JPH0658293B2 - Method and apparatus for measuring wavelength dispersion of optical fiber - Google Patents
Method and apparatus for measuring wavelength dispersion of optical fiberInfo
- Publication number
- JPH0658293B2 JPH0658293B2 JP60166417A JP16641785A JPH0658293B2 JP H0658293 B2 JPH0658293 B2 JP H0658293B2 JP 60166417 A JP60166417 A JP 60166417A JP 16641785 A JP16641785 A JP 16641785A JP H0658293 B2 JPH0658293 B2 JP H0658293B2
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- Prior art keywords
- light
- optical fiber
- measured
- optical
- fluxes
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Classifications
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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
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- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (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、光ファイバの波長分散をその一端から測定す
る装置に関する。特に、短尺および長尺の被測定光ファ
イバに対して高精度の測定が可能な装置に関する。The present invention relates to an apparatus for measuring chromatic dispersion of an optical fiber from one end thereof. In particular, the present invention relates to a device capable of highly accurate measurement for short and long optical fibers to be measured.
本発明は、光ファイバの波長分散を測定する方法および
装置において、 わずかに光周波数の異なる光束の干渉を利用して被測定
光ファイバを伝搬した光と参照光との群遅延差を求め、
異なる光周波数に対して得られる群遅延差によりその被
測定光ファイバの波長分散を求めることにより、 被測定光ファイバが短尺でも高精度に波長分散測定を行
うものである。The present invention, in a method and apparatus for measuring the chromatic dispersion of an optical fiber, obtains the group delay difference between the light propagating through the optical fiber under measurement and the reference light by utilizing the interference of light beams having slightly different optical frequencies,
By measuring the chromatic dispersion of the optical fiber under test from the group delay difference obtained for different optical frequencies, the chromatic dispersion can be measured with high accuracy even if the optical fiber under test is short.
従来の光ファイバの波長分散測定方法では、被測定光フ
ァイバ中に波長の異なるパルスを伝搬させて、パルスの
群遅延差を測定するパルス法、強度変調を受けた異なる
波長の光を被測定光ファイバに入射させ、その出射光の
位相差を測定する位相法、または、光の干渉を利用し、
干渉縞の可視度が最大となる位置を検出する方法等の測
定方法を利用して波長分散を測定していた。光の干渉を
利用する方法に関しては、シバタ（N.Shibata）等によ
り、アプライド・オプティクス（Appl.Opt.）第19巻（1
980年）第1489頁ないし第1492頁に詳しく説明されてい
る。In the conventional optical fiber chromatic dispersion measurement method, a pulse method in which pulses with different wavelengths are propagated in the optical fiber to be measured and the group delay difference of the pulse is measured, and light with different wavelengths subjected to intensity modulation is measured. Using the phase method to measure the phase difference of the light emitted from the fiber, or the interference of light,
The chromatic dispersion is measured by using a measuring method such as a method of detecting a position where the visibility of the interference fringes is maximum. Regarding the method of utilizing the interference of light, Applied Optics (Appl.Opt.) Vol. 19 (1) by Shibata (N. Shibata) et al.
980) 1489 to 1492.
しかし、パルス法および位相法では、測定位置の時間分
解能や変調器の帯域による制限を受けるために、例えば
サブピコ秒程度の群遅延差の測定が困難であり、長尺の
被測定光ファイバが必要となる欠点があった。However, in the pulse method and the phase method, it is difficult to measure the group delay difference of, for example, sub-picosecond because it is limited by the time resolution of the measurement position and the bandwidth of the modulator, and a long optical fiber to be measured is required. There was a drawback that became.
また、光の干渉を利用した測定法では、長尺の被測定光
ファイバを必要とはしないが、干渉させる二つの光束の
光周波数が同一であるため、干渉縞の可視度を光路長変
化に対して逐次観測する必要があり、自動測定を行う場
合に、可視度のデータを自動的に取り込むことが極めて
困難である欠点があった。In addition, in the measurement method using the interference of light, a long optical fiber to be measured is not required, but since the optical frequencies of the two light beams to be interfered are the same, the visibility of the interference fringes can be changed to change the optical path length. On the other hand, there is a drawback that it is extremely difficult to automatically capture the visibility data when performing automatic measurement, since it is necessary to make successive observations.
