JP3482985B2

JP3482985B2 - Method for manufacturing fiber grating, support member, mask, and method for manufacturing optical filter

Info

Publication number: JP3482985B2
Application number: JP28571697A
Authority: JP
Inventors: 芳孝寺尾
Original assignee: Oki Electric Industry Co Ltd
Current assignee: Oki Electric Industry Co Ltd
Priority date: 1997-10-17
Filing date: 1997-10-17
Publication date: 2004-01-06
Anticipated expiration: 2017-10-17
Also published as: JPH11119029A

Description

Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】この発明は、光フィルタ等と
して利用可能なファイバグレーティングの製造方法と、
その実施に好適な光ファイバの支持部材および露光用の
マスクと、小型化に適した光フィルタの製造方法とに関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a fiber grating that can be used as an optical filter or the like,
The present invention relates to a supporting member for an optical fiber and a mask for exposure that are suitable for implementing the method, and a method for manufacturing an optical filter that is suitable for miniaturization.

【０００２】[0002]

【従来の技術】光通信分野では、波長フィルタや分散補
償器などの一実現手段として、ファイバグレーティング
が期待されている（例えば文献1 「応用物理、第６６巻
第１号、第３３〜第３６頁」）。ファイバグレーティン
グは、光ファイバのコアに周期的な屈折率変化を施した
ものである（例えば文献１）。周期的な屈折率変化（屈
折率変調）は、例えば位相マスク法により形成できる
（例えば上記の文献１、または、文献２「米国特許５３
６７５８８号」参照）。2. Description of the Related Art In the field of optical communication, a fiber grating is expected as one means for realizing a wavelength filter, a dispersion compensator and the like (for example, Document 1 "Applied Physics, Vol. 66, No. 1, 33-36"). page"). The fiber grating is a core of an optical fiber in which the refractive index is periodically changed (for example, Document 1). The periodic refractive index change (refractive index modulation) can be formed by, for example, a phase mask method (for example, the above-mentioned Document 1 or Document 2 “US Patent 53”).
67588 ").

【０００３】位相マスク法では、位相マスク（以下、マ
スクともいう。）を介して、光ファイバに紫外線光を照
射する。位相マスクは紫外線光の透過が可能な板状体で
ある。この板状体の表面には複数個の凹部が形成されて
いる。各凹部は所定の間隔をもって直線的に配列されて
いる。これら凹部により紫外線光が回折する。その回折
光の強度は、凹部の配列間隔（ピッチ）に応じた位置で
強められたり弱められたりする。一方、光ファイバのコ
アは、紫外線光によってその屈折率が変化する材料で形
成されている（このような光ファイバを感光性光ファイ
バと称する。）。上述した回折光が光ファイバに対して
照射されるので、光ファイバの延在方向（長手方向、光
の導波方向）に沿って、周期的な屈折率変調すなわちグ
レーティングが、コアに形成される。In the phase mask method, an optical fiber is irradiated with ultraviolet light through a phase mask (hereinafter also referred to as a mask). The phase mask is a plate-shaped body capable of transmitting ultraviolet light. A plurality of recesses are formed on the surface of this plate-shaped body. The concave portions are linearly arranged with a predetermined interval. Ultraviolet light is diffracted by these recesses. The intensity of the diffracted light is strengthened or weakened at the position corresponding to the arrangement interval (pitch) of the concave portions. On the other hand, the core of the optical fiber is formed of a material whose refractive index changes with ultraviolet light (such an optical fiber is referred to as a photosensitive optical fiber). Since the diffracted light described above is applied to the optical fiber, a periodic refractive index modulation, that is, a grating is formed in the core along the extending direction (longitudinal direction, light guiding direction) of the optical fiber. .

【０００４】上述のマスクは、例えば文献３「ＥＬＥＣ
ＴＲＯＮＩＣＳＬＥＴＴＥＲＳ１８ｔｈＭａｒ１
９９３Ｖｏｌ２９Ｎｏ．６」に開示されている製造
方法によって形成される。また、ファイバグレーティン
グにおける反射波長帯域を広くしたい場合には、上記文
献１に開示されているチャープグレーティングの構造に
すればよい。The above-mentioned mask is obtained, for example, in Reference 3 "ELEC.
TRONICS LETTERS 18th Mar 1
993 Vol29 No. 6 ”. Further, when it is desired to widen the reflection wavelength band in the fiber grating, the structure of the chirp grating disclosed in the above-mentioned Document 1 may be used.

【０００５】[0005]

【発明が解決しようとする課題】しかしながら、ファイ
バグレーティングのフィルタ特性、例えば反射波長帯域
や反射スペクトルのトップの平坦性などは、ファイバグ
レーティングのグレーティング書き込み領域の長さすな
わちグレーティング長に依存する。However, the filter characteristics of the fiber grating, such as the flatness of the reflection wavelength band and the top of the reflection spectrum, depend on the length of the grating writing area of the fiber grating, that is, the grating length.

【０００６】例えば、ファイバグレーティングで分散補
償器を構成する場合、反射波長帯域△λは次式（１）で
表される（例えば文献４「アドバンスト・エレクトロニ
クス１−１６，光ファイバとファイバ形デバイス、培風
館、１９９６．７．１０」、第１９７頁）。For example, when a dispersion compensator is constituted by a fiber grating, the reflection wavelength band Δλ is expressed by the following equation (1) (for example, Reference 4 “Advanced Electronics 1-16, optical fiber and fiber type device, Baifukan, 1996.7.10 ", p. 197).

【０００７】△λ＝２Ｌ／（Ｃ・Ｄ）・・・（１）但し、記号Ｌはグレーティング長を表し、記号Ｃは光の
速度を表し、記号Ｄは分散値を表している。Δλ = 2L / (C · D) (1) However, the symbol L represents the grating length, the symbol C represents the speed of light, and the symbol D represents the dispersion value.

【０００８】上式（１）によれば、分散値Ｄを一定とし
たとき、グレーティング長Ｌが長ければ長いほど、反射
波長帯域△λが広がる。しかし、位相マスクのサイズは
それほど大きくできないのが現状である。なぜなら、例
えば、位相マスクを形成するためには、真空装置内での
処理を必要とするが、比較的大きな板状体は真空装置内
に導入することができない。従って、グレーティング長
Ｌもそれほど大きく形成することができない。従来方法
では、せいぜい１００ｍｍ程度のグレーティング長Ｌの
ファイバグレーティングしか形成することができなかっ
た。According to the above equation (1), when the dispersion value D is constant, the longer the grating length L, the wider the reflection wavelength band Δλ. However, the size of the phase mask cannot be so large at present. This is because, for example, in order to form a phase mask, processing in a vacuum apparatus is required, but a relatively large plate-shaped body cannot be introduced into the vacuum apparatus. Therefore, the grating length L cannot be formed so large. According to the conventional method, only a fiber grating having a grating length L of about 100 mm can be formed at most.

【０００９】従って、従来よりも長い、具体的には１０
０ｍｍよりも長いグレーティング長のファイバグレーテ
ィングを製造できる方法の出現が望まれていた。Therefore, it is longer than the conventional one, specifically 10
It has been desired to develop a method capable of manufacturing a fiber grating having a grating length longer than 0 mm.

【００１０】また、長いグレーティングのファイバグレ
ーティングが製造できた後に、該ファイバグレーティン
グを利用して光フィルタを構成する場合に、小型化に適
した構造を有した光フィルタが望まれる。When a fiber grating having a long grating can be manufactured and then an optical filter is constructed using the fiber grating, an optical filter having a structure suitable for miniaturization is desired.

【００１１】[0011]

[Means for Solving the Problems]

（１）そこで、この発明のファイバグレーティングの製
造方法によれば、感光性光ファイバを、回折格子を有し
たマスクを介して露光して、該光ファイバに屈折率変調
部を形成するファイバグレーティングの製造方法におい
て、感光性光ファイバを円筒状の支持部材に螺旋状に巻
き付けておく。次に、該巻き付けた光ファイバの接線に
前記マスクの回折格子が沿うような位置関係で、前記マ
スクと前記支持部材とを対向させる。そして、前記回折
格子の次々の部分と前記支持部材に巻かれている光ファ
イバの次々の部分とが、露光光の照射領域を通過するよ
うに、前記マスクの移動と、前記支持部材の、その軸線
を回転中心とする回転とを行いながら、前記露光をす
る。(1) Therefore, according to the method for manufacturing a fiber grating of the present invention, a photosensitive optical fiber is exposed through a mask having a diffraction grating to form a refractive index modulation part in the optical fiber. In the manufacturing method, the photosensitive optical fiber is spirally wound around the cylindrical support member. Next, the mask and the supporting member are opposed to each other in such a positional relationship that the diffraction grating of the mask is along the tangent line of the wound optical fiber. Then, the successive portions of the diffraction grating and the successive portions of the optical fiber wound around the supporting member pass through the irradiation region of the exposure light, the movement of the mask and the supporting member, The exposure is performed while performing rotation about the axis as a rotation center.

【００１２】この製造方法（以下、第１の製造方法と称
する。）によれば、マスクとして、前記螺旋状に巻かれ
た光ファイバのｍ巻き分の幅以上の幅と、前記支持部材
をその軸線を中心に１回転させた時に進む光ファイバの
距離Ｌ以上の長さとを持つ回折格子を有したマスクを用
い、かつ、前記距離Ｌ分だけ、前記回折格子の次々の部
分と前記支持部材に巻かれている光ファイバの次々の部
分とが、露光光の照射領域を通過するように、前記マス
クの移動と、前記支持部材の前記回転とを行いながら、
前記露光をすることができる。ただし、ｍは２以上の整
数である。According to this manufacturing method (hereinafter referred to as the first manufacturing method), the mask is used as a mask, and the width of the spirally wound optical fiber is equal to or larger than the width of m turns, and the supporting member is used. A mask having a diffraction grating having a length equal to or longer than a distance L of an optical fiber that advances when it is rotated once about an axis is used, and the distance L is used for each part of the diffraction grating and the supporting member. Successive portions of the wound optical fiber, while passing the exposure light irradiation area, while performing the movement of the mask and the rotation of the support member,
The exposure can be performed. However, m is an integer of 2 or more.

