JP2004046104A - Partially spherical lens and partially spherical lens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a partially spherical lens which is easily aligned with a substrate and a partially spherical lens array which is smaller-sized, and has higher performance than before. <P>SOLUTION: The partially spherical lens 10 is made of glass whose refractive index is nearly uniform and has light-transmitting spherical parts 10a and 10b which are spherical surfaces having substantially the same center P of curvature, face each other and that an optical axis passes through, a support spherical surface part 10c which has substantially the same center P of curvature with the light-transmitting spherical surface parts 10a and 10b and serves as a support surface, and plane parts 10d and 10e which are nearly parallel to the optical axis J. The partially spherical lens array 20 is equipped with a substrate 21 having a plurality of V grooves 21b arranged on one surface in parallel at specified pitch, and a plurality of partially spherical lenses 10, and is fixed in a state wherein support spherical surface parts 10c of the partially spherical lenses 10 are supported in V grooves 21b of the substrate 21 to arrange light-transmitting spherical surfaces parts 10a and 10b in parallel at the specified pitch. <P>COPYRIGHT: (C)2004,JPO

Description

【００３９】
【発明の実施の形態】
本発明の一実施の形態について図面を参照して説明する。
【００４０】
図１に示すように、本発明の部分球面レンズ１０は、屈折率が略均一な光学ガラスのＬａＳＦ０１５からなり曲率中心Ｐが実質的に同じで対向する球面であって光軸Ｊが通過する透光球面部１０ａ、１０ｂと、透光球面部１０ａ、１０ｂと曲率中心Ｐが実質的に同じで支持面となる支持球面部１０ｃと、光軸Ｊに略平行な平面部１０ｄ、１０ｅとを有するものである。透光球面部１０ａ、１０ｂ、及び支持球面部１０ｃの曲率半径は０．５ｍｍであり、焦点距離は０．５７３ｍｍである。また、平面部１０ｄ、１０ｅ間の距離は０．４ｍｍと、従来の円柱状レンズに比べて非常に小さくなっている。
【００４１】
部分球面レンズ１０の透光球面部１０ａ、１０ｂには信号光の反射防止のために波長が１２６０〜１６７５ｎｍ（Ｏ、Ｅ、Ｓ、Ｃ、Ｌ、Ｕバンドと呼ばれている・・・ＩＴＵ−Ｔ策定）の光を９９％以上透過する多層構造の減反射膜１１、１２がそれぞれ形成されている。また、平面部１０ｅには光軸Ｊの位置及びその方向を示すＶ溝状のマーキングＭが刻設されている。
【００４２】
また、他の実施の形態での部分球面レンズ１０としては、図２（Ａ）に示すように、部分球面レンズ１０に設けられた平面部が平面部１０ｄの一面だけであり、２個の部分球面レンズ１０を互いの平面部１０ｄ同士を対向配置することで、光軸Ｊを所定の間隔に位置させることができる。この際、マーキングＭが印刷等による凸部となる場合には、透光球面部１０ａ、１０ｂ及び支持球面部１０ｃにかからない球面に設けるとよい。さらに、図２（Ｂ）及び（Ｃ）に示すように、部分球面レンズ１０に、光軸Ｊに略平行な他の平面部１０ｆを設けてもよく、平面部１０ｆを平面状の当接部を有する押圧整列部材等に当接させることで部分球面レンズ１０の整列配置が容易になる。この場合、平面部１０ｆはマーキングＭとしても使用可能である。
【００４３】
図３に示すように、上記の部分球面レンズ１０を、例えば、４個使用した本発明の部分球面レンズアレイ２０は、一面２１ａに光スイッチ用の光路切り替え機能素子の配列間隔に適応した０．５ｍｍピッチで並列配置された４本のＶ溝２１ｂを有する基板２１に、部分球面レンズ１０の支持球面部１０ｃを当接支持して透光球面部１０ａ、１０ｂを０．５ｍｍピッチで並列配置した状態でエポキシ系接着剤２２により固着されているものである。
【００４４】
基板２１は、部分球面レンズ１０を構成するＬａＳＦ０１５の熱膨張係数７４×１０^−７／Ｋと近い５１×１０^−７／Ｋであるホウ珪酸ガラスからなり、一面２１ａに並列配置されたＶ溝２１ｂは、部分球面レンズ１０の支持球面部１０ｃを２点で支持するものであり、底面２１ｃから部分球面レンズ１０の支持球面部１０ｃを２点で支持するＶ溝２１ｂの高さ寸法が所定範囲、例えば、±０．１μｍに管理されており、それぞれの部分球面レンズ１０の光軸Ｊの位置が設計上の中心座標に対して±１μｍ以内で、各部分球面レンズ１０間に集光レンズとしての光学的な特性に実質的な差異が生じないように維持されている。
【００４５】
次に、部分球面レンズアレイ２０を使用した光コリメータ部品について説明する。
【００４６】
図４に示すように、光コリメータ部品３０は、上記の部分球面レンズ１０を基板２１に固着した部分球面レンズアレイ２０と、光ファイバ３１を内孔３２ａに挿着しており外周円柱面３２ｂを基板２１のＶ溝２１ｂに当接させて接着剤３３で毛細管３２とを固着してあるものであり、光ファイバ３１の端面３１ａは、端面３１ａからの反射戻り光を抑制するため、光軸Ｊと直交する平面に対して約８°の傾斜に仕上げられている。
