JPH0528338B2 - - Google Patents
Info
- Publication number
- JPH0528338B2 JPH0528338B2 JP11017685A JP11017685A JPH0528338B2 JP H0528338 B2 JPH0528338 B2 JP H0528338B2 JP 11017685 A JP11017685 A JP 11017685A JP 11017685 A JP11017685 A JP 11017685A JP H0528338 B2 JPH0528338 B2 JP H0528338B2
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- light
- mode
- pulse
- dispersion
- 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
- 239000013307 optical fiber Substances 0.000 claims description 55
- 239000006185 dispersion Substances 0.000 claims description 30
- 238000005259 measurement Methods 0.000 claims description 24
- 230000003287 optical effect Effects 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 3
- 239000004065 semiconductor Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 230000001902 propagating effect Effects 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 230000002123 temporal effect Effects 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
- G01M11/33—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter being disposed at one fibre or waveguide end-face, and a light receiver at the other end-face
- G01M11/332—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter being disposed at one fibre or waveguide end-face, and a light receiver at the other end-face using discrete input signals
-
- 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
- G01M11/33—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter being disposed at one fibre or waveguide end-face, and a light receiver at the other end-face
- G01M11/335—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter being disposed at one fibre or waveguide end-face, and a light receiver at the other end-face using two or more input wavelengths
Description
【発明の詳細な説明】
（発明の技術分野）
本発明は光フアイバの分散特性を測定する装置
に関するものである。TECHNICAL FIELD OF THE INVENTION The present invention relates to an apparatus for measuring the dispersion characteristics of an optical fiber.
（従来技術とその問題点）
光フアイバ通信に使用する光の波長や中継伝送
する際の中継距離は、光フアイバの伝送損失と分
散特性とによつて決定される。特に、光フアイバ
のもつ分散特性は、波形歪を生起させ、デイジタ
ル伝送する際の伝送速度に制限を与える。従つ
て、極低損失光フアイバを用いても光フアイバの
もつ分散特性によつて中継距離が制限されること
もあり、光フアイバの分散特性の測定は、伝送損
失の測定と同様非常に重要なことである。(Prior art and its problems) The wavelength of light used in optical fiber communication and the relay distance during relay transmission are determined by the transmission loss and dispersion characteristics of the optical fiber. In particular, the dispersion characteristics of optical fibers cause waveform distortion and limit the transmission speed during digital transmission. Therefore, even if ultra-low-loss optical fibers are used, the dispersion characteristics of the optical fibers may limit the relay distance, and measuring the dispersion characteristics of optical fibers is as important as measuring transmission loss. That's true.
光フアイバにおける分散とは、光フアイバ内を
伝搬する光の速度が波長によつて異なる現象であ
り、この分散特性の測定法に関してはこれまでい
くつかの方法が提案されている。従来のこの種の
測定装置の代表例を第１図及び第２図に示した。 Dispersion in an optical fiber is a phenomenon in which the speed of light propagating within an optical fiber differs depending on the wavelength, and several methods have been proposed to date to measure this dispersion characteristic. Representative examples of conventional measuring devices of this type are shown in FIGS. 1 and 2.
第１図において、半導体レーザ等の光源１−１
からパルス幅数百ピコ秒の光パルスを光フアイバ
１−２に入射させると、光フアイバ１−２内でラ
マン効果により第１ストークス光、第２ストーク
ス光……第ｎストークス光が発生する。この波長
の異なる各ストークス光のうち１つのストークス
光、例えば、第１ストークス光を波長選択回路１
−５により抽出し、抽出された第１ストークス光
は分光器１−７により分岐され、一方は被測定光
フアイバ１−３に伝搬した後、受光器１−４によ
つて電気パルスに変換され、オシロスコープ１−
６に入力される。分光器１−７によつて分岐され
た他方の第１ストークス光は受光器１−４′で電
気パルスに変換され、基準信号となるように遅延
回路１−８で一定の遅延が与えられ、オシロスコ
ープ１−６に入力される。オシロスコープ１−６
では、基準信号の基準電気パルスと被測定光フア
イバを伝搬した後に電気信号に変換された被測定
用電気パルスとの両パルス位置から相対遅延時間
差を求めることができる。 In FIG. 1, a light source 1-1 such as a semiconductor laser
When a light pulse with a pulse width of several hundred picoseconds is made to enter the optical fiber 1-2, first Stokes light, second Stokes light, . . . n-th Stokes light are generated within the optical fiber 1-2 due to the Raman effect. The wavelength selection circuit 1 selects one Stokes light, for example, the first Stokes light, from among the Stokes lights with different wavelengths.
