JPH0549057B2 - - Google Patents
Info
- Publication number
- JPH0549057B2 JPH0549057B2 JP61051672A JP5167286A JPH0549057B2 JP H0549057 B2 JPH0549057 B2 JP H0549057B2 JP 61051672 A JP61051672 A JP 61051672A JP 5167286 A JP5167286 A JP 5167286A JP H0549057 B2 JPH0549057 B2 JP H0549057B2
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- light
- measured
- polarization
- light source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000013307 optical fiber Substances 0.000 claims description 46
- 230000010287 polarization Effects 0.000 claims description 35
- 238000000926 separation method Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 5
- 239000006185 dispersion Substances 0.000 description 15
- 239000000835 fiber Substances 0.000 description 15
- 230000008878 coupling Effects 0.000 description 10
- 238000010168 coupling process Methods 0.000 description 10
- 238000005859 coupling reaction Methods 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 238000000253 optical time-domain reflectometry Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 2
- NCGICGYLBXGBGN-UHFFFAOYSA-N 3-morpholin-4-yl-1-oxa-3-azonia-2-azanidacyclopent-3-en-5-imine;hydrochloride Chemical compound Cl.[N-]1OC(=N)C=[N+]1N1CCOCC1 NCGICGYLBXGBGN-UHFFFAOYSA-N 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- 229910021532 Calcite Inorganic materials 0.000 description 1
- 238000001069 Raman spectroscopy Methods 0.000 description 1
- 238000000098 azimuthal photoelectron diffraction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/3181—Reflectometers dealing with polarisation
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
【発明の詳細な説明】
≪産業上の利用分野≫
本発明は、OTDR法を用いた光フアイバ測定
器の改良に関するものである。特に光フアイバに
沿つた偏波面モード結合、波長分散、偏波分散あ
るいは伝送帯域を同時に光フアイバの片端だけで
測定できる光フアイバ計測器に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to improvement of an optical fiber measuring instrument using the OTDR method. In particular, it relates to an optical fiber measuring instrument that can simultaneously measure polarization plane mode coupling, wavelength dispersion, polarization dispersion, or transmission band along an optical fiber at only one end of the optical fiber.
≪従来の技術≫
光フアイバにはガラスに固有の散乱が存在す
る。光フアイバコアを伝搬する光波はコア内のド
ーパントなどの散乱源によりレイリー散乱を生じ
る。特にこの散乱光のうちフアイバコア後方（光
源方向）へガイドされた散乱光を後方散乱光と呼
ぶ。<<Prior Art>> Optical fibers have scattering inherent to glass. Light waves propagating through an optical fiber core undergo Rayleigh scattering due to scattering sources such as dopants within the core. In particular, among this scattered light, the scattered light that is guided toward the rear of the fiber core (in the direction of the light source) is called backscattered light.
光フアイバの一端から光パルスを送り、後方散
乱光を観測することによりフアイバの長さ方向の
損失分布や破断点などを検出する手法をOTDR
（Optical Time Domain Reflectometry）法と
いう。 OTDR is a method that detects the loss distribution and break point in the length direction of the fiber by sending a light pulse from one end of the optical fiber and observing the backscattered light.
(Optical Time Domain Reflectometry) method.
第５図は従来のOTDR法を用いた光フアイバ
試験装置の基本構成を示す構成ブロツク図であ
る。光源１から出力された光パルスは方向性結合
器２を通つて被測定フアイバ３に入射する。この
光の一部は後方レイリー散乱光として逆方向へ戻
り、再び方向性結合器２を経由して受光素子４に
入射し検出される。受光素子４の電気出力は増幅
器５で増幅後、演算部６でＡ／Ｄ変換、平均化処
理、対数変換などが行われ、データ保存手段８に
格納されるとともに、表示装置７で表示される。 FIG. 5 is a block diagram showing the basic configuration of an optical fiber testing device using the conventional OTDR method. A light pulse output from a light source 1 passes through a directional coupler 2 and enters a fiber 3 to be measured. A part of this light returns in the opposite direction as backward Rayleigh scattered light, enters the light receiving element 4 via the directional coupler 2 again, and is detected. The electrical output of the light-receiving element 4 is amplified by an amplifier 5, and then subjected to A/D conversion, averaging processing, logarithmic conversion, etc. in an arithmetic unit 6, and is stored in a data storage means 8 and displayed on a display device 7. .
