JP3453746B2 - Optical fiber inspection equipment - Google Patents
Optical fiber inspection equipmentInfo
- Publication number
- JP3453746B2 JP3453746B2 JP02161895A JP2161895A JP3453746B2 JP 3453746 B2 JP3453746 B2 JP 3453746B2 JP 02161895 A JP02161895 A JP 02161895A JP 2161895 A JP2161895 A JP 2161895A JP 3453746 B2 JP3453746 B2 JP 3453746B2
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- Prior art keywords
- frequency
- converter
- signal
- light
- output
- Prior art date
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- Testing Of Optical Devices Or Fibers (AREA)
Description
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は、光ファイバ等の検査装
置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for optical fibers and the like.
【０００２】[0002]
【従来の技術】光ファイバ検査装置には、よく知られて
いるＯＴＤＲ（Optical Time DomainReflectmeter）の
他に、ＯＦＤＲ（Optical Frequency Domain Reflectme
ter）がある。図３にファイバ形干渉計によるＯＦＤＲ
のブロック図を示す。2. Description of the Related Art In addition to a well-known OTDR (Optical Time Domain Reflectmeter), an optical fiber inspection apparatus includes an OFDR (Optical Frequency Domain Reflectme
ter). Figure 3 OFDR with fiber interferometer
The block diagram of is shown.
【０００３】図３において、電気・光変換器（以下Ｅ／
Ｏ変換器という）３から発せられる光（例えばレーザ
光）は、分配器２を介して与えられるスイープ発振器１
の出力により駆動され、出力光の周波数が掃引されるよ
うに制御されている。この出力光は光カプラ４を経て被
測定対象の光ファイバ（以下ＤＵＴ（Device Under Tes
t ）５に入り、ＤＵＴ５中の障害点（例えば、破断面）
等で反射する。その反射光は光カプラ４を経て光・電気
変換器（Ｏ／Ｅ変換器）６に入り、電気信号に変換さ
れ、ミキサ７に入る。In FIG. 3, an electric / optical converter (hereinafter referred to as E /
The light (for example, laser light) emitted from the O converter 3 is supplied to the sweep oscillator 1 through the distributor 2.
It is driven by the output of the output light and is controlled so that the frequency of the output light is swept. The output light passes through the optical coupler 4 and is measured by an optical fiber (hereinafter referred to as DUT (Device Under Tes).
t) 5 is entered and the obstacle point in DUT 5 (eg fracture surface)
And so on. The reflected light enters the optical / electrical converter (O / E converter) 6 through the optical coupler 4, is converted into an electric signal, and enters the mixer 7.
【０００４】ミキサ７にはまた前記スイープ発振器１の
出力が分配器２を経由して入力されており、２つの入力
信号の差周波数の信号を出力する。この信号は周波数ア
ナライザ８に入力され、その差周波数が解析される。The output of the sweep oscillator 1 is also input to the mixer 7 via the distributor 2 and outputs a signal having a difference frequency between the two input signals. This signal is input to the frequency analyzer 8 and its difference frequency is analyzed.
【０００５】ここでスイープ発振器１を、単位時間（Δ
ｔ）当たりΔｆの周波数変化となるようにリニアに掃引
する。ミキサ７の２つの入力周波数差は遅れ時間差に比
例する。遅れ時間差はＤＵＴ５内の障害点までの距離に
比例することから、周波数解析を行うことにより、障害
点までの距離を知ることができ、また信号の大きさから
障害点での反射量すなわち障害点の大きさを知ることが
できる。Here, the sweep oscillator 1 is set to a unit time (Δ
The sweep is performed linearly so that the frequency changes by Δf per t). The difference between the two input frequencies of the mixer 7 is proportional to the delay time difference. Since the delay time difference is proportional to the distance to the fault point in the DUT 5, the distance to the fault point can be known by performing frequency analysis, and the amount of reflection at the fault point, that is, the fault point can be determined from the signal size. You can know the size of.