-5, the extracted first Stokes light is branched by a spectrometer 1-7, and one side propagates to the optical fiber 1-3 to be measured, and then is converted into an electric pulse by a photodetector 1-4. , oscilloscope 1-
6 is input. The other first Stokes light branched by the spectrometer 1-7 is converted into an electric pulse by the photoreceiver 1-4', and a certain delay is given by the delay circuit 1-8 so that it becomes a reference signal. It is input to the oscilloscope 1-6. Oscilloscope 1-6
Now, the relative delay time difference can be determined from the pulse positions of the reference electric pulse of the reference signal and the electric pulse to be measured that has been converted into an electric signal after propagating through the optical fiber to be measured.
次に、波長選択回路１−５で波長の異なる第２
ストークス光を選択し同様の作業を行い、基準信
号との相対遅延時間差を求める。この作業を第ｎ
ストークス光まで繰り返すことにより、光フアイ
バ１−３を伝搬する光の各波長に対する相対遅延
時間の関係が測定され、光フアイバ１−３の分散
特性が求められる（L.G.Cohen et al.Appl.oct.
Vol 16、p3136 1977）。 Next, in the wavelength selection circuit 1-5, a second
Select the Stokes beam and perform the same operation to find the relative delay time difference with the reference signal. This work is done on the nth
By repeating the process up to the Stokes light, the relationship between the relative delay time for each wavelength of the light propagating through the optical fiber 1-3 is measured, and the dispersion characteristics of the optical fiber 1-3 are determined (LGCohen et al.Appl.oct.
Vol 16, p3136 1977).
なお、光源１−１としては、YAGレーザ等の
ような高出力レーザを用い、光フアイバ１−２内
で誘導ラマン現象が発生するようにしている。 Note that a high-output laser such as a YAG laser is used as the light source 1-1, and a stimulated Raman phenomenon is generated within the optical fiber 1-2.
次に、第２図に示す分散測定装置について説明
する。いくつかの波長の異なる半導体レーザ
（LD）２−１の出射光は、シンセサイザ２−６に
よつて周波数ｆで正弦波状に変調される。この変
調された半導体レーザ２−１のうちの一つが光ス
イツチ２−２によつて選択され、その出力が光フ
アイバ２−３に入射される。光フアイバ２−３の
出射光は受光器２−４によつて電気信号２−７に
変換され、基準となる電気信号２−８との位相差
が位相差器２−５によつて求められる。同様にし
て、いくつかの波長に対する変調信号の位相変化
が求められ、この結果から、光フアイバ２−３の
分散特性が求められる（K.Tatekura et al.
Symposium on optical fiber measurements.
Boulder.U.S.A、1984）。 Next, the dispersion measuring device shown in FIG. 2 will be explained. Emitted light from the semiconductor laser (LD) 2-1 having several different wavelengths is sinusoidally modulated at a frequency f by a synthesizer 2-6. One of the modulated semiconductor lasers 2-1 is selected by the optical switch 2-2, and its output is input into the optical fiber 2-3. The light emitted from the optical fiber 2-3 is converted into an electrical signal 2-7 by a light receiver 2-4, and the phase difference with the reference electrical signal 2-8 is determined by a phase shifter 2-5. . Similarly, the phase changes of the modulated signal for several wavelengths are determined, and from this result, the dispersion characteristics of the optical fiber 2-3 are determined (K. Tatekura et al.
Symposium on optical fiber measurements.
Boulder. USA, 1984).