≪発明が解決しようとする問題点≫
しかしながら、上記のような従来の光フアイバ
障害探索装置では、光フアイバに沿つた損失の測
定は可能であるが、偏波面の変化については測定
ができないという欠点を有している。<<Problems to be Solved by the Invention>> However, the conventional optical fiber fault detection device as described above has the disadvantage that although it is possible to measure loss along the optical fiber, it cannot measure changes in the plane of polarization. have.
特に、現状では定偏波面フアイバでも外乱によ
り偏波モード結合（フアイバの直交モード間のモ
ード結合量またはモード変換量）が避けられない
ので、偏波モード結合の大きさは光フアイバ伝送
における伝送帯域を決定する主要因ともなり、そ
の測定は極めて重要である。 In particular, at present, even with a constant polarization plane fiber, polarization mode coupling (amount of mode coupling or mode conversion between orthogonal modes of the fiber) cannot be avoided due to disturbances. It is also the main factor that determines the
また従来の装置では伝送帯域や波長分散（波長
による屈折率の違いが原因で光の伝搬時間に差を
生じる現象）の測定を光フアイバの片端だけで行
うことは不可能であつた。 Furthermore, with conventional equipment, it has been impossible to measure transmission bandwidth and chromatic dispersion (a phenomenon that causes differences in light propagation time due to differences in refractive index depending on wavelength) at only one end of an optical fiber.
本発明は上記の問題点を解決するためになされ
たもので、光フアイバに沿つた偏波モード結合、
伝送帯域および波長分散等を同時に光フアイバの
片端だけで測定できる光フアイバ測定器を実現す
ることを目的としている。 The present invention has been made to solve the above problems, and includes polarization mode coupling along an optical fiber.
The purpose of this invention is to realize an optical fiber measuring instrument that can simultaneously measure transmission band, wavelength dispersion, etc. at only one end of an optical fiber.
≪問題点を解決するための手段≫
本発明は光源からの光を被測定フアイバに入射
し被測定フアイバの後方散乱光を検出することに
より被測定フアイバの状態を観測する光フアイバ
測定器に係るもので、その特徴は可変波長光源
と、この波長可変光源の出力光の偏波面を回転し
て前記被測定光フアイバに入射するフアラデー回
転素子と、前記被測定光フアイバの後方散乱光を
入射する偏波分離手段と、この偏波分離手段の出
力光が電気信号に変換された後、この電気信号が
入力される演算制御部とを備えたところにある。<Means for Solving the Problems> The present invention relates to an optical fiber measuring instrument that observes the state of a fiber to be measured by inputting light from a light source into the fiber to be measured and detecting backscattered light from the fiber to be measured. Its features include a tunable wavelength light source, a Faraday rotation element that rotates the plane of polarization of the output light of the tunable wavelength light source and inputs it into the optical fiber to be measured, and a backscattered light from the optical fiber to be measured that enters the optical fiber. The device includes a polarization separation means and an arithmetic control section into which the output light of the polarization separation means is converted into an electric signal and the electric signal is input thereto.
≪実施例≫ 以下本発明を図面を用いて詳しく説明する。≪Example≫ The present invention will be explained in detail below using the drawings.