【００１３】そのため、ｍ巻き分の光ファイバの各巻き
それぞれに対し回折格子を介しての露光が並列的に行わ
れる。そのため、ｍ×Ｌの長さのファイバグレーティン
グを形成することができる。従って、この製造方法によ
れば長さがＬの回折格子を用いてそれより長いファイバ
グレーテイングを製造できる。具体的には、従来技術で
形成できる最長の回折格子が例えば１００ｍｍであった
とする。この第１の製造方法の発明によれば、この１０
０ｍｍの長さの回折格子をｍ本分並列に並べた様な回折
格子を有したマスクを用いることができる。したがっ
て、長さが１００ｍｍの回折格子を用いてｍ×１００ｍ
ｍのファイバグレーティングを製造することができる。Therefore, the exposure through the diffraction grating is performed in parallel for each of the m turns of the optical fiber. Therefore, it is possible to form a fiber grating having a length of m × L. Therefore, according to this manufacturing method, it is possible to manufacture a longer fiber grating by using a diffraction grating having a length of L. Specifically, it is assumed that the longest diffraction grating that can be formed by the conventional technique is 100 mm, for example. According to the invention of the first manufacturing method,
A mask having a diffraction grating in which 0 diffraction gratings each having a length of 0 are arranged in parallel can be used. Therefore, using a diffraction grating having a length of 100 mm, m × 100 m
m fiber gratings can be manufactured.

【００１４】この第１の製造方法において、用いるマス
クの回折格子を単周期グレーティングとした場合は、長
さがＬの回折格子を用いて、ｍ×Ｌの長さの単周期ファ
イバグレーティングを製造できる。In the first manufacturing method, when the diffraction grating of the mask used is a single-period grating, a length-L diffraction grating can be used to manufacture a single-period fiber grating having a length of m × L. .

【００１５】また、この第１の製造方法において、用い
るマスクの回折格子を前記ｍ巻きの各巻きごとの光ファ
イバ用として用意された互いに平行な第１〜第ｍの回折
格子であって、これら回折格子全体として連続するチャ
ープグレーティングとなるようにそれぞれが個別のチャ
ープグレーティングを有した第１〜第ｍの回折格子単周
期グレーティングとした場合は、長さがＬの回折格子を
用いて、長さがｍ×Ｌのチャープトファイバグレーティ
ングを製造できる。In the first manufacturing method, the diffraction grating of the mask used is the first to m-th diffraction gratings parallel to each other prepared for the optical fiber for each of the m turns. When the first to mth diffraction grating single period gratings each have an individual chirped grating so that the entire diffraction grating is a continuous chirped grating, when a diffraction grating having a length of L is used, Can produce a m × L chirped fiber grating.

【００１６】なお、上述においては、回折格子の幅を、
光ファイバのｍ巻き分の幅以上の幅とし、回折格子の長
さを前記Ｌ以上の長さとすると説明した。回折格子の長
さを上記Ｌより長くしたとしても、支持部材の回転角と
マスクの移動距離とをそれぞれ制御すれば、距離Ｌ相当
の回折格子が実現できるからである。ただし、回折格子
としてチャープグレーティングを用いる場合は、回折格
子の長さはＬとした方が好ましい。第１〜第ｍの回折格
子それぞれのチャープグレーティングの接続が容易にな
るからである。In the above description, the width of the diffraction grating is
It has been described that the width is equal to or larger than the width of m turns of the optical fiber and the length of the diffraction grating is equal to or larger than L. This is because even if the length of the diffraction grating is made longer than the above L, a diffraction grating corresponding to the distance L can be realized by controlling the rotation angle of the support member and the moving distance of the mask. However, when a chirped grating is used as the diffraction grating, the length of the diffraction grating is preferably L. This is because the chirp grating of each of the first to mth diffraction gratings can be easily connected.

【００１７】また、この第１の製造方法の実施に当た
り、次のようにしても良い。すなわち、露光用マスクと
して、前記螺旋状に巻かれた光ファイバのｓ巻き分に相
当する間隔をもって平行に配置された長さがｓ×Ｌ以上
の複数の回折格子を有したマスクを用意する。次に、前
記巻き付けた光ファイバの接線に該マスクの回折格子が
沿うような位置関係で、該マスクと前記支持部材とを対
向させる。そして、前記ｓ×Ｌの距離分だけ、該回折格
子の次々の部分と前記支持部材に巻かれている光ファイ
バの次々の部分とが露光光の照射領域を通過するよう
に、該マスクの移動と、前記支持部材の、その軸線を回
転中心とする回転とを行なわせながら、露光をする。こ
の場合は、ｓ巻き分の光ファイバ単位で、並列的に露光
が行われる。そのため、長さがｓ×Ｌの回折格子を用い
て、それの複数倍のファイバグレーティングを製造でき
る。In carrying out the first manufacturing method, the following may be carried out. That is, as an exposure mask, a mask having a plurality of diffraction gratings having a length of s × L or more arranged in parallel with an interval corresponding to s windings of the spirally wound optical fiber is prepared. Next, the mask and the supporting member are opposed to each other in such a positional relationship that the diffraction grating of the mask is along the tangent line of the wound optical fiber. Then, the mask is moved by a distance of s × L so that the successive portions of the diffraction grating and the successive portions of the optical fiber wound around the support member pass through the exposure light irradiation region. Then, the exposure is performed while rotating the supporting member about its axis. In this case, exposure is performed in parallel for each optical fiber unit for s windings. Therefore, using a diffraction grating having a length of s × L, it is possible to manufacture a fiber grating having a multiple of the length.

【００１８】（２）また、この出願では、ファイバーグ
レーティングの製造方法として、以下の方法（第２の製
造方法と称する）も主張する。(2) The present application also claims the following method (referred to as a second manufacturing method) as a method for manufacturing a fiber grating.

【００１９】すなわち、感光性光ファイバを、回折格子
を有したマスクを介して露光して、該光ファイバに屈折
率変調部を形成するファイバグレーティングの製造方法
において、感光性光ファイバを円筒状の支持部材に螺旋
状に巻き付けておく。また、前記マスクとして、単周期
グレーティングを有した長さがＸの回折格子を有したマ
スクを用意する。そして、前記巻き付けた光ファイバの
接線に前記回折格子が沿うような位置関係で、前記マス
クを前記光ファイバと対向させ、その後、以下の第１お
よび第２の処理を必要数繰り返す方法を主張する。That is, in a method of manufacturing a fiber grating in which a photosensitive optical fiber is exposed through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, the photosensitive optical fiber is formed into a cylindrical shape. It is spirally wound around the support member. Further, as the mask, a mask having a diffraction grating having a length X and having a single period grating is prepared. Then, a method is claimed in which the mask is opposed to the optical fiber in a positional relationship such that the diffraction grating is along the tangent line of the wound optical fiber, and then the following first and second processes are repeated a necessary number of times. .

【００２０】（ａ）前記回折格子の長さ分だけ、該回折
格子の次々の部分と、前記支持部材に巻かれている光フ
ァイバの次々の部分とが露光光の照射領域を通過するよ
うに、該マスクの移動と、前記支持部材の、その軸線を
回転中心とする回転を行いながら、然も、前記照射領域
の前記軸線に沿った幅が、前記螺旋に巻いた光ファイバ
２巻き分の幅未満となるように露光光を絞った状態で、
前記露光をする第１の処理。(A) The length of the diffraction grating is such that successive portions of the diffraction grating and successive portions of the optical fiber wound around the support member pass through the exposure light irradiation area. While the mask is moved and the support member is rotated about its axis, the width of the irradiation region along the axis is equal to that of the two optical fibers wound in the spiral. With the exposure light squeezed so that it is less than the width,
A first process of performing the exposure.

【００２１】（ｂ）前記第１の処理を終えた後、前記露
光終点位置を通り前記軸線に垂直に交わる線分を回転中
心として、前記支持部材を前記マスクに対して相対的に
１８０度回転させる第２の処理。(B) After the completion of the first process, the support member is rotated 180 degrees relative to the mask about a line segment that passes through the exposure end point position and intersects perpendicularly with the axis line. The second process to be performed.

【００２２】この第２の製造方法によれば、長さがＸの
回折格子を介しての露光を終えると上述した１８０度回
転が行われる。このため、支持部材に螺旋状に巻かれた
光ファイバの、次に現れる部分の露光を、この長さＸの
回折格子を介して行うことができる。このため、この第
２の製造方法によれば長さがＸの回折格子であってもそ
れより長い単周期ファイバグレーティングを製造でき
る。According to the second manufacturing method, when the exposure through the diffraction grating having the length X is completed, the above-mentioned rotation of 180 degrees is performed. Therefore, it is possible to expose the portion of the optical fiber spirally wound around the support member, which appears next, through the diffraction grating having the length X. Therefore, according to the second manufacturing method, it is possible to manufacture a single-period fiber grating longer than the diffraction grating having the length X.

【００２３】（３）また、この出願では、ファイバグレ
ーティングの製造方法として、以下の方法（第３の製造
方法と称する）も主張する。(3) The present application also claims the following method (referred to as a third manufacturing method) as a method for manufacturing a fiber grating.

【００２４】すなわち、感光性光ファイバを、回折格子
を有したマスクを介して露光して、該光ファイバに屈折
率変調部を形成するファイバグレーティングの製造方法
において、感光性光ファイバを円筒状の支持部材に螺旋
状に巻き付けておく。また、前記マスクとして、互いに
平行に配置したかつ互いの長さがＸである第１〜第ｍの
回折格子であって、これら回折格子全体として連続する
チャープグレーティングとなるようにそれぞれが個別の
チャープグレーティングを有した第１〜第ｍの回折格子
を有したマスクを用意する。そして、前記巻き付けた光
ファイバの接線に前記第１〜第ｍの回折格子のいずれか
１つが沿うような位置関係で、前記マスクを前記光ファ
イバと対向させ、その後、以下の第１〜第３の処理を必
要数繰り返す方法を主張する。ただし、第２の処理と第
３の処理との順番はいずれが先でも良い。That is, in a method of manufacturing a fiber grating in which a photosensitive optical fiber is exposed through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, the photosensitive optical fiber is formed into a cylindrical shape. It is spirally wound around the support member. The masks are first to mth diffraction gratings arranged in parallel with each other and having a length X, and each of the diffraction gratings has an individual chirp grating so as to form a continuous chirp grating. A mask having first to mth diffraction gratings each having a grating is prepared. Then, the mask is opposed to the optical fiber in a positional relationship such that any one of the first to mth diffraction gratings is along the tangent line of the wound optical fiber, and then the following first to third Insist on a method of repeating the processing of step as many times as necessary. However, the order of the second processing and the third processing may be first.

【００２５】前記回折格子の長さ分だけ、該回折格子
の次々の部分と、前記支持部材に巻かれている光ファイ
バの次々の部分とが露光光の照射領域を通過するよう
に、該マスクの移動と、前記支持部材の、その軸線を回
転中心とする回転とを行いながら、然も、前記照射領域
の前記軸線に沿った幅が、前記螺旋状に巻いた光ファイ
バ２巻き分の幅未満となるように露光光を絞った状態
で、前記露光をする第１の処理。The mask is arranged so that the portions of the diffraction grating and the portions of the optical fiber wound around the support member pass through the exposure light irradiation area by the length of the diffraction grating. And the rotation of the support member about its axis as the center of rotation, the width of the irradiation region along the axis is still the width of two spirally wound optical fibers. The first process of performing the exposure in a state in which the exposure light is narrowed so as to be less than 1.