以上説明したように、従来の光フアイバ分散測
定装置は１つ１つの波長に対して、別々に光フア
イバ内での光遅延又は光遅延差を測定していた。
この測定方法では、測定に時間がかかり、測定
中の温度変化による光フアイバの長さ変動が測定
結果に誤差となつて現れること、光源側と受光
側とが別々の場所に位置しているような場合の測
定、すなわち遠端測定が困難であること、ま
た、波長の異なる光源を必要とすることから、光
源が複雑化すること等の欠点があつた。 As explained above, the conventional optical fiber dispersion measuring device measures the optical delay or optical delay difference within the optical fiber separately for each wavelength.
With this measurement method, measurement takes time, and variations in the length of the optical fiber due to temperature changes during measurement may cause errors in the measurement results.The light source side and light receiving side may be located at different locations. This method has drawbacks such as difficulty in making measurements at long distances, that is, far-end measurements, and complicating the light source because it requires light sources with different wavelengths.
（発明の目的）
本発明は、上述した従来技術の欠点に鑑みなさ
れたもので、高精度でかつ、多波長の相対遅延時
間差を瞬時に測定でき、遠端測定も可能な光フア
イバの分散特性測定装置を提供することを目的と
する。(Object of the Invention) The present invention has been made in view of the above-mentioned shortcomings of the prior art, and is based on the dispersion characteristics of an optical fiber that enables instantaneous measurement of relative delay time differences of multiple wavelengths with high precision, and enables far-end measurement. The purpose is to provide a measuring device.
（発明の構成と作用）
本発明による光フアイバの分散特性測定装置
は、測定光としてパルス幅の狭い縦多モードの光
パルスを発生させて被測定用の光フアイバに入射
させるための光入射手段と、前記光フアイバから
の出射光を集光する集光手段と、該集光手段の出
力を各モードに分離するモード分離手段と、該モ
ード分離手段により分離された各モードの遅延時
間差を求めて前記光フアイバの分散特性として同
一表示面上に同時に可視表示する表示手段とを備
えている。(Structure and operation of the invention) The optical fiber dispersion characteristic measuring device according to the present invention has a light input means for generating a vertical multi-mode optical pulse with a narrow pulse width as measurement light and inputting it into an optical fiber to be measured. , a condensing means for condensing the light emitted from the optical fiber, a mode separating means for separating the output of the condensing means into each mode, and a delay time difference between each mode separated by the mode separating means. and a display means for simultaneously visually displaying the dispersion characteristics of the optical fiber on the same display surface.
以下に図面を用いて本発明を詳細に説明する。 The present invention will be explained in detail below using the drawings.
（実施例）
第３図は本発明による分散測定装置の実施例で
ある。この実施例において、縦多モード発振して
いる半導体レーザ３−１を周波数ｆの正弦波を発
生するシンセサイザ３−６とパルス波形を発生さ
せるためのコムジエネレータあるいはパルス発生
器３−１１とを用いて駆動すると、パルス幅数十
ピコ秒で繰り返し周波数ｆHzの縦多モードを有す
る光パルスが発生する。この発振している光パル
スはレンズ３−２Ａを用いて効率良く被測定媒体
である光フアイバ３−３に入射される。光フアイ
バ３−３の出力側ではレンズ３−２Ｂで光フアイ
バ３−３の出射光を集光し、各波長ごとに分離す
るためのモノクロメータ３−４に導かれる。この
モノクロメータ３−４は、グレーテイングを内蔵
しており、入射光を波長ごとに各モードに空間的
に分離するものであり、モノクロメータ３−４の
出力端にあるスリツトを完全に開放しておくと、
各モード全てが空間的に分離され、出射される。
なお、各モード空間的に分離する手段として、プ
リズムを用いても良い。次に空間的に分離された
各モードは、更に時間的に分離するためにストリ
ークカメラ３−５及びSITメラ、３−７に導かれ
る。この両カメラ３−５及び３−７は、被測定媒
体である光フアイバ３−３によつて各波長ごとに
異なつた遅延時間を例えば縦軸に、各波長を横軸
に電気信号で一次画面上に表示させるための装置
である。また、この両カメラ３−５及び３−７
は、数ピコ秒の精度で時間的に各モードを分離す
ることが可能である。一次画面上にプロツトされ
た各モードの信号は、アナライザ３−９で読み出
され、画像解析能力をもつたテレビモニタ３−１
０に与えられる。(Example) FIG. 3 shows an example of the dispersion measuring device according to the present invention. In this embodiment, a semiconductor laser 3-1 that oscillates in longitudinal multi-mode is connected to a synthesizer 3-6 that generates a sine wave of frequency f and a comb generator or pulse generator 3-11 that generates a pulse waveform. When driven, an optical pulse having a pulse width of several tens of picoseconds and a repetition frequency of fHz and a longitudinal multimode is generated. This oscillating light pulse is efficiently incident on the optical fiber 3-3, which is the medium to be measured, using the lens 3-2A. On the output side of the optical fiber 3-3, the light emitted from the optical fiber 3-3 is collected by a lens 3-2B and guided to a monochromator 3-4 for separating the light into wavelengths. This monochromator 3-4 has a built-in grating that spatially separates the incident light into each mode for each wavelength.The slit at the output end of the monochromator 3-4 is completely opened. If you keep it,
All modes are spatially separated and emitted.
Note that a prism may be used as a means for spatially separating each mode. Next, each spatially separated mode is guided to a streak camera 3-5 and a SIT camera 3-7 for further temporal separation. Both cameras 3-5 and 3-7 display a primary screen using electrical signals, with the vertical axis representing different delay times for each wavelength due to the optical fiber 3-3, which is the medium to be measured, and the horizontal axis representing each wavelength. This is a device for displaying images on the screen. Also, both cameras 3-5 and 3-7
It is possible to temporally separate each mode with an accuracy of several picoseconds. The signals of each mode plotted on the primary screen are read out by an analyzer 3-9 and then displayed on a television monitor 3-1 with image analysis capability.
given to 0.
なお、シンセサイザ３−６の出射光は分岐さ
れ、一方の数十ピコ秒のパルス幅の光パルスを発
生させるためのパルス発生器またはコムゼネレー
タ３−１１へ、他方は、遅延回路３−８によつ
て、一定の遅延時間が与えられて基準信号とな
る。この基準信号は、ストリークカメラ３−５の
トリガパルスとして用いられる。すなわち、波長
の異なる各モードの遅延時間差は、アナライザ３
−９の出力信号を上述の遅延回路３−８によつて
作り出された基準信号をトリガとしてテレビモニ
ター３−１０に可視表示され、可視表示された遅
延時間差から各モードごとの光フアイバ３−３に
よる分散特性を求めることができる。 Note that the output light from the synthesizer 3-6 is branched, and one is sent to a pulse generator or comb generator 3-11 for generating an optical pulse with a pulse width of several tens of picoseconds, and the other is sent to a delay circuit 3-8. Therefore, a certain delay time is given to the reference signal. This reference signal is used as a trigger pulse for the streak camera 3-5. In other words, the delay time difference between modes with different wavelengths is determined by the analyzer 3.
-9 is visually displayed on the television monitor 3-10 using the reference signal generated by the delay circuit 3-8 as a trigger, and from the visually displayed delay time difference, the optical fiber 3-3 for each mode is The dispersion characteristics can be determined by
第４図ａ及びｂは上述した本発明の測定装置を
用いて、分散特性を測定した測定例を示す特性図
である。 FIGS. 4a and 4b are characteristic diagrams showing an example of measurement of dispersion characteristics using the above-mentioned measuring device of the present invention.
