲線は、次式（１）（例えば６次関数）によって近似的に表される。第１の湾曲部１２は、光の伝播方向に連なる長さ１００μｍ以下に分割された複数の微小部分によって構成されている。

Figure 2006201298
The first bending portion 12 has a radius of curvature that gradually decreases from the first straight line portion (minimum curvature portion) 11 toward the maximum curvature portion 12a, and from the maximum curvature portion 12a to the connection portion (minimum curvature portion) 13. It is a curved waveguide along a curve in which the radius of curvature gradually increases. This curve is approximately expressed by the following equation (1) (for example, a sixth-order function). The first bending portion 12 is composed of a plurality of minute portions divided into lengths of 100 μm or less that are continuous in the light propagation direction.
Figure 2006201298

式（１）における定数ｋは、例えば下記の表１に基いて決まる。始点の一例は、第１の直線部１１と第１の湾曲部１２との境界である。終点の一例は、第２の湾曲部１４と第２の直線部１５との境界である。表１の例では、自由度の合計が３であるから、ｋは３である。

Figure 2006201298
The constant k in the formula (1) is determined based on, for example, Table 1 below. An example of the starting point is a boundary between the first straight portion 11 and the first curved portion 12. An example of the end point is a boundary between the second curved portion 14 and the second straight portion 15. In the example of Table 1, since the total degree of freedom is 3, k is 3.
Figure 2006201298

式（１）のｆ（ｚ）を求める方法の一例を以下に示す。この例の境界条件は表２のとおりである。また、ｎ＝０とする。

Figure 2006201298
An example of a method for obtaining f (z) in Expression (1) is shown below. Table 2 shows the boundary conditions in this example. Also, n = 0.
Figure 2006201298

上記の境界条件から、下記の連立方程式が与えられる。

Figure 2006201298
From the above boundary conditions, the following simultaneous equations are given.
Figure 2006201298

以上の式（２．１）〜（２．６）をＣｊについて解けば、ｆ（ｚ）を決定することができる。 By solving the above equations (2.1) to (2.6) for C j , f (z) can be determined.

図１に模式的に示すように、第１の湾曲部１２の微小部分の曲率半径は、Ｒ１，Ｒ２…Ｒｎと順次変化している。なお、図１に示す２点鎖線Ｌ１は、半径ｒ１の単一の円弧であり、従来はこの円弧に沿って曲り導波路が形成されていた。   As schematically shown in FIG. 1, the curvature radius of the minute portion of the first bending portion 12 sequentially changes as R1, R2,... Rn. The two-dot chain line L1 shown in FIG. 1 is a single arc having a radius r1, and conventionally a curved waveguide is formed along this arc.

この明細書で言う微小部分は、物理的に微小に区画された部分という意味ではなく、湾曲部１２，１４の曲率変化を説明するために便宜上用いる設計思想上の微小部分である。すなわち湾曲部１２，１４を構成するコア２１は、光学的かつ物理的に光軸方向に途切れることなく１本に連続しているものである。   The minute portion mentioned in this specification does not mean a physically minutely divided portion, but is a minute portion on the design philosophy that is used for convenience in order to explain the curvature change of the bending portions 12 and 14. That is, the cores 21 constituting the bending portions 12 and 14 are continuous in one optically and physically without being interrupted in the optical axis direction.

第２の湾曲部１４は第１の湾曲部１２とは逆方向に曲がっている。この第２の湾曲部１４は、接続部（曲率最小部）１３から曲率最大部１４ａに向かって曲率半径が次第に小さくなり、かつ、曲率最大部１４ａから第２の直線部（曲率最小部）１５に向かって曲率半径が次第に大きくなる曲線に沿う曲り導波路である。この曲線も、第１の湾曲部１２と同様に、式（１）（例えば６次関数）によって近似的に表される。   The second bending portion 14 is bent in the opposite direction to the first bending portion 12. The second bending portion 14 has a radius of curvature that gradually decreases from the connecting portion (minimum curvature portion) 13 toward the maximum curvature portion 14a and from the maximum curvature portion 14a to the second straight portion (minimum curvature portion) 15. This is a curved waveguide along a curve in which the radius of curvature gradually increases toward. This curve is also approximately expressed by the expression (1) (for example, a sixth-order function), similarly to the first bending portion 12.