【０００６】例えば、スイープ発振器１の出力信号は１
ＧＨｚ／ｓｅｃの割合で掃引されているものとする。Ｄ
ＵＴ５が屈折率ｎ＝１．５の光ファイバであれば、ファ
イバ内を光が１ｍ往復する時間ｔは、
ｔ＝２×ｎ／Ｃ≒１×１０-8（ｓｅｃ）
ただし、Ｃは真空中の光速
である。スイープ発振器１の掃引レートよりこの時間ｔ
では１０Ｈｚの周波数差を生じる。つまり、周波数アナ
ライザ８で差周波数を解析することにより、１０Ｈｚあ
たり１ｍで障害点の位置を検出することができる。For example, the output signal of the sweep oscillator 1 is 1
It is assumed that the sweep is performed at a rate of GHz / sec. D
If the UT 5 is an optical fiber with a refractive index of n = 1.5, the time t during which light travels back and forth through the fiber for 1 m is: t = 2 × n / C≈1 × 10 −8 (sec) where C is in vacuum Is the speed of light. From the sweep rate of the sweep oscillator 1, this time t
Causes a frequency difference of 10 Hz. That is, by analyzing the difference frequency with the frequency analyzer 8, the position of the fault point can be detected at 1 m per 10 Hz.
【０００７】さて、光の可干渉距離について考察すると
次の通りである。簡易的に可干渉距離Ｌは、
Ｌ＝Ｃ／Δν
ただし、Δνはスペクトル線幅（半値幅）
である。そして、スペクトル線幅Δνが１００ＭＨｚで
あるとすると、
Ｌ＝３（ｍ）
となる。これは真空中の片道距離であるので、ファイバ
中の往復と屈折率（ｎ＝１．５）を考慮して換算すると
１ｍに相当する。Now, the coherence length of light will be considered as follows. The coherence length L is simply L = C / Δν, where Δν is the spectral line width (half-value width). Then, assuming that the spectral line width Δν is 100 MHz, L = 3 (m). Since this is a one-way distance in a vacuum, it corresponds to 1 m when converted in consideration of the round trip in the fiber and the refractive index (n = 1.5).
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、ＤＵＴ
５内の障害点が複数かつ近接している場合、Ｅ／Ｏとし
て可干渉性の高いもの（レーザ光等）を使用すると、近
接した障害点からの反射光どうしが干渉し、ノイズ成分
となってしまうという問題があった。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
If multiple obstacle points in 5 are close and if E / O with high coherence is used (laser light etc.), the reflected lights from the adjacent obstacle points interfere with each other and become a noise component. There was a problem that it would end up.
【０００９】本発明の目的は、強度変調形ＯＦＤＲにお
いてＤＵＴに与える光が可干渉性の低いものとなるよう
にして上記課題を解決した光ファイバ検査装置を提供す
ることにある。It is an object of the present invention to provide an optical fiber inspection apparatus which solves the above problems by making the light applied to the DUT in the intensity modulation type OFDR have low coherence.
【００１０】[0010]
【課題を解決するための手段】このような目的を達成す
るために本発明では、可干渉性の高いレーザ光を発生す
ると共にスイープ発振器の出力により強度変調されるＥ
／Ｏ変換器を使用し、周波数がリニアに掃引されるスイ
ープ発振器の出力信号により前記Ｅ／Ｏ変換器を制御し
てその出力光の強度変調周波数を掃引し、このＥ／Ｏ変
換器の出力光を光カプラを介して被測定対象に入射し、
被測定対象内で反射して戻ってきた光をＯ／Ｅ変換器に
より電気信号に変換し、この電気信号と前記スイープ発
振器の出力信号とをミキサでミキシングすることにより
差周波数の信号を得て、この差周波数信号を周波数アナ
ライザで解析することにより被測定対象内の反射点まで
の距離と反射量を検出するように構成した光ファイバ検
査装置であって、前記被測定対象に与える光のスペクト
ル線幅を元のＥ／Ｏ変換器の出力光のスペクトル線幅よ
りも広くするための手段を備えたことを特徴とする。In order to achieve such an object, in the present invention, a laser beam having a high coherence is generated, and the intensity is modulated by the output of the sweep oscillator.
