JPS6130741A - Method and apparatus for detecting rearwardly scattered light abnormal pattern of optical fiber - Google Patents
Method and apparatus for detecting rearwardly scattered light abnormal pattern of optical fiberInfo
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- JPS6130741A JPS6130741A JP15343684A JP15343684A JPS6130741A JP S6130741 A JPS6130741 A JP S6130741A JP 15343684 A JP15343684 A JP 15343684A JP 15343684 A JP15343684 A JP 15343684A JP S6130741 A JPS6130741 A JP S6130741A
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- Prior art keywords
- curve
- optical fiber
- backscattered light
- points
- abnormal pattern
- Prior art date
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- 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
- G01M11/3109—Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR
- G01M11/3145—Details of the optoelectronics or data analysis
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (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)
Abstract
Description
【発明の詳細な説明】
(イ)発明の属する技術分野
本発明は光ファイバの後方散乱光測定に関し、より詳細
には光ファイバの後方散乱光測定により得られたBS曲
線をもとに光ファイバの欠陥の存在有無およびその種類
の判定を行うための方法および装置に関する。DETAILED DESCRIPTION OF THE INVENTION (a) Technical field to which the invention pertains The present invention relates to backscattered light measurement of an optical fiber, and more specifically, to the measurement of optical fiber backscattered light based on the BS curve obtained by the backscattered light measurement of an optical fiber. The present invention relates to a method and apparatus for determining the presence or absence of a defect and its type.
(ロ)従来技術とその問題点
光ファイバの欠陥、たとえば段、うねり2曲り等を検出
する方法として第1図にそのシステム概要を示すような
後方散乱光測定法が用いられている。第1図において、
パルス発生器1.光送信部2が協働して光パルスを発生
させ、この光パルスがレンズ3.ハーフミラ−5および
レン、ズ4を経て光ファイバ6の一端に入射される。光
ファイバ6の内部で反射した光が後方散乱光として逆方
向に戻り、ハーフミラ−5で反射されてレンズ7を経て
受光装置8により受けられる。そして表示又は記録装置
9により横軸を伝播時間、縦軸を受光パワーであられし
た後方散乱光の受光パワー曲線すなわち138曲線とし
て表示される。被測定光ファイバにたとえば段、うねり
1曲り等の欠陥が存在していた場合にはその欠陥がBS
曲線上にそれぞれ第2図、第3図および第4図にやや誇
張的に示すような異常パターンとしてあられれる。これ
によりBS曲線のパターンを見ることにより光ファイバ
の欠陥の存在有無およびその欠陥の種類を判定すること
ができる。このようにBS曲線の目視観察により光ファ
イバの判定を行うのが従来の方法であった。(b) Prior art and its problems As a method for detecting defects in optical fibers, such as steps, undulations, double bends, etc., a backscattered light measurement method is used, as shown in FIG. 1. In Figure 1,
Pulse generator 1. The optical transmitter 2 cooperates to generate a light pulse, which is transmitted to the lens 3. The light passes through a half mirror 5 and a lens 4 and enters one end of an optical fiber 6. The light reflected inside the optical fiber 6 returns in the opposite direction as backscattered light, is reflected by the half mirror 5, passes through the lens 7, and is received by the light receiving device 8. Then, the display or recording device 9 displays the backscattered light as a received light power curve, ie, a 138 curve, with the horizontal axis representing the propagation time and the vertical axis representing the received light power. If there is a defect in the optical fiber to be measured, such as a step or a single bend, the defect is considered to be BS.
Abnormal patterns appear on the curves as shown somewhat exaggeratedly in FIGS. 2, 3, and 4, respectively. Thereby, by looking at the pattern of the BS curve, it is possible to determine the presence or absence of a defect in the optical fiber and the type of the defect. As described above, the conventional method is to judge the optical fiber by visually observing the BS curve.
