JPH04102042A - Otdr type measurement method - Google Patents
Otdr type measurement methodInfo
- Publication number
- JPH04102042A JPH04102042A JP21948790A JP21948790A JPH04102042A JP H04102042 A JPH04102042 A JP H04102042A JP 21948790 A JP21948790 A JP 21948790A JP 21948790 A JP21948790 A JP 21948790A JP H04102042 A JPH04102042 A JP H04102042A
- Authority
- JP
- Japan
- Prior art keywords
- length
- optical fiber
- optical fibers
- distance resolution
- measurement method
- 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
- 238000000691 measurement method Methods 0.000 title claims description 10
- 239000013307 optical fiber Substances 0.000 claims abstract description 39
- 238000000253 optical time-domain reflectometry Methods 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 7
- 238000005259 measurement Methods 0.000 abstract description 3
- 238000003491 array Methods 0.000 abstract 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Landscapes
- Testing Of Optical Devices Or Fibers (AREA)
Abstract
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明はＯＴＤＲ方式測定方法に関するものである。[Detailed description of the invention] [Industrial application field] The present invention relates to an OTDR measurement method.
［従来の技術］
従来のＯＴ Ｄ Ｒ（０ｐｔｉｃａｌ Ｔｉｍｅ Ｄｏ
ｍａｉｎ Ｒｅｆｒａｃｔｏｍｅｔｒｙ ）方式測定方
法は第３図に示されているように、単心の光ファイバ１
にパルス光２を入射し、光ファイバーの各部分からの散
乱光３の−・部の後方散乱光４を入射端で受信し、例え
ば温度分布測定を行っている。なお同図は５は透過光で
ある。[Conventional technology] Conventional OT DR (0ptical time do
As shown in Figure 3, the main refractometry method is a measurement method using a single optical fiber 1.
Pulsed light 2 is incident on the optical fiber, and the backscattered light 4 of the - part of the scattered light 3 from each part of the optical fiber is received at the input end to measure, for example, temperature distribution. Note that in the figure, 5 is transmitted light.
［発明が解決しようとする課題］
上記従来技術は、ＬＡを距離分解能、王を入射パルス光
の時間幅、Ｃを光フアイバ内の光の速度とした場合に、
ＬＡ＝ＴＣ／２・・・（１）で算出される距離分解能Ｌ
Ａで決まる長さ内で発停する後光散乱光の総量を受信し
、測定を行っている。従って装置のサンプリング時間を
短くしても、距離分解能しＡは（１）式で決まるので短
くならない。[Problems to be Solved by the Invention] In the above-mentioned prior art, when LA is the distance resolution, K is the time width of the incident pulsed light, and C is the speed of light within the optical fiber,
LA=TC/2... Distance resolution L calculated by (1)
The total amount of backlight scattered light that starts and stops within the length determined by A is received and measured. Therefore, even if the sampling time of the device is shortened, the distance resolution A will not be shortened because it is determined by equation (1).
光の速度Ｃは物理的に決まる値であるから、距離分解能
Ｌ を高める即らＬＡを小さくするためには入射パルス
光の時間幅Ｔを短かくしなければならない。しかし、Ｏ
ＴＤＲ方式測定装置では高い強度の入）１パルス光を必
要とし、時間幅Ｔを知かくするのは非常に困難である。Since the speed of light C is a physically determined value, in order to increase the distance resolution L, that is, to reduce LA, the time width T of the incident pulsed light must be shortened. However, O
The TDR type measuring device requires one pulse of high-intensity light, and it is very difficult to control the time width T.
本発明は以上の点に鑑みなされたものであり、距離分解
能を大幅に高めることを可能とした○ＴＤＲ方式測定方
法を提供することを目的とするものである。The present invention has been made in view of the above points, and it is an object of the present invention to provide a ○TDR type measurement method that makes it possible to significantly improve distance resolution.
［課題を解決するための手段］
上記目的は、光ファイバを複数のＮ本並列に配列し、そ
の配列したＮ本の光ファイバを長さ［／Ｎの接続用光フ
ァイバで直列に接続して後方散乱光を測定することによ
り、達成される。[Means for solving the problem] The above object is to arrange a plurality of N optical fibers in parallel, and connect the arranged N optical fibers in series with a connecting optical fiber of length [/N]. This is accomplished by measuring backscattered light.
［作用］
上記手段を設けたので、距離分解能で法談る長さＬの１
／Ｎの長さの部分の後方散乱光が算出できるようになっ
て、Ｌ／Ｎの距離分解能の測定が可能となる。[Operation] Since the above-mentioned means is provided, 1 of the length L of the sermon with distance resolution
The backscattered light of a portion with a length of /N can now be calculated, making it possible to measure a distance resolution of L/N.
［実施例］
以下、図示した実施例に基づいて本発明を説明する。第
１図には本発明の一実施例が示されている。なお、従来
と同じ部品には同じ符号を付したので説明を省略する。[Example] The present invention will be described below based on the illustrated example. FIG. 1 shows an embodiment of the invention. It should be noted that the same parts as in the prior art have been given the same reference numerals, so their explanation will be omitted.