この第２の湾曲部１４は、第１の湾曲部１２と同様に、光の伝播方向に連なる長さ１００μｍ以下に分割された複数の微小部分によって構成されている。なお、図１に示す２点鎖線Ｌ２は、半径ｒ２の単一の円弧であり、従来はこの円弧に沿って曲り導波路が形成されていた。   Similar to the first bending portion 12, the second bending portion 14 includes a plurality of minute portions divided into lengths of 100 μm or less that are continuous in the light propagation direction. The two-dot chain line L2 shown in FIG. 1 is a single arc having a radius r2, and conventionally a curved waveguide is formed along this arc.

図３は、第１の湾曲部１２と第２の湾曲部１４の曲率が光の伝播方向（Ｚ軸方向）に変化する様子を示している。曲率は曲率半径Ｒの逆数（１／Ｒ）である。第１の湾曲部１２と第２の湾曲部１４のそれぞれの中間部に、曲率が最大（曲率半径Ｒが最小）となる部位すなわち曲率最大部１２ａ，１４ａが存在している。   FIG. 3 shows how the curvatures of the first bending portion 12 and the second bending portion 14 change in the light propagation direction (Z-axis direction). The curvature is the reciprocal (1 / R) of the radius of curvature R. A portion where the curvature is maximum (the curvature radius R is minimum), that is, the maximum curvature portions 12a and 14a exist in the intermediate portions of the first bending portion 12 and the second bending portion 14, respectively.

このように本実施形態の第１の湾曲部１２は、前記微小部分の曲率半径Ｒが第１の直線部１１から曲率最大部１２ａに向かって、無限大から次第に小さくなるように変化し、かつ、曲率最大部１２ａから接続部１３に向かって曲率半径が次第に大きくなって無限大へと変化する形状となっている。   Thus, the first bending portion 12 of the present embodiment changes so that the radius of curvature R of the minute portion gradually decreases from infinity toward the maximum curvature portion 12a from the first straight portion 11 and The radius of curvature gradually increases from the maximum curvature portion 12a toward the connection portion 13 and changes to infinity.

本実施形態の第２の湾曲部１４は、前記微小部分の曲率半径が、接続部１３から曲率最大部１４ａに向かって無限大から次第に小さくなるように変化し、かつ、曲率最大部１４ａから第２の直線部１５に向かって曲率半径が次第に大きくなって無限大へと変化する形状である。   In the second bending portion 14 of the present embodiment, the radius of curvature of the minute portion changes so as to gradually decrease from infinity toward the maximum curvature portion 14a from the connection portion 13, and from the maximum curvature portion 14a. In this shape, the radius of curvature gradually increases toward infinity toward the straight line portion 15 of the second line.

このように構成された本実施形態の曲り導波路１６は、接続部１３が実質的に直線となる。この接続部１３に対して、第１の湾曲部１２と第２の湾曲部１４がそれぞれ曲率が変化しながら滑らかに連続し、曲率変化点が存在しない。   In the bent waveguide 16 of the present embodiment configured as described above, the connection portion 13 is substantially straight. The first bending portion 12 and the second bending portion 14 continue smoothly with respect to the connecting portion 13 while the curvature changes, and there is no curvature change point.

これに対し従来の曲り導波路は、図１に２点鎖線Ｌ１，Ｌ２で示す単一の円弧からなるため、図３に２点鎖線で示すように接続部において曲率が不連続となり曲率変化点が存在している。このような曲率変化点は接続部でのモード不整合の原因となる。   On the other hand, the conventional curved waveguide is composed of a single circular arc indicated by two-dot chain lines L1 and L2 in FIG. 1, so that the curvature becomes discontinuous at the connecting portion as indicated by the two-dot chain line in FIG. Is present. Such a curvature change point causes a mode mismatch at the connection portion.