【００４７】
また、図４に示すように、光コリメータ部品３０の部分球面レンズ１０は高精度に加工された球レンズから作製されているので、例えば、その球レンズの直径を±０．００１ｍｍ、即ち、部分球面レンズ１０の球面（透光球面部１０ａ、１０ｂ及び支持球面部１０ｃ）の曲率半径公差を±０．０００５ｍｍで管理することが可能である。また、光コネクタなどに用いる±０．０００５ｍｍの外径公差で作製された毛細管３２を用いることで、部分球面レンズアレイ２０の光軸Ｊに対する出射光線の傾き角を非常に小さくすることができる。そこで、光学ガラスのＬａＳＦ０１５からなる直径１ｍｍ±０．００１ｍｍの球レンズから作製した部分球面レンズ１０を用いれば、数１から、部分球面レンズアレイ２０の光軸Ｊに対する出射光線の傾き角は、最大でも０．１°程度となり、ＧＲＩＮレンズなどを用いた場合の０．３°程度と比較すると大幅に小さくなっており、これまで困難とされていたアライメントの自動化を容易に行うことが可能となった。
【００４８】
上記の光コリメータ部品３０は、図５に示すように、光スイッチ用の光路切り替え機能素子や、波長フィルター他の光機能素子４０を挟んでベース基板４１上に対向配置されて各光コリメータ部品３０、３０及び光機能素子４０の光軸Ｊが整合されている。
【００４９】
次に、光コリメータ部品３０の挿入損失の測定を行った。
【００５０】
作動距離が５．５ｍｍとなるように設定した光コリメータ部品３０の作動距離と挿入損失との関係について、測定を行った結果のデータを表１に、そのプロットを図６に示す。
【００５１】
【表１】

【００５２】
本発明の光コリメータ部品３０は、図６に示すように、作動距離５．５ｍｍおよび、その作動距離の±０．５ｍｍにおいて、挿入損失が０．３ｄＢであり、光スイッチ等の光部品に用いることが十分可能な性能を有している。
【００５３】
次に、図１に示す本発明の部分球面レンズ１０を作製する方法について一例を説明する。
【００５４】
まず、光学ガラスのＬａＳＦ０１５からなるガラス材料を曲率半径が０．５ｍｍ、即ち、直径１ｍｍで真球度が１μｍ以下の球レンズを作製し、研削加工により光軸Ｊに略平行な平面部１０ｄ、１０ｅを形成する。次いで、透光球面部１０ａ、１０ｂに波長が１２６０〜１６７５ｎｍの光を９９％以上透過する多層構造の減反射膜１１、１２を形成する。この際、平面部１０ｅに光軸Ｊの位置及びその方向を示すＶ溝状のマーキングＭを刻設する。
【００５５】
次に、図３に示す本発明の部分球面レンズアレイ２０を作製する方法について一例を説明する。
【００５６】
部分球面レンズ１０と同様の光学ガラス、ホウ珪酸ガラスまたは結晶化ガラスを使用して、一面２１ａに光スイッチ用の光路切り替え機能素子、波長フィルター他の配列間隔に適応した０．５ｍｍピッチで並列配置された４本のＶ溝２１ｂを有する基板２１を精密研削・研磨、精密プレス成型、または延伸成形により作製する。
【００５７】
次いで、基板２１のＶ溝２１ｂに、支持球面部１０ｃを当接させてマーキングＭの方向及び向きが同じになるように上記部分球面レンズ１０を整列配置し、透光球面部１０ａ、１０ｂが所定の位置になるように、図示しない治具により透光球面部１０ａ、１０ｂにキズや汚れがつかないように位置決めする。この状態で、接着剤２２を塗布し、接着剤２２が熱硬化性の場合には乾燥炉で、光硬化性の場合には光照射装置を使用して基板２１に部分球面レンズ１０を固着する。
【００５８】
なお、減反射膜１１、１２は、基板２１に部分球面レンズ１０を固着した後に透光球面部１０ａ、１０ｂに形成してもよい。
【００５９】
次に、図７に本発明の他の部分球面レンズアレイ５０を示す。部分球面レンズアレイ５０は、先出の図２（Ａ）に示す部分球面レンズ１０を、その平面部１０ｄを互いに対向配置した状態で接着剤５２により基板５１に固着させたものである。このような部分球面レンズアレイ５０は、図２（Ａ）に示す平面部１０ｄのみの部分球面レンズ１０を用いることにより、光通信ネットワークを構築する際に数多く使用される２×２光スイッチを効率よく安価に作製することが可能となる。もちろん、先出の図２（Ａ）に示す部分球面レンズ１２の代わりに、図２（Ｂ）、（Ｃ）に示す部分球面レンズを用いても２×２光スイッチを安価に作製することが可能となる。
【００６０】
なお、上記光コリメータ部品の挿入損失の測定は以下のようにして行った。即ち、作製した上記光コリメータ部品を２つ準備し、波長が１５５０ｎｍのレーザーダイオード安定化光源に光ファイバを繋ぎ、この光ファイバに一方の光コリメータ部品を融着スプライスにて接続する。この光コリメータ部品をＸＹＺの空間軸と直交する２つの回転軸を有する５軸光学ステージに固定する。次に、他方の光コリメータ部品を光学架台に固定し、光コリメータ部品のピグテールとなっている光ファイバの先端をパワーメータに接続する。その後、５軸ステージを操作して、２つの光コリメータ部品間の光学的な結合が最良となるように調心し、その状態でパワーメータにより受光量（単位：ｄＢｍ）を測定する。この受光量を予め測定しておいた安定化光源とパワーメータを光ファイバで直結したときの受光量（単位：ｄＢｍ）の測定値から差し引いて挿入損失を算出した。
【００６１】
【発明の効果】
本発明に係る部分球面レンズは、屈折率が略均一なガラスからなり、曲率中心が実質的に同じで対向する球面であって光軸が通過する透光球面部と、該透光球面部と曲率中心が実質的に同じで支持面となる支持球面部と、光軸に略平行な平面部とを有し、支持球面部の位置を制御することにより、容易に部分球面レンズの光軸位置を管理することが可能となり、かつ光軸に略平行な平面部により光軸に直交する方向の寸法を小さくすることが可能となるので、従来よりも高密度配置されたレンズアレイを作製することができる。
【００６２】
また、本発明の部分球面レンズは、平面部が２面以上あり、その内の２面が光軸を挟んで対向しており、複数の部分球面レンズを互いの平面部を対向させて並べると、光軸が通過する透光球面部を従来よりもはるかに小さいピッチで並列配置することが可能となるので、レンズを並列配置するレンズアレイの場合、従来よりも配置が大幅に高密度化されたレンズアレイを作製することができる。
【００６３】
また、本発明の部分球面レンズは、部分球面レンズの透光球面部に光学膜が形成されているので、減反射膜やフィルター膜等の光学膜を形成することにより高速・大容量化が進む光通信用途に対応するレンズアレイを作製することが可能となる。
