JPH0362212B2 - - Google Patents
Info
- Publication number
- JPH0362212B2 JPH0362212B2 JP60186530A JP18653085A JPH0362212B2 JP H0362212 B2 JPH0362212 B2 JP H0362212B2 JP 60186530 A JP60186530 A JP 60186530A JP 18653085 A JP18653085 A JP 18653085A JP H0362212 B2 JPH0362212 B2 JP H0362212B2
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- optical component
- measured
- optical
- frequency
- 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 - Lifetime
Links
- 230000003287 optical effect Effects 0.000 claims description 53
- 239000004065 semiconductor Substances 0.000 claims description 37
- 238000000034 method Methods 0.000 claims description 24
- 239000013307 optical fiber Substances 0.000 description 16
- 238000000253 optical time-domain reflectometry Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 238000010408 sweeping Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000002168 optical frequency-domain reflectometry Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 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
- G01M11/3172—Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection
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、光部品に光を照射したときのその光
が反射する反射点位置の測定方法に関するもので
あり、特に半導体レーザに正弦波等で変調をか
け、その周波数を掃引したときの出力光を被測定
光部品に入射させ、その反射光を半導体レーザに
入射させることにより半導体レーザの出力光を周
波数領域（ドメイン）で観測し、そこに現われ雑
音ピークの周波数間隔から、被測定光部品の反射
点位置を測定する光部品の反射点測定方法に関す
るものである。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for measuring the position of a reflection point where light is reflected when an optical component is irradiated with light. By applying modulation and sweeping the frequency, the output light is incident on the optical component to be measured, and the reflected light is incident on the semiconductor laser.The output light of the semiconductor laser is observed in the frequency domain (domain). This invention relates to a method for measuring a reflection point of an optical component in which the position of a reflection point of an optical component to be measured is measured from the frequency interval of noise peaks appearing in .
（従来の技術）
従来、光フアイバケーブル等の光部品における
障害点や破断点等の不連続点までの距離を求める
方法として、OTDR法（Optical Time Domain
Reflectometory法）が一般的に用いられている。(Prior Technology) Conventionally, the OTDR method (Optical Time Domain
Reflectometric method) is commonly used.
これは、反射光を時間領域で観測する技術手法
である。（例えば、特開昭51−83546号公報及び特
開昭60−86438号公報）すなわち光部品の光フア
イバケーブルの一端から光パルスを入射し、その
反射して返つてきた反射波のレベルを縦軸に時間
を横軸にとる時間領域での観測に基づいて光フア
イバケーブルの障害点若しくは破断点等の不連続
点の存否を探索し、不連続点までの距離を得てい
る。 This is a technical method for observing reflected light in the time domain. (For example, JP-A-51-83546 and JP-A-60-86438) In other words, a light pulse is input from one end of an optical fiber cable of an optical component, and the level of the reflected wave that is reflected back is measured vertically. Based on observations in the time domain, where the axis is time and the horizontal axis is time, we search for the presence or absence of discontinuous points such as failure points or break points in the optical fiber cable, and obtain the distance to the discontinuous points.
（発明が解決しようとする問題点）
光パルスを用いて光部品、例えば被測定光フア
イバケーブルの障害若しくは破断点等の不連続点
を探索する場合、光の速度が相当大きいため、時
間領域での観測では、距離の分解能が低く、さら
に光パルスを被測定光フアイバケーブルに入射さ
せたとき、その入射面で生じるレベルの大きなフ
レネル反射のため、近距離（光パルス幅＋数ｍ以
内）に破断点が存在しても、受光系が飽和しこれ
を検出することができなかつた。従つて極々近距
離例えば光コネクタ内や光スイツチ、光減衰器内
での反射点は当然のことながらOTDR法では検
出できない。また上記のOTDR法で、たとえ入
射面で生じるフレネル反射をおさえるため、微弱
な光を入射させて使用したとしても、電気信号処
理が可能なレベルの反射光を受光できない。この
フレネル反射だけを除去する方法も考えられる
が、高速の光シヤツタが得られず、その実施が不
可能で、いずれにしてもOTDR法によつては極
く近距離の反射点を検出できない欠点があつた。(Problem to be Solved by the Invention) When searching for discontinuities such as faults or break points in optical components such as optical fiber cables to be measured using optical pulses, the speed of light is quite high, so it is difficult to find discontinuities in the time domain. In the observation of Even if a break point existed, the light receiving system was saturated and could not be detected. Therefore, it goes without saying that reflection points at extremely short distances, such as inside optical connectors, optical switches, and optical attenuators, cannot be detected by the OTDR method. Furthermore, in the above-mentioned OTDR method, even if weak light is incident in order to suppress Fresnel reflection occurring at the incident surface, reflected light cannot be received at a level that allows electrical signal processing. A method of removing only this Fresnel reflection can be considered, but it is impossible to achieve high-speed optical shutter, and in any case, the OTDR method has the drawback that it cannot detect reflection points at extremely close distances. It was hot.
本発明は上記の欠点を解決することを目的とし
ており、従来技術の時間領域での観測とは異な
り、周波数領域での観測を行う点に特徴がある。
したがつて、半導体レーザに、例えば正弦波で変
調をかけ、その正弦波の周波数を掃引したときの
出力光を被測点光部品に入射させ、その反射光を
半導体レーザに入射させることにより半導体レー
ザの出力光に現われる雑音のピークの周波数間隔
から、極く近距離の被測定光部品内の反射点位置
を検出するOFDR法（Optical Frequency
Domain Reflectmetory法）による光部品の反射
点測定方法を提供することを目的としている。 The present invention aims to solve the above-mentioned drawbacks, and is characterized in that it performs observation in the frequency domain, unlike the observation in the time domain of the prior art.
Therefore, by modulating a semiconductor laser with a sine wave, for example, and then sweeping the frequency of the sine wave, the output light is incident on the optical component at the measurement point, and the reflected light is incident on the semiconductor laser. The OFDR method (Optical Frequency
The purpose of this research is to provide a method for measuring reflection points on optical components using the domain reflectmetry method.
（問題点を解決するための手段）
上記の目的を達成するため、すなわち、周波数
領域（周波数ドメイン）での観測を容易にするた
めに、本発明の光部品の反射点測定方法は半導体
レーザに交流電流を印加して変調をかけるととも
に、その変調周波数を掃引させるか、若しくは半
導体レーザのしきい値電流値近傍の直流電流を印
加して得られる出力光を被測定光部品の端面に入
射し、入射された光が該被測定光部品の不連続面
で反射して返つてくる反射光を前記半導体レーザ
に入射させ、半導体レーザの出力光に現われる雑
音のピークの周波数間隔から被測定光部品の反射
点位置を指示させるようにしたことを特徴として
いる。以下図面を参照しながら本発明を説明す
る。(Means for Solving the Problems) In order to achieve the above object, that is, to facilitate observation in the frequency domain, the method for measuring reflection points of optical components of the present invention is applied to semiconductor lasers. Apply alternating current to apply modulation and sweep the modulation frequency, or apply direct current near the threshold current value of the semiconductor laser and make the output light incident on the end face of the optical component to be measured. The incident light is reflected by the discontinuous surface of the optical component to be measured, and the reflected light that returns is incident on the semiconductor laser, and the optical component to be measured is determined based on the frequency interval of the peak of noise appearing in the output light of the semiconductor laser. The feature is that the position of the reflection point is indicated. The present invention will be described below with reference to the drawings.
（実施例）
第１図は本発明に係る光部品の反射点測定方法
を示す図、第２図は半導体レーザに印加される電
流の周波数と反射波による雑音出力レベルとの関
係を示す図、第３図は本発明に係る光部品の反射
点測定方法の一実施例構成である。(Example) Fig. 1 is a diagram showing a method for measuring a reflection point of an optical component according to the present invention, and Fig. 2 is a diagram showing the relationship between the frequency of the current applied to a semiconductor laser and the noise output level due to reflected waves. FIG. 3 shows the configuration of an embodiment of the method for measuring reflection points of optical components according to the present invention.
第１図において、１は半導体レーザ、２は変調
用電気信号発生装置、３は受光素子、４は増幅
器、５は周波数掃引付レベル測定装置、６は被測
定光部品である。 In FIG. 1, 1 is a semiconductor laser, 2 is a modulation electric signal generator, 3 is a light receiving element, 4 is an amplifier, 5 is a level measuring device with frequency sweep, and 6 is an optical component to be measured.
一般に、半導体レーザ１の出力光が、被測定光
部品６、例えば光フアイバケーブル端等から反射
してその反射光が再び半導体レーザ１の活性層に
戻ると、自己結合現象により動作特性が変化し、
雑音が発生することが知られている。例えば半導
体レーザ１の原理的な雑音発生機構は、注入キヤ
リアと光子の粒子性に基づく量子シヨツト雑音
（quantum shot noise）にある。すなわち全くラ
ンダムに自然放出や誘導放出及び吸収が発生する
ために、光出力のゆらぎ（雑音）が生じる。この
雑音は閾値でピークをもつ。そして閾値近傍では
利得の大きくなつた状態で、ランダムに発生する
自然放出及び誘導放出が増幅されて多縦モードに
寄与するから、光出力の大きなゆらぎとなる。 Generally, when the output light of the semiconductor laser 1 is reflected from the optical component 6 to be measured, such as the end of an optical fiber cable, and the reflected light returns to the active layer of the semiconductor laser 1, the operating characteristics change due to a self-coupling phenomenon. ,
It is known that noise is generated. For example, the fundamental noise generation mechanism of the semiconductor laser 1 is quantum shot noise based on the particle nature of injected carriers and photons. That is, since spontaneous emission, stimulated emission, and absorption occur completely randomly, fluctuations (noise) in the optical output occur. This noise has a peak at the threshold. In the vicinity of the threshold, the spontaneous emission and stimulated emission that occur randomly are amplified in a state where the gain is large and contribute to multiple longitudinal modes, resulting in large fluctuations in the optical output.
半導体レーザ１と被測定光部品６の光フアイバ
ケーブルとを結合し、半導体レーザ１に例えば直
流バイアスを印加する。そして半導体レーザ１に
閾値近傍の直流電流又は交流電流を流してやる
と、上記シヨツト雑音が反射光により増大する現
象が見られる。これはコネクタ部やスプライス部
などの不連続面からの反射光が半導体レーザ１に
入射し、該半導体レーザ１の発振状態が変化する
ことにより生ずることは前述した通りである。 The semiconductor laser 1 and the optical fiber cable of the optical component to be measured 6 are coupled, and a DC bias, for example, is applied to the semiconductor laser 1. When a direct current or an alternating current near the threshold is caused to flow through the semiconductor laser 1, a phenomenon is observed in which the shot noise increases due to reflected light. As described above, this occurs when reflected light from a discontinuous surface such as a connector portion or a splice portion enters the semiconductor laser 1 and the oscillation state of the semiconductor laser 1 changes.
半導体レーザ１から出た光は、被測定光部品６
に入射されると、
半導体レーザ１へのキヤリア注入電流によつ
て誘起される光
反射点から戻つてくる光
によるモード同期が起る。レーザ発振状態は上記
，の外部注入信号によつて一定周波数間隔で
雑音ピークが生じる。この雑音ピークをスペクト
ラムアナライザ等の測定器で測定する。この周波
数間隔は被測定光部品６、すなわち光フアイバケ
ーブル長に起因している。 The light emitted from the semiconductor laser 1 is transmitted to the optical component 6 to be measured.
When the laser beam is incident on the semiconductor laser 1, mode locking occurs due to the light induced by the carrier injection current into the semiconductor laser 1 and the light returning from the reflection point. In the laser oscillation state, noise peaks occur at constant frequency intervals due to the externally injected signal mentioned above. This noise peak is measured with a measuring instrument such as a spectrum analyzer. This frequency interval is caused by the length of the optical component 6 to be measured, that is, the optical fiber cable.
次に本願発明の一実施例を第１図に示されたよ
うな系のもとに説明する。 Next, an embodiment of the present invention will be described based on a system as shown in FIG.
半導体レーザ１の変調用電気信号装置２からの
正弦波電流を印加して変調をかけ、例えば周波数
掃引付レベル測定装置５からの掃引信号に基づい
て上記正弦波電流の周波数を掃引させた場合、半
導体レーザ１からの後方光を受光素子３で電気信
号に変換し、増幅器４で適宜増幅した後モニタし
てその出力波形を周波数掃引付レベル測定装置
５、例えばスペクトラムアナライザや周波数が掃
引できる選択レベル計等で観測すると、第２図に
示された如く、外部共振器等の長さできまる周波
数間隔Δfで雑音ピークが現れる。そして被測定
光部品６の反射点までの距離及びその群屈折率を
Ｌ，ｎ、光速をｃ（ｃ＝３×103m／sec）、とした
とき、
上記Δf、すなわち観測波形の雑音ピークの周
波数間隔との間には
Δf＝ｃ／2Ln ……(1)
が成立する。 When modulating the semiconductor laser 1 by applying a sine wave current from the electrical signal device 2 for modulation, and sweeping the frequency of the sine wave current based on a sweep signal from the level measuring device 5 with frequency sweep, for example, The backward light from the semiconductor laser 1 is converted into an electric signal by the light receiving element 3, appropriately amplified by the amplifier 4, and then monitored and the output waveform is measured by a level measuring device 5 with frequency sweep, such as a spectrum analyzer or a selection level that can sweep the frequency. When observed with a meter or the like, as shown in FIG. 2, noise peaks appear at frequency intervals Δf determined by the length of the external resonator, etc. Then, when the distance to the reflection point of the optical component 6 to be measured and its group refractive index are L and n, and the speed of light is c (c = 3 × 10 3 m/sec), the above Δf, that is, the noise peak of the observed waveform Δf=c/2Ln...(1) holds true between the frequency interval of .
従つて式(1)は
Ｌ＝ｃ／2Δfn ……(2)
となり、ｃ，ｎは定数で、Δfは周波数掃引レベ
ル測定装置５から測定できるので、被測定光部品
６の反射点位置までの距離Ｌを求めることができ
る。 Therefore, equation (1) becomes L=c/2Δfn (2), where c and n are constants, and Δf can be measured from the frequency sweep level measuring device 5, so the distance to the reflection point position of the optical component 6 to be measured is The distance L can be determined.
第３図は本発明に係る光部品の反射点測定方法
の一実施例構成を示しており、７は半導体レー
ザ、８はアバランシエフオトダイオード、９はネ
ツトワークアナライザ、１０は光フアイバケーブ
ルである。 FIG. 3 shows the configuration of an embodiment of the method for measuring reflection points of optical components according to the present invention, in which 7 is a semiconductor laser, 8 is an avalanche photodiode, 9 is a network analyzer, and 10 is an optical fiber cable. .
ネツトワークアナライザ９の出力端子から周波
数が掃引された交流電力が出力され、半導体レー
ザ７に直接変調をかける。従つて半導体レーザ７
から変調された光が出力される。この出力は光フ
アイバケーブル１０の一端から入射され、光フア
イバケーブル１０内を伝送するが、該光フアイバ
ケーブル１０内の終端或いは破断点で反射された
反射光が光フアイバケーブル１０の入射点に戻つ
てくる。そして該反射光は半導体レーザ７に入射
する。 The frequency-swept alternating current power is output from the output terminal of the network analyzer 9, and directly modulates the semiconductor laser 7. Therefore, the semiconductor laser 7
Modulated light is output from the This output is input from one end of the optical fiber cable 10 and transmitted within the optical fiber cable 10, but the reflected light reflected at the termination or break point within the optical fiber cable 10 returns to the input point of the optical fiber cable 10. It's coming. The reflected light then enters the semiconductor laser 7.
半導体レーザ７は前記説明の如く該反射光の入
射によつて発振状態が変化し、光強度雑音が発生
する。半導体レーザ７からの後方出力光を受光し
ているアバランシエフオトダイオード８で変換さ
れた電気信号には、上記光強度雑音が包含されて
おり、光電変換された電気信号は増幅器１１で増
幅された後、ネツトワークアナライザ９のＴ入力
端子に入力される。一方ネツトワークアナライザ
９の出力端子から出力された周波数の掃引された
交流電力が、Ｒ端子に入力されているので、上記
光強度雑音が第２図図示の如く測定されてネツト
ワークアナライザ９の表示装置に表示される。ネ
ツトワークアナライザ９の表示装置に表示された
雑音ピーク間の間隔周波数Δfを読みとり、式(2)
を適用することにより、光フアイバケーブル１０
内で反射して返つてくる反射光の反射点位置まで
の距離Ｌを求めることができる。 As described above, the oscillation state of the semiconductor laser 7 changes due to the incidence of the reflected light, and light intensity noise is generated. The electrical signal converted by the avalanche photodiode 8 receiving the backward output light from the semiconductor laser 7 contains the above-mentioned optical intensity noise, and the photoelectrically converted electrical signal is amplified by the amplifier 11. After that, it is input to the T input terminal of the network analyzer 9. On the other hand, since the frequency-swept AC power output from the output terminal of the network analyzer 9 is input to the R terminal, the above-mentioned optical intensity noise is measured as shown in FIG. 2 and displayed on the network analyzer 9. displayed on the device. Read the interval frequency Δf between the noise peaks displayed on the display device of the network analyzer 9, and use equation (2)
By applying the optical fiber cable 10
The distance L to the reflection point position of the reflected light that is reflected and returned within can be determined.
ここで、ネツトワークアナライザ９の測定可能
な雑音ピーク間隔周波数Δfを例えば500MHzとす
ると、最短の反射点までの距離Ｌは、光フアイバ
ケーブル１０の群屈折率ｎを1.5としたとき
Ｌ＝３×103／２×1.5×500×106＝0.2（ｍ）
となる。 Here, if the measurable noise peak interval frequency Δf of the network analyzer 9 is, for example, 500 MHz, then the distance L to the shortest reflection point is L=3× when the group refractive index n of the optical fiber cable 10 is 1.5. 10 3 /2×1.5×500×10 6 =0.2 (m).
このように本発明に係る反射点測点法によれ
ば、光フアイバケーブル１０の不連続点を求める
ことができる。そして特に近距離の反射点の測定
時に威力を発揮する。 As described above, according to the reflection point measuring point method according to the present invention, discontinuous points of the optical fiber cable 10 can be found. It is especially effective when measuring reflective points at short distances.
なお反射点までの距離Ｌに対する分解能は式(2)
から明らかな様に雑音ピークの周波数間隔Δfの
精度に依存する。従つてネツトワークアナライザ
９の分解能、すなわち一般に周波数掃引付レベル
測定装置５の分解能の優れた測定器を使用すれ
ば、近点の反射点測定にも充分に使用することが
できることを意味している。このことから光フア
イバケーブル１０に換え、他の光部品、例えば光
コネクタ、光分岐器、光スイツチ、光減衰器等光
回路構成部品の近距離の反射点位置を測定するこ
とができ、光回路の障害点を容易に検出すること
ができる。 The resolution for the distance L to the reflection point is expressed by formula (2)
As is clear from the above, it depends on the accuracy of the frequency interval Δf of the noise peaks. This means that if a measuring device with excellent resolution of the network analyzer 9, or generally the level measuring device 5 with frequency sweep, is used, it can be used satisfactorily for measuring near-point reflection points. . Therefore, instead of using the optical fiber cable 10, it is possible to measure the reflection point position of other optical components such as optical connectors, optical splitters, optical switches, optical attenuators, and other optical circuit components at short distances. failure points can be easily detected.
上記説明は交流電流を半導体レーザに印加した
実施例を主に説明したが、前述の直流電流を印加
した場合も同様である。 Although the above description mainly describes the embodiment in which an alternating current is applied to the semiconductor laser, the same applies to the case in which the above-mentioned direct current is applied.
しかも使用する周波数掃引付レベル測定装置の
読み取り精度の高い測定器を使用すれば、分解能
が高くなり、不連続点位置までの距離の精度が上
る。 Moreover, if a level measuring device with frequency sweep is used that has high reading accuracy, the resolution will be high and the accuracy of the distance to the discontinuity point position will be improved.
（発明の効果）
以上の実施例の説明で述べたように、たとえば
スペクトラムアナライザを用いて受光した光強度
を観測し、第２図のような波形を解析して測定す
るようにした。したがつて、本発明によれば、従
来の時間領域（時間ドメイン）での測定と異な
り、周波数ドメインで反射点を検出するので光部
品の近距離の不連続点位置を容易に検出すること
ができる。さらには、実施例で述べたように、従
来の時間ドメインによるOTDR法では入射端の
レベルの高い反射光に覆い隠され、数米以内の近
距離の反射点は測定できなかつたものが0.2米ま
で本願の方法により測定できるようになつた。ま
た光回路における各光部品の障害位置を高精度で
検出することができる。また近距離の不連続点を
検出できることから、光スイツチの動作を調べる
ことが極めて容易に行える。(Effects of the Invention) As described in the above description of the embodiment, the intensity of the received light is observed using, for example, a spectrum analyzer, and the waveform as shown in FIG. 2 is analyzed and measured. Therefore, according to the present invention, unlike the conventional measurement in the time domain, reflection points are detected in the frequency domain, so it is possible to easily detect the position of a discontinuous point in a short distance of an optical component. can. Furthermore, as mentioned in the example, in the conventional time-domain OTDR method, reflection points within a few meters could not be measured because they were obscured by the high-level reflected light at the input end. It has now become possible to measure up to 10% using the method of the present application. Furthermore, the location of a fault in each optical component in an optical circuit can be detected with high precision. Furthermore, since it is possible to detect discontinuous points at short distances, it is extremely easy to investigate the operation of the optical switch.
第１図は本発明に係る光部品の反射点測定方法
を説明するための図、第２図は半導体レーザに印
加される電流の周波数と反射波による雑音出力レ
ベルとの関係を示す図、第３図は本発明に係る光
部品の反射点測定方法の一実施例構成である。
図中、１は半導体レーザ、２は変調用電気信号
発生装置、３は受光素子、４は増幅器、５は周波
数掃引付レベル測定装置、６は被測定光部品、７
は半導体レーザ、８はアバランシエフオトダイオ
ード、９はネツトワークアナライザ、１０は光フ
アイバケーブルである。
FIG. 1 is a diagram for explaining the reflection point measuring method of an optical component according to the present invention, FIG. 2 is a diagram showing the relationship between the frequency of the current applied to the semiconductor laser and the noise output level due to reflected waves, and FIG. FIG. 3 shows the configuration of an embodiment of the method for measuring reflection points of optical components according to the present invention. In the figure, 1 is a semiconductor laser, 2 is a modulation electric signal generator, 3 is a light receiving element, 4 is an amplifier, 5 is a level measuring device with frequency sweep, 6 is an optical component to be measured, 7
8 is a semiconductor laser, 8 is an avalanche photodiode, 9 is a network analyzer, and 10 is an optical fiber cable.
Claims (1)
力光を得る段階と、該出力光を被測定光部品の端
面に入射する段部と、該被測定光部品が有する不
連続面からの反射光を前記半導体レーザに入射さ
せて、前記半導体レーザの出力光を受光する段階
と、該受光した出力光の光強度を周波数ドメイン
で観測したときにもたらされる雑音ピークの周波
数間隔を測定する段階と、該測定された周波数間
隔から被測定光部品の反射点位置を求める段階と
から成る光部品の反射点測定方法。 ２ 前記所定の電気信号が、その周波数が掃引さ
れている交流電流であることを特徴とする特許請
求の範囲第(1)項記載の光部品の反射点測定方法。 ３ 前記所定の電気信号が、前記半導体レーザの
電流しきい値の近傍の値の直流電流であることを
特徴とする特許請求の範囲第１項記載の光部品の
反射点測定方法。[Claims] 1. A step of applying a predetermined electric signal to a semiconductor laser to obtain output light, a step portion for making the output light incident on an end face of an optical component to be measured, and a step portion of the optical component to be measured. a step of making reflected light from a continuous surface enter the semiconductor laser and receiving output light of the semiconductor laser; and a frequency interval of noise peaks produced when the optical intensity of the received output light is observed in the frequency domain. A method for measuring a reflection point of an optical component, comprising the steps of: measuring the frequency interval; and determining the position of the reflection point of the optical component to be measured from the measured frequency interval. 2. The method for measuring reflection points of an optical component according to claim (1), wherein the predetermined electric signal is an alternating current whose frequency is swept. 3. The method for measuring a reflection point of an optical component according to claim 1, wherein the predetermined electric signal is a direct current having a value near a current threshold value of the semiconductor laser.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18653085A JPS6246227A (en) | 1985-08-24 | 1985-08-24 | Method for measuring reflective point of optical part |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18653085A JPS6246227A (en) | 1985-08-24 | 1985-08-24 | Method for measuring reflective point of optical part |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6246227A JPS6246227A (en) | 1987-02-28 |
| JPH0362212B2 true JPH0362212B2 (en) | 1991-09-25 |
Family
ID=16190105
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18653085A Granted JPS6246227A (en) | 1985-08-24 | 1985-08-24 | Method for measuring reflective point of optical part |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6246227A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5694979B2 (en) * | 2012-03-14 | 2015-04-01 | 日本電信電話株式会社 | Optical line monitoring device |
| JP5886681B2 (en) * | 2012-04-27 | 2016-03-16 | 日本電信電話株式会社 | Optical line monitoring device |
| JP5991859B2 (en) * | 2012-06-14 | 2016-09-14 | 日本電信電話株式会社 | Optical line monitoring device and control method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5183546A (en) * | 1974-12-07 | 1976-07-22 | Licentia Gmbh | |
| JPS6086438A (en) * | 1983-10-18 | 1985-05-16 | Nippon Telegr & Teleph Corp <Ntt> | Method and apparatus for testing optical fiber |
-
1985
- 1985-08-24 JP JP18653085A patent/JPS6246227A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5183546A (en) * | 1974-12-07 | 1976-07-22 | Licentia Gmbh | |
| JPS6086438A (en) * | 1983-10-18 | 1985-05-16 | Nippon Telegr & Teleph Corp <Ntt> | Method and apparatus for testing optical fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6246227A (en) | 1987-02-28 |
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