【００２６】前記第１の処理を終えた後、前記露光終
点位置を通り前記軸線に垂直に交わる線分を回転中心と
して、前記支持部材を前記マスクに対して相対的に１８
０度回転させる第２の処理。After the completion of the first process, the support member is moved relative to the mask by a line segment that passes through the exposure end point position and intersects perpendicularly to the axis with the support member as the center of rotation.
Second process of rotating 0 degree.

【００２７】前記第１の処理を終えた後、今まで露光
に用いた回折格子の隣に位置する回折格子が前記露光終
了位置と対向するように、前記マスクおよび前記支持部
材を相対的に移動させる第３の処理。After the completion of the first process, the mask and the supporting member are relatively moved so that the diffraction grating located next to the diffraction grating used for the exposure so far faces the exposure end position. Third process to be performed.

【００２８】この第３の製造方法によれば、長さがＸの
回折格子を介しての露光を終えると上述した１８０度回
転と、マスクおよび支持部材の相対的な移動とが行われ
る。このため、支持部材に螺旋状に巻かれた光ファイバ
の、次に現れる部分の露光を、第１〜第ｍの回折格子を
順に使用して行うことができる。第１〜第ｍの回折格子
はいずれも長さがＸのものでよい。このため、この第３
の製造方法によれば、長さがＸの回折格子を用いてそれ
より長いチャープトファイバグレーティングを製造でき
る。According to the third manufacturing method, when the exposure through the diffraction grating having the length X is completed, the above-described 180 ° rotation and the relative movement of the mask and the supporting member are performed. Therefore, the exposure of the portion of the optical fiber spirally wound around the support member that appears next can be performed by sequentially using the first to mth diffraction gratings. Each of the first to mth diffraction gratings may have a length of X. Therefore, this third
According to the manufacturing method of (1), it is possible to manufacture a longer chirped fiber grating by using a diffraction grating having a length of X.

【００２９】（４）また、この出願では、上述の第１〜
第３の製造方法を容易に実施するための支持部材として
以下のような支持部材を主張する。(4) Further, in this application, the above-mentioned first to first
The following support members are claimed as support members for easily carrying out the third manufacturing method.

【００３０】すなわち、感光性光ファイバを螺旋状に巻
き付けるための螺旋状の溝を有した円柱上の支持部材で
あって、表面に、前記光ファイバを露光する露光光につ
いての実質的な無反射コーティングが施されている支持
部材を主張する。That is, a cylindrical support member having a spiral groove for spirally winding a photosensitive optical fiber, the surface of which is substantially non-reflective with respect to exposure light for exposing the optical fiber. Claim a support member that has been coated.

【００３１】上述の第１〜第３の製造方法を実施するに
は、感光性光ファイバを支持部材に螺旋状に所定のリー
ド角で巻き付ける必要がある。このようなとき、この発
明の支持部材によれば、上記の巻き付けを容易に実現で
きる。In order to carry out the above-mentioned first to third manufacturing methods, it is necessary to spirally wind the photosensitive optical fiber around the supporting member at a predetermined lead angle. In such a case, according to the support member of the present invention, the above winding can be easily realized.

【００３２】さらにこの支持部材は、所定の無反射コー
ティングを施してある。そのため、周期的な屈折率変調
の形成に寄与しない反射光を実質的に無くすことができ
る。Further, this support member is provided with a predetermined antireflection coating. Therefore, it is possible to substantially eliminate the reflected light that does not contribute to the formation of the periodic refractive index modulation.

【００３３】なお、支持部材の発明を実施するに当た
り、前記溝の深さを前記感光性光ファイバの直径よりも
大きくしておくのが好適である。こうすると、感光性光
ファイバとマスクとが接触してしまうのを防ぐことがで
きる。従って、マスクおよび光ファイバの保護が図れ
る。また、感光性光ファイバが溝からはみ出しにくくな
るので、所望の巻き付けをより良好に行える。In carrying out the invention of the supporting member, it is preferable to make the depth of the groove larger than the diameter of the photosensitive optical fiber. This can prevent the photosensitive optical fiber and the mask from coming into contact with each other. Therefore, the mask and the optical fiber can be protected. Further, since the photosensitive optical fiber is less likely to stick out of the groove, desired winding can be performed better.

【００３４】（５）また、この出願の光フィルタの製造
方法に係る発明によれば、支持部材と、該支持部材に螺
旋状に巻き付けられたファイバグレーティングとを具え
た光フィルタを製造するに当たり、上述した（１）〜
（３）の項で説明した手順によってファイバグレーティ
ングを製造する。(5) Further, according to the invention relating to the method of manufacturing an optical filter of this application, in manufacturing an optical filter including a supporting member and a fiber grating spirally wound around the supporting member, Above (1)-
The fiber grating is manufactured by the procedure described in the section (3).

【００３５】上述した光フィルタの製造方法によれば、
長いファイバグレーティングをコンパクトに収納できる
光フィルタの製造が実現できる。そのため、この光フィ
ルタの製造方法では、反射波長帯域や反射スペクトルの
トップの平坦性などの特性を実現するために長いファイ
バグレーティングを有する光フィルタの小型化が図りや
すい。According to the above-mentioned optical filter manufacturing method,
It is possible to manufacture an optical filter that can accommodate a long fiber grating compactly. Therefore, in this method of manufacturing an optical filter, it is easy to downsize an optical filter having a long fiber grating in order to realize characteristics such as the reflection wavelength band and the flatness of the top of the reflection spectrum.

【００３６】用いる支持部材は、好ましくは、細長い形
状でかつファイバグレーティングを巻きつけ易い形状の
ものとする。円柱状の支持部材や多角柱状の支持部材
は、用いる支持部材として好ましい。The support member used is preferably an elongated shape and has a shape in which the fiber grating can be easily wound. A columnar support member or a polygonal columnar support member is preferable as the support member used.

【００３７】また、この光フィルタの製造方法の発明を
実施するに当たり、前記支持部材として、前記感光性光
ファイバを巻き付けるための螺旋状の溝を具えた支持部
材を用いるのが好適である。そして、該溝に沿って前記
感光性光ファイバを巻き付けることにより、この光フィ
ルタの製造方法において製造されたファイバグレーティ
ングの位置決めと、固定とを容易に行うことができる等
の利点が得られる。In carrying out the invention of the method for manufacturing an optical filter, it is preferable to use, as the supporting member, a supporting member having a spiral groove for winding the photosensitive optical fiber. By winding the photosensitive optical fiber along the groove, it is possible to easily position and fix the fiber grating manufactured by the method for manufacturing the optical filter.

【００３８】なお、支持部材に設ける螺旋状の溝の深さ
は、ファイバグレーティングの位置決めおよび固定がで
きる深さであれば特に限定されない。しかし、この溝の
深さを、ファイバグレーティングの直径より深くする
と、ファイバグレーティングが支持部材内に隠れた構造
の光フィルタが実現できる。ファイバグレーティング
が、支持部材内に隠れた構造であると、ファイバグレー
ティングの保護が図り易い。さらに、例えば、支持部材
を内包する筒状のカバーを実装することができるので、
光フィルタの外装を容易に完了できるという利点なども
得られる。The depth of the spiral groove provided in the support member is not particularly limited as long as it is the depth at which the fiber grating can be positioned and fixed. However, if the depth of this groove is made deeper than the diameter of the fiber grating, an optical filter having a structure in which the fiber grating is hidden in the support member can be realized. When the fiber grating has a structure hidden in the support member, it is easy to protect the fiber grating. Furthermore, for example, since a cylindrical cover including the support member can be mounted,
There is also an advantage that the exterior of the optical filter can be easily completed.

【００３９】[0039]

【発明の実施の形態】以下、図面を参照して、この発明
の実施の形態につき説明する。尚、説明に用いる各図
は、この発明が理解できる程度に、構造、大きさおよび
配置関係を概略的に示してあるにすぎない。また、以下
に記載する数値等の条件や材料は単なる一例に過ぎな
い。従って、この発明は、この実施の形態に何ら限定さ
れることがない。また、各図において同様な構成成分に
ついては、同一の番号を付して示し、その重複する説明
を省略する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that each of the drawings used for the description only schematically shows the structure, size, and arrangement relationship to the extent that the present invention can be understood. The conditions such as numerical values and materials described below are merely examples. Therefore, the present invention is not limited to this embodiment. Moreover, in each figure, the same components are denoted by the same reference numerals, and the duplicated description thereof will be omitted.

【００４０】１．第１の製造方法の説明ファイバグレーティングの第１の製造方法の実施の形態
につき説明する。先ず、感光性光ファイバ１１と、支持
部材１３とについて説明する。図１は、円柱状の支持部
材１３および、該支持部材１３に感光性光ファイバ１１
を巻き付けた状態をそれぞれ説明する図である。1. Description of First Manufacturing Method An embodiment of the first manufacturing method of the fiber grating will be described. First, the photosensitive optical fiber 11 and the support member 13 will be described. FIG. 1 shows a cylindrical support member 13 and a photosensitive optical fiber 11 on the support member 13.
It is a figure which respectively illustrates the state which wound.

【００４１】感光性光ファイバ１１として、例えばコー
ニング社製のＳＭＦ２８（商品名）と称される感光性光
ファイバを用いる。もちろん、他の感光性光ファイバを
用いても良い。As the photosensitive optical fiber 11, for example, a photosensitive optical fiber called SMF28 (trade name) manufactured by Corning is used. Of course, other photosensitive optical fibers may be used.

【００４２】感光性光ファイバ１１の被覆層（図示せ
ず）を予め剥がして、クラッド層を露出させる。被覆層
の剥離は、たとえば、ファイバストリッパ等の治具を用
いるか、または、ファイバ自体をジクロロエタンに浸漬
して被覆層を溶解させることで行える。なお、被覆層の
剥離は、感光性光ファイバ単体の状態で行っても良い
し、支持部材１３に光ファイバ１１を巻き付けた後に
行っても良い。The coating layer (not shown) of the photosensitive optical fiber 11 is previously peeled off to expose the clad layer. The coating layer can be peeled off by using a jig such as a fiber stripper or by immersing the fiber itself in dichloroethane to dissolve the coating layer. The coating layer may be peeled off in the state of the photosensitive optical fiber alone, or after the optical fiber 11 is wound around the support member 13.

【００４３】支持部材１３は、所定のリード角をもった
螺旋状の溝１３ａを有する。リード角は、螺旋状の溝１
３ａの接線Ｍ（図１参照）と、支持部材１３の軸線ａｂ
に垂直な平面とのなす角θである（図１参照）。The support member 13 has a spiral groove 13a having a predetermined lead angle. Lead angle is spiral groove 1
Tangent M of 3a (see FIG. 1) and axis ab of the support member 13
Is an angle θ with a plane perpendicular to (see FIG. 1).