第１図は本発明に係る光フアイバ測定器の一実
施例を示す構成ブロツク図である。１１は温度制
御により発振波長を変えることができる半導体レ
ーザや、NdドープYAGレーザやArレーザなど
をポンピング源とし回折格子やプリズムなどで波
長選択できる光フアイバ・ラマン・レーザなどを
用いた可変波長光源、１２はこの可変波長光源１
１の出力光を入射する集光用のレンズ、２はこの
レンズ１２の出力光を入射する方向性結合器でこ
こでは偏波面依存性のないハーフミラーなどを用
いたもの、１３はこの方向性結合器２の出力光を
入射するフアラデー回転素子で、例えばYIG単結
晶のまわりにソレノイド状に導線を巻いたもの、
１４はこのフアラデー回転素子１３の出力光を集
光するレンズ、３はこのレンズ１４の出力光を入
射する被測定光フアイバ、１５はこの被測定光フ
アイバ３の後方散乱光を前記レンズ１４、前記フ
アイバ回転素子１３および前記方向性結合器２を
介して入射する偏光プリズムや方解石などを用い
た偏波分離素子、１６，１７はこの偏波分離素子
１５の透過光、反射光をそれぞれ入射する集光用
レンズ、１８，１９はこのレンズ１６，１７の出
力光をそれぞれ入射するAPD（アバランシエ・フ
オトダイオード）と増幅器などからなる受光部、
２０はこの受光部１８，１９の出力電気信号を入
力する演算制御回路、２１は前記可変波長光源１
１の温度を検出する温度検出器、２２は前記フア
ラデー回転素子１３の温度を検出する温度検出素
子である。 FIG. 1 is a block diagram showing an embodiment of an optical fiber measuring device according to the present invention. 11 is a variable wavelength light source that uses a semiconductor laser whose oscillation wavelength can be changed by temperature control, or an optical fiber Raman laser whose pumping source is an Nd-doped YAG laser or Ar laser and whose wavelength can be selected using a diffraction grating or prism. , 12 is this variable wavelength light source 1
1 is a condensing lens into which the output light from lens 12 is incident; 2 is a directional coupler into which the output light from lens 12 is incident; in this case, a half mirror or the like with no polarization dependence is used; 13 is a directional coupler A Faraday rotary element that receives the output light from the coupler 2, for example, a YIG single crystal with a conductive wire wound around it in the shape of a solenoid.
14 is a lens that condenses the output light of this Faraday rotation element 13; 3 is an optical fiber to be measured into which the output light of this lens 14 is incident; 15 is a lens that collects the backscattered light of this optical fiber 3 to be measured; A polarization separation element using a polarizing prism, calcite, etc., which enters through the fiber rotation element 13 and the directional coupler 2; Optical lenses 18 and 19 are light-receiving parts consisting of APDs (avalanche photodiodes) and amplifiers that receive the output lights of the lenses 16 and 17, respectively;
20 is an arithmetic control circuit that inputs the output electric signals of the light receiving sections 18 and 19; 21 is the variable wavelength light source 1;
A temperature detector 22 detects the temperature of the Faraday rotary element 13;
このような構成の光フアイバ測定器の動作を次
に説明する。可変波長光源１１から出力された光
はレンズ１２で集光されて方向性結合器２に入射
し、その出力光がフアラデー回転素子１３で偏波
面を回転する。フアラデー回転素子１３の出力光
はレンズ１４で集光されて被測定フアイバ３に入
射し、その散乱光は被測定フアイバ３を逆行して
再びレンズ１４、フアラデー回転素子１３を通
り、方向性結合素子２を介して偏波分離素子１５
に入射する。偏波分離素子１５で入射光は２つの
直交成分に分離され、それぞれが受光部１８，１
９で検出・増幅される。受光部１８，１９の出力
電気信号は演算制御回路２０に入力して後述のよ
うな所定の信号処理を行う。また演算制御回路２
０は温度センサ２１，２２の出力に基づいて可変
波長光源１１、フアラデー回転素子１３の温度制
御も行つている。 The operation of the optical fiber measuring instrument having such a configuration will be explained next. The light output from the variable wavelength light source 11 is focused by a lens 12 and enters the directional coupler 2, and the output light has its plane of polarization rotated by a Faraday rotation element 13. The output light of the Faraday rotation element 13 is focused by the lens 14 and enters the fiber 3 to be measured, and the scattered light travels backward through the fiber 3 to be measured, passes through the lens 14 and the Faraday rotation element 13 again, and is then passed through the directional coupling element. Polarization separation element 15 via 2
incident on . The incident light is separated into two orthogonal components by the polarization separation element 15, and each of the light receiving parts 18, 1
Detected and amplified at 9. The output electrical signals from the light receiving sections 18 and 19 are input to an arithmetic and control circuit 20 to undergo predetermined signal processing as described below. Also, the arithmetic control circuit 2
0 also controls the temperature of the variable wavelength light source 11 and the Faraday rotation element 13 based on the outputs of the temperature sensors 21 and 22.