しかしながら上記従来の光ファイバの後方散乱光異常パ
ターン検出方法においては、光ファイバに実際に欠陥が
存在する場合でもB、S曲線に必ずしも明確な異常バタ
τンがあられれるとは限らず、またノイズの影響もうけ
るためBS曲線の目視観察では光ファイバの欠陥の存在
有無およびその種類に関し正確かつ客観的な判断を下す
ことが困難な場合が多かった。However, in the conventional optical fiber backscattered light abnormal pattern detection method described above, even if there is actually a defect in the optical fiber, a clear abnormal pattern τ is not necessarily formed on the B and S curves, and Due to the influence of defects, it is often difficult to make accurate and objective judgments regarding the presence or absence and type of defects in optical fibers by visual observation of the BS curve.
eう 発明の目的
本発明は上記従来の事情に鑑みなされたものであって、
光ファイバの欠陥の存在有無およびその種類の判定を正
確かつ客観的に行うことを可能にする光ファイバの後方
散乱光異常パターン検出方法およびその装置を提供する
ことを目的としている。Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and
It is an object of the present invention to provide a method and apparatus for detecting an abnormal pattern of backscattered light in an optical fiber, which makes it possible to accurately and objectively determine the presence or absence of a defect in an optical fiber and its type.
に)発明の構成
本発明は光ファイバの後方散乱光測定にて得られたBS
曲線をその平均直線から上記BS曲線上の各点までの隔
りを示す曲線に変換し、上記隔りを示す曲線を平滑化処
理し、上記平滑化処理後の上記隔りを示す曲線の極大点
および極小点の個数とその絶対値をパラメータとし、あ
らかじめ同一の平滑化条件にて求めておいたパラメータ
基準値と比較することにより光ファイバ°の欠陥の存在
有無およびその種類を判定することを特徴とする。B) Structure of the invention The present invention is based on the BS obtained by measuring backscattered light of an optical fiber.
Converting the curve into a curve showing the distance from the average straight line to each point on the BS curve, smoothing the curve showing the distance, and calculating the maximum of the curve showing the distance after the smoothing process. The number of points and minimum points and their absolute values are used as parameters, and the presence or absence of defects in optical fibers and their types can be determined by comparing them with parameter reference values determined in advance under the same smoothing conditions. Features.
これにより光ファイバの欠陥の存在の有無およびその種
類の判定を正確かつ客観的に行うことが可能な光ファイ
バの後方散乱光異常パターン検出方法および装置が提供
される。Thereby, a method and apparatus for detecting an abnormal pattern of backscattered light in an optical fiber are provided, which can accurately and objectively determine the presence or absence of a defect in an optical fiber and its type.
(ホ)発明の実施例
光パルス試験器により得られた後方散乱光特性をあられ
すBS曲線の一例が第5図に11で示されている。横軸
は光ファイバ端からの距離または伝播時間を示し、縦軸
は受光パワー(dn)を示す。(E) Embodiment of the Invention An example of the BS curve showing the backscattered light characteristics obtained by the optical pulse tester is shown at 11 in FIG. The horizontal axis shows the distance or propagation time from the end of the optical fiber, and the vertical axis shows the received light power (dn).
このBS曲線11からBS曲線の平均直線12が求めら
れる。平均直線12からBS曲線11上の一定時間間隔
ごとの各点までの隔りを示すBS変換曲線]4が、水平
軸13に関し連続的なドツトとして縦軸に関し拡大され
た座標で示されている。From this BS curve 11, an average straight line 12 of the BS curve is determined. A BS conversion curve showing the distance from the average straight line 12 to each point at regular time intervals on the BS curve 11] 4 is shown as a continuous dot with respect to the horizontal axis 13 and with enlarged coordinates with respect to the vertical axis. .