【００６４】
また、本発明の部分球面レンズは、光軸が通過する透光球面部を識別するマーキングを有するので、支持部材に対して部分球面レンズの支持面球面を当接させて光軸方向を設定する際に、間違うことがなく正確にレンズアレイを作製することができる。
【００６５】
本発明に係る部分球面レンズアレイは、一面に所定ピッチで並列配置された断面が略Ｖ形の複数の凹部を備えた基板と、屈折率が略均一なガラスからなり、曲率中心が実質的に同じで対向する球面であって光軸が通過する透光球面部、該透光球面部と曲率中心が実質的に同じで支持面となる支持球面部、及び光軸に略平行な平面部とを有する複数の部分球面レンズとを備え、前記基板の凹部に前記部分球面レンズの支持球面部を支持して透光球面部を所定ピッチで並列配置した状態で固定されているので、従来よりも小さい光機能素子の配列間隔に適応した小さいピッチでレンズが並列配置された高精度なレンズアレイを提供することができる。
【００６６】
また、本発明の部分球面レンズアレイは、部分球面レンズの平面部が２面以上あり、その内の２面が光軸を挟んで対向しているので、従来よりもはるかに小さい光機能素子の配列間隔に適応した小さいピッチで高密度に並列配置させたレンズアレイを提供することができる。
【００６７】
また、本発明の部分球面レンズアレイは、部分球面レンズの透光球面部に光学膜が形成されているので、減反射膜やフィルター膜等の光学膜を有する高速・大容量化が進む光通信用途に対応する高密度に並列配置させたレンズアレイを提供することができる。
【００６８】
また、本発明の部分球面レンズアレイは、基板がガラス、結晶化ガラス、またはシリコン結晶からなるので、精密研削・研磨、精密プレス成型、延伸成形等が可能となり、容易に部分球面レンズと熱膨張係数の近い材料が得られ、信頼性が高く安価なレンズアレイを提供することができる。
【００６９】
さらに、本発明の部分球面レンズアレイでは、その部分球面レンズは、球面の曲率半径公差が高精度であり、且つ毛細管の外径公差が高精度であり、部分球面レンズアレイの光軸に対する出射光線の傾き角を非常に小さくすることができるので、アライメントの自動化を容易に行うことが可能なレンズアレイを提供することができる。
【図面の簡単な説明】
【図１】本発明に係る部分球面レンズの説明図であって、（Ａ）は光軸に平行な側面図、（Ｂ）は光軸に垂直な正面図。
【図２】本発明に係る他の部分球面レンズの説明図であって、（Ａ）は平面部が１面である部分球面レンズの正面図、（Ｂ）は平面部が３面である部分球面レンズの側面図、（Ｃ）は（Ｂ）の正面図。
【図３】本発明に係る部分球面レンズアレイの説明図であって、（Ａ）は平面図、（Ｂ）は（Ａ）のＹ−Ｙ断面図、（Ｃ）は（Ａ）の側面図。
【図４】本発明の部分球面レンズアレイを使用した光コリメータ部品の説明図であって、（Ａ）は平面図、（Ｂ）は側面図。
【図５】光コリメータ部品の使用例の説明図であって、（Ａ）は平面図、（Ｂ）は側面図。
【図６】本発明の部分球面レンズアレイを使用した光コリメータ部品の挿入損失を作動距離に対してプロットした説明図。
【図７】本発明に係る他の部分球面レンズアレイの説明図であって、（Ａ）は平面図、（Ｂ）は（Ａ）のＸ−Ｘ断面図。
【図８】従来のレンズアレイの構造を示す説明図であって、（Ａ）は平面図、（Ｂ）は光軸に垂直な方向の正面図。
【符号の説明】
１　ドラムレンズ
１ａ　円柱部
２ａ、２１ｂ　Ｖ溝
２、２１、５１　基板
３　レンズアレイ
１０　部分球面レンズ
１０ａ、１０ｂ　透光球面部
１０ｃ　支持球面部
１０ｄ、１０ｅ、１０ｆ　平面部
１１、１２　減反射膜
２２、３３、５２　接着剤
２０、５０　部分球面レンズアレイ
２１ａ　一面
２１ｂ　Ｖ溝
２１ｃ　底面
３０　光コリメータ部品
３１　光ファイバ
３１ａ　端面
３２　毛細管
３２ａ　内孔
３２ｂ　外周円柱面
４０　光機能素子
４１　ベース基板
Ｊ　光軸
Ｍ　マーキング
Ｐ　曲率中心[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a partial spherical lens and a partial spherical lens array having a spherical surface with excellent sphericity suitable for optical communication such as an optical switch.
[0002]
[Prior art]
Many optical devices are used when constructing a high-speed and large-capacity optical fiber communication system. Among them, one that extracts an optical signal of an arbitrary wavelength from an optical signal in which a plurality of wavelengths are multiplexed, one that uses an optical crystal to match the phase of the optical signal, and one that switches the optical line to operate the optical signal There are optical switches and the like, and a large number of optical collimators that collimate an optical signal emitted from an optical fiber and spread are used.
[0003]
Conventionally, in an optical device for inputting and outputting a plurality of optical signals, as shown in FIG. 8, a drum lens 1 obtained by grinding a spherical lens into a cylindrical shape, a cylindrical GRIN lens, or the like is used. A lens array 3 fixed to a substrate 2 having a V-shaped groove 2a is used.