【００４４】この支持部材１３の表面は、ファイバグレ
ーティング製造のための露光光に対して実質的に無反射
となるコーティング（図示せず）が施してある。このコ
ーティングは、たとえば、支持部材１３の表面に黒色塗
料を焼き付け塗装する等の方法で、実現できる。The surface of the support member 13 is coated with a coating (not shown) that is substantially non-reflecting to the exposure light for manufacturing the fiber grating. This coating can be realized by, for example, a method of baking and painting a black paint on the surface of the support member 13.

【００４５】螺旋状の溝１３ａの幅ｗおよび深さｄは
（図２参照）、感光性光ファイバ１１の位置決めができ
れば、任意とできる。ただし、溝１３ａの幅は、好まし
くは、おおよそ光ファイバ１１の直径（被覆層も含めた
直径）とする。また、溝１３ａの深さは、好ましくは、
光ファイバの直径の半分より大きく直径以下の範囲の値
とする。例えば、光ファイバ１１の直径が１２５μｍで
あるなら、溝１３ａの幅を１２０〜１３０μｍとし、溝
１３ａの深さを６０〜１２０μｍとする。図２（Ａ）
は、このような、溝１３ａと光ファイバ１１との関係を
示した図である。The width w and the depth d of the spiral groove 13a (see FIG. 2) can be arbitrarily determined as long as the photosensitive optical fiber 11 can be positioned. However, the width of the groove 13a is preferably approximately the diameter of the optical fiber 11 (the diameter including the coating layer). The depth of the groove 13a is preferably
The value is in the range of more than half the diameter of the optical fiber and less than or equal to the diameter. For example, if the diameter of the optical fiber 11 is 125 μm, the width of the groove 13a is 120 to 130 μm, and the depth of the groove 13a is 60 to 120 μm. Figure 2 (A)
FIG. 6 is a diagram showing such a relationship between the groove 13 a and the optical fiber 11.

【００４６】なお、光ファイバ１１とマスク（図３参
照）とが直接接触する危険を低減したい場合は、溝１３
ａの深さを、光ファイバ１１の直径より大きな値にす
る。図２（Ｂ）は、このような、溝１３ａと光ファイバ
１１との関係を示した図である。In order to reduce the risk of direct contact between the optical fiber 11 and the mask (see FIG. 3), the groove 13
The depth of a is set to a value larger than the diameter of the optical fiber 11. FIG. 2B is a diagram showing such a relationship between the groove 13 a and the optical fiber 11.

【００４７】このような螺旋状の溝１３ａに光ファイバ
１１を入れながら、支持部材１３に光ファイバ１１を巻
き付ける。巻き付けられた光ファイバ１１の１巻き分の
長さ（図１のＰ１〜Ｐ２までの長さ）は、Ｌになる。す
なわち、支持部材１３をその軸線ａｂを回転中心として
１回転させたときに光ファイバ１１が進む距離は、Ｌに
なる。The optical fiber 11 is wound around the supporting member 13 while the optical fiber 11 is being inserted into the spiral groove 13a. The length of one turn of the wound optical fiber 11 (the length from P1 to P2 in FIG. 1) becomes L. That is, the distance traveled by the optical fiber 11 when the support member 13 is rotated once about the axis ab of the support member 13 is L.

【００４８】次に、露光用のマスクについて説明する。
図３はこのマスク１５の一例を説明する平面図である。Next, the exposure mask will be described.
FIG. 3 is a plan view illustrating an example of the mask 15.

【００４９】マスク１５を、この場合、露光光に対して
透明な基板１５ａと、この基板に設けた回折格子１７と
で構成してある。In this case, the mask 15 is composed of a substrate 15a transparent to the exposure light and a diffraction grating 17 provided on this substrate.

【００５０】基板１５ａを、例えば合成石英基板などの
任意好適な基板で構成してある。The substrate 15a is composed of any suitable substrate such as a synthetic quartz substrate.

【００５１】回折格子１７の、支持部材１３の軸線ａｂ
（図１参照）に沿った幅Ｗ０を、支持部材１３に螺旋状
に巻かれた光ファイバ１１のｍ巻き分の幅以上（この幅
と同じでも良い。）としてある。しかも、この回折格子
１７の長さを、前記距離Ｌ以上の長さ、この実施の形態
の場合は前記距離Ｌと同じ長さＬとしてある。The axis ab of the support member 13 of the diffraction grating 17
The width W0 along (see FIG. 1) is set to be equal to or larger than the width of m turns of the optical fiber 11 spirally wound around the support member 13 (the width may be the same). Moreover, the length of the diffraction grating 17 is set to a length equal to or greater than the distance L, that is, the same length L as the distance L in the case of this embodiment.

【００５２】しかも、この実施の形態の場合の回折格子
１７は、螺旋状に巻かれた光ファイバ１１の各巻きごと
の光ファイバ用として用意された、互いに平行な第１〜
第ｍの回折格子１７ａ〜１７ｍであって、それぞれが長
さＬの第１〜第ｍの回折格子１７ａ〜１７ｍで構成して
ある。ここで、各巻きとは、支持部材１３をその軸線ａ
ｂを回転中心として１回転させた時の１巻き分であり、
図１でいえば、Ｐ１〜Ｐ２間に相当する部分である。Moreover, the diffraction grating 17 in the case of the present embodiment is prepared for the optical fiber for each winding of the spirally wound optical fiber 11 and is parallel to each other.
The m-th diffraction gratings 17a to 17m are composed of the first to m-th diffraction gratings 17a to 17m each having a length L. Here, each winding means that the support member 13 has its axis a.
It is one turn when one rotation is made with b as the center of rotation,
In FIG. 1, it is a portion corresponding to between P1 and P2.

【００５３】第１〜第ｍの回折格子１７ａ〜１７ｍそれ
ぞれは、これら回折格子全体として連続するチャープグ
レーティングとなるように、個別のチャープグレーティ
ングを有している。具体的には、第１の回折格子１７ａ
は、例えば、１７ａ１〜１７ａｎのｎ個の部分で構成さ
れる。ただし、ｎは任意の整数である。そして、第１の
部分１７ａ１は、長さがΛ１の周期構造をＳ１回繰り返
した構造とされている。また、第２の部分１７ａ２は、
長さがΛ２（Λ１＜Λ２）の周期構造をＳ２回繰り返し
た構造とされている。また、第ｎの部分１７ａｎは、長
さがΛｎ（Λｎ−１＜Λｎ）の周期構造をＳｎ回繰り返
した構造とされている。Ｓ１〜Ｓｎは、同じでも異なっ
ても良い。Each of the first to mth diffraction gratings 17a to 17m has an individual chirp grating so that the entire diffraction grating is a continuous chirp grating. Specifically, the first diffraction grating 17a
Is composed of, for example, n parts 17a1 to 17an. However, n is an arbitrary integer. The first portion 17a1 has a structure in which the periodic structure having a length Λ1 is repeated S1 times. Also, the second portion 17a2 is
A periodic structure having a length of Λ2 (Λ1 <Λ2) is repeated S2 times. The n-th portion 17an has a structure in which a periodic structure having a length of Λn (Λn-1 <Λn) is repeated Sn times. S1 to Sn may be the same or different.

【００５４】上記の周期構造それぞれは、例えば、従来
と同様に、凹部と凸部とを長さが１対１の割合となるよ
うに連ねた構造としてある。この周期構造は、公知のリ
ソグラフィ技術およびエッチング技術により形成でき
る、以下、周期構造の長さを順に違えて第２の回折格子
１７ｂ〜第ｍの回折格子１７ｍをそれぞれ構成してあ
る。Each of the above-described periodic structures is, for example, a structure in which concave portions and convex portions are connected in a length ratio of 1: 1 as in the conventional case. This periodic structure can be formed by a known lithography technique and etching technique. Hereinafter, the lengths of the periodic structure are sequentially changed to form the second diffraction grating 17b to the m-th diffraction grating 17m.

【００５５】第１〜第ｍの回折格子１７ａ〜１７ｍそれ
ぞれの幅ｗ１〜ｗｍは、螺旋状に巻かれた光ファイバ
の、２巻き分以上とファイバと対向することが無いよう
な狭い幅としてある。The widths w1 to wm of the first to mth diffraction gratings 17a to 17m, respectively, are such narrow widths that two or more turns of the spirally wound optical fiber do not face the fiber. .

【００５６】次に、光ファイバ１１が螺旋状に巻かれて
いる支持部材１３と、マスク１５との配置のさせ方と、
これらの移動方法と、露光の手順について説明する。図
４はその説明図である。Next, how to dispose the support member 13 in which the optical fiber 11 is spirally wound and the mask 15,
These moving methods and the exposure procedure will be described. FIG. 4 is an explanatory diagram thereof.

【００５７】支持部材１３に螺旋状に巻き付けた光ファ
イバ１１の接線（図１のＭと同じ）にマスク１５の回折
格子１７の長手方向が沿うような位置関係で、マスク１
５と、該支持部材１３とを対向させる（図４の平面図参
照）。しかも、回折格子１７の長手方向の一方の端部分
を、支持部材１３と対向させる。The mask 1 has a positional relationship such that the longitudinal direction of the diffraction grating 17 of the mask 15 is aligned with the tangent line of the optical fiber 11 spirally wound around the support member 13 (the same as M in FIG. 1).
5 and the supporting member 13 are opposed to each other (see the plan view of FIG. 4). Moreover, one end portion of the diffraction grating 17 in the longitudinal direction is opposed to the support member 13.

【００５８】なお、回折格子１７の一方の端部分を支持
部材に対向させる場合、図４の例では、図３中のマスク
１５の右端に示したＰ１およびＰ２が、図４中の露光領
域１９の位置になるようにする方法、または、図３中の
マスク１５を紙面内で１８０度回転させて図３中のマス
ク１５の左端に示したＰ３およびＰ４が図４中の露光領
域１９の位置になる方法のいずれとしても良い。どちら
の方法をとっても、結果的にはチャープトファイバグレ
ーティングが得られる。When one end of the diffraction grating 17 is made to face the support member, in the example of FIG. 4, P1 and P2 shown at the right end of the mask 15 in FIG. 3 are the exposure regions 19 in FIG. 3 or by rotating the mask 15 in FIG. 3 by 180 degrees in the plane of the drawing and P3 and P4 shown at the left end of the mask 15 in FIG. 3 are the positions of the exposure area 19 in FIG. You can use any of the following methods. Either method results in a chirped fiber grating.