本実施例では光ファイバ１を２本並列に配列し、その配
列した２本の光ファイバ１を長さ［／２の接続用光ファ
イバ６で直列に接続して後方散乱光を測定した。このよ
うにすることにより距離分解能で決まる長さ［の１／２
の長さの部分の後光散乱光が算出できるようになって、
Ｌｌ２の距離分解能の測定が可能となり、距離分解能を
大幅に高めることを可能としたＯＴＤＲ方式測定方法を
得ることができる。In this example, two optical fibers 1 were arranged in parallel, and the two arranged optical fibers 1 were connected in series with a connecting optical fiber 6 having a length of [/2] to measure backscattered light. By doing this, the length [1/2] determined by the distance resolution
It is now possible to calculate the backlight scattered light of the length of .
It becomes possible to measure the distance resolution of Ll2, and it is possible to obtain an OTDR measurement method that makes it possible to significantly improve the distance resolution.
すなわち２本の光ファイバーを同一経路に設置し、その
終端を距離分解能で決まる長さしのＬｌ２の長さの接続
用光ファイバ６で光フアイバ接続点７を介して接続する
。このようにして直列に接続した光ファイバーを入射パ
ルス光２の入射端から距離分解能で決まる長さし毎に分
ける。同図では例として８区間に分けし。、Ｌｌ・・・
・・・・・・Ｌ７とする。さらに各Ｌ （ｎ＝ｏ、１
〜７）を半分の良さに分け、入射端に近い方’ｎａ、遠
い方を１゜。That is, two optical fibers are installed on the same path, and their terminal ends are connected via an optical fiber connection point 7 with a connecting optical fiber 6 having a length Ll2 determined by the distance resolution. In this way, the optical fibers connected in series are divided into lengths determined by the distance resolution from the input end of the input pulsed light 2. In the figure, it is divided into eight sections as an example. , Ll...
......L7. Furthermore, each L (n=o, 1
Divide ~7) into halves, the one closer to the incident end 'na' and the one farther away 1 degree.
とする。終端の接続用光ファイバ６がＬｌ２なので、’
７ｂと１゜ｂとは同図にも示されているように同じ位置
になる。shall be. Since the connecting optical fiber 6 at the end is Ll2, '
7b and 1°b are at the same position as shown in the figure.
Ｌｏの区間に発生する後方散乱光の総量をＰ。The total amount of backscattered light generated in the section Lo is P.
とじ、’ｎａ、’ｎｂの区間に発生する後方散乱光の総
量をｐｎａ、ｐｎｂとする。Ｌ。 （１ｏ８、Ｊｏｂ）
と’７ｂとの光ファイバーの状態を均一にし、そこで発
生する後方散乱光の量も同じになるようにすると、次の
（２）、（３）が成り立つ。Let pna and pnb be the total amounts of backscattered light generated in the sections ``na'' and ``nb''. L. (1o8, Job)
If the conditions of the optical fibers and '7b are made uniform, and the amount of backscattered light generated therein is also the same, then the following (2) and (3) hold true.
ｐＯａ−ｐＯｂ＝ＰＯ／２−（２） ｐ７ｂ＝ ｐ□ｂ−−（３） また、一般に （４）式が成り立つ。pOa-pOb=PO/2-(2) p7b= p□b--(3) Further, in general, equation (4) holds true.
Ｐ ＝ｐｎａ＋ｐｎｂ・・・（４） ｎ＝７の場合、（４）式より （５）式が成り立つ。P=pna+pnb...(4) When n=7, equation (5) holds true from equation (4).
Ｐ ＝ ｐ７ａ ＋ ｐ ７ｂ・・・（５）（２）
、（３） 、 （５１式より （６））式が成り立つ。P = p7a + p7b...(5)(2)
, (3) , (From equation 51, equation (6)) holds true.
ｐ ＝Ｐ Ｐｏ／２・・・・・・（６）７ａ
７
ｐ、ｐ７はＯＴＤＲ方式測定装置が受信可能な値である
から、（６）式を使って距離分解能で決まる長さＬの半
分の長さであるＪ２７８の部分の後方散乱光ｐ７ａを算
出することができる。p = P Po/2 (6) 7a
7 Since p and p7 are values that can be received by the OTDR measurement device, use equation (6) to calculate the backscattered light p7a of the portion J278, which is half the length L determined by the distance resolution. be able to.
また、１□、とｆｌｌａとは同じ位置なので、光ファイ
バ１の状態も同じと考えられるから、 （７）式が成り
立つ。Furthermore, since 1□ and fla are at the same position, the state of the optical fiber 1 can be considered to be the same, so equation (7) holds true.
ｐ１ａ＝ｐ７ａ ・・・・・・（７）（４） 、（
６）、（７）、式より（８）式が成り立つ。p1a=p7a ・・・・・・(7)(4) ,(
Equation (8) holds true from Equations 6) and (7).