[0004]
Patent Document 1 discloses an optical fiber array in which a spherical lens is held in a V-groove, Patent Document 2 discloses a processed spherical lens, and Patent Document 3 discloses an upper and lower processed flat lens. A disclosed spherical lens is disclosed.
[0005]
[Patent Document 1]
JP-A-59-36214 (page 2-3, FIG. 1-2)
[Patent Document 2]
Japanese Utility Model Laid-Open Publication No. 61-76407 (page 1, FIG. 2)
[Patent Document 3]
U.S. Pat. No. 6,207,950 (pages 11-12, FIG. 1-6)
[0006]
[Problems to be solved by the invention]
In a conventional cylindrical lens, the diameter of the cylindrical portion 1a is about φ1.0 mm even in a small type, and it is physically impossible to fabricate the lens array 3 with a lens pitch at least equal to or less than the diameter of the cylindrical portion 1a. It is possible. In addition, it is technically difficult to control the diameter and surface state of the cylindrical portion 1a of the cylindrical lens and the cylindricity with high precision, and in the GRIN lens, the axial symmetry of the refractive index distribution is precisely controlled. It is difficult to manage. Therefore, simply fixing the columnar lens to the V-groove substrate does not result in a lens array having excellent optical characteristics, and requires adjustment.
[0007]
Similarly, it is physically impossible to produce a lens array with a lens pitch equal to or less than the diameter of the spherical lenses disclosed in Patent Documents 1 to 3.
[0008]
Such a restriction of the cylindrical lens is an obstacle in producing a lens array in which the lens has a small optical axis pitch of, for example, 1 mm or less and in which the lenses are accurately aligned.
[0009]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a partial spherical lens that facilitates alignment work between a lens and a substrate, and a partial spherical lens array that is smaller and has higher performance than conventional ones.
[0010]
[Means for Solving the Problems]
The partial spherical lens according to the present invention is made of glass having a substantially uniform refractive index, and has a translucent spherical portion having substantially the same center of curvature and opposed to each other and having an optical axis passing therethrough. It is characterized in that it has a support spherical surface portion having substantially the same center of curvature and serving as a support surface, and a planar portion substantially parallel to the optical axis.
[0011]
As the spherical surface constituting the partial spherical lens, it is preferable to use a spherical lens having excellent sphericity as a material. By using the spherical lens, the centers of curvature of the translucent spherical surface portion and the supporting spherical surface portion opposed to each other are precisely controlled. That is, the translucent spherical portion and the supporting spherical portion are substantially spherical with the same center, and by controlling the position of the supporting spherical portion, the optical axis position of the partial spherical lens can be easily managed. . Thus, in order to reduce the size and diameter of the optical collimator, a partial spherical lens manufactured by grinding the periphery of a partial spherical lens having high sphericity is suitable.
[0012]
A flat portion substantially parallel to the optical axis can be used if the distance between the flat portions is smaller than the pitch of the translucent spherical portions when the partial spherical lenses are aligned. It is possible to increase the position to a position where the loss is such that the signal light transmitted through the optical spherical portion is not hindered. Practically, it is preferable that the flat portion has a light-transmitting spherical portion slightly larger than the beam diameter of the signal light.
[0013]
As the material of the partial spherical lens used in the present invention, any material can be used as long as it is made of optical glass or the like having a substantially uniform refractive index and can be processed into a true spherical shape to produce a partial spherical lens having high focusing accuracy. is there. As the glass used for the partial spherical lens, it is preferable to use optical glass such as BK7, K3, TaF3, LaF01, and LaSF015.
[0014]
Further, the partial spherical lens according to the present invention is characterized in that there are two or more flat portions, and two of the flat portions face each other across the optical axis.
[0015]
The fact that there are two or more flat portions of the partial spherical lens and two of them face each other across the optical axis means, for example, that the flat portions 10d and 10e of the partial spherical lens 10 in FIG. When the partial spherical lenses are aligned, they can be used as long as the distance between the plane portions is smaller than the pitch between the translucent spherical portions. It is possible to enlarge the area. Practically, it is preferable that the flat portion has a light-transmitting spherical portion slightly larger than the beam diameter of the signal light. The other plane part substantially parallel to the optical axis can be used for positioning, fixing, and the like of the partial spherical lens within a dimension range that does not interfere with the signal light.
[0016]
Further, the partial spherical lens according to the present invention is characterized in that an optical film is formed on a translucent spherical portion.
[0017]
As the optical film formed on the translucent spherical portion, an anti-reflection film, a filter, or the like can be used according to the purpose.
[0018]
Further, the partial spherical lens according to the present invention is characterized in that it has a marking for identifying a translucent spherical portion through which the optical axis passes.
[0019]
The marking for identifying the translucent spherical portion through which the optical axis passes can be provided on a flat portion substantially parallel to another optical axis or on a flat portion facing the other optical axis.
[0020]
The partial spherical lens array according to the present invention is composed of a substrate having a plurality of concave portions each having a substantially V-shaped cross section and arranged in parallel at a predetermined pitch on one surface, and a glass having a substantially uniform refractive index, and having a center of curvature substantially. A light-transmitting spherical portion that is the same opposing spherical surface and through which the optical axis passes, a supporting spherical portion that has a substantially same center of curvature as the light-transmitting spherical portion and serves as a supporting surface, and a flat portion that is substantially parallel to the optical axis. And a plurality of partial spherical lenses having the following. The supporting spherical portion of the partial spherical lens is supported in the concave portion of the substrate, and the light transmitting spherical portions are fixedly arranged in parallel at a predetermined pitch.
[0021]
The substrate used in the present invention includes a substantially funnel-shaped concave portion and a V-shaped groove as a plurality of concave portions having a substantially V-shaped cross section arranged in parallel at a predetermined pitch on one surface, and the V-shaped groove supports a partial spherical lens. Any pitch can be used as long as the spherical portion can be supported at two points, and the predetermined pitch may be a pitch adapted to the arrangement interval of optical functional elements such as a wavelength filter. It is important that the dimensions, such as the angle and the depth, of the plurality of V-grooves that support the supporting spherical portion of the partial spherical lens from the bottom surface at two points are maintained within a predetermined range in order to maintain optical characteristics. Become.