図４は従来の単一の円弧からなる曲り導波路と、本実施形態の湾曲部１２，１４を有する曲り導波路１６との、それぞれの曲り損失の波長依存性を示している。図４から、本実施形態の曲り導波路１６は、従来の曲り導波路と比較して曲り損失が大幅に減少していることが判る。   FIG. 4 shows the wavelength dependence of the respective bending losses of the conventional curved waveguide formed of a single arc and the curved waveguide 16 having the curved portions 12 and 14 of the present embodiment. From FIG. 4, it can be seen that the bending loss of the bent waveguide 16 of this embodiment is significantly reduced as compared with the conventional bent waveguide.

図５は、本実施形態の曲り導波路１６において、湾曲部１２，１４の微小部分の長さを４種類に変化させたときの曲り損失を比較したものである。図５から判るように、微小部分の分割長さが１μｍ〜１００μｍまでは互いに遜色がなく十分低損失であり、本発明の目的にかなうものとなっている。これに対し微小部分の分割長さが１５０μｍの場合は、広い波長域にわたって曲り損失が０．０１ｄＢよりも大きくなっている。   FIG. 5 compares the bending loss when the lengths of the microscopic portions of the bending portions 12 and 14 are changed to four types in the bending waveguide 16 of the present embodiment. As can be seen from FIG. 5, when the division length of the minute portion is 1 μm to 100 μm, there is no inferiority and the loss is sufficiently low, which meets the object of the present invention. On the other hand, when the division length of the minute portion is 150 μm, the bending loss is larger than 0.01 dB over a wide wavelength range.

なお前記実施形態では、湾曲部１２，１４を構成する微小部分が１００μｍ以下に分割された直線形状である場合について述べた。その場合、湾曲部１２，１４の曲率半径は各微小部分ごとに段階的に変化することになる。しかし本発明を実施するに当たって、湾曲部が微小な円弧からなる多数の微小部分の連続によって構成されていてもよい。その場合には、曲率最小部から曲率最大部に向かって曲率半径が連続的に変化する。   In the above-described embodiment, the case where the minute portions constituting the bending portions 12 and 14 have a linear shape divided into 100 μm or less has been described. In that case, the curvature radii of the curved portions 12 and 14 change stepwise for each minute portion. However, in carrying out the present invention, the curved portion may be constituted by a continuation of a large number of minute portions composed of minute arcs. In that case, the radius of curvature continuously changes from the minimum curvature portion to the maximum curvature portion.

図６は、本発明の一つの実施形態に係る光通信部品３０を模式的に示している。この光通信部品３０は、曲り導波路１６の一端１６ａに光学的に接続される第１の接続相手パーツ３１と、曲り導波路１６の他端１６ｂに光学的に接続される第２の接続相手パーツ３２と、曲り導波路１６を有する曲り導波路パーツ３３とからなっている。   FIG. 6 schematically shows an optical communication component 30 according to one embodiment of the present invention. The optical communication component 30 includes a first connection partner part 31 that is optically connected to one end 16 a of the bent waveguide 16 and a second connection partner that is optically connected to the other end 16 b of the bent waveguide 16. It consists of a part 32 and a bent waveguide part 33 having a bent waveguide 16.

曲り導波路１６は、第１の湾曲部１２と第２の湾曲部１４を備えている。第１の接続相手パーツ３１に第１の直線部１１が形成されている。第２の接続相手パーツ３２に第２の直線部１５が形成されている。湾曲部１２，１４は、それぞれ、前記の式（１）によって求めた曲線に沿う形状である。直線部１１，１５と曲り導波路１６のコアサイズは、いずれも６×６μｍ、比屈折率差Δ０．４５％である。   The bent waveguide 16 includes a first bending portion 12 and a second bending portion 14. The first straight part 11 is formed in the first connection counterpart part 31. A second straight portion 15 is formed on the second connection counterpart part 32. Each of the bending portions 12 and 14 has a shape along the curve obtained by the equation (1). The core sizes of the straight portions 11 and 15 and the curved waveguide 16 are all 6 × 6 μm and the relative refractive index difference is Δ0.45%.