次に偏波モード結合、波長分散および偏波分散
等を測定する場合の上記光フアイバ測定器の動作
を説明する。 Next, the operation of the optical fiber measuring instrument when measuring polarization mode coupling, wavelength dispersion, polarization dispersion, etc. will be explained.
(イ) 偏波モード結合の測定法
光源１１からのパルス光に基づいて受光素子
１８，１９からそれぞれ出力される２つの直交
成分の信号強度S1(t)、S2(t)を時間に対してグラ
フ化したものを第２図Ａ，Ｂに例示する。例え
ば第２図Ａのａ点および第２図Ｂのｂ点は被測
定フアイバ３の同一点で生じたフレネル反射に
よる損失を表しているが、両者の大きさは異な
つている。すなわちフレネル反射に偏波面依存
性があることを示している。この偏波依存性の
尺度となる偏波モード結合の値は
θ(t)＝sin-1√1(t)2(t)（rad） ……(1)
で表される。この演算を演算制御回路２０が行
うことにより、被測定フアイバ３の長手方向に
沿つて偏波モード結合を測定できる。(b) Measuring method of polarization mode coupling The signal intensities S 1 (t) and S 2 (t) of the two orthogonal components output from the light receiving elements 18 and 19, respectively, based on the pulsed light from the light source 11 are measured over time. Figures 2A and 2B show examples of the graphs shown in FIG. For example, point a in FIG. 2A and point b in FIG. 2B represent losses due to Fresnel reflection occurring at the same point on the fiber 3 to be measured, but their magnitudes are different. In other words, this shows that Fresnel reflection has polarization plane dependence. The value of polarization mode coupling, which is a measure of this polarization dependence, is expressed as θ(t)=sin -1 √ 1 (t) 2 (t) (rad) ...(1). By performing this calculation by the calculation control circuit 20, polarization mode coupling can be measured along the longitudinal direction of the fiber 3 to be measured.
また被測定フアイバ３の長手方向に沿つての
損失は次式
Ｌ(t)＝√1(t)2＋2(t)2 ……(2)
で演算できる。 Further, the loss along the longitudinal direction of the fiber 3 to be measured can be calculated using the following equation: L(t)=√ 1 (t) 2 + 2 (t) 2 . . . (2).
(ロ) 波長分散の測定法
可変波長光源１１から波長を順次変化させた
光パルスを送出し、光フアイバ３終端からのフ
レネル反射光などを利用してその後方散乱光の
時間遅れを測定する。一般に光パルスの時間遅
れを波長の関数として表すと第３図Ａのように
なり、演算制御回路２０において、対応する第
３図Ｂの波長分散を公知の計算方法で演算する
ことができる。またパルスの時間遅れが最小値
となるところで波長分散が０となるので波長分
散が０となる波長を演算することもできる。ま
た演算により高次の波長分散を求めれば、これ
を用いて入力パルス幅と出力パルス幅の関係が
分るので、第４図に示すような伝送帯域特性を
演算することができる（図のλ1、λ2は波長）。(b) Measuring method of chromatic dispersion A light pulse whose wavelength is successively changed is sent out from the variable wavelength light source 11, and the time delay of the backscattered light is measured using the Fresnel reflected light from the end of the optical fiber 3. Generally, when the time delay of an optical pulse is expressed as a function of wavelength, it is as shown in FIG. 3A, and the corresponding chromatic dispersion shown in FIG. 3B can be calculated in the calculation control circuit 20 using a known calculation method. Furthermore, since the chromatic dispersion becomes 0 when the time delay of the pulse becomes the minimum value, it is also possible to calculate the wavelength at which the chromatic dispersion becomes 0. In addition, if higher-order chromatic dispersion is calculated, the relationship between the input pulse width and the output pulse width can be determined using this, so the transmission band characteristics as shown in Figure 4 can be calculated (λ 1 , λ 2 is the wavelength).