[0022]
Further, the partial spherical lens array according to the present invention is characterized in that the partial spherical lens has two or more flat portions, and two of the flat portions face each other across the optical axis.
[0023]
Further, the partial spherical lens array of the present invention is characterized in that an optical film is formed on a light transmitting spherical portion of the partial spherical lens.
[0024]
In the partial spherical lens array according to the present invention, the substrate is made of glass, crystallized glass, or silicon crystal.
[0025]
Any glass, crystallized glass, or silicon crystal constituting the substrate can be used as long as it can be precisely ground and polished. Further, it is preferably glass or crystallized glass that can be precision press-molded, and more preferably one that can be stretch-molded. Further, a lens having a thermal expansion coefficient close to that of the partial spherical lens is preferable. As the glass, borosilicate glass, optical glass or the like can be used, and as the crystallized glass, silica-alumina-lithia-based glass can be used.
[0026]
Furthermore, in the partial spherical lens array of the present invention, the spherical surface of the partial spherical lens has a radius of curvature tolerance of ± 0.0015 mm, and the outer diameter tolerance of the capillary is ± 0.001 mm, and the partial spherical lens array has an optical axis with respect to the optical axis. The inclination angle of the emitted light beam is 0.2 ° or less.
[0027]
As the partial spherical lens, for example, a lens manufactured from a spherical lens that has been processed with high precision, and as the capillary, for example, a high-precision lens manufactured with a tolerance of a ferrule for an optical connector is used.
[0028]
[Action]
The partial spherical lens according to the present invention is made of glass having a substantially uniform refractive index, and has a translucent spherical portion having substantially the same center of curvature and opposed to each other and having an optical axis passing therethrough. Since the center of curvature has substantially the same center of curvature and a supporting spherical surface serving as a supporting surface, and a plane portion substantially parallel to the optical axis, by controlling the position of the supporting spherical surface, the optical axis position of the partial spherical lens can be easily adjusted. Can be managed, and the dimension in the direction orthogonal to the optical axis can be reduced by the plane portion substantially parallel to the optical axis.
[0029]
Further, since the partial spherical lens of the present invention has two or more flat portions, and two of the flat portions are opposed to each other with the optical axis interposed therebetween, a plurality of partial spherical lenses are arranged with the flat portions facing each other. Then, it becomes possible to arrange the translucent spherical portions through which the optical axis passes at a much smaller pitch than in the past.
[0030]
Further, in the partial spherical lens of the present invention, since the optical film is formed on the light-transmitting spherical portion of the partial spherical lens, the formation of an optical film such as an anti-reflection film or a filter film increases the speed and capacity. It is possible to support optical communication applications.
[0031]
In addition, since the partial spherical lens of the present invention has a marking for identifying the translucent spherical portion through which the optical axis passes, the optical axis direction is set by bringing the support surface spherical surface of the partial spherical lens into contact with the support member. In this case, there is no mistake and the automation of the alignment becomes easy.
[0032]
The partial spherical lens array according to the present invention is composed of a substrate having a plurality of concave portions each having a substantially V-shaped cross section and arranged in parallel at a predetermined pitch on one surface, and a glass having a substantially uniform refractive index, and having a center of curvature substantially. A light-transmitting spherical surface portion that is the same and opposing spherical surface and through which the optical axis passes, a supporting spherical surface portion having substantially the same center of curvature as the light-transmitting spherical surface portion and serving as a supporting surface, and a plane portion substantially parallel to the optical axis And a plurality of partial spherical lenses having the following. The supporting spherical portion of the partial spherical lens is supported in the concave portion of the substrate, and the light transmitting spherical portions are fixed in a state of being arranged in parallel at a predetermined pitch, so that the optical function is improved. A substrate in which dimensions such as angles and depths of a plurality of V-grooves and the like that support the supporting spherical portion of the partial spherical lens from the bottom surface at two points are controlled within a predetermined range at a predetermined pitch adapted to the arrangement interval of the elements, A translucent spherical part and a supporting spherical part having a plane part substantially parallel to the optical axis There by using the partially spherical lens that is managed in a predetermined range in the spherical surface of substantially the same center, high-precision lens array lens are arranged parallel with a pitch smaller than the conventional can be obtained.
[0033]
Further, in the partial spherical lens array of the present invention, the partial spherical lens has two or more flat portions, and two of the two flat surfaces are opposed to each other with the optical axis interposed therebetween. Are arrayed on a substrate provided with a plurality of concave portions having a substantially V-shaped cross-section so that light-transmitting spherical portions through which the optical axis passes are arranged in parallel at a much smaller pitch than in the past with high density. Is obtained.
[0034]
In the partial spherical lens array of the present invention, since the optical film is formed on the light transmitting spherical portion of the partial spherical lens, high speed and large capacity can be achieved by forming an optical film such as an anti-reflection film or a filter film. It becomes possible to provide a lens array arranged in parallel at high density corresponding to the advanced optical communication applications.
[0035]
In addition, since the substrate is made of glass, crystallized glass, or silicon crystal, the partial spherical lens array of the present invention can be subjected to precision grinding / polishing, precision press molding, stretch molding, etc., and can be easily thermally expanded with the partial spherical lens. It is possible to use a material having a similar coefficient.
[0036]
Further, in the partial spherical lens of the present invention, the spherical surface of the partial spherical lens has a radius of curvature tolerance of ± 0.0015 mm and the capillary has an outer diameter tolerance of ± 0.001 mm, and the partial spherical lens array emits light with respect to the optical axis. Since the inclination angle of the light beam is 0.2 ° or less, the automation of the alignment is further facilitated by making the inclination angle of the outgoing light beam with respect to the optical axis of the partial spherical lens array extremely small.