第2図乃至第4図に例示したようなBS曲線の異常パタ
ーンの判定をしやすくするためのBS曲線の平滑化を行
うにあたり、水平軸に関l一連続的なドツトで示したB
S変換曲線14をもとに平滑化処理を行う。本例におい
ては5゛0点の移動平均を求めた結果が第6図に示され
ている。第6図の曲線ではまだ平滑化が不十分であるた
め滑かさにかげ、それぞれN印およびN印で示されるよ
うに極太、極小点が曲線に沿って多数存在していること
が分る。そこで第6図の曲線をもとにさらに50点の移
動平均を求めた結果が第7図に示されている。第7図の
曲線ではかなりの程度まで平滑化がなされており滑かな
曲線を示している。極太、極小点はそれぞれN印および
N印で示されるよう各一点づつのみ存在している。When smoothing the BS curve to facilitate the determination of abnormal patterns in the BS curve as illustrated in Figs. 2 to 4, the B
Smoothing processing is performed based on the S conversion curve 14. In this example, the results of calculating the moving average of 50 points are shown in FIG. The curve in FIG. 6 has not yet been sufficiently smoothed, so despite its smoothness, it can be seen that there are many very thick and minimal points along the curve, as shown by N marks and N marks, respectively. Therefore, a moving average of 50 points was calculated based on the curve shown in FIG. 6, and the results are shown in FIG. The curve in FIG. 7 has been smoothed to a considerable extent and shows a smooth curve. Only one extremely thick point and one extremely small point exist as shown by N marks and N marks, respectively.
正常な光ファイバと各種の欠陥、ここではそれぞれ段、
うねり2曲りを有する光ファイバについて上述と同一の
方法にてBS変換曲線に関する平滑化を行い、その極太
、極小点のあられれ方を調べたところ下表のような結果
が得られた(表1)。Normal optical fiber and various defects, here each stage,
We smoothed the BS conversion curve for an optical fiber with two undulations using the same method as described above, and examined the appearance of extremely thick and minimum points, and obtained the results shown in the table below (Table 1) ).
表1
ここで極太、極小の最大、最小値の単位は1カー20d
Iiに相当する。表1の極太および極小点数から段、う
ねりおよび曲りを有する光ファイバのBS曲線が概ね第
2図乃至第4図に示したようなパターンを有することを
示しており、各種欠陥の種類に応じて18曲線にあられ
れるべき特徴的ノ(ターンが平滑化の結果間らかになる
ことが分る。Table 1 Here, the maximum and minimum values of extremely thick and extremely small are in units of 1 car and 20 d.
Corresponds to Ii. The extremely thick and minimum points in Table 1 indicate that the BS curve of an optical fiber with steps, undulations, and bends generally has a pattern as shown in Figures 2 to 4. It can be seen that the characteristic turns that should appear on the 18 curve become smoother as a result of smoothing.
すなわち18曲線の生データでは必ずしも明確に示され
ないBS曲線の異常パターンのマクロ的特徴が平滑化に
より明確化されるのである。また光ファイバが正常な場
合は極太、極小点数が欠陥ありの場合に比べ多(、シか
も極太、極小の最大。In other words, the macro features of the abnormal pattern of the BS curve, which are not necessarily clearly shown in the raw data of the 18 curves, are clarified by smoothing. In addition, when the optical fiber is normal, the number of extremely thick and minimum points is higher than when there is a defect.
最小値の絶対値が/」・さいことが分る。It turns out that the absolute value of the minimum value is /''.
以上の結果にもとづき、平滑化処理されたBS変換曲線
の極太、極小点数と極太の最大値、極小の最小値の絶対
値をパラメータとしであるBS曲線を示した光ファイバ
の欠陥の存在有無およびその種類を判定することが可能
となることが分る。Based on the above results, the presence or absence of defects in an optical fiber exhibiting a BS curve using the number of extremely thick and minimum points of the smoothed BS conversion curve, the maximum value of the extremely thick, and the absolute value of the minimum value of the extremely small as parameters are determined. It turns out that it is possible to determine the type.