【００５９】次に、回折格子１７の長手方向の次々の部
分と、支持部材１３に巻かれている光ファイバ１１の次
々の部分とが、露光光の照射領域１９を通過するよう
に、マスク１５の移動と、支持部材１３の、その軸線ａ
ｂを回転中心とする回転とを行う。しかも、これら移動
および回転は、上述した距離Ｌ分だけ、回折格子１７の
長手方向の次々の部分と、支持部材１３に巻かれている
光ファイバ１１の次々の部分とが、照射領域１９を通過
するように行う。そして、このような移動および回転を
させながら、マスク１５を介して光ファイバ１１を露光
する。Next, the mask 15 is arranged so that the successive portions in the longitudinal direction of the diffraction grating 17 and the successive portions of the optical fiber 11 wound around the supporting member 13 pass through the exposure light irradiation region 19. Movement of the support member 13 and its axis a
Rotation with b as the center of rotation is performed. In addition, these movements and rotations are performed by the distance L described above such that the successive portions in the longitudinal direction of the diffraction grating 17 and the successive portions of the optical fiber 11 wound around the support member 13 pass through the irradiation region 19. Do as you do. Then, the optical fiber 11 is exposed through the mask 15 while being moved and rotated.

【００６０】回折格子１７の長手方向の次々の部分と、
支持部材１３に巻かれている光ファイバ１１の次々の部
分とが照射領域１９を通過するようにするには、図４の
平面図の初期状態からの場合、マスク１５を図中右方向
に平行移動し、かつ、支持部材１３をその軸線ａｂを回
転中心として図の矢印方向に回転（右回転）させれば良
い。ただし、マスク１５を移動させることで回折格子１
７が進む距離と、支持部材１３を回転させることで光フ
ァイバ１１が進む距離とが同じになるように、マスク移
動装置（図示せず）と、支持部材回転装置（図示せず）
とを、同期させる。Successive portions of the diffraction grating 17 in the longitudinal direction,
In order to allow successive portions of the optical fiber 11 wound around the support member 13 to pass through the irradiation region 19, in the initial state of the plan view of FIG. 4, the mask 15 is parallel to the right direction in the figure. It suffices to move the support member 13 and rotate the support member 13 in the direction of the arrow (right rotation) around the axis ab of the support member 13. However, by moving the mask 15, the diffraction grating 1
So that the distance traveled by 7 and the distance traveled by the optical fiber 11 by rotating the support member 13 become the same, and a mask moving device (not shown) and a support member rotating device (not shown).
And are synchronized.

【００６１】なお、露光光の照射領域１９の、支持部材
１３の軸線ａｂに沿う方向の幅Ｗｘは、光ファイバｍ巻
き分の幅以上の幅としておく。The width Wx of the exposure light irradiation area 19 in the direction along the axis ab of the support member 13 is set to be equal to or larger than the width of m turns of the optical fiber.

【００６２】上記の露光をするための光学系は、任意好
適な光学系とできる。この実施の形態では、レーザ光源
２１と、アッテネータ２３と、ミラー２５と、ビームエ
キスパンダ２７と、シリンドリカルレンズ２９とで、構
成してある。The optical system for performing the above exposure can be any suitable optical system. In this embodiment, a laser light source 21, an attenuator 23, a mirror 25, a beam expander 27, and a cylindrical lens 29 are used.

【００６３】レーザ光源２１として、ラムダフィジック
ス社製のＫｒＦエキシマレーザを用いる。レーザ光源２
１から出たレーザ光は、ビームエキスパンダ２７により
ビーム径が広げられる。さらに、シリンドリカルレンズ
２９によって、上述した所望の照射領域１９を示す光に
なる。As the laser light source 21, a KrF excimer laser manufactured by Lambda Physics is used. Laser light source 2
The beam diameter of the laser light emitted from the beam No. 1 is expanded by the beam expander 27. Further, the cylindrical lens 29 turns the light into the desired irradiation region 19 described above.

【００６４】マスク１５の移動と、光ファイバ１１が巻
かれている支持部材１３の回転とを上記のごとく行う
と、螺旋状に巻かれた光ファイバの各巻き部分は、第１
〜第ｍの回折格子１７ａ〜１７ｍのうちの対応する回折
格子を介して、レーザ光によって並列的に露光される。
そのため、第１〜第ｍの回折格子で構成される回折縞
が、光ファイバ１１に一度に照射されるので、光ファイ
バ１１上にΛ１〜Λｍｎまでのチャープグレーティング
が形成される。したがって、長さがＬの回折格子を用い
ているにもかかわらず、長さがｍ×Ｌのチャープトファ
イバグレーティングを製造することができる。図５は、
このように製造されたチャープトファイバグレーティン
グ３０を模式的に示した図である。When the movement of the mask 15 and the rotation of the support member 13 around which the optical fiber 11 is wound are carried out as described above, each winding portion of the spirally wound optical fiber is moved to the first position.
~ The parallel exposure is performed by the laser light through the corresponding diffraction grating of the mth diffraction gratings 17a to 17m.
Therefore, the diffraction fringes formed by the first to mth diffraction gratings are irradiated onto the optical fiber 11 at one time, so that a chirp grating of Λ1 to Λmn is formed on the optical fiber 11. Therefore, it is possible to manufacture a chirped fiber grating having a length of m × L, although a diffraction grating having a length of L is used. Figure 5
It is the figure which showed typically the chirped fiber grating 30 manufactured in this way.

【００６５】なお、支持部材１３の表面には上述したよ
うに無反射コーティングを施してあるので、上記の露光
工程において露光光が支持部材１３で反射される程度を
低減できる。そのため、支持部材１３の表面で反射され
た光によって光ファイバ上に無益な屈折率変化が生じる
のを、防止できる。Since the surface of the support member 13 is coated with a non-reflective coating as described above, it is possible to reduce the degree to which the exposure light is reflected by the support member 13 in the above-mentioned exposure process. Therefore, it is possible to prevent useless change in the refractive index on the optical fiber due to the light reflected on the surface of the support member 13.

【００６６】また、この発明の製造方法では、支持部材
に光ファイバを巻き付けた状態で作業を行えるので、フ
ァイバグレーティングの製造工程から、目的の素子例え
ば波長フィルタを得る工程までのハンドリングが容易と
なるという効果も得られる。また、支持部材と光ファイ
バとを一体とした状態で、パッケージングすることも可
能という効果も得られる。Further, according to the manufacturing method of the present invention, since the work can be performed with the optical fiber wound around the supporting member, the handling from the manufacturing step of the fiber grating to the step of obtaining the target element, for example, the wavelength filter becomes easy. You can also get the effect. Further, there is an effect that it is possible to package the support member and the optical fiber in an integrated state.

【００６７】なお、上述においては、チャープトファイ
バグレーティングを製造する例を説明したが、単周期フ
ァイバグレーティングを製造する場合にも、上述の製造
方法はもちろん適用できる。その場合は、図３を用いて
説明したマスクの第１〜第ｍの回折格子１７ａ〜１７ｍ
それぞれを、単周期グレーティングに変更すれば良い。
具体的には、周期構造Λ１〜Λｍｎを同じ構造にすれば
良い。Although an example of manufacturing a chirped fiber grating has been described above, the manufacturing method described above can be applied to the manufacturing of a single-period fiber grating. In that case, the first to mth diffraction gratings 17a to 17m of the mask described with reference to FIG.
Each may be changed to a single period grating.
Specifically, the periodic structures Λ1 to Λmn may have the same structure.

【００６８】また、単周期ファイバグレーティングを製
造する場合は、回折格子１７を、第１〜第ｍの回折格子
１７ａ〜１７ｍに分けずに、図６に示したように、ｍ巻
き分の幅以上の幅を持った、かつ、一体型の回折格子を
用いる場合があっても良い。こうすると、第１〜第ｍの
回折格子に分ける場合に比べて、マスクの構造を間単に
できると考えられる。In the case of manufacturing a single-period fiber grating, the diffraction grating 17 is not divided into the first to mth diffraction gratings 17a to 17m, and as shown in FIG. There may be a case where an integrated diffraction grating having a width of 1 is used. It is considered that this makes it possible to simplify the structure of the mask, as compared with the case where the mask is divided into the first to mth diffraction gratings.

【００６９】また、上述においては、支持部材に螺旋状
に巻かれた光ファイバの一巻きごとに第１〜第ｍの回折
格子のいずれか１つを対向させる例を説明した。しか
し、図７に示したように、支持部材１３に螺旋状に巻か
れた光ファイバ１１のｓ巻き分に相当する間隔をもって
平行に配置された長さがｓ×Ｌ以上の複数の回折格子１
７１ａ〜１７１ｊを有したマスク１７１を用意する。次
に、巻き付けた光ファイバ１１の接線に該マスク１７１
の回折格子が沿うような位置関係で、該マスク１７１と
支持部材１３とを対向させる。そして、前記ｓ×Ｌの距
離分だけ、該回折格子の次々の部分と前記支持部材に巻
かれている光ファイバの次々の部分とが露光光の照射領
域を通過するように、該マスクの移動と、前記支持部材
の、その軸線を回転中心とする回転とを行なわせなが
ら、露光をしても良い。支持部材１３の回転とマスク１
７１の移動とは、図４を用いて説明したと同様な手順で
行えば良い。Further, in the above description, an example has been described in which any one of the first to m-th diffraction gratings is opposed to each other for each turn of the optical fiber spirally wound on the support member. However, as shown in FIG. 7, a plurality of diffraction gratings 1 having a length of s × L or more arranged in parallel with an interval corresponding to s windings of the optical fiber 11 spirally wound around the supporting member 13.
A mask 171 having 71a to 171j is prepared. Next, the mask 171 is attached to the tangent line of the wound optical fiber 11.
The mask 171 and the support member 13 are opposed to each other in such a positional relationship that the diffraction grating of FIG. Then, the mask is moved by a distance of s × L so that the successive portions of the diffraction grating and the successive portions of the optical fiber wound around the support member pass through the exposure light irradiation region. Then, the exposure may be performed while rotating the support member about the axis of the support member. Rotation of support member 13 and mask 1
The movement of 71 may be performed in the same procedure as described with reference to FIG.

【００７０】こうした場合も、螺旋状に巻かれた光ファ
イバの複数巻き部分に対して並列的な露光ができるの
で、回折格子の長さより長いファイバグレーテイングを
製造できる。In such a case as well, since the multiple turns of the spirally wound optical fiber can be exposed in parallel, a fiber grating longer than the length of the diffraction grating can be manufactured.