図６に示すような曲り導波路１６における境界条件は、曲り導波路１６と第１および第２の直線部１１，１５とのそれぞれの境界に曲率変化点を生じさせることなく滑らかに接続させる条件とする。一例として、式（１）における定数ｋを、下記の表３に基いて求める。この場合、自由度の合計は６であるから、ｋは６である。

Figure 2006201298
The boundary condition in the curved waveguide 16 as shown in FIG. 6 is a condition in which the curved waveguide 16 and the first and second linear portions 11 and 15 are smoothly connected without causing a curvature change point at each boundary. And As an example, the constant k in Formula (1) is obtained based on Table 3 below. In this case, the total number of degrees of freedom is 6, so k is 6.
Figure 2006201298

図７は前記光通信部品３０（図６に示す）において、表３に示す境界条件を用いた場合の、曲り導波路の曲率と角度の変化を示している。式（１）中の任意のパラメータ“ｎ”は０とした。境界（Ｚ＝５００μｍと１５００μｍ）において、曲り導波路の角度と曲率がそれぞれ０になっていることが判る。   FIG. 7 shows changes in the curvature and angle of the curved waveguide when the boundary conditions shown in Table 3 are used in the optical communication component 30 (shown in FIG. 6). An arbitrary parameter “n” in the formula (1) is set to 0. It can be seen that at the boundary (Z = 500 μm and 1500 μm), the angle and curvature of the curved waveguide are 0 respectively.

すなわち、光通信部品３０を構成する曲り導波路パーツ３３の光導波路（曲り導波路１６）の一端１６ａの曲率半径および角度が、第１の接続相手パーツ３１の曲率半径および角度と等しい。また、曲り導波路１６の他端１６ｂの曲率半径および角度が、第２の接続相手パーツ３２の曲率半径および角度と等しい。   That is, the radius of curvature and the angle of the one end 16 a of the optical waveguide (the curved waveguide 16) of the curved waveguide part 33 constituting the optical communication component 30 are equal to the radius of curvature and the angle of the first connection counterpart part 31. Further, the radius of curvature and the angle of the other end 16 b of the curved waveguide 16 are equal to the radius of curvature and the angle of the second connection counterpart part 32.

前記の式（１）によって表される曲線に基いて、曲り導波路１６のコア２１（図２に示す）を形成するための成膜用マスクパターンを作る。このマスクパターンに基いて、ＣＶＤ等の成膜方法によって、下部クラッド層２０（図２に示す）の上にコア２１および上部クラッド層２２を形成することにより、所望の曲り導波路１６を有する光通信部品３０が製造される。   A film forming mask pattern for forming the core 21 (shown in FIG. 2) of the curved waveguide 16 is formed based on the curve represented by the above formula (1). Based on this mask pattern, the core 21 and the upper clad layer 22 are formed on the lower clad layer 20 (shown in FIG. 2) by a film forming method such as CVD, so that the light having the desired bent waveguide 16 is obtained. The communication component 30 is manufactured.

図８は、曲り導波路内を進む光の光軸のピーク位置ずれを模式的に示している。光は曲り導波路内を蛇行しながら進む。
図９は、本発明に係る曲り導波路と、従来の曲り導波路の光軸ずれ量を解析した結果である。解析は光導波路解析で主に用いられるビーム伝播法に基くソフトウェアによって行った。初期光軸ずれは１μｍである。 FIG. 8 schematically shows the peak position deviation of the optical axis of the light traveling in the curved waveguide. Light travels in a meandering manner in a curved waveguide.
FIG. 9 shows the result of analyzing the amount of optical axis misalignment between the bent waveguide according to the present invention and the conventional bent waveguide. The analysis was performed by software based on the beam propagation method mainly used in optical waveguide analysis. The initial optical axis deviation is 1 μm.

図９に示されように本発明に係る曲り導波路では、１２００μｍ付近から光軸ずれ量がゼロに収束している。これに対し従来の曲り導波路では、曲率が不連続となる変化点において光のピーク位置のずれが多重に発生し、光軸ずれが収束しないまま、曲り導波路内を伝播している。   As shown in FIG. 9, in the bent waveguide according to the present invention, the optical axis deviation amount converges to zero from around 1200 μm. On the other hand, in the conventional bent waveguide, the shift of the light peak position occurs multiple times at the changing point where the curvature becomes discontinuous, and the optical axis shift propagates through the bent waveguide without converging.