すなわち、各種欠陥を有する、および正常な光ファイバ
についてあらかじめそれらのBS変換曲線から平滑化処
理により上記パラメータの基準値を求めておき、同じ条
件で平滑化処理した未判定の光ファイバのBS変換曲線
から得られた上記パラメータ値を基準値と比較すること
により光ファイバの欠陥の存在有無およびその種類を判
定できるのである。−例として第1表に示したデータを
もとに、BS変換曲線からある時間間隔でとった50点
の移動平均を2回くり返すという平滑化条件にて、下記
を判定のためのパラメータ基準値とすることができる(
表2)。In other words, standard values of the above parameters are obtained in advance by smoothing processing from the BS conversion curves of optical fibers with various defects and normal optical fibers, and the BS conversion curve of the undetermined optical fiber is smoothed under the same conditions. By comparing the parameter values obtained from the above with reference values, it is possible to determine the presence or absence of a defect in the optical fiber and its type. -As an example, based on the data shown in Table 1, the parameter criteria for determining the following are the smoothing conditions of repeating twice the moving average of 50 points taken at a certain time interval from the BS conversion curve. Can be a value (
Table 2).
麦 2
なおりS変換曲線の平滑化条件はBS曲線のマクロ的異
常パターンが最も良くあられれるように決めれば良いの
で、上記例に限らず生データの条件に応じて任意に、た
とえば移動平均3回繰り返しを行うように、設定するこ
とができる。Mugi 2 The smoothing conditions for the Naori S conversion curve can be determined in such a way that the macroscopic abnormal pattern of the BS curve can be best expressed, so it is not limited to the above example, but can be arbitrarily determined depending on the raw data conditions, for example, the moving average 3 It can be set to repeat twice.
上記光ファイバの後方散乱光異常パターン検出方法は機
械的にかつ自動的に実施することも可能である。すなわ
ち第8図にシステム構成の概念を示すようにBS変換曲
線の生データを1段もしくは複数段のフィルタ回路15
を通すことにより1回もしくは複数回の平滑化処理を行
い、その結果得られた極太、極小点の個数とその絶対値
の大きさをコンピュータを利用したコンパン−夕16に
て、あらかじめ同一条件にて各種の光ファイバから得た
パラメータ基準値と比較することにより、被測定光ファ
イバの欠陥の存在の有無またその欠陥の種類の判定を自
動的かつ即座に行うことができる。こうして光ファイバ
の自動検査装置を提供することも可能となる。The method for detecting an abnormal pattern of backscattered light in an optical fiber can also be performed mechanically and automatically. That is, as shown in the concept of the system configuration in FIG.
The number of extremely thick and extremely small points obtained as a result and the magnitude of their absolute value are calculated in advance under the same conditions using a computer-based Compan-Y16. By comparing the parameters with reference parameter values obtained from various types of optical fibers, it is possible to automatically and immediately determine the presence or absence of a defect in the optical fiber to be measured and the type of the defect. In this way, it is also possible to provide an automatic optical fiber inspection device.
(1発明の効果
以上のように本発明は光ファイバの後方散乱光測定にて
得られたBS曲線をその平均直線から上記BS曲線上の
各点までの隔りを示す曲線に変換し、上記隔りを示す曲
線を平滑化処理し、上記平滑化処理後の上記隔りを示す
曲線の極大点および極小点の個数とその絶対値をパラメ
ータとし、あらかじめ同一の平滑化条件にて求めておい
たパラメータ基準値と比較することにより光ファイバの
欠陥の存在有無およびその種類を判定することを特徴と
する。(1) Effects of the Invention As described above, the present invention converts the BS curve obtained by measuring backscattered light of an optical fiber into a curve indicating the distance from the average straight line to each point on the BS curve, and The curve showing the gap is smoothed, and the number and absolute value of the maximum and minimum points of the curve showing the gap after the smoothing process are used as parameters, and the values are calculated in advance under the same smoothing conditions. The present invention is characterized in that the presence or absence of a defect in the optical fiber and its type are determined by comparing it with a parameter reference value that has been determined.