本発明は、以上の問題点を解決し、被測定光ファイバが
短尺でも長尺でも、被測定光ファイバの一端から波長分
散を高精度に測定できる方法およびその装置を提供する
ことを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a method and an apparatus for accurately measuring chromatic dispersion from one end of an optical fiber to be measured, whether the optical fiber to be measured is short or long. .
本発明の光ファイバの波長分散測定方法は、光源から可
干渉性の出力光を発生し、この出力光を第一および第二
の光束に分岐し、この第一および第二の光束の少なくと
も一方を変調し、第一の光束を被測定光ファイバの一端
に入射させ、この被測定光ファイバの他端で折り返し反
射させ、この被測定光ファイバの上記一端からの出射光
および第二の光束を同一の観測面に導き、この観測面に
生じたビート信号の振幅が最大になるように第一および
第二の光束の光路長を変化させ、複数の光周波数に対す
るビート信号の振幅が最大となる光路長差の変化により
被測定光ファイバの波長分散を求める光ファイバの波長
分散測定方法において、変調を実質的に一定の光周波数
偏移として与えることを特徴とする。The optical fiber chromatic dispersion measuring method of the present invention generates coherent output light from a light source, splits the output light into first and second light beams, and at least one of the first and second light beams. Modulated, the first light flux is incident on one end of the measured optical fiber, reflected back at the other end of the measured optical fiber, the emitted light from the one end of the measured optical fiber and the second light flux. Guide to the same observation plane, change the optical path length of the first and second light flux so that the amplitude of the beat signal generated on this observation plane becomes maximum, and maximize the amplitude of the beat signal for multiple optical frequencies An optical fiber wavelength dispersion measuring method for obtaining a wavelength dispersion of an optical fiber to be measured by a change in optical path length difference is characterized in that modulation is given as a substantially constant optical frequency shift.
変調を強度変調あるいは位相変調により行うと、干渉信
号には変調周波数成分に加えてその逓倍成分が高次項ま
で含まれるため、それらのいずれか１つだけの周波数成
分の変化を測定する必要があり、信号対雑音特性の点で
難点がある。これに対し、一方の光束を一定の光周波数
だけ偏移させれば、干渉信号には、直流成分を除くと変
調周波数成分の項だけが存在し、より良好な信号対雑音
特性が得られる。When the modulation is performed by intensity modulation or phase modulation, the interference signal contains not only the modulation frequency component but also its multiplication component up to higher order terms, so it is necessary to measure the change of only one of these frequency components. However, there is a problem in terms of signal-to-noise characteristics. On the other hand, if one light beam is deviated by a certain optical frequency, the interference signal has only the term of the modulation frequency component excluding the DC component, and a better signal-to-noise characteristic is obtained.
本発明の光ファイバの波長分散測定装置はこの方法を実
現する装置であり、可干渉性の出力光を発生する光源
と、この光源の出力光を第一および第二の光束に分岐す
る分岐手段と、分岐された光束の少なくとも一方を変調
する変調手段と、第一の光束を被測定光ファイバの一端
に入射させる手段と、この被測定光ファイバの他端で折
り返し反射させる手段と、この被測定光ファイバの一端
からの出射光および第二の光束を同一の観測面に導く光
学系と、第一および第二の光束の光路長の少なくとも一
方を変化させる手段と、観測面に生じたビート信号の振
幅を測定する手段とを備えた光ファイバの波長分散測定
装置において、分岐手段および変調手段が、入射光を二
つの光束に空間的に分岐するとともにその一方の光束の
周波数を偏移させる音響光学偏向器により構成されたこ
とを特徴とする。An optical fiber wavelength dispersion measuring apparatus of the present invention is an apparatus for realizing this method, and includes a light source that generates coherent output light and a branching unit that branches the output light of this light source into first and second light beams. A modulation means for modulating at least one of the branched light fluxes, a means for causing the first light flux to enter one end of the measured optical fiber, a means for reflecting and reflecting the other light flux at the other end of the measured optical fiber, An optical system for guiding the light emitted from one end of the measurement optical fiber and the second light flux to the same observation surface, a means for changing at least one of the optical path lengths of the first and second light fluxes, and a beat generated on the observation surface. In an optical fiber chromatic dispersion measuring apparatus having means for measuring the amplitude of a signal, the branching means and the modulating means spatially split the incident light into two light beams and shift the frequency of one light beam. Characterized in that it consists of sounding an optical deflector.