The output signal of the sweep oscillator whose frequency is swept linearly is used to control the E / O converter to sweep the intensity modulation frequency of its output light, and the output of this E / O converter is used. Light is incident on the object to be measured through an optical coupler,
The light reflected and returned in the object to be measured is converted into an electric signal by an O / E converter, and the electric signal and the output signal of the sweep oscillator are mixed by a mixer to obtain a signal of a difference frequency. An optical fiber inspection device configured to detect the distance to a reflection point and the amount of reflection in a measured object by analyzing the difference frequency signal with a frequency analyzer, the spectrum of light given to the measured object. It is characterized in that a means for making the line width wider than the spectral line width of the output light of the original E / O converter is provided.
【００１１】[0011]
【作用】ＤＵＴに入射する光が可干渉性の低いものとな
るようにする手段を設け、スペクトル線幅を元のＥ／Ｏ
変換器のものより拡大させることにより、近接する反射
光どうしの干渉を防止する。A means for ensuring that the light incident on the DUT has low coherence is provided, and the spectral line width is set to the original E / O.
By making it larger than that of the converter, interference between reflected lights that are close to each other is prevented.
【００１２】[0012]
【実施例】以下本発明を詳しく説明する。図１は本発明
に係る光ファイバ検査装置の一実施例を示す構成図であ
り、ＤＵＴ５に与える光を元のＥ／Ｏ変換器の光のスペ
クトル線幅よりも拡大し障害点からの反射光どうしの干
渉を防ぐための手段として、Ｅ／Ｏ駆動信号に高周波を
重畳する高周波信号発生器と合成器を用いたものであ
る。なお、図３と同等部分には同一符号を付し、その部
分の説明は省略する。図において、９は高周波信号（波
形は例えば正弦波）を発生する高周波信号発生器、１０
は分配器２の出力に高周波信号発生器９の出力を重畳す
る合成器である。The present invention will be described in detail below. FIG. 1 is a block diagram showing an embodiment of the optical fiber inspection apparatus according to the present invention, in which the light given to the DUT 5 is expanded more than the spectral line width of the light of the original E / O converter, and the reflected light from the fault point As a means for preventing mutual interference, a high frequency signal generator for superimposing a high frequency on the E / O drive signal and a synthesizer are used. The same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. In the figure, 9 is a high-frequency signal generator that generates a high-frequency signal (waveform is, for example, a sine wave), 10
Is a combiner that superimposes the output of the high-frequency signal generator 9 on the output of the distributor 2.
【００１３】このような構成において、Ｅ／Ｏ変換器３
は、スイープ発振器１の出力信号と高周波信号発生器９
の出力信号とを合成した信号により駆動される。なお、
この場合Ｅ／Ｏ変換器３としてはレーザダイオードを用
いる。これによりレーザダイオードからはスペクトル線
幅の拡大されたレーザ光を容易に発生することができ、
ＤＵＴ５内の障害点が複数かつ近接している場合でも、
障害点からの反射光どうしの干渉を防ぐことができる。
なお、高周波信号発生器９の出力信号の周波数はスイー
プ発振器１の出力信号の周波数と異ならせておくのが望
ましい。In such a configuration, the E / O converter 3
Is the output signal of the sweep oscillator 1 and the high frequency signal generator 9
It is driven by a signal obtained by combining the output signal of In addition,
In this case, a laser diode is used as the E / O converter 3. This allows the laser diode to easily generate laser light with an expanded spectral line width,
Even if there are multiple points of failure in the DUT 5
It is possible to prevent interference between reflected lights from the obstacle point.
The frequency of the output signal of the high frequency signal generator 9 is preferably different from the frequency of the output signal of the sweep oscillator 1.