【００７１】２．第２の製造方法の説明上述においては、回折格子の長さが螺旋状に巻いた光フ
ァイバ１巻き分の長さと同じか（図３）、それより長い
例（図７）での、製造方法を説明した。しかし、光ファ
イバを損傷することなく曲げることができる曲げ可能半
径が小さい場合は、円柱状の支持部材１３として、直径
の大きなものを用いる必要が生じる。すると、回折格子
の長さが螺旋状に巻いた光ファイバ１巻き分の長さより
短くなる場合もある。そのような場合は、上述の第１の
製造方法では、所望のファイバグレティングを製造でき
ない。この第２の製造方法は、その対策を施したファイ
バグレーティングの製造方法である。2. Description of Second Manufacturing Method In the above description, the manufacturing method is based on whether the length of the diffraction grating is the same as the length of one spirally wound optical fiber (FIG. 3) or longer (FIG. 7). Explained. However, when the bendable radius that allows the optical fiber to be bent without damage is small, it is necessary to use a cylindrical support member 13 having a large diameter. Then, the length of the diffraction grating may be shorter than the length of one spirally wound optical fiber. In such a case, the desired fiber grating cannot be manufactured by the first manufacturing method described above. The second manufacturing method is a manufacturing method of the fiber grating which takes the countermeasure.

【００７２】図８は、第２の製造方法で用いるマスク３
１と、感光性光ファイバ１１等の構造とを説明する図で
ある。また、図９，図１０は、製造工程図である。FIG. 8 shows a mask 3 used in the second manufacturing method.
1 is a diagram illustrating 1 and the structure of a photosensitive optical fiber 11 and the like. FIG. 9 and 10 are manufacturing process diagrams.

【００７３】感光性光ファイバ１１を円筒状の支持部材
１３に螺旋状に巻き付けておく。ただし、光ファイバ１
１の被覆層（図示せず）は剥がして、クラッド層を露出
させておく。また、マスク３１として、単周期グレーテ
ィングを有した長さがＸの回折格子３３を有したマスク
３１を用意する。The photosensitive optical fiber 11 is spirally wound around the cylindrical support member 13. However, optical fiber 1
The coating layer 1 (not shown) is peeled off to expose the clad layer. Further, as the mask 31, a mask 31 having a diffraction grating 33 having a length of X and having a single period grating is prepared.

【００７４】次に、図９（Ａ）に示したように、支持部
材１３に螺旋状に巻き付けた前記光ファイバの接線に、
前記回折格子３３の長手方向が沿うような位置関係で、
前記マスク３１を前記光ファイバ１１と対向させる。然
も、回折格子３３の一端が露光光の照射領域（ビーム３
５）の位置に一致するようにマスク３１を光ファイバ１
１と対向させる。Next, as shown in FIG. 9A, the tangent to the optical fiber spirally wound around the support member 13 is
With a positional relationship such that the longitudinal direction of the diffraction grating 33 is along,
The mask 31 faces the optical fiber 11. Of course, one end of the diffraction grating 33 has an exposure light irradiation region (beam 3).
5) The mask 31 is attached to the optical fiber 1 so as to match the position of
Face 1

【００７５】ただし、露光光を照射する領域（照射領
域）の前記軸線に沿った幅が、螺旋に巻いた光ファイバ
２巻き分の幅未満となるようにする。すなわち、露光光
のビーム３５の径を、例えば光ファイバ１１の直径より
やや大きい程度にしておく。このようなビームを得るに
は、例えば、図４を用いて説明した光学系から、ビーム
エキスパンダ２７を除去した光学系を用いれば良い。However, the width of the area (irradiation area) irradiated with the exposure light along the axis is less than the width of two spirally wound optical fibers. That is, the diameter of the beam 35 of the exposure light is set to be slightly larger than the diameter of the optical fiber 11, for example. To obtain such a beam, for example, an optical system in which the beam expander 27 is removed from the optical system described with reference to FIG. 4 may be used.

【００７６】次に、回折格子３３の長さＸ分だけ、回折
格子３３の次々の部分と、支持部材１３に巻かれている
光ファイバ１１の次々の部分とが、照射領域（ビーム３
５が当たる領域）を通過するように、マスク３１の移動
と、支持部材１３の軸線ａｂを回転中心とする回転とを
行う。これら移動および回転は、この例の場合は、マス
ク３１については図９（Ａ）の右から左へ移動し、支持
部材１３については、軸線ａｂを回転中心として図９
（Ａ）に矢印を付した方向に回転（右回転）させる。Next, by the length X of the diffraction grating 33, the successive portions of the diffraction grating 33 and the successive portions of the optical fiber 11 wound around the support member 13 are irradiated to the irradiation region (beam 3).
The mask 31 is moved and rotated about the axis ab of the supporting member 13 as a center of rotation so that the mask 31 passes through the area 5). In the case of this example, these movements and rotations move from right to left in FIG. 9A for the mask 31, and for the support member 13 with the axis ab as the center of rotation.
Rotate (clockwise) in the direction indicated by the arrow in (A).

【００７７】マスク３１の移動および支持部材１３の回
転を上記のように行った後、露光終点位置Ｐ（図９
（Ｂ）参照）を通り前記軸線ａｂに垂直に交わる線分を
回転中心として、支持部材１３をマスク３１に対して相
対的に１８０度回転させる（図１０（Ａ））。After the mask 31 is moved and the support member 13 is rotated as described above, the exposure end position P (see FIG. 9).
The support member 13 is rotated 180 degrees relative to the mask 31 with a line segment passing through (see (B)) and perpendicularly intersecting the axis ab as a rotation center (FIG. 10A).

【００７８】次に、回折格子３３の長さＸ分だけ、回折
格子３３の次々の部分と、支持部材１３に巻かれている
光ファイバ１１の次々の新たな部分とが次々に対向する
ように、マスク３１の移動および支持部材１３の軸線ａ
ｂを回転中心とする回転を行う（図１０（Ｂ））。これ
ら移動および回転は、この例の場合は、マスク３１につ
いては図１０（Ｂ）の左から右へ移動し、支持部材１３
については、軸線ｂａを回転中心として図中の矢印の方
向に回転（左回転）させる。Next, each part of the diffraction grating 33 and each new part of the optical fiber 11 wound around the support member 13 are opposed to each other by the length X of the diffraction grating 33. , The movement of the mask 31 and the axis a of the support member 13
Rotation is performed with b as the center of rotation (FIG. 10 (B)). In the case of this example, these movements and rotations move the mask 31 from left to right in FIG.
With respect to, about the axis ba as the center of rotation, the axis is rotated (counterclockwise) in the direction of the arrow in the figure.

【００７９】このような操作を必要数繰り返すと、長さ
がＸの回折格子１つを用いて光ファイバの次々の部分を
露光できる。そのため、この回折格子より長い長さの単
周期ファイバグレーティングを製造できる。When the above operation is repeated a required number of times, one portion of the optical fiber can be exposed by using one diffraction grating of length X. Therefore, a single-period fiber grating having a length longer than that of this diffraction grating can be manufactured.

【００８０】３．第３の製造方法の説明次に、第３の製造方法の実施の形態について説明する。
この第３の製造方法はチャープトファイバグレーティン
グの製造に特に好適な方法である。図１１〜図１３はそ
の説明図である。図１１は主にマスク４１と回折格子４
３とを説明する平面図、図１２および図１３はファイバ
グレーティングの製造工程図である。3. Description of Third Manufacturing Method Next, an embodiment of the third manufacturing method will be described.
This third manufacturing method is a particularly suitable method for manufacturing a chirped fiber grating. 11 to 13 are explanatory diagrams thereof. FIG. 11 mainly shows the mask 41 and the diffraction grating 4.
3A and 3B are plan views, and FIGS. 12 and 13 are manufacturing process diagrams of the fiber grating.

【００８１】支持部材１３に光ファイバ１１を、今まで
の実施の形態と同様に螺旋状に巻き付けておく。The optical fiber 11 is spirally wound around the support member 13 as in the previous embodiments.

【００８２】また、マスク４１として、図１１に示した
様に、互いに平行に配置した第１〜第ｍの回折格子４３
ａ〜４３ｍを有したマスクを用意する。第１〜第ｍの回
折格子４３ａ〜４３ｍそれぞれは、長さがＸで、かつ、
幅が螺旋状に巻かれた光ファイバの２巻き分の幅未満と
してある。然も、これら回折格子４３ａ〜４３ｍ全体と
して連続するチャープグレーティングとなるようにそれ
ぞれが個別のチャープグレーティングを有している。As the mask 41, as shown in FIG. 11, the first to mth diffraction gratings 43 arranged in parallel with each other.
A mask having a to 43 m is prepared. Each of the first to mth diffraction gratings 43a to 43m has a length of X, and
The width is less than the width of two turns of the spirally wound optical fiber. Of course, each of the diffraction gratings 43a to 43m has an individual chirp grating so as to be a continuous chirp grating.

【００８３】第１〜第ｍの回折格子４３ａ〜４３ｍは、
基本的には、第１の製造方法の実施の形態で説明した回
折格子１７ａ〜１７ｍと同様で良い。ただし、周期構造
の並び具合を、第１の発明の場合に比べて違えてある。The first to mth diffraction gratings 43a to 43m are
Basically, it may be the same as the diffraction gratings 17a to 17m described in the embodiment of the first manufacturing method. However, the arrangement of the periodic structures is different from that of the first invention.

【００８４】具体的には、第１の回折格子４３ａは、例
えば、４３ａ１〜４３ａｎのｎ個の部分で構成される。
ただし、ｎは任意の整数である。そして、第１の部分４
３ａ１は、長さがΛ１の周期構造をＳ１回繰り返した構
造とされている。第２の部分４３ａ２は、長さがΛ２
（Λ１＜Λ２）の周期構造をＳ２回繰り返した構造とさ
れている。第ｎの部分４３ａｎは、長さがΛｎ（Λｎ−
１＜Λｎ）の周期構造をＳｎ回繰り返した構造とされて
いる。Ｓ１〜Ｓｎは、同じでも異なっても良い。Specifically, the first diffraction grating 43a is composed of, for example, n portions 43a1 to 43an.
However, n is an arbitrary integer. And the first part 4
3a1 has a structure in which a periodic structure having a length of Λ1 is repeated S1 times. The second portion 43a2 has a length Λ2.
It is said that the periodic structure of (Λ1 <Λ2) is repeated S2 times. The n-th portion 43an has a length Λn (Λn−
It is assumed that the periodic structure of 1 <Λn) is repeated Sn times. S1 to Sn may be the same or different.