光源としては、一個の素子で複数の光周波数の出力光を
発生するものでもよく、それぞれ白色光を出力する複数
の発光素子を含んでもよい。さらに光源そのものを交換
できる構成でもよい。観測を自動化するためには、電気
的に光周波数が可変の光源が望ましい。As the light source, one element may generate output light of a plurality of optical frequencies, and may include a plurality of light emitting elements that respectively output white light. Further, the light source itself may be exchangeable. In order to automate the observation, a light source with an electrically variable optical frequency is desirable.
本発明の光ファイバの波長分散測定方法は、わずかに異
なる二つの光束の干渉を利用し、被測定光ファイバを伝
搬した光と参照光との群遅延差を求める。この群遅延差
を異なる光周波数に対して求めることにより、上記被測
定光ファイバの波長分散を簡単な演算により求めること
ができる。測定は被測定光ファイバの一端で行うことが
できる。光の干渉を利用することによりサブピコ秒の時
間分解能が得られるので、１ｍ以下の短尺な光ファイバ
でも、数kmの長さの光ファイバでも、高精度に測定する
ことができる。本発明の装置は自動化測定を行うに適す
る。The wavelength dispersion measuring method for an optical fiber according to the present invention utilizes the interference of two slightly different luminous fluxes to obtain the group delay difference between the light propagating through the optical fiber to be measured and the reference light. By obtaining this group delay difference for different optical frequencies, the chromatic dispersion of the optical fiber under measurement can be obtained by a simple calculation. The measurement can be performed at one end of the optical fiber to be measured. Since sub-picosecond time resolution can be obtained by utilizing the interference of light, it is possible to measure with high accuracy both a short optical fiber of 1 m or less and an optical fiber of several km long. The device of the invention is suitable for making automated measurements.
第１図は本発明第一実施例の光ファイバの波長分散測定
装置のブロック構成図である。FIG. 1 is a block diagram of the wavelength dispersion measuring apparatus for optical fiber according to the first embodiment of the present invention.
光源１の出力光は、音響光学偏向器２により二つの光束
に分岐される。音響光学偏向器２には、これを駆動する
ための発振器３が接続される。音響光学偏向器２により
分岐された二つの光束は、一方が光路長可変装置４を経
由して参照用光ファイバ５に入射し、他方が被測定光フ
ァイバ６に入射する。参照用光ファイバ５に入射した光
束は、反射鏡７で反射して再び参照用光ファイバ５を通
り、光路長可変装置４および音響光学偏向器２を経由し
て光検出器９に入射する。被測定光ファイバ６に入射し
た光束は、反射鏡８で反射して再び被測定光ファイバ６
を通り、音響光学偏向器２を経由して光検出器９に入射
する。The output light of the light source 1 is split into two light beams by the acousto-optic deflector 2. An oscillator 3 for driving the acousto-optic deflector 2 is connected to the acousto-optic deflector 2. One of the two light beams split by the acousto-optic deflector 2 enters the reference optical fiber 5 via the optical path length varying device 4, and the other enters the measured optical fiber 6. The light flux that has entered the reference optical fiber 5 is reflected by the reflecting mirror 7, passes through the reference optical fiber 5 again, and enters the photodetector 9 through the optical path length varying device 4 and the acousto-optic deflector 2. The light beam incident on the measured optical fiber 6 is reflected by the reflecting mirror 8 and is again measured.
And enters the photodetector 9 via the acousto-optic deflector 2.
光検出器９は帯域フィルタ10に接続される。帯域フィル
タ10は波形記録装置11に接続される。波形記録装置11は
光路長可変装置４に接続される。The photodetector 9 is connected to the bandpass filter 10. The bandpass filter 10 is connected to the waveform recording device 11. The waveform recording device 11 is connected to the optical path length varying device 4.
光源１は周波数ｆ０の可干渉性出力光を発生する。The light source 1 produces a coherent output light of frequency f 0 .