【００１４】図２は本発明の他の実施例であり、ＤＵＴ
５に与える光を元のＥ／Ｏ変換器の光のスペクトル線幅
よりも拡大し障害点からの反射光どうしの干渉を防ぐた
めの手段として、可干渉性の高いレーザ光（スペクトル
線幅１００ＭＨｚ以下）と光周波数シフタを用いたもの
である。図において、１１はＥ／Ｏ変換器３の出力光の
周波数をシフトしスペクトル線幅を拡大する周波数シフ
タである。なお、Ｅ／Ｏ変換器３としては可干渉性の高
いレーザ光（スペクトル線幅１００ＭＨｚ以下）を発生
するレーザダイオードも使用できる。これにより、上記
実施例と同様に障害点からの反射光どうしの干渉を防ぐ
ことができる。FIG. 2 shows another embodiment of the present invention, which is a DUT.
As a means for preventing the interference of the reflected light from the fault point with each other by expanding the light to be given to 5 to the spectral line width of the light of the original E / O converter, a highly coherent laser beam (spectral line width 100 MHz The following) and an optical frequency shifter are used. In the figure, 11 is a frequency shifter for shifting the frequency of the output light of the E / O converter 3 and expanding the spectral line width. It should be noted that the E / O converter 3 generates laser light with high coherence (spectral line width 100 MHz or less) .
A laser diode can be used. As a result, it is possible to prevent the interference of the reflected lights from the obstacle points, as in the above-described embodiment.
【００１５】なお本発明は上記実施例に限定されるもの
ではない。例えば、高周波信号発生器と合成器や、周波
数シフタ１１を用いることなく、Ｅ／Ｏ変換器３として
スペクトル線幅が１００ＭＨｚ以上のレーザ光を使用し
てもよく、同様の効果を得ることができる。また、Ｅ／
Ｏ変換器３として、発光ダイオード（ＬＥＤ）、高輝度
ダイオード（ＳＬＤ）を用いてもよい。また、Ｅ／Ｏ変
換器３の出力光を直接的に変える方式ではないが、周波
数解析方法においてフーリエ変換を利用し、近接の障害
点を見つけ得るようにすることもできる。The present invention is not limited to the above embodiment. For example, a laser beam having a spectral line width of 100 MHz or more may be used as the E / O converter 3 without using the high frequency signal generator and the synthesizer or the frequency shifter 11, and the same effect can be obtained. . Also, E /
A light emitting diode (LED) or a high brightness diode (SLD) may be used as the O converter 3. Further, although it is not a method of directly changing the output light of the E / O converter 3, it is also possible to use Fourier transform in the frequency analysis method to find a fault point in the vicinity.
【００１６】また、光の伝送損失の大きい場合、障害点
での光反射量の小さい場合等の用途には光アンプ（ファ
イバ形）を設けても良い。さらにまた、運用している光
ファイバを測定する場合には、運用している光の波長と
異なる波長をＥ／Ｏ変換器として使用し、さらに必要で
あればＯ／Ｅ変換器６の前段に不要な波長を除去する波
長弁別器を用いる。この際の波長弁別器としては、光学
フィルタ、干渉フィルタ、物質の吸収を用いることがで
きる。例えば、１．５５μｍで使用している光ファイバ
の検査には、１．６５μｍで発光するＥ／Ｏ変換器を使
用し、必要であればＯ／Ｅ変換器の前段に１．５５μｍ
を除去する波長弁別器を用いる。Further, an optical amplifier (fiber type) may be provided for applications such as when the transmission loss of light is large or when the amount of light reflection at a fault point is small. Furthermore, when measuring an operating optical fiber, a wavelength different from the operating light wavelength is used as an E / O converter, and if necessary, it is placed in front of the O / E converter 6. A wavelength discriminator that removes unnecessary wavelengths is used. As the wavelength discriminator in this case, an optical filter, an interference filter, or substance absorption can be used. For example, to inspect an optical fiber used at 1.55 μm, an E / O converter that emits light at 1.65 μm is used, and if necessary, 1.55 μm is provided before the O / E converter.
A wavelength discriminator that removes is used.
【００１７】[0017]
【発明の効果】以上説明したように本発明によれば次の
ような効果がある。強度変調形のＯＦＤＲは、測定可能
距離の大幅な延長が可能であるが（光周波数変調形ＯＦ
ＤＲにては、光源の可干渉距離にて制限を受ける）、２
点の近接した障害点がある場合には、この反射光どうし
が干渉してしまい、ノイズ成分となる。このためＥ／Ｏ
変換器として可干渉距離の短い光源が必要となる。本発
明によれば、可干渉距離の短い（等価的な場合も含む）
光源を使用することにより、２点の近接した障害点があ
る場合にも高い分解能（＜１ｍ）で障害点を検出できる
光ファイバ検査装置を実現することができる。As described above, the present invention has the following effects. Although the intensity modulation type OFDR can greatly extend the measurable distance (optical frequency modulation type OFDR
In DR, it is limited by the coherence length of the light source), 2
If there are obstacle points close to each other, the reflected lights interfere with each other and become a noise component. Therefore, E / O
A light source with a short coherence length is required as a converter. According to the present invention, the coherence length is short (including equivalent cases).
By using the light source, it is possible to realize an optical fiber inspection apparatus capable of detecting a fault point with high resolution (<1 m) even when there are two fault points that are close to each other.
【図１】本発明に係る光ファイバ検査装置の一実施例を
示す構成図FIG. 1 is a configuration diagram showing an embodiment of an optical fiber inspection apparatus according to the present invention.
【図２】本発明の他の実施例構成図FIG. 2 is a block diagram of another embodiment of the present invention.
【図３】従来の光ファイバ検査装置の一例を示す構成図
である。FIG. 3 is a configuration diagram showing an example of a conventional optical fiber inspection apparatus.
１ スイープ発振器 ２ 分配器 ３ Ｅ／Ｏ変換器 ４ 光カプラ ５ ＤＵＴ ６ Ｏ／Ｅ変換器 ７ ミキサ ８ 周波数アナライザ ９ 高周波信号発生器 １０ 合成器 １１ 周波数シフタ 1 Sweep oscillator 2 distributor 3 E / O converter 4 Optical coupler 5 DUT 6 O / E converter 7 mixer 8 frequency analyzer 9 High frequency signal generator 10 synthesizer 11 frequency shifter
フロントページの続き (56)参考文献 特開 平３−206935（ＪＰ，Ａ) 特開 平８−220579（ＪＰ，Ａ) 特開 平８−210944（ＪＰ，Ａ) 特開 平８−201225（ＪＰ，Ａ) 特開 平８−54586（ＪＰ，Ａ) 特開 平７−270841（ＪＰ，Ａ) 特開 平７−5068（ＪＰ，Ａ) 特開 平６−74710（ＪＰ，Ａ) 特開 平６−66517（ＪＰ，Ａ) 特開 平６−53590（ＪＰ，Ａ) 特開 平５−275782（ＪＰ，Ａ) 特開 平４−248434（ＪＰ，Ａ) 特開 平３−175333（ＪＰ，Ａ) 特開 平３−122538（ＪＰ，Ａ) 特開 平２−6724（ＪＰ，Ａ) 特開 昭57−118136（ＪＰ，Ａ) 特開 昭53−47701（ＪＰ，Ａ) 米国特許5062703（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01M 11/00 - 11/02 G01J 1/00 G01J 9/00 - 9/04 G01J 11/00 G01B 9/02 G01B 11/00 G01K 11/12 G02B 6/00 G02F 1/01 - 2/02 H01S 3/00 H01S 5/06 H04B 3/46 H04B 10/08 H04B 17/00 - 17/02 Continuation of front page (56) Reference JP-A-3-206935 (JP, A) JP-A-8-220579 (JP, A) JP-A-8-210944 (JP, A) JP-A-8-201225 (JP , A) JP 8-54586 (JP, A) JP 7-270841 (JP, A) JP 7-5068 (JP, A) JP 6-74710 (JP, A) JP 6-66517 (JP, A) JP-A-6-53590 (JP, A) JP-A-5-275782 (JP, A) JP-A-4-248434 (JP, A) JP-A-3-175333 (JP, A) A) JP-A-3-122538 (JP, A) JP-A-2-6724 (JP, A) JP-A-57-118136 (JP, A) JP-A-53-47701 (JP, A) US Pat. (US, A) (58) Fields investigated (Int.Cl. 7 , DB name) G01M 11/00-11/02 G01J 1/00 G01J 9/00-9/04 G01J 11/00 G01B 9/02 G01B 11 / 00 G01K 11/12 G02B 6/00 G02F 1/01-2/02 H01S 3/00 H01S 5/06 H04B 3/46 H04B 10/08 H04B 17/00-17/02
Claims (4)
スイープ発振器の出力により強度変調されるＥ／Ｏ変換
器を使用し、周波数がリニアに掃引されるスイープ発振
器の出力信号により前記Ｅ／Ｏ変換器を制御してその出
力光の強度変調周波数を掃引し、このＥ／Ｏ変換器の出
力光を光カプラを介して被測定対象に入射し、被測定対
象内で反射して戻ってきた光をＯ／Ｅ変換器により電気
信号に変換し、この電気信号と前記スイープ発振器の出
力信号とをミキサでミキシングすることにより差周波数
の信号を得て、この差周波数信号を周波数アナライザで
解析することにより被測定対象内の反射点までの距離と
反射量を検出するように構成した光ファイバ検査装置で
あって、 前記被測定対象に与える光のスペクトル線幅を元のＥ／
Ｏ変換器の出力光のスペクトル線幅よりも広くするため
の手段を備えたことを特徴とする光ファイバ検査装置。1. A with generating a coherent highly laser light
An E / O converter that is intensity-modulated by the output of the sweep oscillator is used, and the E / O converter is controlled by the output signal of the sweep oscillator whose frequency is swept linearly to sweep the intensity-modulated frequency of the output light. Then, the output light of the E / O converter is incident on the object to be measured through the optical coupler, and the light reflected and returned in the object to be measured is converted into an electric signal by the O / E converter. The signal of the difference frequency is obtained by mixing the electric signal and the output signal of the sweep oscillator with a mixer, and the distance and the reflection amount to the reflection point in the object to be measured by analyzing the difference frequency signal with a frequency analyzer. Is an optical fiber inspection device configured to detect a light beam having a spectral line width of an original E /
An optical fiber inspection device comprising means for making the spectrum line width of the output light of the O converter wider.
光カプラの間に接続されＥ／Ｏ変換器の出力光の周波数
をシフトする光周波数シフタを使用したことを特徴とす
る請求項１記載の光ファイバ検査装置。2. The E / O converter and the means as the means
The optical fiber inspection apparatus according to claim 1, wherein an optical frequency shifter connected between the optical couplers to shift the frequency of the output light of the E / O converter is used.
信号発生器と、前記スイープ発振器の出力に前記高周波
信号を重畳しその信号で前記Ｅ／Ｏ変換器を駆動する合
成器からなることを特徴とする請求項１記載の光ファイ
バ検査装置。3. The high-frequency signal generator for generating a high-frequency signal, the means for superimposing the high-frequency signal on an output of the sweep oscillator , and driving the E / O converter with the signal.
Optical fiber inspection apparatus according to claim 1, characterized in that it consists of forming device.