(ハ) 偏波分散の測定法。(c) Measurement method of polarization dispersion.
偏波分散は入射光の偏波方向の違いによる伝
送速度の違いで、単位長当りの直交偏波モード
間の群遅延差で定義される。波長可変光源１１
から波長を順次変化させた光パルスを送出する
とともに、各波長毎にその偏波面を光フアイバ
の主軸に合せたものと主軸に直交する方向に合
せたものをフアラデー回転素子により順次発生
させ、フアイバ端のフレネル反射などを利用し
てそれぞれの後方散乱光の時間差を計測する。
ここで被測定光フアイバ３として定偏波面光フ
アイバを用いれば、従来例で述べたように、特
に意味のある測定を行うことができる。 Polarization dispersion is a difference in transmission speed due to a difference in the polarization direction of incident light, and is defined as a group delay difference between orthogonal polarization modes per unit length. Tunable wavelength light source 11
At the same time, a Faraday rotation element sequentially generates optical pulses whose wavelengths are changed sequentially from the optical fiber, and one whose polarization plane is aligned with the main axis of the optical fiber and another whose polarization plane is aligned with the main axis of the optical fiber for each wavelength, and one whose polarization plane is aligned with the direction perpendicular to the optical fiber's main axis. The time difference between each backscattered light is measured using Fresnel reflection at the edge.
If a constant polarization plane optical fiber is used as the optical fiber 3 to be measured, particularly meaningful measurements can be performed as described in the conventional example.
なお上記の実施例において、フアラデー回転素
子１３を方向性結合器２の手前に配置してもよ
い。 In the above embodiment, the Faraday rotation element 13 may be placed before the directional coupler 2.
≪発明の効果≫
以上述べたように本発明によれば、光フアイバ
の長手方向に沿つた偏波モード結合、波長分散、
偏波分散、損失、伝送帯域特性などを同時に光フ
アイバの片端だけで測定できる光フアイバ測定器
を簡単な構成で実現することができる。<<Effects of the Invention>> As described above, according to the present invention, polarization mode coupling along the longitudinal direction of the optical fiber, chromatic dispersion,
An optical fiber measuring instrument that can simultaneously measure polarization dispersion, loss, transmission band characteristics, etc. at only one end of an optical fiber can be realized with a simple configuration.
第１図は本発明に係わる光フアイバ測定器の一
実施例を示す構成ブロツク図、第２図〜第４図は
第１図装置の動作を説明するための特性曲線図、
第５図は従来の光フアイバ測定器を示す構成ブロ
ツク図である。
３……被測定フアイバ、１１……可変波長光
源、１５……偏波分離素子、１３……フアラデー
回転素子、２０……演算制御部。
FIG. 1 is a configuration block diagram showing an embodiment of the optical fiber measuring device according to the present invention, FIGS. 2 to 4 are characteristic curve diagrams for explaining the operation of the device shown in FIG.
FIG. 5 is a block diagram showing a conventional optical fiber measuring instrument. 3... Fiber to be measured, 11... Variable wavelength light source, 15... Polarization separation element, 13... Faraday rotation element, 20... Arithmetic control unit.