音響光学偏向器２は、この光源１からの出力光を二つの
光束に空間的に分岐するとともに、その一方の光束の周
波数をΔｆだけ偏移させる。二つの光束の回折角θは、
発振器３から音響光学偏向器２に入力される音波の波長
Δおよび光の波長λにより、 sin θ＝λ／２Δ ……(1) として表される。周波数の異なる光束に対してθが変化
することを補償するため、発振器３の駆動周波数を変化
させ、λ／２Δが一定になるように設定できる。これに
より、回折角θの変化にともなう光学系の光軸調整およ
び光路長の再調整が不用となる。The acousto-optic deflector 2 spatially splits the output light from the light source 1 into two light beams, and shifts the frequency of one light beam by Δf. The diffraction angle θ of the two light beams is
The wavelength Δ of the sound wave and the wavelength λ of the light input from the oscillator 3 to the acousto-optic deflector 2 are expressed as sin θ = λ / 2Δ (1). In order to compensate for the change in θ with respect to light fluxes having different frequencies, the drive frequency of the oscillator 3 can be changed so that λ / 2Δ can be set to be constant. As a result, it becomes unnecessary to adjust the optical axis of the optical system and readjust the optical path length due to the change of the diffraction angle θ.
音響光学偏向器２から出射された光束のうち、周波数ｆ
０の光束を参照光、周波数ｆ０−Δｆの光束を信号光と
する。二つの光束の光路長を同程度に設定し、参照用光
ファイバ５にはその波長分散特性が既知のものを使用す
る。Of the luminous flux emitted from the acousto-optic deflector 2, the frequency f
A luminous flux of 0 is used as reference light, and a luminous flux of frequency f 0 −Δf is used as signal light. The optical path lengths of the two light beams are set to the same degree, and the reference optical fiber 5 having a known wavelength dispersion characteristic is used.
参照用光ファイバ５を往復した参照光は、光路長可変装
置４を経由して再び音響光学偏向器２へ入射し、その周
波数がｆ０＋Δｆに偏移されて光検出器９に入射する。
被測定光ファイバ６を往復した信号光は、音響光学偏向
器２を経由して、周波数ｆ０−Δｆのまま光検出器９に
入射する。この場合の回折角θは上述の回折角θと一致
する。The reference light that has reciprocated through the reference optical fiber 5 again enters the acousto-optic deflector 2 via the optical path length varying device 4, the frequency thereof is shifted to f 0 + Δf, and enters the photodetector 9.
The signal light that has reciprocated through the optical fiber 6 to be measured passes through the acousto-optic deflector 2 and is incident on the photodetector 9 as the frequency f 0 −Δf. The diffraction angle θ in this case matches the above-mentioned diffraction angle θ.
光検出器９に入射する光強度Ｉ(t) は、 と表される。ここで、Ｉ１、Ｉ２は信号光および参照光
の強度、｜γ(τ)｜はコヒーレンス度、τおよびδは信
号光と参照光との群遅延差および位相差、２Δｆはビー
ト周波数である。光強度Ｉ(t)のビート周波数成分の振
幅は｜γ(τ)｜に比例する。このため、光路長可変装置
４により光路長差を調節して、 ｜γ(τ)｜＝１ ……(3) とすることにより、光強度Ｉ(t) を最大にすることがで
きる。The light intensity I (t) incident on the photodetector 9 is Is expressed as Where I 1 and I 2 are the intensities of the signal light and the reference light, | γ (τ) | is the coherence degree, τ and δ are the group delay difference and phase difference between the signal light and the reference light, and 2Δf is the beat frequency. is there. The amplitude of the beat frequency component of the light intensity I (t) is proportional to | γ (τ) |. Therefore, the optical intensity I (t) can be maximized by adjusting the optical path length difference by the optical path length varying device 4 so that | γ (τ) | = 1 (3).
光源１の出力光の周波数を変化させるか、または光源１
そのものを交換して周波数を変化させると、参照用光フ
ァイバ５および被測定光ファイバ６による群遅延差τが
変化し、(3)式を満足する光路長差も変化する。二つの
異なる周波数を用いて、光強度Ｉ(t) が最大となるよう
に光路長可変装置４を設定する。このときの設定位置の
差、すなわち補正距離Δｄは、参照用光ファイバ５およ
び被測定光ファイバ６の波長分散による光路長差を示
し、群遅延差の変化量Δτに対して、 Δｄ＝ｃΔτ ……(4) の関係がある。ここでｃは光速である。The frequency of the output light of the light source 1 is changed, or the light source 1
If they are exchanged and the frequency is changed, the group delay difference τ due to the reference optical fiber 5 and the measured optical fiber 6 changes, and the optical path length difference that satisfies the expression (3) also changes. The optical path length varying device 4 is set so that the light intensity I (t) is maximized by using two different frequencies. The difference between the set positions at this time, that is, the correction distance Δd indicates the optical path length difference due to the wavelength dispersion of the reference optical fiber 5 and the measured optical fiber 6, and Δd = cΔτ with respect to the change amount Δτ of the group delay difference. There is a relationship of (4). Here, c is the speed of light.