【００８５】また、第２の回折格子４３ｂは、例えば、
４３ｂ１〜４３ｂｎのｎ個の部分で構成される。ただ
し、ｎは任意の整数である。そして、第ｎの部分４３ｂ
ｎは、長さがΛｎ＋１の周期構造をＳｎ＋１回繰り返し
た構造とされている。第ｎ−１の部分４３ｂｎ−１は、
長さがΛｎ＋２の周期構造をＳｎ＋２回繰り返した構造
とされている。第１の部分４３ｂ１は、長さがΛ２ｎの
周期構造を繰り返した構造としてある。すなわち、第１
の回折格子を左端から右端にたどり、次に、第２の回折
格子４３ｂを右端から左端にたどるというように、ジグ
ザグに各回折格子４３ａ〜を４３ｍをたどると、チャー
プグレーティングの配列になるように、周期構造を配置
してある。The second diffraction grating 43b is, for example,
It is composed of n parts of 43b1 to 43bn. However, n is an arbitrary integer. And the n-th portion 43b
n has a structure in which a periodic structure having a length of Λn + 1 is repeated Sn + 1 times. The n−1 th portion 43bn−1 is
It is a structure in which a periodic structure having a length of Λn + 2 is repeated Sn + 2 times. The first portion 43b1 has a structure in which a periodic structure having a length of Λ2n is repeated. That is, the first
Tracing each diffraction grating 43a to 43m in a zigzag manner so as to form a chirp grating array. , The periodic structure is arranged.

【００８６】次に、図１２（Ａ）に示したように、支持
部材１３に螺旋状に巻き付けた前記光ファイバの接線
に、前記回折格４３ａの長手方向が沿うような位置関係
で、前記マスク４１を前記光ファイバ１１と対向させ
る。然も、回折格子４３ａの一端が露光光のビーム３５
の位置に一致するようにマスク４１を光ファイバ１１と
対向させる。Next, as shown in FIG. 12 (A), the mask is placed in such a positional relationship that the longitudinal direction of the diffraction grating 43a is along the tangent of the optical fiber spirally wound around the support member 13. 41 is opposed to the optical fiber 11. Of course, one end of the diffraction grating 43a has a beam 35 of exposure light.
The mask 41 is opposed to the optical fiber 11 so as to match the position of.

【００８７】次に、回折格子４３の長さＸ分だけ、回折
格子４３の次々の部分と、支持部材１３に巻かれている
光ファイバ１１の次々の部分とが、ビーム３５の位置を
通過するように、マスク４１の移動と、支持部材１３の
軸線ａｂを回転中心とする回転とを行う。これら移動お
よび回転は、この例の場合は、マスク４１については図
１２（Ａ）の右から左へ移動し、支持部材１３について
は、軸線ａｂを回転中心として図中矢印で示す方向に回
転（右回転）させる。Next, the portions of the diffraction grating 43 and the portions of the optical fiber 11 wound around the support member 13 pass the position of the beam 35 by the length X of the diffraction grating 43. In this way, the mask 41 is moved and the support member 13 is rotated about the axis ab. In the case of this example, these movements and rotations are such that the mask 41 moves from right to left in FIG. 12A, and the support member 13 rotates about the axis ab in the direction indicated by the arrow in the drawing ( Rotate right).

【００８８】マスク４１の移動および支持部材１３の回
転を上記のように行った後、露光終点位置Ｐ（図１２
（Ｂ）参照）を通り前記軸線ａｂに垂直に交わる線分を
回転中心として、支持部材１３をマスク４１に対して相
対的に１８０度回転させる（図１２（Ｃ）、図１３
（Ａ））。After the movement of the mask 41 and the rotation of the support member 13 are performed as described above, the exposure end point position P (see FIG. 12).
The support member 13 is rotated 180 degrees relative to the mask 41 with a line segment passing through (see (B)) and perpendicularly intersecting the axis ab as a rotation center (FIGS. 12C and 13C).
(A)).

【００８９】次に、今まで露光に用いた回折格子４３ａ
の隣に位置する回折格子、すなわちこの場合は第２の回
折格子４３ｂが、光ファイバ１１の前記露光終了位置Ｐ
と対向するように、マスク４１および支持部材１３を相
対的に、ｙ方向（図１３（Ｂ）に移動させる。Next, the diffraction grating 43a used for the exposure so far.
Of the diffraction grating positioned next to, that is, the second diffraction grating 43b in this case is the exposure end position P of the optical fiber 11.
The mask 41 and the support member 13 are relatively moved in the y direction (FIG. 13 (B)) so that they face each other.

【００９０】次に、回折格子４３ｂの長さＸ分だけ、回
折格子４３ｂの次々の部分と、支持部材１３に巻かれて
いる光ファイバ１１の次々の部分とが、ビーム３５の位
置を通過するように、マスク４１の移動および支持部材
１３の軸線ｂａを回転中心とする回転を行う。これら移
動および回転は、この例の場合は、マスク４１について
は図１３（Ｂ）の左から右へ移動し、支持部材１３につ
いては、軸線ｂａを回転中心として図１３（Ｂ）の矢印
の方向に回転させる。Next, the portions of the diffraction grating 43b and the portions of the optical fiber 11 wound around the supporting member 13 pass the position of the beam 35 by the length X of the diffraction grating 43b. As described above, the mask 41 is moved and the support member 13 is rotated about the axis ba of the support member 13. In the case of this example, these movements and rotations move from left to right in FIG. 13B for the mask 41, and for the support member 13, with the axis ba as the center of rotation, the direction of the arrow in FIG. 13B. Rotate to.

【００９１】このような操作を必要数繰り返すと、第１
〜第ｍの回折格子４３ａ〜４３ｍを次々用いて光ファイ
バの次々の新たな部分を露光できる。このため、長さが
Ｘの回折格子を用いてこの回折格子より長い長さのチャ
ープトファイバグレーティングを製造できる。When the above operation is repeated a required number of times, the first
~ Each new portion of the optical fiber can be exposed using the mth diffraction gratings 43a to 43m one after another. Therefore, a diffraction grating having a length of X can be used to manufacture a chirped fiber grating having a length longer than the diffraction grating.

【００９２】なお、この第３の製造方法は、単周期ファ
イバグレーティングを製造する場合にも適用できる。そ
の場合は、第１〜第ｍの回折格子４３ａ〜４３ｍそれぞ
れを、単周期グレーティングに変更する。すなわち、周
期構造Λ１〜Λｍｎを同じ構造にする。The third manufacturing method can also be applied to manufacturing a single-period fiber grating. In that case, each of the first to mth diffraction gratings 43a to 43m is changed to a single period grating. That is, the periodic structures Λ1 to Λmn have the same structure.

【００９３】[0093]

【発明の効果】この発明のファイバグレーティングの製
造方法によれば、円筒状の支持部材に感光性光ファイバ
を螺旋状に巻き付けておく。そして、該巻き付けた光フ
ァイバの接線に露光用マスクの回折格子が沿うような位
置関係で、マスクと支持部材とを対向させる。そして、
回折格子の次々の部分と支持部材に巻かれている光ファ
イバの次々の部分とが露光光の照射領域を通過するよう
に、前記マスクの移動と、前記支持部材の、その軸線を
回転中心とする回転とを行いながら、光ファイバをマス
クを介して露光する。According to the fiber grating manufacturing method of the present invention, the photosensitive optical fiber is spirally wound around the cylindrical supporting member. Then, the mask and the supporting member are opposed to each other in such a positional relationship that the diffraction grating of the exposure mask is along the tangent line of the wound optical fiber. And
The movement of the mask and the axis of the support member as the center of rotation so that the successive portions of the diffraction grating and the successive portions of the optical fiber wound around the support member pass through the exposure light irradiation region. The optical fiber is exposed through the mask while being rotated.

【００９４】そのため、光ファイバｍ巻き分の幅以上の
幅を持ち長さがＬの回折格子を有したマスクを用いて光
ファイバｍ巻き分を並列に露光することができる。こう
した場合、長さがＬの回折格子で長さがｍ×Ｌのファイ
バグレーティングを製造できる。Therefore, it is possible to expose m windings of optical fiber in parallel by using a mask having a diffraction grating having a length L and a width equal to or larger than the width of m windings of optical fiber. In such a case, a fiber grating having a length of m × L can be manufactured with a diffraction grating having a length of L.

【００９５】また、光ファイバのｓ巻き分に相当する間
隔をもって長さがｓ×Ｌの回折格子を平行に配置したマ
スクを用いて光ファイバを並列的に露光することができ
る。こうした場合、長さがｓ×Ｌの回折格子で長さがそ
の複数倍のファイバグレーティングを製造できる。Further, the optical fibers can be exposed in parallel by using a mask in which diffraction gratings having a length of s × L are arranged in parallel with an interval corresponding to s turns of the optical fiber. In such a case, it is possible to manufacture a fiber grating having a length of s × L and a length thereof being a multiple thereof.

【００９６】また、支持部材に螺旋状に巻かれた光ファ
イバに対し長さがＸの回折格子を用いて長さＸ分だけ露
光をし、その後、支持部材と回折格子との相対的な位置
を１８０度変更して、再び長さＸ分の露光をする方法
（第２、第３の製造方法）もとれる。こうした場合も、
長さがＸの回折格子で長さがＸより長いファイバグレー
ティングを製造できる。Further, the optical fiber spirally wound on the supporting member is exposed by the length X by using the diffraction grating having the length X, and thereafter, the relative position between the supporting member and the diffraction grating is exposed. Is changed by 180 degrees, and exposure for the length X is performed again (second and third manufacturing methods). In such cases,
A fiber grating having a length longer than X can be manufactured with a diffraction grating having a length X.

【００９７】したがって、この出願の各製造方法によれ
ば、回折格子の長さより長いファイバグレーティングを
容易に製造できる。Therefore, according to each manufacturing method of this application, a fiber grating longer than the length of the diffraction grating can be easily manufactured.

【００９８】また、この出願のファイバーグレーティン
グの各製造方法によれば、支持部材と、該支持部材に螺
旋状に巻き付けられたファイバーグレーティングとを具
えた光フィルタを容易に製造できるという効果もさらに
得られる。Further, according to the respective manufacturing methods of the fiber grating of this application, it is possible to obtain the effect that the optical filter including the supporting member and the fiber grating spirally wound around the supporting member can be easily manufactured. To be

【００９９】この光フィルタの製造方法によれば、長い
ファイバグレーティングをコンパクトに収納できる光フ
ィルタの製造が実現できる。そのため、この光フィルタ
の製造方法では、反射波長帯域や反射スペクトルのトッ
プの平坦性などの特性を実現するために長いファイバグ
レーティングを有する光フィルタの小型化が図りやす
い。According to this optical filter manufacturing method, it is possible to manufacture an optical filter which can accommodate a long fiber grating in a compact manner. Therefore, in this method of manufacturing an optical filter, it is easy to downsize an optical filter having a long fiber grating in order to realize characteristics such as the reflection wavelength band and the flatness of the top of the reflection spectrum.

[Brief description of drawings]

【図１】感光性光ファイバと支持部材との説明図であ
る。FIG. 1 is an explanatory diagram of a photosensitive optical fiber and a supporting member.

【図２】支持部材に設けた螺旋状の溝の説明図である。FIG. 2 is an explanatory diagram of a spiral groove provided in a support member.