同図ａは、数十ピコ秒のパルス幅で縦多モード
発振している半導体レーザからの出射光を、被測
定媒体である光フアイバ３−３を通さずに、直接
モノクロメータ３−４に入射させた時の、テレビ
モニタ３−１０によつてとらえたストリーク像で
ある。光フアイバ３−３を通さない時は、波長の
異なる縦多モード発振している100ps以下の光パ
ルスが横軸に一列になつており、波長が異なつて
も遅延時間がないことがわかる。なお、同図で輝
度は光強度に相当している。 Figure a shows that the emitted light from a semiconductor laser oscillating in longitudinal multi-mode with a pulse width of several tens of picoseconds is directly input to a monochromator 3-4 without passing through the optical fiber 3-3, which is the medium to be measured. This is a streak image captured by the television monitor 3-10 when the light is incident. When the optical fiber 3-3 is not passed, optical pulses of 100 ps or less oscillating in longitudinal multimode with different wavelengths are aligned on the horizontal axis, and it can be seen that there is no delay time even if the wavelengths are different. Note that in the figure, brightness corresponds to light intensity.
次に、第４図ｂは長さ4.5〔Km〕光フアイバ３−
３を伝搬した上述の光パルスをテレビモニタ３−
１０で測定したストリーク像である。同図から各
モードのストリーク像が斜めに傾斜していること
が分かる。これは各波長（各モード）によつて光
フアイバ３−３の伝搬時間が異なることを意味
し、各波長に対して伝搬時間が異なる性質、すな
わち、各波長の相対遅延時間差が求めようとする
光フアイバ３−３の分散特性である。例えば、同
図から波長1.29μｍにおける分散値Ｄは、次式の
通りである。 Next, Figure 4b shows the length of 4.5 [Km] optical fiber 3-
The above-mentioned optical pulse propagated through 3 is displayed on a television monitor 3-
This is a streak image measured at 10. It can be seen from the figure that the streak images of each mode are obliquely inclined. This means that the propagation time of the optical fiber 3-3 differs depending on each wavelength (each mode), and we are trying to find the property that the propagation time is different for each wavelength, that is, the relative delay time difference of each wavelength. This is the dispersion characteristic of the optical fiber 3-3. For example, from the figure, the dispersion value D at a wavelength of 1.29 μm is as shown in the following equation.
Ｄ＝T1−T2／ΔW×ｌ＝471〔ps〕−189〔ps〕／0.0768
〔μｍ〕×4.5〔Km〕≒0.0816〔ps／Km・μ〕＝8.16〔p
s／Km・ｎｍ〕
但し、T1は1.28616μｍ（1.29−ΔW／２）にお
ける遅延時間〔ps〕
T2は1.29384μｍ（1.29＋ΔW／２）における遅
延時間〔ps〕
ΔWはT2の波長−T1の波長（μｍ）
ｌは光フアイバの長さ（Km）
である。D=T 1 −T 2 /ΔW×l=471[ps]−189[ps]/0.0768
[μm] × 4.5 [Km] ≒ 0.0816 [ps/Km・μ] = 8.16 [p
s/Km・nm] However, T 1 is the delay time at 1.28616 μm (1.29 − ΔW/2) [ps] T 2 is the delay time at 1.29384 μm (1.29 + ΔW/2) [ps] ΔW is the wavelength of T 2 − The wavelength of T 1 (μm) l is the length of the optical fiber (Km).
尚、第４図ｂは横軸と縦軸の単位が極めて不明
確になつているが、実際のテレビモニタ３−１０
では、横軸が１〔ｎｍ〕、縦軸が1.63〔ps〕まで解
読できるようになつている。 Although the units of the horizontal and vertical axes in Figure 4b are extremely unclear, they are similar to the actual TV monitor 3-10.
The horizontal axis is 1 [nm] and the vertical axis is 1.63 [ps].
また、通常は上式により測定者による計算処理
によつて分散値Ｄを求めるのではなく、図示され
ていないが、テレビモニタ３−１０に内蔵されて
いるマイコン等により計算されて、そのモニタ表
示面上に第４図ｂのように表示する。さらに、求
められた分散値Ｄをデイジタル表示あるいは印字
するような構造としてもよい。 In addition, normally, the dispersion value D is not calculated by the measurement person using the above formula, but is calculated by a microcomputer, etc. built into the TV monitor 3-10, and is displayed on the monitor. It is displayed on the screen as shown in FIG. 4b. Furthermore, a structure may be adopted in which the obtained dispersion value D is displayed digitally or printed.