[0037]
The inclination angle of the outgoing light beam with respect to the optical axis of the partial spherical lens array has a relationship represented by the following equation using the amount of deviation of the optical axis between the capillary and the partial spherical lens and the focal length of the partial spherical lens.
[0038]
(Equation 1)

[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0040]
As shown in FIG. 1, the partial spherical lens 10 of the present invention is a transparent spherical surface made of optical glass LaSF015 having a substantially uniform refractive index, having substantially the same center of curvature P and facing the optical axis J. It has optical spherical portions 10a and 10b, a supporting spherical portion 10c having substantially the same center of curvature P as the translucent spherical portions 10a and 10b and serving as a supporting surface, and flat portions 10d and 10e substantially parallel to the optical axis J. Things. The radius of curvature of the translucent spherical portions 10a and 10b and the supporting spherical portion 10c is 0.5 mm, and the focal length is 0.573 mm. The distance between the flat portions 10d and 10e is 0.4 mm, which is much smaller than that of a conventional cylindrical lens.
[0041]
The light transmitting spherical portions 10a and 10b of the partial spherical lens 10 have wavelengths of 1260 to 1675 nm (referred to as O, E, S, C, L and U bands) to prevent reflection of signal light. The antireflection films 11 and 12 each having a multilayer structure that transmits 99% or more of the light of T) are formed. Further, a V-groove-shaped marking M indicating the position and the direction of the optical axis J is engraved on the flat portion 10e.
[0042]
Further, as the partial spherical lens 10 according to the other embodiment, as shown in FIG. 2A, the plane part provided on the partial spherical lens 10 is only one plane of the plane part 10d, and the two parts By arranging the spherical lenses 10 such that the flat portions 10d face each other, the optical axis J can be positioned at a predetermined interval. At this time, when the marking M is a convex portion formed by printing or the like, it is preferable to provide the marking M on a spherical surface that does not cover the translucent spherical portions 10a and 10b and the supporting spherical portion 10c. Further, as shown in FIGS. 2B and 2C, the partial spherical lens 10 may be provided with another flat portion 10f substantially parallel to the optical axis J, and the flat portion 10f may be provided as a flat contact portion. The partial aspherical lens 10 can be easily aligned and arranged by contacting the pressing and aligning member having the above. In this case, the flat portion 10f can also be used as the marking M.
[0043]
As shown in FIG. 3, the partial spherical lens array 20 of the present invention using the above-mentioned four partial spherical lenses 10, for example, has a surface 21a adapted to the arrangement interval of the optical path switching function elements for the optical switch. On a substrate 21 having four V-grooves 21b arranged in parallel at a pitch of 5 mm, the supporting spherical portion 10c of the partial spherical lens 10 is abutted and supported, and the translucent spherical portions 10a and 10b are arranged in parallel at a pitch of 0.5 mm. In this state, it is fixed by the epoxy adhesive 22.
[0044]
The substrate 21 has a thermal expansion coefficient of 74 × 10 of LaSF015 constituting the partial spherical lens 10. ^-7 51 × 10 close to / K ^-7 The V-grooves 21b, which are made of borosilicate glass of / K and are arranged in parallel on one surface 21a, support the supporting spherical portion 10c of the partial spherical lens 10 at two points, and support the partial spherical lens 10 from the bottom surface 21c. The height dimension of the V-groove 21b supporting the spherical portion 10c at two points is controlled within a predetermined range, for example, ± 0.1 μm, and the position of the optical axis J of each partial spherical lens 10 is the center coordinate in design. Within ± 1 μm, the optical characteristics as a condenser between the partial spherical lenses 10 are maintained so as not to cause a substantial difference.
[0045]
Next, an optical collimator component using the partial spherical lens array 20 will be described.
[0046]
As shown in FIG. 4, the optical collimator component 30 has a partial spherical lens array 20 in which the partial spherical lens 10 is fixed to a substrate 21, an optical fiber 31 inserted into an inner hole 32a, and an outer cylindrical surface 32b. The capillary 32 is fixed to the V-groove 21b of the substrate 21 with an adhesive 33 so as to be in contact with the V-groove 21b. The end face 31a of the optical fiber 31 has an optical axis J for suppressing reflected return light from the end face 31a. It is finished at an inclination of about 8 ° with respect to a plane orthogonal to.
[0047]
Further, as shown in FIG. 4, since the partial spherical lens 10 of the optical collimator component 30 is made of a spherical lens processed with high precision, for example, the diameter of the spherical lens is ± 0.001 mm, that is, The radius of curvature tolerance of the spherical surface of the spherical lens 10 (the translucent spherical portions 10a and 10b and the supporting spherical portion 10c) can be controlled to ± 0.0005 mm. In addition, the inclination angle of the outgoing light beam with respect to the optical axis J of the partial spherical lens array 20 can be made extremely small by using the capillary tube 32 having an outer diameter tolerance of ± 0.0005 mm used for an optical connector or the like. Therefore, if the partial spherical lens 10 made of a spherical lens having a diameter of 1 mm ± 0.001 mm made of optical glass LaSF015 is used, the inclination angle of the outgoing ray with respect to the optical axis J of the partial spherical lens array 20 becomes the maximum from Equation 1. However, the angle is about 0.1 °, which is much smaller than about 0.3 ° when a GRIN lens or the like is used. This makes it easy to automate alignment, which has been difficult until now. Was.
[0048]
As shown in FIG. 5, the above-mentioned optical collimator components 30 are disposed opposite to each other on a base substrate 41 with an optical path switching function element for an optical switch and an optical function element 40 other than a wavelength filter interposed therebetween. , 30 and the optical function element 40 are aligned.
[0049]
Next, the insertion loss of the optical collimator component 30 was measured.