Claims (1)
測定光フアイバの後方散乱光を検出することによ
り被測定光フアイバの状態を観測する光フアイバ
測定器において、 可変波長光源と、この可変波長光源の出力光の
偏波面を回転して前記被測定光フアイバに入射す
るフアラデー回転素子と、前記被測定光フアイバ
の後方散乱光を入射する偏波分離手段と、この偏
波分離手段の出力光が電気信号に変換された後、
この電気信号が入力される演算制御部とを備えた
ことを特徴とする光フアイバ測定器。 ２ 可変波長光源の出力光を入力する光方向性結
合器を備え、光方向性結合器の出力光をフアラデ
ー回転素子を介して被測定光フアイバに入射し、
被測定光フアイバの後方散乱光を前記フアラデー
回転素子および前記方向性結合器を介して偏波分
離手段に入射するように構成した特許請求の範囲
第１項記載の光フアイバ測定器。[Scope of Claims] 1. An optical fiber measuring instrument that observes the state of an optical fiber to be measured by inputting light from a light source into the optical fiber to be measured and detecting backscattered light of the optical fiber to be measured, comprising: a variable wavelength light source; a Faraday rotation element that rotates the plane of polarization of the output light of the variable wavelength light source and inputs the output light into the optical fiber to be measured; a polarization separation unit that inputs backscattered light from the optical fiber to be measured; After the output light of the separation means is converted into an electrical signal,
An optical fiber measuring instrument comprising: an arithmetic control section to which the electrical signal is input. 2. comprises an optical directional coupler that inputs the output light of the variable wavelength light source, and inputs the output light of the optical directional coupler into the optical fiber to be measured via the Faraday rotation element;
2. The optical fiber measuring instrument according to claim 1, wherein the backscattered light of the optical fiber to be measured is made to enter the polarization separation means via the Faraday rotation element and the directional coupler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5167286A JPS62207927A (en) | 1986-03-10 | 1986-03-10 | Optical fiber measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5167286A JPS62207927A (en) | 1986-03-10 | 1986-03-10 | Optical fiber measuring instrument |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62207927A JPS62207927A (en) | 1987-09-12 |
| JPH0549057B2 true JPH0549057B2 (en) | 1993-07-23 |
Family
ID=12893369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5167286A Granted JPS62207927A (en) | 1986-03-10 | 1986-03-10 | Optical fiber measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62207927A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02103434A (en) * | 1988-10-13 | 1990-04-16 | Fujikura Ltd | Method for measuring strain distribution in longitudinal direction of optical fiber cable and apparatus and optical fiber used in said method |
| JPH04274724A (en) * | 1991-03-02 | 1992-09-30 | Fujikura Ltd | Otdr apparatus |
| IT1291413B1 (en) * | 1997-02-13 | 1999-01-11 | Andrea Galtarossa | REFLECTOMETRIC INSTRUMENT FOR THE MEASUREMENT OF BIRIFRANGENCE DISTRIBUTED IN SINGLE-MODE FIBER OPTICS |
| EP1134572B1 (en) * | 1999-09-06 | 2006-11-15 | Anritsu Corporation | System for measuring wavelength dispersion of optical fiber |
| JP2002048680A (en) * | 2000-08-01 | 2002-02-15 | Anritsu Corp | Polarization mode dispersion distribution measuring method and apparatus for optical fiber |
| EP1526368A4 (en) | 2002-07-19 | 2007-07-18 | Fujikura Ltd | Optical fiber polarization mode dispersion measurement method and measurement device |
| JP4498818B2 (en) * | 2004-05-14 | 2010-07-07 | 株式会社フジクラ | Optical fiber transmission line pass / fail judgment method |
| JP4717724B2 (en) * | 2006-06-08 | 2011-07-06 | 日本電信電話株式会社 | Polarization dispersion measuring instrument |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5712088A (en) * | 1980-06-27 | 1982-01-21 | Toa Gurauto Kogyo Kk | Stabilizing agent for excavation surface |
-
1986
- 1986-03-10 JP JP5167286A patent/JPS62207927A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5712088A (en) * | 1980-06-27 | 1982-01-21 | Toa Gurauto Kogyo Kk | Stabilizing agent for excavation surface |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62207927A (en) | 1987-09-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |