JPS63132205A - Optical fiber device - Google Patents
Optical fiber deviceInfo
- Publication number
- JPS63132205A JPS63132205A JP62125441A JP12544187A JPS63132205A JP S63132205 A JPS63132205 A JP S63132205A JP 62125441 A JP62125441 A JP 62125441A JP 12544187 A JP12544187 A JP 12544187A JP S63132205 A JPS63132205 A JP S63132205A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- grating
- optical
- photosensitive material
- refractive index
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 49
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 19
- 238000005530 etching Methods 0.000 claims abstract description 7
- 230000003287 optical effect Effects 0.000 claims description 36
- 238000005253 cladding Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- 239000011347 resin Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000000835 fiber Substances 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 30
- 230000000737 periodic effect Effects 0.000 abstract description 10
- 230000008859 change Effects 0.000 abstract description 6
- 239000004065 semiconductor Substances 0.000 abstract description 6
- 230000002250 progressing effect Effects 0.000 abstract 1
- 230000008878 coupling Effects 0.000 description 7
- 238000010168 coupling process Methods 0.000 description 7
- 238000005859 coupling reaction Methods 0.000 description 7
- 239000010409 thin film Substances 0.000 description 7
- 230000035945 sensitivity Effects 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052798 chalcogen Inorganic materials 0.000 description 1
- 150000001787 chalcogens Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
- G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
- G02B6/02123—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating
- G02B6/02133—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating using beam interference
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Abstract
Description
【発明の詳細な説明】
蓋生左互
本発明は、光ファイバを伝搬路とする光信号の周波数選
択を行なう光フイルタ特性をもたせた光ファイバ・デバ
イスに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber device having optical filter characteristics for frequency selection of an optical signal using an optical fiber as a propagation path.
灸来１帆
一般に、光ファイバに多数の異なる波長をもった光信号
をのせるいわゆる周波数多重方式によって光通信システ
ムを構成する際、特定または任意に選択された周波数の
光信号を送受させるために光フィルタは不可欠なものと
なっている。Generally speaking, when an optical communication system is constructed using the so-called frequency multiplexing method, in which optical signals with many different wavelengths are placed on an optical fiber, it is necessary to send and receive optical signals of a specific or arbitrarily selected frequency. Optical filters have become essential.
従来、この種の光フィルタとしては、第１図に示すよう
に、入力側の光ファイバ１によって送られてきた光信号
を屈折率の周期的変化をもってグレイティング２が形成
された薄膜光導波路３に導入させ、その部分で特定波長
の光波を反射させ。Conventionally, as shown in FIG. 1, this type of optical filter uses a thin film optical waveguide 3 in which a grating 2 is formed to periodically change the refractive index of an optical signal sent through an optical fiber 1 on the input side. and reflect light waves of a specific wavelength at that part.
必要波長の光信号を出力側の光ファイバ４に導波させる
ようにしたものが用いられている。しかし、このような
周期的なグレイティング２が形成された薄膜光導波路３
による光フィルタを実際の光フアイバ通信網に適用しよ
うとする場合、入力および出力側の各光ファイバ１，４
とその薄膜光導波路３とを効率よく直接結合させる方法
が未だ確立されていないためにその結合部分での結合効
率が問題となり、そのため専用の光結合器を必要として
装置全体としては精巧かつ複雑なものにならざるを得な
い、また、薄膜光導波路３の膜厚は数μｍ程度にしかす
ぎず、光結合のための位置合せや光ファイバの端面の平
坦度に対する要求が極めて厳しく、実用化に際して種々
の問題が残されている。An optical fiber having a required wavelength is guided to an optical fiber 4 on the output side. However, the thin film optical waveguide 3 in which such a periodic grating 2 is formed
When trying to apply an optical filter according to the above to an actual optical fiber communication network, each optical fiber 1 and
Since a method for directly and efficiently coupling the thin film optical waveguide 3 with the thin film optical waveguide 3 has not yet been established, the coupling efficiency at the coupling part becomes a problem, and therefore a dedicated optical coupler is required, making the entire device sophisticated and complicated. In addition, the film thickness of the thin-film optical waveguide 3 is only about a few μm, and the requirements for alignment for optical coupling and flatness of the end face of the optical fiber are extremely strict, making it difficult to put it into practical use. Various problems remain.
月］ｒ
本発明は以上の点を考慮してなされたもので、前述の薄
膜光導波路の有する問題を解消させるためには周期的グ
レイティングを光フアイバ部分に直接形成させればよい
ことに着目し、光フィルタの機能を光ファイバそのもの
にもたせるようにした新規な光ファイバ・デバイスを提
供するものである。The present invention has been made in consideration of the above points, and focuses on the fact that in order to solve the problems of the thin film optical waveguide described above, it is sufficient to form periodic gratings directly on the optical fiber portion. The present invention provides a novel optical fiber device in which the optical fiber itself has the function of an optical filter.