これにより光ファイバの欠陥の存在有無およびその種類
の判定を視覚的な主観を排し正確かつ客観的に行うこと
を可能にする光ファイバの後方散乱光異常パターン検出
方法および装置が提供される0This provides a method and apparatus for detecting abnormal backscattered light patterns in optical fibers, which makes it possible to accurately and objectively determine the presence or absence of a defect in an optical fiber and its type without visual subjectivity.
第1図は光ファイバの後方散乱光測定システムの構成を
示す概要図、
第2図は段を有する光ファイバのBS曲線の異常パター
ンの一例を示す図、
第3図はうねりを有する光ファイバのBS曲線の異常パ
ターンの一例を示す図、
第4図は曲りを有する光ファイバのBS 曲線の異常
パターンの一例を示す図、
第5図はBS曲線の一例とそのBS変換曲線を示す図、
第6図は第5図のBS変換曲線を1回平滑化処理した後
の曲線、
第7図は第5図のBS変換曲線を2回平滑化処理した後
の曲線、
第8図は光ファイバの後方散乱光異常ノ(ターン検出装
置の概念図。
11・・・BS曲線 14・・・BS変換曲線15・
・・ファルタ回路’ 、16・・・コンノくレーク特許
出願人 住友電気工業株式会社
同 日本電信電話公社
(外5名)
奉1図
寅識v!r藺
秦57
算、4圀
イラ\il1竿Fも電
本7図
イう己、[一時開
葬ッ6凹
/FFigure 1 is a schematic diagram showing the configuration of an optical fiber backscattered light measurement system, Figure 2 is a diagram showing an example of an abnormal pattern of the BS curve of an optical fiber with steps, and Figure 3 is a diagram of an optical fiber with undulations. FIG. 4 is a diagram showing an example of an abnormal pattern of a BS curve of a curved optical fiber; FIG. 5 is a diagram showing an example of a BS curve and its BS conversion curve; Figure 6 shows the curve after smoothing the BS conversion curve in Figure 5 once, Figure 7 shows the curve after smoothing the BS conversion curve in Figure 5 twice, and Figure 8 shows the curve after smoothing the BS conversion curve in Figure 5 twice. Backscattered light abnormality (conceptual diagram of turn detection device. 11... BS curve 14... BS conversion curve 15.
...Falta circuit', 16... Konnok Lake patent applicant Sumitomo Electric Industries, Ltd. Nippon Telegraph and Telephone Public Corporation (5 others) Bong 1 diagram Tora knowledge v! r Ai Qin 57 calculation, 4 Kuni Ira \il 1 rod F also electric book 7 I, [temporary burial 6 depression/F
Claims (6)
線をその平均直線から該BS曲線上の各点までの隔りを
示す曲線に変換し、該隔りを示す曲線を平滑化処理し、
該平滑化処理後の該隔りを示す曲線の極大点、極小点の
個数とその絶対値をパラメータとし、あらかじめ同一の
平滑化条件にて求めておいたパラメータ基準値と比較す
ることにより光ファイバの欠陥の存在有無およびその種
類を判定することを特徴とする光ファイバの後方散乱光
異常パターン検出方法。(1) Convert the BS curve obtained by measuring the backscattered light of an optical fiber into a curve that shows the distance from the average straight line to each point on the BS curve, and smooth the curve that shows the distance. death,
The number of maximum points and minimum points of the curve indicating the gap after the smoothing process and their absolute values are used as parameters, and the optical fiber is 1. A method for detecting an abnormal pattern of backscattered light in an optical fiber, the method comprising determining the presence or absence of a defect and its type.
との複数の点に関する移動平均を求める操作を1回また
は複数回くりかえすことを特徴とする特許請求の範囲第
1項に記載の光ファイバの後方散乱光異常パターン検出
方法。(2) The smoothing process is characterized in that the operation of obtaining a moving average of a plurality of points at regular intervals on a curve indicating the gap is repeated once or multiple times. A method for detecting abnormal patterns of backscattered light in optical fibers.