ｐ ＝Ｐ −（Ｐ −Ｐｏ／２）・ （８）１ｂ
１ ７
同様にして全てのｐｎａＳｐｏｂが算出でき、その値よ
りＬｌ２の距離分解能の測定が可能となる。p = P - (P - Po/2) (8) 1b
1 7 All pnaSpob values can be calculated in the same way, and the distance resolution of Ll2 can be measured from the calculated values.
このように本実施例の方を法用いると、従来のＯＴＤＲ
方式測定方法の距離分解能を大幅に高めることができる
。When the method of this embodiment is used in this way, the conventional OTDR
The distance resolution of the method measurement method can be greatly improved.
第２図には本発明の他の実施例が示されている。Another embodiment of the invention is shown in FIG.
本実施例は距離分解能をＬ／ｋに高める方法を示したも
のである。ｋ本の光ファイバ１を同一経路に設置し、そ
のに本の光ファイバ１をＬ／にの長さの接続用光ファイ
バ８で直列に接続する。同図に示されている入射パルス
光２の入射端のＬｏと同じ位置にあるに本の光ファイバ
１を均一な状態にする。このようにすることにより上述
の場合と同じ方法でＬ／にの長さ毎の後方散乱光の算出
が可能となる。This example shows a method for increasing the distance resolution to L/k. K optical fibers 1 are installed in the same path, and the optical fibers 1 are connected in series to them by a connecting optical fiber 8 having a length of L/. The optical fiber 1 is brought into a uniform state at the same position as the input end Lo of the input pulsed light 2 shown in the figure. By doing this, it becomes possible to calculate the backscattered light for each length of L/ using the same method as in the above case.
［発明の効果］
上述のように本発明は光ファイバを複数のＮ本並列に配
列し、その配列したＮ本の光ファイバを長さＬ／Ｎの接
続用光ファイバで直列に接続して後方散乱光を測定した
ので、距離分解能で決まる長さしの１／Ｎの長さの部分
の後光散乱光が算出比できるようになって、Ｌ／Ｎの距
離分解能の測定が可能となり、距離分解能を大幅に＾め
ることを可能としたＯＴＤＲ方式測定方法を得ることが
できる。[Effects of the Invention] As described above, the present invention arranges a plurality of N optical fibers in parallel, and connects the arranged N optical fibers in series with a connecting optical fiber having a length of L/N. Since we have measured the scattered light, we can calculate the backscattered light at a length of 1/N of the length determined by the distance resolution, making it possible to measure the distance resolution of L/N. It is possible to obtain an OTDR measurement method that makes it possible to significantly increase the resolution.
第１図および第２図は本発明のＯＴＤＲ方式測定方沫の
夫々異なる実施例による光ファイバの接続を示す説明図
、第３図は従来のＯＴＤＲ方式測定方法による測定を示
す説明図である。
１：光ファイバ、
２：入射パルス光、
４：後方散乱光、
６．８：接続用光ファイバ。FIGS. 1 and 2 are explanatory diagrams showing the connection of optical fibers according to different embodiments of the OTDR measurement method of the present invention, and FIG. 3 is an explanatory diagram showing measurement by the conventional OTDR measurement method. 1: Optical fiber, 2: Incident pulsed light, 4: Backscattered light, 6.8: Optical fiber for connection.
Claims (1)
る長さＬ内で発生する後光錯散乱光の総量を受信・測定
するＯＴＤＲ方式測定方法において、前記長さＬ内に前
記光ファイバを複数のＮ本並列に配列し、その配列した
Ｎ本の光ファイバを長さＬ／Ｎの接続用光ファイバで直
列に接続して後方散乱光を測定するようにしたことを特
徴とするＯＴＤＲ方式測定方法。1. In an OTDR measurement method in which a pulsed light is input into an optical fiber and the total amount of backlight scattered light generated within a length L determined by the distance resolution is received and measured, the optical fiber is inserted into the optical fiber within the length L. An OTDR method characterized by arranging a plurality of N optical fibers in parallel and connecting the arranged N optical fibers in series with a connecting optical fiber having a length of L/N to measure backscattered light. Measuring method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21948790A JPH04102042A (en) | 1990-08-21 | 1990-08-21 | Otdr type measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21948790A JPH04102042A (en) | 1990-08-21 | 1990-08-21 | Otdr type measurement method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04102042A true JPH04102042A (en) | 1992-04-03 |
Family
ID=16736217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21948790A Pending JPH04102042A (en) | 1990-08-21 | 1990-08-21 | Otdr type measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04102042A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2022073128A (en) * | 2020-10-30 | 2022-05-17 | アンリツ株式会社 | Otdr measurement device and otdr measurement method |
-
1990
- 1990-08-21 JP JP21948790A patent/JPH04102042A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2022073128A (en) * | 2020-10-30 | 2022-05-17 | アンリツ株式会社 | Otdr measurement device and otdr measurement method |
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