１氏
光波長オーダの周期的グレイティングを微小径の光フア
イバ自体に機械的手段をもって形成させることは困難で
あるため、本発明による光ファイバ・デバイスでは感光
性物質を用いて光学的干渉法によって光フアイバ部分に
周期的グレイティング像を露光形成させ、その感光物質
中における周期的な屈折率変化を利用して光フアイバ自
体に光フイルタ特性をもたせるようにしたものである。Since it is difficult to form a periodic grating on the order of 1 degree optical wavelength in a micro-diameter optical fiber itself by mechanical means, the optical fiber device according to the present invention uses a photosensitive material to form a periodic grating by optical interference method. A periodic grating image is formed on the optical fiber by exposure, and periodic changes in the refractive index in the photosensitive material are utilized to impart optical filter characteristics to the optical fiber itself.
その際、特に本発明による光ファイバ・デバイスでは、
感光性物質としてのホトレジストを、それに露光形成さ
れたグレイティング像のパターンに応じてエツチング処
理することにより、グレイティングの構造化を図るよう
にしている。In particular, in the optical fiber device according to the invention,
The grating is structured by etching the photoresist as a photosensitive material in accordance with the pattern of the grating image formed by exposure.
以下、添付図面を参照して本発明の一実施例について詳
述する。Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.
まず、本発明による光ファイバ・デバイスの基本的な構
成について説明する。First, the basic configuration of the optical fiber device according to the present invention will be explained.
本発明による光ファイバ・デバイスにあっては、まず第
２図に示すように、光ファイバ５のクラッド６部分を適
当な長さだけ取り除いてコア７部分を露出させたものを
用意する。光ファイバ５としては、普通、その外形が２
００〜３５０μｍ、コア径が１０〜１５０μｍ程度のも
のが使用される。次に、第３図（ａ）、（ｂ）に示すよ
うに、クラッド６の除去された部分に、露光によって屈
折率が変化する、例えばホトレジスト、ホトポリマー、
アモルファス半導体などの感光性物質８を充填する。な
お、この感光性物質８は、その屈折率がコア７の屈折率
よりわずかに小さいものを用いるのが望ましい。さらに
、第４図に示すように、Ａｒレーザなどを用いて感光性
物質８に感度を示す平行ビームＢｌ、Ｂ２により、互い
のビームのなす角が２０゜になるようにその感光性物質
８に入射させ、２つのビームＢｌ、Ｂ２の干渉波をそれ
に露光形成させる。In the optical fiber device according to the present invention, first, as shown in FIG. 2, an optical fiber 5 is prepared by removing the cladding 6 of an appropriate length to expose the core 7. The optical fiber 5 usually has an outer diameter of 2
00 to 350 μm, with a core diameter of about 10 to 150 μm. Next, as shown in FIGS. 3(a) and 3(b), a photoresist, photopolymer, etc., whose refractive index changes upon exposure, is applied to the removed portion of the cladding 6.
A photosensitive material 8 such as an amorphous semiconductor is filled. Note that it is desirable to use a photosensitive material 8 whose refractive index is slightly smaller than the refractive index of the core 7 . Furthermore, as shown in FIG. 4, parallel beams Bl and B2, which are sensitive to the photosensitive material 8 using an Ar laser or the like, are applied to the photosensitive material 8 so that the angle between the beams is 20 degrees. The interference waves of the two beams Bl and B2 are formed by exposure thereto.
また、感光性物質８への２つのビーム照射により、その
感光性物質８には第５図に示す方向に、次式に示される
周期Ａのグレイティング像（干渉縞）９が光ファイバ５
の軸に沿って多数現われ、その感光性物質８は周期へで
光信号の進行方向に対して光の屈折率変化を生じさせる
ようになる（第６図参照）。Furthermore, by irradiating the photosensitive material 8 with the two beams, a grating image (interference fringe) 9 with a period A shown in the following equation is formed on the optical fiber 5 in the direction shown in FIG.
A large number of photosensitive materials 8 appear along the axis of , and the photosensitive material 8 causes a change in the refractive index of light with respect to the direction in which the optical signal travels (see FIG. 6).