実施例 ２
実施例１では、送信側と受信側とが同一地点に
ある場合、例えば光フアイバ製造の工場内等にお
いて測定する近端測定の分散特性測定装置につい
て説明した。しかし、通常は測定しようとする光
フアイバの長さが数十キロメータと長いため、送
信側と受信側とが互いに離れた地点で測定するの
が通例である。この遠端測定を行う場合、基準信
号をどのように取り出すか、あるいは、受信側で
送信側に同期した基準信号を作り出すかが問題と
なり、従来は分散特性の遠端測定が可能な測定方
式については何ら開示されていない。Embodiment 2 In Embodiment 1, a dispersion characteristic measuring device for near-end measurement was described in which the transmitting side and the receiving side are located at the same location, for example, in an optical fiber manufacturing factory. However, since the length of the optical fiber to be measured is typically long, several tens of kilometers, it is customary to perform measurements at locations where the transmitter and receiver are separated from each other. When performing this far-end measurement, the problem is how to extract the reference signal, or how to create a reference signal on the receiving side that is synchronized with the transmitting side. Conventionally, measurement methods that can perform far-end measurements of dispersion characteristics are difficult to solve. has not been disclosed at all.
第５図は本発明の他の実施例であり、分散特性
を遠端測定より測定する場合の構成図である。 FIG. 5 is another embodiment of the present invention, and is a block diagram in which the dispersion characteristics are measured by far-end measurement.
(1) 送信器 まず送信器の構成について説明する。(1) Transmitter First, the configuration of the transmitter will be explained.
送信器としては、縦多モード発振する１個の
光源３−１と、その光源から出射光が少なくと
も数十ピコ秒のパルス幅を有する光パルスとな
るような変調手段があれば良い。同図では、変
調手段として、シンセサイザ３−６とパルス発
生器３−１１とを組合わせたものを用いている
が、シンセサイザ３−６とコムジエネレータと
の組合わせでも良い。また、光源３−１からの
出力光を効率良く光フアイバ３−３に入射させ
るために凸レンズ３−２Ａを用いればさらに効
果的である。 The transmitter may include one light source 3-1 that oscillates in longitudinal multimode mode, and a modulation means so that the light emitted from the light source becomes a light pulse having a pulse width of at least several tens of picoseconds. In the figure, a combination of a synthesizer 3-6 and a pulse generator 3-11 is used as the modulation means, but a combination of a synthesizer 3-6 and a comb generator may also be used. Furthermore, it is even more effective to use a convex lens 3-2A in order to efficiently make the output light from the light source 3-1 enter the optical fiber 3-3.
(2) 受信器
光フアイバ３−３からの出射光を集光させる
レンズ３−２Ｂから遅延時間差を可視表示させ
るテレビモニタ３−１０までは、第３図と全く
同一である。(2) Receiver The components from the lens 3-2B that condenses the light emitted from the optical fiber 3-3 to the television monitor 3-10 that visually displays the delay time difference are exactly the same as in FIG.
第３図と異なる点は、新たに基準信号を作り
出す手段を有している点である。すなわち、受
信器にシンセサイザ３−６′と可変遅延器３−
１２とを設け、送信器のシンセサイザ３−６と
同期をとるようにしている。ところで可変遅延
器３−１２の遅延量Ｄとしては
Ｄ＝ｌ／ｃ／ｎ＝ｌ・ｎ／ｃ ……(1)
で与えられる。但し、Ｃは真空中における光
速、ｌは光フアイバ３−３の長さ、ｎは光フア
イバ３−３の屈折率である。または、遅延量Ｄ
として、テレビモニタ３−１０を見ながらスト
リーク像がテレビ画面の中央に写し出されるよ
うに調整しても良い。 The difference from FIG. 3 is that a means for newly generating a reference signal is provided. That is, the receiver includes a synthesizer 3-6' and a variable delay device 3-6'.
12 is provided to synchronize with the synthesizer 3-6 of the transmitter. By the way, the delay amount D of the variable delay device 3-12 is given by D=l/c/n=l·n/c (1). However, C is the speed of light in vacuum, l is the length of the optical fiber 3-3, and n is the refractive index of the optical fiber 3-3. Or delay amount D
Alternatively, while viewing the television monitor 3-10, adjustments may be made so that the streak image is displayed in the center of the television screen.