【図３】第１の製造方法の実施の形態で用いたマスクお
よび回折格子の説明図である。FIG. 3 is an explanatory diagram of a mask and a diffraction grating used in the embodiment of the first manufacturing method.

【図４】マスクと支持部材との位置関係の説明図であ
る。FIG. 4 is an explanatory diagram of a positional relationship between a mask and a support member.

【図５】この発明の製造方法で製造されるファイバグレ
ーティングの説明図である。FIG. 5 is an explanatory diagram of a fiber grating manufactured by the manufacturing method of the present invention.

【図６】第１の製造方法の第１の変形例の説明図であ
る。FIG. 6 is an explanatory diagram of a first modified example of the first manufacturing method.

【図７】第１の製造方法の第２の変形例の説明図であ
る。FIG. 7 is an explanatory diagram of a second modified example of the first manufacturing method.

【図８】第２の製造方法で用いるマスク等の説明図であ
る。FIG. 8 is an explanatory diagram of a mask and the like used in the second manufacturing method.

【図９】第２の製造方法の実施の形態の工程図である。FIG. 9 is a process drawing of the embodiment of the second manufacturing method.

【図１０】第２の製造方法の実施の形態の図９に続く工
程図である。FIG. 10 is a process diagram following the FIG. 9 of the second embodiment of the manufacturing method.

【図１１】第３の製造方法で用いるマスクと回折格子と
を説明する図である。FIG. 11 is a diagram illustrating a mask and a diffraction grating used in a third manufacturing method.

【図１２】第３の製造方法の実施の形態の工程図であ
る。FIG. 12 is a process drawing of the embodiment of the third manufacturing method.

【図１３】第３の製造方法の実施の形態の図１２に続く
工程図である。FIG. 13 is a process drawing that follows FIG. 12 of the embodiment of the third manufacturing method.

[Explanation of symbols]

１１：感光性光ファイバ１３：円柱状の支持部材１３ａ：螺旋状の溝１５：マスク１７：回折格子１７ａ〜１７ｍ：第１〜第ｍの回折格子１９：露光光の照射領域３１：マスク３３：長さＸの回折格子３５：露光光の照射領域（ビーム）Ｐ：露光終了位置４１：マスク４３ａ〜４３ｍ：第１〜第ｍの回折格子１７１：マスク１７１ａ〜１７１ｊ：回折格子 11: Photosensitive optical fiber 13: Cylindrical support member 13a: spiral groove 15: Mask 17: Diffraction grating 17a to 17m: 1st to mth diffraction gratings 19: Exposure light irradiation area 31: Mask 33: Diffraction grating of length X 35: Irradiation area (beam) of exposure light P: exposure end position 41: Mask 43a to 43m: 1st to mth diffraction gratings 171: Mask 171a to 171j: Diffraction grating

Claims

(57) [Claims]

1. A method for manufacturing a fiber grating, which comprises exposing a photosensitive optical fiber through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, wherein the photosensitive optical fiber is cylindrical. Spirally wound around the supporting member of the mask, and the mask and the supporting member are opposed to each other in such a positional relationship that the diffraction grating of the mask is along the tangent line of the wound optical fiber, and the successive portions of the diffraction grating are The mask is moved and the support member is rotated about its axis so that the optical fiber and the subsequent portions of the optical fiber wound around the support member pass through the exposure light irradiation region. The method of manufacturing a fiber grating, wherein the exposure is performed while

2. The method of manufacturing a fiber grating according to claim 1, wherein the mask has a width equal to or larger than a width of m turns of the spirally wound optical fiber, and the support member is centered on an axis thereof. A mask having a diffraction grating having a length equal to or longer than the distance L of the optical fiber which advances when it is rotated once is prepared, and the diffraction grating of the mask is placed along the tangent line of the wound optical fiber. The mask and the support member are opposed to each other so that the distance L and the subsequent portions of the diffraction grating and the optical fiber wound around the support member pass through the exposure light irradiation region. The method of manufacturing a fiber grating, wherein the exposure is performed while the mask is moved and the support member is rotated about the axis thereof (where m is 2 or more). Is an integer of.).

3. The method of manufacturing a fiber grating according to claim 2, wherein the diffraction grating is a first to an m-th diffraction grating parallel to each other prepared for an optical fiber for each of the m turns. A method of manufacturing a fiber grating, wherein each of the diffraction gratings is composed of first to mth diffraction gratings having individual chirp gratings so as to form a continuous chirped grating.

4. The method for manufacturing a fiber grating according to claim 2, wherein the diffraction grating is a first to an m-th diffraction grating parallel to each other prepared for an optical fiber for each of the m turns. A method of manufacturing a fiber grating, characterized in that each of the diffraction gratings comprises a first to mth diffraction grating having a single period grating.

5. The method for manufacturing a fiber grating according to claim 2, wherein the diffraction grating has a single-period grating, has a width equal to or larger than the width of the m turns, and is of an integral type. A method of manufacturing a fiber grating, which comprises a diffraction grating.

6. The method of manufacturing a fiber grating according to claim 1, wherein the mask has a length of s × arranged in parallel with an interval corresponding to s windings of the spirally wound optical fiber. A mask having a plurality of L or more diffraction gratings is prepared, the mask and the supporting member are opposed to each other in a positional relationship such that the diffraction grating of the mask is along a tangent line of the wound optical fiber, and the s × The mask is moved and the supporting member is moved so that the successive portions of the diffraction grating and the successive portions of the optical fiber wound around the supporting member pass through the irradiation region of the exposure light by the distance of L. And performing the rotation while rotating about the axis thereof as a rotation center (where L is the rotation of the support member once about the axis thereof). Distance of the optical fiber traveling at a, s is an integer of 2 or more.).

7. The method of manufacturing a fiber grating according to claim 6, wherein each of the plurality of diffraction gratings is a diffraction grating having a single period grating.

8. The method of manufacturing a fiber grating according to claim 6, wherein each of the plurality of diffraction gratings has an individual chirped grating so that the entire diffraction grating is a continuous chirped grating. And a method for manufacturing a fiber grating.

9. A method of manufacturing a fiber grating, which comprises exposing a photosensitive optical fiber through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, wherein the photosensitive optical fiber is cylindrical. Is wound around the supporting member in a spiral shape, and a mask having a diffraction grating having a length of X and having a single period grating is prepared as the mask, and the diffraction grating is aligned with the tangent line of the wound optical fiber. The mask is made to face the optical fiber in a different positional relationship, and thereafter, the following first and second processes are repeated a necessary number of times, and a method for manufacturing a fiber grating. (A) The mask so that the portions of the diffraction grating and the portions of the optical fiber wound around the support member pass through the irradiation region of the exposure light by the length of the diffraction grating. And the rotation of the support member about its axis is performed, the width of the irradiation region along the axis is less than the width of two spirally wound optical fibers. The first process in which the exposure is performed in a state where the exposure light is focused so that (B) After finishing the first process, the support member is rotated 180 degrees relative to the mask with a line segment passing through the exposure end point position and intersecting perpendicularly to the axis line as a rotation center. Processing.

10. A method for manufacturing a fiber grating, which comprises exposing a photosensitive optical fiber through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, wherein the photosensitive optical fiber has a cylindrical shape. The first to mth diffraction gratings, which are spirally wound around the supporting member, are arranged in parallel with each other as the mask and have a mutual length of X, and the chirp grating is continuous as a whole of these diffraction gratings. A mask having first to m-th diffraction gratings each having an individual chirped grating is prepared so that any one of the first to m-th diffraction gratings is provided on a tangent line of the wound optical fiber. The mask is opposed to the optical fiber in such a positional relationship as to be aligned with each other.
~ A method of manufacturing a fiber grating, which is characterized by repeating the required number of times of the third treatment (however, the order of the second treatment and the third treatment may be first). The mask is moved so that successive portions of the diffraction grating and successive portions of the optical fiber wound around the support member pass through the exposure light irradiation region by the length of the diffraction grating. While rotating the support member about its axis, the width of the irradiation region along the axis is less than the width of two spirally wound optical fibers. The first process of performing the exposure in a state where the exposure light is narrowed. After finishing the first process, a second process in which the support member is rotated by 180 degrees relative to the mask with a line segment passing through the exposure end point position and intersecting perpendicularly to the axis line as a rotation center. After finishing the first process, the mask and the supporting member are moved relatively so that the diffraction grating located next to the diffraction grating used for exposure so far faces the exposure end position. Processing.

11. A cylindrical support member having a spiral groove for spirally winding a photosensitive optical fiber, the surface of which is substantially non-reflective with respect to exposure light for exposing the optical fiber. A support member characterized by being coated.

12. The support member according to claim 11, wherein the depth of the groove is larger than the diameter of the optical fiber.

13. A mask for exposing a photosensitive optical fiber through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, wherein the diffraction grating is the optical fiber. A width of at least m windings of the wound optical fiber in the case of spirally winding a cylindrical support member, and the distance of the optical fiber traveling when the support member is rotated once about its axis. A mask characterized by being a diffraction grating having a length of L or more.

14. The mask according to claim 13, wherein the diffraction gratings are parallel first to mth diffraction gratings prepared for an optical fiber for each of the m turns. A mask comprising first to mth diffraction gratings each having an individual chirped grating so that the entire diffraction grating is a continuous chirped grating.

15. The mask according to claim 13, wherein the diffraction gratings are parallel first to mth diffraction gratings prepared for an optical fiber for each of the m turns, Is a first to mth diffraction grating having a single-period grating, and is a mask.

16. The mask according to claim 13, wherein the diffraction grating has a single period grating and has a width W or more for the m turns and is an integral diffraction grating. A mask characterized by becoming.

17. A mask for exposing a photosensitive optical fiber through a mask having a diffraction grating to form a refractive index modulation section in the optical fiber, wherein the diffraction grating is the optical fiber. A mask comprising a plurality of diffraction gratings having a length of s × L or more arranged in parallel with an interval of s windings when the is wound spirally on a cylindrical support member.

18. The mask according to claim 17, wherein each of the plurality of diffraction gratings is a diffraction grating having a single period grating.

19. The mask according to claim 17, wherein each of the plurality of diffraction gratings is a diffraction grating having an individual chirped grating so that the entire diffraction grating is a continuous chirped grating. Characteristic mask.

20. A method of manufacturing a fiber grating according to claim 1, wherein an optical filter comprising a support member and a fiber grating spirally wound around the support member is manufactured. Is carried out to manufacture the fiber grating.

21. The method of manufacturing an optical filter according to claim 20, wherein the photosensitive optical fiber is wound along a spiral groove of the supporting member.

22. The method of manufacturing an optical filter according to claim 21, wherein the depth of the groove is larger than the diameter of the optical fiber.