２ｓｉｎθ０
したがって、感光性物質８に周期的グレイティング像９
が露光された光ファイバ５に光信号を送ると、次式で示
される波長λをもった光波のみが選択的に感光性物質８
部分で反射され他の波長をもった光波が感光性物質８部
分を通過する、いわゆる周波数選択フィルタ（バンドパ
スフィルタ）として作用することになる。2sinθ0 Therefore, a periodic grating image 9 is formed on the photosensitive material 8.
When a light signal is sent to the exposed optical fiber 5, only the light wave having a wavelength λ shown by the following equation is selectively transmitted to the photosensitive material 8.
The photosensitive material 8 functions as a so-called frequency selection filter (bandpass filter) in which light waves having other wavelengths are reflected by the photosensitive material 8 and pass through the photosensitive material 8.
ｓｉｎ ０口
なお、感光性物質８にホトポリマーを用いた場合、その
感度としてはλＬ＝３２００〜５５００人で１０〜２０
ｍＪ／ａＪのものが一般的であり、またその屈折率変化
はΔｎ＝ｏ、００５〜０．０１５程度のものとなる。sin 0 Note that when a photopolymer is used as the photosensitive material 8, its sensitivity is λL = 10 to 20 for 3200 to 5500 people.
mJ/aJ is common, and the refractive index change is Δn=o, about 005 to 0.015.
また、アモルファス半導体はＡ ｓ ｚ Ｓ ３系、Ａ
ｓ−５ｅ−Ｇｅ系などのカルコゲンガラス半導体が代表
的なものであり、λＬ＝４０００〜５０００人で感度を
示す。普通、光通信に用いられる光源としては、Ｇ ａ
Ａ ｓ系半導体レーザ、ＬＥＤが主体で、そのビーム
波長は７５００〜９０００人程度であり、このような高
い波長をもった光信号が光ファイバ５に入射されても感
光性物質８は何ら感度を示すことがな’Ｉｔ’ｅ
このようなものにあって、特に本発明では、前述の光学
的干渉法のみならずホトリソグラフィーの技術をも導入
して、感光性物質８に露光形成されたグレイティング像
９の構造化を図るようにしている。In addition, amorphous semiconductors are A s z S 3 series, A
Chalcogen glass semiconductors such as s-5e-Ge type semiconductors are typical, and exhibit sensitivity at λL = 4,000 to 5,000 people. Usually, the light source used for optical communication is Ga
The main components are As-based semiconductor lasers and LEDs, and their beam wavelengths are approximately 7,500 to 9,000. Even if an optical signal with such a high wavelength is input to the optical fiber 5, the photosensitive material 8 will not exhibit any sensitivity. In the present invention, not only the above-mentioned optical interference method but also photolithography technology is introduced to obtain the gray light formed by exposure on the photosensitive material 8. In this embodiment, the tinging image 9 is structured.
すなわち、まず第７図に示すように、前述と同様に光フ
ァイバ５のクラッド６が一部取り除かれてコア７が露出
された部分に感光性物質としてのホトレジストを塗布し
て層形成させ、そのホトレジスト層１０に感度を示す２
つの平行ビームＢｌ。That is, as shown in FIG. 7, a portion of the cladding 6 of the optical fiber 5 is partially removed and the core 7 is exposed in the same manner as described above, and a photoresist as a photosensitive material is coated to form a layer. 2 exhibiting sensitivity to the photoresist layer 10
Two parallel beams Bl.
Ｂ２を互いに２０゜の角度をもって照射させ、それによ
りホトレジスト層１０に前記（１）式と同様の周期へを
もった光の明暗によるグレイティング像（干渉縞）９を
第５図の場合と同様に露光形成させる。次いで、ホトエ
ツチングによりグレイティング像９が形成されていない
部分のホトレジストを取り除くことにより、第８図に示
すような屈折率の周期的変化をもったグレイティング構
造を得ることができる。このように構成された光ファイ
バ・デバイスにあっても、前記（２）式に示される波長
λの光信号のみを選択的に反射させる周波数選択フィル
タとしての作用を有することはいうまでもない。B2 are irradiated at an angle of 20 degrees to each other, thereby forming a grating image (interference fringes) 9 on the photoresist layer 10 due to the brightness and darkness of the light having a period similar to that of equation (1) above, as in the case of FIG. is formed by exposure to light. Next, by removing the photoresist in the portion where the grating image 9 is not formed by photoetching, a grating structure having a periodic change in refractive index as shown in FIG. 8 can be obtained. It goes without saying that the optical fiber device configured in this manner also functions as a frequency selective filter that selectively reflects only the optical signal of wavelength λ shown in equation (2) above.
しかしてこのようなホトレジストによるグレイティング
の構造化が図られることにより、前述のように感光性物
質８に像形成されたものに比してグレイティングの構造
自体が強固になる。However, by structuring the grating using photoresist, the structure of the grating itself becomes stronger than that formed by image formation on the photosensitive material 8 as described above.