なお、本発明の光導波路は必ずしも直線部を有していなくてもよく、要するに曲率半径が最大となる曲率最小部（その一例が直線部）と、曲率半径が最小となる曲率最大部とを有し、これら曲率最小部と曲率最大部との間の曲率が段階的あるいは連続的に変化するように導波路コアがパターニングされていればよい。   In addition, the optical waveguide of the present invention does not necessarily have a straight portion. In short, a minimum curvature portion (an example is a straight portion) in which the curvature radius is maximum and a maximum curvature portion in which the curvature radius is minimum. The waveguide core may be patterned so that the curvature between the minimum curvature portion and the maximum curvature portion changes stepwise or continuously.

また前記実施形態では２つの湾曲部１２，１４と１つの接続部１３とからなるＳ形曲り導波路１６について述べたが、本発明は１つの湾曲部と直線部とからなる曲り導波路に適用することもできる。   In the above-described embodiment, the S-shaped curved waveguide 16 including the two curved portions 12 and 14 and the one connecting portion 13 has been described. However, the present invention is applied to a curved waveguide composed of one curved portion and a straight portion. You can also

本発明の一実施形態の曲り導波路を有する光導波路の平面図。The top view of the optical waveguide which has the curved waveguide of one Embodiment of this invention. 図１中のＦ２−Ｆ２線に沿う光導波路の断面図。Sectional drawing of the optical waveguide which follows the F2-F2 line | wire in FIG. 本発明の曲り導波路と従来の曲り導波路のそれぞれのＺ軸方向の曲率の変化を示す図。The figure which shows the change of the curvature of each Z-axis direction of the bending waveguide of this invention, and the conventional bending waveguide. 本発明の曲り導波路と従来の曲り導波路のそれぞれ波長と曲り損失との関係を示す図。The figure which shows the relationship between each wavelength and bending loss of the bending waveguide of this invention, and the conventional bending waveguide. ４種類の微小部分の長さに関して、波長と曲り損失との関係を示す図。The figure which shows the relationship between a wavelength and a bending loss regarding the length of four types of micro parts. 光通信部品の形状例を示す図。The figure which shows the example of a shape of an optical communication component. 図６に示された光通信部品の曲り導波路の曲率と角度の変化を示す図。The figure which shows the curvature and angle change of the bending waveguide of the optical communication component shown by FIG. 曲り導波路内を進む光の光軸ずれを模式的に示す図。The figure which shows typically the optical axis offset of the light which advances the inside of a curved waveguide. 本発明に係る曲り導波路と従来の曲り導波路のそれぞれの光軸ずれ量を示す図。The figure which shows each optical axis deviation | shift amount of the curved waveguide which concerns on this invention, and the conventional curved waveguide. 従来の曲り導波路を示す平面図。The top view which shows the conventional bending waveguide.

符号の説明Explanation of symbols

１０…光導波路
１１…第１の直線部
１２…第１の湾曲部
１２ａ…曲率最大部
１３…接続部
１４…第２の湾曲部
１４ａ…曲率最大部
１５…第２の直線部
１６…曲り導波路
３０…光通信部品
３１…第１の接続相手パーツ
３２…第２の接続相手パーツ
３３…曲り導波路パーツ DESCRIPTION OF SYMBOLS 10 ... Optical waveguide 11 ... 1st linear part 12 ... 1st curved part 12a ... Curvature maximum part 13 ... Connection part 14 ... 2nd curved part 14a ... Curvature maximum part 15 ... 2nd linear part 16 ... Curve guidance Waveguide 30 ... Optical communication component 31 ... First connection partner part 32 ... Second connection partner part 33 ... Curved waveguide part

Claims (3)