長さＬの光ファイバの単位長さあたりの波長分散Ｄは、
光源の波長λに対して、 の関係がある。したがって、異なる周波数に対して上記
の補正距離Δｄを求めることにより、(4)式および(5)式
から波長分散Ｄが得られる。ここで、(4)式および(5)式
から得られる波長分散は、参照用光ファイバ５による波
長分散Ｄ′を含んでいる。この値は既知であり、この値
を差し引くことにより求めるべき被測定光ファイバ６の
波長分散が得られる。The chromatic dispersion D per unit length of the optical fiber of the length L is
For the wavelength λ of the light source, Have a relationship. Therefore, by obtaining the correction distance Δd for different frequencies, the chromatic dispersion D can be obtained from the equations (4) and (5). Here, the wavelength dispersion obtained from the equations (4) and (5) includes the wavelength dispersion D ′ due to the reference optical fiber 5. This value is known, and by subtracting this value, the chromatic dispersion of the measured optical fiber 6 to be obtained can be obtained.
この実施例では、光路長可変装置４を、音響光学偏向器
２と参照用光ファイバ５との間に配置している。しか
し、参照光と信号光との光路長の差を変化させることが
できるならば、二つの光路上のどこに配置してもよく、
双方の光路上に配置してもよい。In this embodiment, the optical path length varying device 4 is arranged between the acousto-optic deflector 2 and the reference optical fiber 5. However, if the difference in optical path length between the reference light and the signal light can be changed, it may be arranged anywhere on the two optical paths,
You may arrange | position on both optical paths.
第２図は本発明第二実施例光ファイバの波長分散測定装
置のブロック構成図である。この実施例では、光路長可
変装置４のかわりに可動鏡23を用いて光路長を変化させ
る。FIG. 2 is a block diagram of the wavelength dispersion measuring apparatus for optical fiber according to the second embodiment of the present invention. In this embodiment, a movable mirror 23 is used instead of the optical path length varying device 4 to change the optical path length.
光源１と音響光学偏向器２との間に半透鏡21を配置す
る。この半透鏡21は、光源１の出力光を透過させ、参照
用光ファイバ５から音響光学偏向器２を通過した周波数
ｆ０の参照光と、被測定光ファイバ６から音響光学偏向
器２を経由してさらに周波数が偏移した周波数ｆ０−２
Δｆの信号光とを光検出器９に反射させる。A semi-transparent mirror 21 is arranged between the light source 1 and the acousto-optic deflector 2. The semi-transmissive mirror 21, via the output light of the light source 1 is transmitted through, and the reference light frequency f 0 having passed through the acoustooptic deflector 2 from the reference optical fiber 5, an acousto-optic deflector 2 from the measured optical fiber 6 And the frequency is further shifted, the frequency f 0 -2
The signal light of Δf is reflected by the photodetector 9.
被測定光ファイバ６から音響光学偏向器２を経由した周
波数ｆ０−Δｆの信号光と、参照用光ファイバ５から音
響光学偏向器２により周波数が偏移した周波数ｆ０＋Δ
ｆの参照光との光路上に、この光路上を移動する可動鏡
23が配置される。この可動鏡23は、到来した光束を同じ
光路上に反射する。さらに、可動鏡23により反射された
光束を光検出器９に導くように、半透鏡22を配置する。The signal light of the frequency f 0 −Δf from the measured optical fiber 6 via the acousto-optic deflector 2 and the frequency f 0 + Δ of the frequency shifted from the reference optical fiber 5 by the acousto-optic deflector 2.
A movable mirror that moves on the optical path of the reference light of f
23 are placed. The movable mirror 23 reflects the incoming light flux on the same optical path. Further, the semi-transparent mirror 22 is arranged so as to guide the light beam reflected by the movable mirror 23 to the photodetector 9.