このような構造のグレイティングをそのまま光フィルタ
として用いてもよいが、その際さらにグレイティング構
造の強固を確保するとともに最大の結合効率が得られる
ようにするため、ホトレジスト層１０に露光形成された
グレイティング像９の干渉縞パターンにしたがって光フ
ァイバ５のコア７部分の適宜深さに至るまでエツチング
したうえで、残りのホトレジストをエツチングにより全
て取り除いて、第９図に示すように、コア７部分に直接
グレイティング構造を形成させるようにしてもよい。Although a grating having such a structure may be used as it is as an optical filter, in order to further ensure the strength of the grating structure and obtain maximum coupling efficiency, a grating is formed by exposure on the photoresist layer 10. The core 7 portion of the optical fiber 5 is etched to an appropriate depth according to the interference fringe pattern of the grating image 9, and the remaining photoresist is completely removed by etching to form the core 7 portion as shown in FIG. Alternatively, the grating structure may be directly formed.
さらに本発明では、光ファイバ５に直接形成されたグレ
イティング構造をより強固なものにするため、第１０図
に示すように、第８図または第９図に示されるグレイテ
ィング構造部分１２を樹脂層１３によって被覆してその
部分を保護させるようにすることも可能である。Furthermore, in the present invention, in order to make the grating structure formed directly on the optical fiber 5 stronger, as shown in FIG. 10, the grating structure portion 12 shown in FIG. It is also possible to cover the area with a layer 13 to protect it.
羞困
以上、本発明による光ファイバ・デバイスにあっては、
光ファイバのクラッドを一部除去して露出されたコア部
分にホトレジスト層を設け、光学的干渉法により光ファ
イバの軸に沿ってそのホトレジスト層に露光形成された
周期的に屈折率を変化させるグレイティング像のパター
ンに応じてホトレジスト層をエツチング処理することに
よってグレイティング構造を形成させるようにしたもの
で、光波長オーダの屈折率の周期的変化をもった光フィ
ルタを光信号の伝送路である光ファイバと一体的に良好
な結合効率をもって、かつ強固に設けることができ、従
来のように光ファイバと光フィルタとの間における光結
合の問題を何ら生ずることなく、高能率にフィルタ作用
を行なわせることができるという優れた利点を有してい
る。Unfortunately, in the optical fiber device according to the present invention,
A photoresist layer is provided on the exposed core part by removing part of the cladding of the optical fiber, and a gray layer that periodically changes the refractive index is formed by exposing the photoresist layer along the axis of the optical fiber using optical interference method. A grating structure is formed by etching a photoresist layer according to the pattern of a grating image, and an optical filter with a periodic change in refractive index on the order of the optical wavelength is used as a transmission path for optical signals. It can be installed firmly and integrally with an optical fiber with good coupling efficiency, and can perform a filtering action with high efficiency without causing any optical coupling problems between the optical fiber and the optical filter as in the past. It has the excellent advantage of being able to
第１図は従来の薄膜光導波路を用いた光フィルタを示す
簡略構成図、第２図は光ファイバのクラッドを一部除去
した状態を示す正断面図、第３図（ａ）、 （ｂ）はク
ラッド除去部分に感光性物質を充填した状態を示す正断
面図および斜視図、第４図は感光性物質にビーム照射し
ている状態を示す斜視図、第５図は感光性物質に周期的
なグレイティング像が露光形成される状態を示す図、第
６図は光ファイバのコア上に設けられた感光性物質に露
光形成されるグレイティング像を示す正断面図、第７図
は本発明の一実施例による光ファイバ・デバイスの製造
過程を示す斜視図、第８図は本発明の一実施例による光
ファイバ・デバイスを示す正断面図、第９図および第１
０＠は本発明の他の実施例をそれぞれ示す正断面図であ
る。
５・・・光ファイバ ６・・・クラッド ７・・・コア
８・・・感光性物質 ９・・・グレイティング像 １
ｏ・・・ホトレジスト層 １２・・・グレイティング
構造部分１３・・・樹脂層。
出願人代理人 鳥 井 清
第７図Fig. 1 is a simplified configuration diagram showing an optical filter using a conventional thin film optical waveguide, Fig. 2 is a front cross-sectional view showing a state in which the cladding of the optical fiber is partially removed, and Figs. 3 (a) and (b). 4 is a front sectional view and a perspective view showing the state in which the photosensitive material is filled in the cladding removed part, FIG. 4 is a perspective view showing the state in which the photosensitive material is irradiated with a beam, and FIG. FIG. 6 is a front cross-sectional view showing a grating image formed by exposure on a photosensitive material provided on the core of an optical fiber, and FIG. 7 is a diagram showing how a grating image is formed by exposure. 8 is a perspective view showing the manufacturing process of an optical fiber device according to an embodiment of the present invention, FIG. 8 is a front sectional view showing an optical fiber device according to an embodiment of the present invention, FIG.