なお、シンセサイザ３−６′の周波数ｆにつ
いては、予め送受信側で決めておく必要があ
る。 Note that the frequency f of the synthesizer 3-6' must be determined in advance by the transmitting and receiving sides.
以上のように送信器と同期のとれた基準信号を
作り出し、第３図と同様にストリークカメラ３−
５にトリガとして与えれば良い。 As described above, a reference signal synchronized with the transmitter is created, and the streak camera 3-
5 as a trigger.
実施例 ３
第６図は本発明による他の実施例であり、遠端
測定に用いる受信器の構成図である。本実施例で
は基準信号を送信側の変調周波数ｆを取り出して
用いることに特徴があり、集光レンズ３−２Ｂの
後に光を分岐するための分光器３−１３を挿入
し、一方は第５図と同様の測定系に行き、他方の
基準信号を作るための受光素子３−１４に入力さ
れる。受光素子３−１４はAPD等の半導体受光
素子を用いれば良く、数十ピコ秒のパルス幅の光
パルスを受光した時のみ電気信号に変換されるよ
うに構成しておく。このような構成にすれば、受
信側で送信側と同期の取れた基準信号を簡単に作
り出すことができる。なお、図示していないが被
測定媒体がある光フアイバ３−３が長い場合に
は、半導体受光素子３−１４の後に増幅器を挿入
すれば良い。Embodiment 3 FIG. 6 is another embodiment according to the present invention, and is a block diagram of a receiver used for far-end measurement. This embodiment is characterized in that the modulation frequency f on the transmitting side is extracted and used as the reference signal, and a spectroscope 3-13 for splitting light is inserted after the condenser lens 3-2B, and one The signal goes to a measurement system similar to that shown in the figure, and is input to a light receiving element 3-14 for generating the other reference signal. The light-receiving element 3-14 may be a semiconductor light-receiving element such as an APD, and is configured so that it is converted into an electrical signal only when it receives a light pulse with a pulse width of several tens of picoseconds. With this configuration, it is possible to easily create a reference signal on the receiving side that is synchronized with the transmitting side. Although not shown, if the optical fiber 3-3 containing the medium to be measured is long, an amplifier may be inserted after the semiconductor light-receiving element 3-14.
（発明の効果）
以上のように、本発明の測定装置を用いれば、
各波長に対する光フアイバの分散特性が同時に可
視表示が出来るとともに瞬時に測定が可能であ
り、周囲の環境温度による測定誤差もなくすこと
ができる。また、1ps以下の時間分解能が期待で
きるので、高精度の分散特性を求めることができ
る。更に、従来の技術では困難であつた遠端測定
も可能となりその効果は極めて大である。(Effect of the invention) As described above, if the measuring device of the present invention is used,
The dispersion characteristics of the optical fiber for each wavelength can be visually displayed at the same time and can be measured instantly, and measurement errors due to surrounding environmental temperature can be eliminated. Furthermore, since a time resolution of 1 ps or less can be expected, highly accurate dispersion characteristics can be obtained. Furthermore, far-end measurements, which were difficult with conventional techniques, are now possible, which is extremely effective.