[0050]
Regarding the relationship between the working distance and the insertion loss of the optical collimator component 30 set so that the working distance is 5.5 mm, data obtained as a result of measurement are shown in Table 1, and a plot thereof is shown in FIG.
[0051]
[Table 1]

[0052]
As shown in FIG. 6, the optical collimator component 30 of the present invention has an insertion loss of 0.3 dB at a working distance of 5.5 mm and ± 0.5 mm of the working distance, and is used for an optical component such as an optical switch. It has enough possible performance.
[0053]
Next, an example of a method for manufacturing the partial spherical lens 10 of the present invention shown in FIG. 1 will be described.
[0054]
First, a spherical lens having a radius of curvature of 0.5 mm, that is, a sphericity of 1 μm or less is produced from a glass material made of optical glass LaSF015, and a flat portion 10 d substantially parallel to the optical axis J is formed by grinding. 10e is formed. Next, antireflection films 11 and 12 having a multilayer structure that transmits 99% or more of light having a wavelength of 1260 to 1675 nm are formed on the translucent spherical portions 10a and 10b. At this time, a V-groove-shaped marking M indicating the position and direction of the optical axis J is engraved on the flat surface 10e.
[0055]
Next, an example of a method for producing the partial spherical lens array 20 of the present invention shown in FIG. 3 will be described.
[0056]
Using the same optical glass, borosilicate glass, or crystallized glass as the partial spherical lens 10, the optical path switching function element for the optical switch, the wavelength filter, and the like are arranged in parallel on the one surface 21a at a 0.5 mm pitch adapted to the arrangement interval. The substrate 21 having the four V-grooves 21b is manufactured by precision grinding and polishing, precision press molding, or stretch molding.
[0057]
Next, the supporting spherical portion 10c is brought into contact with the V groove 21b of the substrate 21, and the partial spherical lenses 10 are aligned and arranged so that the direction and the direction of the marking M become the same. The jig (not shown) is used to position the light-transmitting spherical portions 10a and 10b so as not to be scratched or stained. In this state, the adhesive 22 is applied, and when the adhesive 22 is thermosetting, the partial spherical lens 10 is fixed to the substrate 21 by using a drying furnace when the adhesive 22 is photocurable, or by using a light irradiation device when the adhesive 22 is photocurable. .
[0058]
The anti-reflection films 11 and 12 may be formed on the translucent spherical portions 10a and 10b after the partial spherical lens 10 is fixed to the substrate 21.
[0059]
Next, FIG. 7 shows another partial spherical lens array 50 of the present invention. The partial spherical lens array 50 is obtained by fixing the above-described partial spherical lens 10 shown in FIG. 2A to a substrate 51 with an adhesive 52 in a state where the flat portions 10d are arranged to face each other. By using the partial spherical lens 10 having only the flat portion 10d shown in FIG. 2A, such a partial spherical lens array 50 can efficiently use a 2 × 2 optical switch that is frequently used when constructing an optical communication network. It can be manufactured well and inexpensively. Of course, a 2 × 2 optical switch can be manufactured at low cost by using the partial spherical lens shown in FIGS. 2B and 2C instead of the partial spherical lens 12 shown in FIG. It becomes possible.
[0060]
The measurement of the insertion loss of the optical collimator component was performed as follows. That is, two prepared optical collimator components are prepared, an optical fiber is connected to a laser diode stabilized light source having a wavelength of 1550 nm, and one optical collimator component is connected to this optical fiber by a fusion splice. This optical collimator component is fixed to a 5-axis optical stage having two rotation axes orthogonal to the XYZ spatial axes. Next, the other optical collimator component is fixed to the optical gantry, and the tip of an optical fiber serving as a pigtail of the optical collimator component is connected to the power meter. Thereafter, the five-axis stage is operated to perform alignment so that the optical coupling between the two optical collimator components is the best, and in this state, the amount of received light (unit: dBm) is measured by the power meter. The amount of received light was subtracted from the measured value of the amount of received light (unit: dBm) when the stabilized light source and the power meter were directly connected by an optical fiber, and the insertion loss was calculated.
[0061]
【The invention's effect】
The partial spherical lens according to the present invention is made of glass having a substantially uniform refractive index, and has a translucent spherical portion having substantially the same center of curvature and opposed to each other and having an optical axis passing therethrough. An optical axis position of the partial spherical lens can be easily controlled by controlling a position of the supporting spherical surface portion, which has a supporting spherical surface portion having substantially the same center of curvature as a supporting surface and a flat surface portion substantially parallel to the optical axis. It is possible to reduce the size in the direction perpendicular to the optical axis by using a flat portion that is substantially parallel to the optical axis. Can be.
[0062]
In addition, the partial spherical lens of the present invention has two or more flat portions, two of which face each other across the optical axis, and a plurality of partial spherical lenses are arranged with their flat portions facing each other. Since it is possible to arrange light-transmitting spherical portions through which the optical axis passes in parallel at a much smaller pitch than in the past, in the case of a lens array in which lenses are arranged in parallel, the arrangement is significantly higher than in the past. Lens arrays can be produced.
[0063]
Further, in the partial spherical lens of the present invention, since the optical film is formed on the light-transmitting spherical portion of the partial spherical lens, the formation of an optical film such as an anti-reflection film or a filter film increases the speed and capacity. It is possible to manufacture a lens array corresponding to optical communication applications.
[0064]
In addition, since the partial spherical lens of the present invention has a marking for identifying the translucent spherical portion through which the optical axis passes, the optical axis direction is set by bringing the support surface spherical surface of the partial spherical lens into contact with the support member. In this case, a lens array can be accurately manufactured without making a mistake.