0 is a front sectional view showing other embodiments of the present invention. 5... Optical fiber 6... Clad 7... Core 8... Photosensitive material 9... Grating image 1
o... Photoresist layer 12... Grating structure portion 13... Resin layer. Applicant's agent Kiyoshi Torii Figure 7
Claims (1)
ア部分にホトレジスト層を設け、光学的干渉法により光
ファイバの軸に沿ってそのホトレジスト層に露光形成さ
れた周期的に屈折率を変化させるグレイティング像のパ
ターンに応じてホトレジスト層をエッチング処理するこ
とによってグレイティング構造を形成させた光ファイバ
・デバイス。 ２、ホトレジスト層に露光形成されたグレイティング像
のパターンに応じてエッチング処理する際、コア部に至
るまでエッチングしてグレイティング構造を直接コア部
分に形成したことを特徴とする前記第１項の記載による
光ファイバ・デバイス。 ３、グレイティング構造部分を樹脂層によって被覆した
ことを特徴とする前記第１項または第２項の記載による
光ファイバ・デバイス。[Claims] 1. A photoresist layer is provided on the exposed core portion of the optical fiber by removing a portion of the cladding, and a period is formed by exposing the photoresist layer along the axis of the optical fiber by optical interference method. An optical fiber device in which a grating structure is formed by etching a photoresist layer according to a grating image pattern that changes the refractive index. 2. The grating structure of item 1 above is characterized in that when etching is performed in accordance with the pattern of the grating image formed by exposure on the photoresist layer, the grating structure is formed directly on the core portion by etching down to the core portion. Fiber optic device as described. 3. The optical fiber device according to item 1 or 2, characterized in that the grating structure portion is covered with a resin layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62125441A JPS63132205A (en) | 1987-05-22 | 1987-05-22 | Optical fiber device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62125441A JPS63132205A (en) | 1987-05-22 | 1987-05-22 | Optical fiber device |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1805679A Division JPS55110207A (en) | 1979-02-19 | 1979-02-19 | Optical fiber device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63132205A true JPS63132205A (en) | 1988-06-04 |
Family
ID=14910164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62125441A Pending JPS63132205A (en) | 1987-05-22 | 1987-05-22 | Optical fiber device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63132205A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2779238A1 (en) * | 1998-06-02 | 1999-12-03 | Alsthom Cge Alcatel | FILTERING OPTICAL FIBER WITH MODIFIED PHOTOSENSITIVITY PROFILE |
| US6124959A (en) * | 1995-09-27 | 2000-09-26 | Nec Corporation | Optical wavelength-division multiplexing transmission system |
| WO2001099323A1 (en) * | 2000-06-21 | 2001-12-27 | Mitsubishi Denki Kabushiki Kaisha | Data transmission system |
| US7352967B1 (en) | 2000-06-21 | 2008-04-01 | Mitsubishi Denki Kabushiki Kaisha | Data transmission system |
| KR101139632B1 (en) | 2010-07-26 | 2012-05-14 | 한양대학교 산학협력단 | Method to fabricate long-period fiber grating and fiber to fabricate by using the method |
-
1987
- 1987-05-22 JP JP62125441A patent/JPS63132205A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6124959A (en) * | 1995-09-27 | 2000-09-26 | Nec Corporation | Optical wavelength-division multiplexing transmission system |
| FR2779238A1 (en) * | 1998-06-02 | 1999-12-03 | Alsthom Cge Alcatel | FILTERING OPTICAL FIBER WITH MODIFIED PHOTOSENSITIVITY PROFILE |
| EP0962791A1 (en) * | 1998-06-02 | 1999-12-08 | Alcatel | Filtering optical fibre with modified photosensibility profile |
| WO2001099323A1 (en) * | 2000-06-21 | 2001-12-27 | Mitsubishi Denki Kabushiki Kaisha | Data transmission system |
| US7352967B1 (en) | 2000-06-21 | 2008-04-01 | Mitsubishi Denki Kabushiki Kaisha | Data transmission system |
| KR101139632B1 (en) | 2010-07-26 | 2012-05-14 | 한양대학교 산학협력단 | Method to fabricate long-period fiber grating and fiber to fabricate by using the method |
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