第１図及び第２図は従来の分散測定装置の構成
図、第３図は本発明の一実施例を示す構成図、第
４図ａ及びｂは本発明による分散測定装置を用い
て測定した特性例図、第５図及び第６図は本発明
による遠端測定を行うための実施例の構成図であ
る。
１−１……光源、１−２……光フアイバ、１−
３……光フアイバ（被測定用）、１−４……受光
器、１−４′……受光器、１−５……波長選択回
路、１−６……オシロスコープ、１−７……分光
器、１−８……遅延回路、２−１……半導体レー
ザ、２−２……光スイツチ、２−３……光フアイ
バ、２−４……受光器、２−５……位相差器、２
−６……シンセサイザ、２−７……受信電気信
号、２−８……基準電気信号、３−１……光源、
３−２Ａ……レンズ、３−２Ｂ……レンズ、３−
３……光フアイバ、３−４……モノクロメータ、
３−５……ストリークカメラ、３−６……シンセ
サイザ、３−７……SITカメラ、３−８……遅延
回路、３−９……アナライザ、３−１０……テレ
ビモニタ、３−１１……パルス発生器、３−１２
……可変遅延回路、３−１３……分光器、３−１
４……受光素子。
Figures 1 and 2 are block diagrams of a conventional dispersion measuring device, Figure 3 is a block diagram showing an embodiment of the present invention, and Figures 4 a and b are measurements taken using the dispersion measuring device according to the present invention. The characteristic diagrams, FIGS. 5 and 6, are configuration diagrams of an embodiment for performing far-end measurement according to the present invention. 1-1...Light source, 1-2...Optical fiber, 1-
3... Optical fiber (for measurement), 1-4... Light receiver, 1-4'... Light receiver, 1-5... Wavelength selection circuit, 1-6... Oscilloscope, 1-7... Spectroscopy 1-8...Delay circuit, 2-1...Semiconductor laser, 2-2...Optical switch, 2-3...Optical fiber, 2-4...Photodetector, 2-5...Phase shifter ,2
-6...Synthesizer, 2-7...Received electrical signal, 2-8...Reference electrical signal, 3-1...Light source,
3-2A...Lens, 3-2B...Lens, 3-
3... Optical fiber, 3-4... Monochromator,
3-5...Streak camera, 3-6...Synthesizer, 3-7...SIT camera, 3-8...Delay circuit, 3-9...Analyzer, 3-10...TV monitor, 3-11... ...Pulse generator, 3-12
... Variable delay circuit, 3-13 ... Spectrometer, 3-1
4... Light receiving element.
Claims (1)
光パルスを発生させて被測定用の光フアイバに入
射させるための光入射手段と、前記光フアイバか
らの出射光を集光する集光手段と、該集光手段の
出力を各モードに分離するモード分離手段と、該
モード分離手段により分離された各モードの遅延
時間差を求めて前記光フアイバの分散特性として
同一表示面上に同時に可視表示する表示手段とを
備えた光フアイバの分散特性測定装置。1. A light input means for generating a vertical multi-mode optical pulse with a narrow pulse width as measurement light and inputting it into an optical fiber to be measured; and a condensing means for condensing the light emitted from the optical fiber. , a mode separation means for separating the output of the light condensing means into each mode, and a delay time difference between each mode separated by the mode separation means, which is visually displayed simultaneously on the same display surface as a dispersion characteristic of the optical fiber. An apparatus for measuring dispersion characteristics of an optical fiber, comprising display means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11017685A JPS61269037A (en) | 1985-05-24 | 1985-05-24 | System for measuring dispersing characteristics of optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11017685A JPS61269037A (en) | 1985-05-24 | 1985-05-24 | System for measuring dispersing characteristics of optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61269037A JPS61269037A (en) | 1986-11-28 |
| JPH0528338B2 true JPH0528338B2 (en) | 1993-04-26 |
Family
ID=14528973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11017685A Granted JPS61269037A (en) | 1985-05-24 | 1985-05-24 | System for measuring dispersing characteristics of optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61269037A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01176920A (en) * | 1987-12-31 | 1989-07-13 | Hamamatsu Photonics Kk | Spectral measuring instrument |
| AU2001281363A1 (en) * | 2000-08-01 | 2002-02-13 | Wavecrest Corporation | Electromagnetic and optical analyzer |
| AU2001277208A1 (en) * | 2000-08-01 | 2002-02-13 | Wavecrest Corporation | Multichannel system analyzer |
| JP5835807B2 (en) * | 2012-07-04 | 2015-12-24 | 日本電信電話株式会社 | Optical device frequency measurement device |
| JP6562781B2 (en) * | 2015-09-03 | 2019-08-21 | Kddi株式会社 | Propagation delay difference measuring device |
-
1985
- 1985-05-24 JP JP11017685A patent/JPS61269037A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61269037A (en) | 1986-11-28 |
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