本実施例の場合は、光検出器９で得られる光のビート周
波数が、Δｆ、２Δｆおよび３Δｆの三種類となる。こ
のうち、３Δｆの成分が、参照用光ファイバ５からの周
波数ｆ０＋Δｆの参照光と、被測定光ファイバ６からの
周波数ｆ０−２Δｆの信号光との干渉によるものであ
る。したがって、この成分を用いることにより、第一実
施例と同様の測定ができる。In the case of the present embodiment, the beat frequencies of light obtained by the photodetector 9 are of three types, Δf, 2Δf, and 3Δf. Among them, the component of 3Δf is due to the interference between the reference light of the frequency f 0 + Δf from the reference optical fiber 5 and the signal light of the frequency f 0 −2Δf from the measured optical fiber 6. Therefore, by using this component, the same measurement as in the first embodiment can be performed.
第３図および第４図は、光路長可変装置４の例を示す。
第３図では、反射鏡31、32および二枚の反射鏡を備えた
可動鏡33を用いた例を示し、第４図では、光ファイバ41
と伸縮素子42により、光ファイバ41の伸縮による光路長
の変化を利用する例を示す。FIG. 3 and FIG. 4 show an example of the optical path length varying device 4.
FIG. 3 shows an example using the reflecting mirrors 31, 32 and a movable mirror 33 having two reflecting mirrors, and in FIG.
An example in which a change in optical path length due to expansion and contraction of the optical fiber 41 is used by the expansion and contraction element 42 will be described.
以上の実施例では、参照光路に参照用光ファイバ５を用
いていた。しかし、被測定光ファイバ６が短尺な場合に
は、参照光を自由空間に往復伝搬させても本発明を同様
に実施できる。In the above embodiments, the reference optical fiber 5 is used in the reference optical path. However, when the optical fiber 6 to be measured is short, the present invention can be similarly implemented even if the reference light is propagated back and forth in the free space.
以上説明したように、本発明の光ファイバの波長分散測
定方法および装置は、光ヘテロダイン検波に基づいた測
定が可能であり、高精度で波長分散を測定できる効果が
ある。また、光束を光ファイバ中で往復させているの
で、簡単な光学系の構成で光ファイバの一端にて測定を
行うことができる効果がある。As described above, the optical fiber chromatic dispersion measuring method and apparatus of the present invention can perform measurement based on optical heterodyne detection, and has an effect of measuring chromatic dispersion with high accuracy. Further, since the light flux is reciprocated in the optical fiber, there is an effect that the measurement can be performed at one end of the optical fiber with a simple optical system configuration.
第１図は本発明第一実施例光ファイバの波長分散測定装
置のブロック構成図。 第２図は本発明第二実施例光ファイバの波長分散測定装
置のブロック構成図。 第３図は光路長可変装置の一例を示す図。 第４図は光路長可変装置の一例を示す図。 １……光源、２……音響光学偏向器、３……発振器、４
……光路長可変装置、５……参照用光ファイバ、６……
被測定光ファイバ、７、８……反射鏡、９……光検出
器、10……帯域フィルタ、11……波形記録装置、21、22
……半透鏡、23……可動鏡、31、32……反射鏡、33……
可動鏡、41……光ファイバ、42……伸縮素子。FIG. 1 is a block diagram of the wavelength dispersion measuring apparatus for an optical fiber according to the first embodiment of the present invention. FIG. 2 is a block diagram of the wavelength dispersion measuring apparatus for optical fiber according to the second embodiment of the present invention. FIG. 3 is a diagram showing an example of an optical path length varying device. FIG. 4 is a diagram showing an example of an optical path length varying device. 1 ... Light source, 2 ... Acousto-optic deflector, 3 ... Oscillator, 4
...... Optical path length variable device, 5 ...... Reference optical fiber, 6 ......
Optical fiber to be measured, 7, 8 ... Reflector, 9 ... Photodetector, 10 ... Bandpass filter, 11 ... Waveform recording device, 21, 22
...... Semi-transparent mirror, 23 …… Movable mirror, 31, 32 …… Reflector, 33 ……
Movable mirror, 41 ... Optical fiber, 42 ... Telescopic element.