コアとクラッド層によって構成され光の伝播方向の少なくとも一部に湾曲部を有する光導波路であって、
前記湾曲部が光の伝播方向に連なる複数の微小部分からなり、
前記湾曲部が、
曲率半径が最大の曲率最小部と、
曲率半径が最小の曲率最大部とを含み、
前記各微小部分の曲率半径が、前記曲率最小部から曲率最大部に向かって順次小さくなる形状であり、かつ、
前記湾曲部が次式
Figure 2006201298
 で表される曲線に沿う形状であることを特徴とする光導波路。 An optical waveguide composed of a core and a cladding layer and having a curved portion in at least a part of the light propagation direction,
The curved portion is composed of a plurality of minute portions continuous in the light propagation direction,
The curved portion is
The smallest curvature part with the largest curvature radius,
Including a maximum curvature portion with a minimum curvature radius,
The radius of curvature of each of the minute portions is a shape that sequentially decreases from the minimum curvature portion to the maximum curvature portion, and
The bending portion is
Figure 2006201298
 An optical waveguide having a shape along a curve represented by 請求項１に記載の前記光導波路が形成された曲り導波路パーツと、
前記光導波路の一端に光学的に接続される第１の接続相手パーツと、
前記光導波路の他端に光学的に接続される第２の接続相手パーツと、
を具備し、
前記曲り導波路パーツの光導波路の前記一端の曲率半径および角度が前記第１の接続相手パーツの曲率半径および角度と等しく、
前記曲り導波路パーツの光導波路の前記他端の曲率半径および角度が前記第２の接続相手パーツの曲率半径および角度と等しいことを特徴とする光通信部品。 A bent waveguide part in which the optical waveguide according to claim 1 is formed;
A first connection partner part optically connected to one end of the optical waveguide;
A second connection partner part optically connected to the other end of the optical waveguide;
Comprising
A radius of curvature and an angle of the one end of the optical waveguide of the curved waveguide part are equal to a radius of curvature and an angle of the first connection counterpart part;
An optical communication component, wherein a radius of curvature and an angle of the other end of the optical waveguide of the curved waveguide part are equal to a radius of curvature and an angle of the second connection counterpart part. 前記湾曲部が光の伝播方向に連なる長さ１００μｍ以下の直線形状の多数の微小部分からなり、該湾曲部における曲率半径がこれら微小部分ごとに段階的に変化することを特徴とする光通信部品。   An optical communication component characterized in that the curved portion is composed of a large number of linear minute portions having a length of 100 μm or less that are continuous in the light propagation direction, and the radius of curvature of the curved portion changes stepwise for each minute portion. .
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Cited By (7)

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JP2008241818A (en) * 2007-03-26 2008-10-09 National Institute Of Advanced Industrial & Technology Optical waveguide and optical device system
JP2009301620A (en) * 2008-06-11 2009-12-24 Nitto Denko Corp Suspension substrate with circuit
JP2011181164A (en) * 2010-02-05 2011-09-15 Nitto Denko Corp Suspension substrate with circuit
JP2017116862A (en) * 2015-12-25 2017-06-29 株式会社豊田中央研究所 Optical waveguide
US10585242B1 (en) 2018-09-28 2020-03-10 Corning Research & Development Corporation Channel waveguides with bend compensation for low-loss optical transmission
US10690858B2 (en) 2018-02-28 2020-06-23 Corning Incorporated Evanescent optical couplers employing polymer-clad fibers and tapered ion-exchanged optical waveguides
CN114594554A (en) * 2020-12-04 2022-06-07 青岛海信宽带多媒体技术有限公司 Optical module

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008241818A (en) * 2007-03-26 2008-10-09 National Institute Of Advanced Industrial & Technology Optical waveguide and optical device system
JP2009301620A (en) * 2008-06-11 2009-12-24 Nitto Denko Corp Suspension substrate with circuit
US8184931B2 (en) 2008-06-11 2012-05-22 Nitto Denko Corporation Suspension board with circuit
JP2011181164A (en) * 2010-02-05 2011-09-15 Nitto Denko Corp Suspension substrate with circuit
US8770865B2 (en) 2010-02-05 2014-07-08 Nitto Denko Corporation Suspension board with circuit
JP2017116862A (en) * 2015-12-25 2017-06-29 株式会社豊田中央研究所 Optical waveguide
US10690858B2 (en) 2018-02-28 2020-06-23 Corning Incorporated Evanescent optical couplers employing polymer-clad fibers and tapered ion-exchanged optical waveguides
US10585242B1 (en) 2018-09-28 2020-03-10 Corning Research & Development Corporation Channel waveguides with bend compensation for low-loss optical transmission
CN114594554A (en) * 2020-12-04 2022-06-07 青岛海信宽带多媒体技术有限公司 Optical module

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