とを特徴とする特許請求の範囲第2項に記載の光ファイ
バの後方散乱光異常パターン検出方法。(3) The method for detecting an abnormal pattern of backscattered light in an optical fiber according to claim 2, wherein the operation for determining the moving average is repeated twice.
曲線から変換された該BS曲線の平均直線から該BS曲
線上の各点までの隔りを示す曲線を平滑化処理するため
のフィルタ回路と;該フィルタ回路による平滑化処理に
より得られた曲線の極大点、極小点の個数とその絶対値
をあらかじめ同一の平滑化条件にて求めておいたパラメ
ータ基準値と比較することにより該光ファイバの欠陥の
存在有無およびその種類を判定するためのコンパレータ
とを含むことを特徴とする光ファイバの後方散乱光異常
パターン検出装置。(4) BS of optical fiber obtained by optical pulse tester
a filter circuit for smoothing a curve that indicates the distance from the average straight line of the BS curve to each point on the BS curve; a curve obtained by the smoothing process by the filter circuit; A comparator for determining the presence or absence of a defect in the optical fiber and its type by comparing the number of maximum points and minimum points and their absolute values with parameter reference values determined in advance under the same smoothing conditions. An optical fiber backscattered light abnormal pattern detection device comprising:
示す曲線上の一定間隔ごとの複数の点に関する移動平均
を求めるための1段または複数段のフィルタ回路である
ことを特徴とする特許請求の範囲第4項に記載の光ファ
イバの後方散乱光異常パターン検出装置。(5) The filter circuit for performing the smoothing process is a one-stage or multi-stage filter circuit for obtaining a moving average of a plurality of points at regular intervals on the curve indicating the gap. An optical fiber backscattered light abnormal pattern detection device according to claim 4.
あることを特徴とする特許請求の範囲第5項に記載の光
ファイバの後方散乱光異常パターン検出装置。(6) The optical fiber backscattered light abnormal pattern detection device according to claim 5, wherein the plurality of stages of filter circuits are two-stage filter circuits.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15343684A JPS6130741A (en) | 1984-07-24 | 1984-07-24 | Method and apparatus for detecting rearwardly scattered light abnormal pattern of optical fiber |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15343684A JPS6130741A (en) | 1984-07-24 | 1984-07-24 | Method and apparatus for detecting rearwardly scattered light abnormal pattern of optical fiber |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6130741A true JPS6130741A (en) | 1986-02-13 |
JPH0544975B2 JPH0544975B2 (en) | 1993-07-07 |
Family
ID=15562478
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15343684A Granted JPS6130741A (en) | 1984-07-24 | 1984-07-24 | Method and apparatus for detecting rearwardly scattered light abnormal pattern of optical fiber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6130741A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0407009A2 (en) * | 1989-05-05 | 1991-01-09 | Tektronix, Inc. | Estimation of fiber loss and return signal power |
JPH0422836A (en) * | 1990-05-18 | 1992-01-27 | Kokusai Denshin Denwa Co Ltd <Kdd> | Faulty point measuring method by pulse echo |
JP2011158330A (en) * | 2010-01-29 | 2011-08-18 | Nippon Telegr & Teleph Corp <Ntt> | Apparatus and method for measurement of optical path |
-
1984
- 1984-07-24 JP JP15343684A patent/JPS6130741A/en active Granted
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0407009A2 (en) * | 1989-05-05 | 1991-01-09 | Tektronix, Inc. | Estimation of fiber loss and return signal power |
JPH0422836A (en) * | 1990-05-18 | 1992-01-27 | Kokusai Denshin Denwa Co Ltd <Kdd> | Faulty point measuring method by pulse echo |
JP2011158330A (en) * | 2010-01-29 | 2011-08-18 | Nippon Telegr & Teleph Corp <Ntt> | Apparatus and method for measurement of optical path |
Also Published As
Publication number | Publication date |
---|---|
JPH0544975B2 (en) | 1993-07-07 |
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