フロントページの続き (72)発明者 青海 恵之 茨城県那珂郡東海村大字白方字白根162番 地 日本電信電話株式会社茨城電気通信研 究所内 (56)参考文献 特公 平５−64289（ＪＰ，Ｂ２)Front page continuation (72) Inventor Yoshiyuki Aomi 162 Shirahane, Shirahoji, Naka-gun, Naka-gun, Ibaraki Prefecture Nippon Telegraph and Telephone Corporation, Ibaraki Telecommunications Research Institute (56) Reference Japanese Patent Publication 5-64289 (JP) , B2)
Claims (2)
記第二の光束を同一の観測面に導き、 上記観測面に生じたビート信号の振幅が最大になるよう
に上記第一および第二の光束の光路長差を変化させ、 複数の光周波数に対するビート信号の振幅が最大となる
光路長差の変化により上記被測定光ファイバの波長分散
を求める 光ファイバの波長分散測定方法において、 上記変調を実質的に一定の光周波数偏移として与える ことを特徴とする光ファイバの波長分散測定方法。1. A coherent output light is generated from a light source, the output light is branched into first and second light fluxes, and at least one of the first and second light fluxes is modulated. The light flux of is incident on one end of the optical fiber to be measured and is reflected back at the other end of the optical fiber to be measured, and the light emitted from the one end of the optical fiber to be measured and the second light flux are incident on the same observation surface. The optical path length difference between the first and second light fluxes is changed so that the amplitude of the beat signal generated on the observation surface becomes maximum, and the optical path length difference at which the amplitude of the beat signal becomes maximum for a plurality of optical frequencies In the chromatic dispersion measuring method of the optical fiber for obtaining the chromatic dispersion of the optical fiber to be measured, the modulation is given as a substantially constant optical frequency deviation.
岐手段と、 分岐された光束の少なくとも一方を変調する変調手段
と、 上記第一の光束を被測定光ファイバの一端に入射させる
手段と、 この被測定光ファイバの他端で折り返し反射させる手段
と、 この被測定光ファイバの上記一端からの出射光および上
記第二の光束を同一の観測面に導く光学系と、 上記第一および第二の光束の光路長の少なくとも一方を
変化させる手段と、 上記観測面に生じたビート信号の振幅を測定する手段と を備えた光ファイバの波長分散測定装置において、 上記分岐手段および上記変調手段が、入射光を二つの光
束に空間的に分岐するとともにその一方の光束の周波数
を偏移させる音響光学偏光器により構成された ことを特徴とする光ファイバの波長分散測定装置。2. A light source for generating coherent output light, a branching means for branching the output light of the light source into first and second light fluxes, and a modulating means for modulating at least one of the branched light fluxes. Means for causing the first light flux to enter one end of the measured optical fiber, means for reflecting the reflected light at the other end of the measured optical fiber, and light emitted from the one end of the measured optical fiber and the second An optical system that guides the luminous flux of the above to the same observation surface, a means for changing at least one of the optical path lengths of the first and second luminous fluxes, and a means for measuring the amplitude of the beat signal generated on the observation surface. In the optical fiber chromatic dispersion measuring apparatus, the branching means and the modulating means spatially split the incident light into two light fluxes, and use an acousto-optic polarizer for shifting the frequency of one of the light fluxes. Wavelength dispersion measuring apparatus of an optical fiber, characterized in that it is.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60166417A JPH0658293B2 (en) | 1985-07-26 | 1985-07-26 | Method and apparatus for measuring wavelength dispersion of optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60166417A JPH0658293B2 (en) | 1985-07-26 | 1985-07-26 | Method and apparatus for measuring wavelength dispersion of optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6225232A JPS6225232A (en) | 1987-02-03 |
| JPH0658293B2 true JPH0658293B2 (en) | 1994-08-03 |
Family
ID=15831035
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60166417A Expired - Fee Related JPH0658293B2 (en) | 1985-07-26 | 1985-07-26 | Method and apparatus for measuring wavelength dispersion of optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0658293B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2546272B2 (en) * | 1987-06-20 | 1996-10-23 | ヤマハ株式会社 | Automatic musical instrument accompaniment device |
| FR2751746B1 (en) * | 1996-07-24 | 1998-10-23 | Boitel Michel | REFLECTOMETRY MEASURING METHOD AND DEVICE FOR FIBER OPTIC CONNECTION |
| CN114184356B (en) * | 2021-11-25 | 2024-01-09 | 苏州六幺四信息科技有限责任公司 | Nonlinear analysis method and nonlinear analysis device for photoelectric detector |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2900652B2 (en) * | 1991-09-04 | 1999-06-02 | 松下電器産業株式会社 | Microphone device |
-
1985
- 1985-07-26 JP JP60166417A patent/JPH0658293B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6225232A (en) | 1987-02-03 |
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