[0065]
The partial spherical lens array according to the present invention is composed of a substrate having a plurality of concave portions each having a substantially V-shaped cross section and arranged in parallel at a predetermined pitch on one surface, and a glass having a substantially uniform refractive index, and having a center of curvature substantially. A light-transmitting spherical portion that is the same opposing spherical surface and through which the optical axis passes, a supporting spherical portion that has a substantially same center of curvature as the light-transmitting spherical portion and serves as a supporting surface, and a flat portion that is substantially parallel to the optical axis. And a plurality of partial spherical lenses having the same.The supporting spherical portion of the partial spherical lens is supported in the concave portion of the substrate, and the light transmitting spherical portions are fixed in a state of being arranged in parallel at a predetermined pitch. It is possible to provide a high-precision lens array in which lenses are arranged in parallel at a small pitch adapted to the arrangement interval of small optical function elements.
[0066]
Further, in the partial spherical lens array of the present invention, since the planar portion of the partial spherical lens has two or more surfaces, and two of the two surfaces are opposed to each other with the optical axis interposed therebetween, the optical functional element of the optical functional device is much smaller than before. It is possible to provide a lens array which is arranged at high density in parallel with a small pitch adapted to the arrangement interval.
[0067]
In the partial spherical lens array according to the present invention, since the optical film is formed on the translucent spherical portion of the partial spherical lens, optical communication having an optical film such as an anti-reflection film or a filter film is being performed at a high speed and with a large capacity. It is possible to provide a lens array arranged in parallel at high density corresponding to the application.
[0068]
In addition, since the substrate is made of glass, crystallized glass, or silicon crystal, the partial spherical lens array of the present invention can be subjected to precision grinding / polishing, precision press molding, stretch molding, etc., and can be easily thermally expanded with the partial spherical lens. A material having a close coefficient can be obtained, and a highly reliable and inexpensive lens array can be provided.
[0069]
Further, in the partial spherical lens array of the present invention, the partial spherical lens has a highly accurate radius of curvature tolerance of the spherical surface, and a highly accurate outer diameter tolerance of the capillary, and emits light with respect to the optical axis of the partial spherical lens array. Since the inclination angle of the lens array can be made very small, it is possible to provide a lens array that can easily automate the alignment.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a partial spherical lens according to the present invention, wherein (A) is a side view parallel to the optical axis, and (B) is a front view perpendicular to the optical axis.
FIGS. 2A and 2B are explanatory views of another partial spherical lens according to the present invention, wherein FIG. 2A is a front view of a partial spherical lens having one flat surface, and FIG. The side view of a spherical lens, (C) is the front view of (B).
3A and 3B are explanatory views of a partial spherical lens array according to the present invention, wherein FIG. 3A is a plan view, FIG. 3B is a cross-sectional view taken along line Y-Y of FIG. 3A, and FIG. 3C is a side view of FIG. .
4A and 4B are explanatory views of an optical collimator component using the partial spherical lens array of the present invention, wherein FIG. 4A is a plan view and FIG. 4B is a side view.
5A and 5B are explanatory views of an example of use of the optical collimator component, wherein FIG. 5A is a plan view and FIG. 5B is a side view.
FIG. 6 is an explanatory diagram in which the insertion loss of the optical collimator component using the partial spherical lens array of the present invention is plotted against the working distance.
7A and 7B are explanatory views of another partial spherical lens array according to the present invention, wherein FIG. 7A is a plan view and FIG. 7B is a cross-sectional view taken along line XX of FIG.
8A and 8B are explanatory views showing the structure of a conventional lens array, wherein FIG. 8A is a plan view and FIG. 8B is a front view in a direction perpendicular to the optical axis.
[Explanation of symbols]
1 Drum lens
1a Column
2a, 21b V groove
2,21,51 substrate
3 Lens array
10 Partially spherical lens
10a, 10b Translucent spherical part
10c Support spherical surface
10d, 10e, 10f flat part
11, 12 Anti-reflection film
22, 33, 52 adhesive
20, 50 partial spherical lens array
21a one side
21b V groove
21c bottom
30 Optical collimator parts
31 Optical fiber
31a end face
32 capillaries
32a inner hole
32b Outer cylinder surface
40 Optical function element
41 Base substrate
J optical axis
M marking
P center of curvature

Claims (9)

A translucent spherical portion which is made of glass having a substantially uniform refractive index, has substantially the same center of curvature, and has the same center of curvature, and the optical axis passes through the translucent spherical portion. A partial spherical lens, comprising: a supporting spherical surface serving as a surface; and a plane portion substantially parallel to an optical axis. 2. The partial spherical lens according to claim 1, wherein there are two or more flat portions, and two of the flat portions face each other across the optical axis. The partial spherical lens according to claim 1, wherein an optical film is formed on the translucent spherical portion. The partial spherical lens according to any one of claims 1 to 3, further comprising a marking for identifying a translucent spherical portion through which the optical axis passes. A substrate having a plurality of concave portions each having a substantially V-shaped cross-section and arranged in parallel at a predetermined pitch on one surface is made of glass having a substantially uniform refractive index. A plurality of partial spherical lenses having a light-transmitting spherical surface portion, a supporting spherical surface portion having a substantially same center of curvature as the light-transmitting spherical surface portion and a supporting surface, and a flat portion substantially parallel to the optical axis;
A partial spherical lens array in which a supporting spherical portion of the partial spherical lens is supported by a concave portion of the substrate and light transmitting spherical portions are fixed in a state of being arranged in parallel at a predetermined pitch. 6. The partial spherical lens array according to claim 5, wherein the partial spherical lens has two or more flat portions, and two surfaces thereof are opposed to each other across the optical axis. 7. The partial spherical lens array according to claim 5, wherein an optical film is formed on a light transmitting spherical portion of the partial spherical lens. The partial spherical lens array according to any one of claims 5 to 7, wherein the substrate is made of glass, crystallized glass, or silicon crystal. The tolerance of the radius of curvature of the spherical surface of the partial spherical lens is ± 0.0015 mm, the tolerance of the outer diameter of the capillary is ± 0.001 mm, and the inclination angle of the emitted light beam with respect to the optical axis of the partial spherical lens array is 0.2 ° or less. The partial spherical lens array according to any one of claims 5 to 8, wherein

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