振器の出力信号の周波数以外の周波数としたことを特徴
とする請求項３記載の光ファイバ検査装置。4. The optical fiber inspection apparatus according to claim 3 , wherein the frequency of the high frequency signal is a frequency other than the frequency of the output signal of the sweep oscillator.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02161895A JP3453746B2 (en) | 1995-02-09 | 1995-02-09 | Optical fiber inspection equipment |
| EP96901143A EP0754939B1 (en) | 1995-02-02 | 1996-01-30 | Optical fibre detecting device |
| US08/727,377 US5844235A (en) | 1995-02-02 | 1996-01-30 | Optical frequency domain reflectometer for use as an optical fiber testing device |
| PCT/JP1996/000170 WO1996024038A1 (en) | 1995-02-02 | 1996-01-30 | Optical fibre detecting device |
| DE69632000T DE69632000T2 (en) | 1995-02-02 | 1996-01-30 | MEASURING DEVICE FOR OPTICAL FIBERS |
| DE0754939T DE754939T1 (en) | 1995-02-02 | 1996-01-30 | MEASURING DEVICE FOR OPTICAL FIBERS |
| US09/039,944 US6008487A (en) | 1995-02-02 | 1998-03-16 | Optical-fiber inspection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02161895A JP3453746B2 (en) | 1995-02-09 | 1995-02-09 | Optical fiber inspection equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08219947A JPH08219947A (en) | 1996-08-30 |
| JP3453746B2 true JP3453746B2 (en) | 2003-10-06 |
Family
ID=12060046
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02161895A Expired - Fee Related JP3453746B2 (en) | 1995-02-02 | 1995-02-09 | Optical fiber inspection equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3453746B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3453745B2 (en) * | 1995-02-02 | 2003-10-06 | 横河電機株式会社 | Optical fiber inspection equipment |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5347701A (en) * | 1976-10-13 | 1978-04-28 | Nippon Telegr & Teleph Corp <Ntt> | Optical sweep signal generator |
| JPS57118136A (en) * | 1981-01-14 | 1982-07-22 | Nippon Telegr & Teleph Corp <Ntt> | Fault searching method by optical fiber |
| DE68908054T2 (en) * | 1988-01-21 | 1994-03-10 | Genentech Inc | REINFORCEMENT AND DETECTION OF NUCLEIC ACID SEQUENCES. |
| US5062703A (en) * | 1988-01-21 | 1991-11-05 | Hewlett-Packard Company | Method and apparatus for measuring the length of, or distances to discontinuities in, an optical transmission medium |
| FR2640379B1 (en) * | 1988-12-14 | 1994-07-01 | Centre Nat Rech Scient | METHOD FOR THE ANALYSIS OF GUIDED OPTICAL COMPONENTS, OPTICAL FIBERS OR OPTICAL GUIDE NETWORKS BY TIME REFLECTOMETRY AND REFLECTOMETER IN THE TIME AREA |
| US5175492A (en) * | 1989-08-08 | 1992-12-29 | Hewlett-Packard Company | Calibration and error correction for electrical-source-to-e/o-device impedance mismatch and o/e-device-to-electrical-receiver impedance mismatch in a lightwave component analyzer |
| JP2626099B2 (en) * | 1989-09-26 | 1997-07-02 | 横河電機株式会社 | Optical transmission line measuring instrument |
| JP2907350B2 (en) * | 1991-02-04 | 1999-06-21 | 日本電信電話株式会社 | Optical line remote testing equipment |
| JPH05275782A (en) * | 1992-03-30 | 1993-10-22 | Nec Corp | Analog optical transmitter |
| DE4244605A1 (en) * | 1992-05-27 | 1993-12-02 | Hewlett Packard Co | Optical low-coherence reflectometer with improved sensitivity with optical attenuation |
| US5268738A (en) * | 1992-06-30 | 1993-12-07 | Hewlett-Packard Company | Extended distance range optical low-coherence reflectometer |
| JPH0653590A (en) * | 1992-07-31 | 1994-02-25 | Hitachi Ltd | Method for stabilizing optical fsk frequency displacement amount |
| JP3282135B2 (en) * | 1993-06-17 | 2002-05-13 | 日本電信電話株式会社 | Optical frequency domain reflectometer |
| JPH07270841A (en) * | 1994-03-31 | 1995-10-20 | Ando Electric Co Ltd | Sweep optical frequency generator |
| JPH0854586A (en) * | 1994-08-10 | 1996-02-27 | Nippon Telegr & Teleph Corp <Ntt> | Light source for optical frequency sweeping |
| JPH08201225A (en) * | 1995-01-27 | 1996-08-09 | Yokogawa Electric Corp | Variable light frequency light source |
| JP3453745B2 (en) * | 1995-02-02 | 2003-10-06 | 横河電機株式会社 | Optical fiber inspection equipment |
| JPH08220579A (en) * | 1995-02-10 | 1996-08-30 | Yokogawa Electric Corp | Strength modulating frequency variable light source |
-
1995
- 1995-02-09 JP JP02161895A patent/JP3453746B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08219947A (en) | 1996-08-30 |
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