JPH0363008B2 - - Google Patents
Info
- Publication number
- JPH0363008B2 JPH0363008B2 JP16751382A JP16751382A JPH0363008B2 JP H0363008 B2 JPH0363008 B2 JP H0363008B2 JP 16751382 A JP16751382 A JP 16751382A JP 16751382 A JP16751382 A JP 16751382A JP H0363008 B2 JPH0363008 B2 JP H0363008B2
- Authority
- JP
- Japan
- Prior art keywords
- light source
- noise
- fiber
- light
- etalon
- 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
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
Description
【発明の詳細な説明】
(1) 発明の技術分野
本発明はフアイバチユーナブルエタロンを用い
た、光源のAM・FM雑音の特性評価方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for evaluating characteristics of AM/FM noise of a light source using a fiber retunable etalon.
(2) 従来技術と問題点
従来、レーザダイオード等を用いた光源の光源
波長測定装置としてはスペクトラムアナライザが
用いられている。すなわち光源からの光を光検出
器において検出し、電気信号に変換し、変換され
た電気信号をスペクトラムアナライザにより周波
数分析し、その結果、被測定光源の波長が測定さ
れる。被測定光源の中心波長のゆらぎについて
も、上述のスペクトラムアナライザを用いる方法
で測定が可能であるが、その測定感度において必
ずしも満足する結果が得られていない実状であ
る。(2) Prior Art and Problems Conventionally, a spectrum analyzer has been used as a light source wavelength measuring device for a light source using a laser diode or the like. That is, light from a light source is detected by a photodetector, converted into an electrical signal, and the frequency of the converted electrical signal is analyzed by a spectrum analyzer. As a result, the wavelength of the light source to be measured is measured. Fluctuations in the center wavelength of the light source to be measured can also be measured by the method using the above-mentioned spectrum analyzer, but the actual situation is that satisfactory results are not always obtained in terms of measurement sensitivity.
(3) 発明の目的
本発明の目的は、前述の従来の方法における実
状にかんがみ、帯域制限効果のあるフアイバチユ
ーナブルエタロンを測定系に用いるという着想に
基づき、光源のAM・FM雑音を高感度で測定で
きるようにし、より詳細な光源の特性評価ができ
るようにすることにある。(3) Purpose of the Invention In view of the actual situation in the conventional method described above, the purpose of the present invention is to reduce the AM/FM noise of the light source with high sensitivity based on the idea of using a fiber retunable etalon with a band-limiting effect in the measurement system. The objective is to enable more detailed light source characteristics evaluation.
(4) 発明の構成
本発明においては特定発明として、被測定光源
よりの光を帯域制限効果のあるフアイバチユーナ
ブルエタロン中を通過させることにより、該光源
の中心波長のゆらぎを振幅変調に変換し、前記振
幅変調された光を光検出器に加えて検出し、電力
信号に変換し、該変換された電力信号により、光
源のAM・FM雑音の特性評価を行うことを特徴
とする光源のAM・FM雑音の特性評価方法が提
供される。(4) Structure of the Invention In the present invention, as a specific invention, the fluctuation of the center wavelength of the light source is converted into amplitude modulation by passing the light from the light source to be measured through a fiber variable etalon having a band-limiting effect. , the amplitude modulated light is applied to a photodetector to be detected and converted into a power signal, and the AM/FM noise characteristics of the light source are evaluated using the converted power signal. - A method for characterizing FM noise is provided.
(5) 発明の実施例
本発明の一実施例としての光源のAM・FM雑
音の特性評価方法を行う測定装置のブロツク図が
第１図に示される。図において光源（LD）１１
からの光は伝送路を介してフアイバチユーナブル
エタロン１２に加えられ、フアイバチユーナブル
エタロン１２を通過した後、光検出器１３に加え
られる。光検出器１３の出力は狭帯域レベルメー
タ、パワーメータまたはスペクトラムアナライザ
等の測定器（MA）１４に供給される。(5) Embodiment of the Invention FIG. 1 shows a block diagram of a measuring device for performing a method for evaluating characteristics of AM/FM noise of a light source as an embodiment of the present invention. In the figure, light source (LD) 11
The light is applied to the fiber repeatable etalon 12 via the transmission path, and after passing through the fiber repeatable etalon 12, is applied to the photodetector 13. The output of the photodetector 13 is supplied to a measuring instrument (MA) 14 such as a narrowband level meter, power meter or spectrum analyzer.
次に上述の装置の動作を第２図を参照して説明
する。第２図１は光源からの光のスペクトラム
（本例ではレーザスペクトラム）を示し、横軸は
波長λを、縦軸は光パワー（LP）を表わす。中
心波長はλ0で表わされる。第２図２はフアイバチ
ユーナブルエタロン１２の特性を示し、横軸は波
長λを、縦軸は透過率（TF）を表わす。第２図
１に示されるようなスペクトラムを有する光がフ
アイバチユーナブルエタロン１２を通過すると、
光の中心波長λ0がエタロン特性における最大透過
率を示す波長と一致していれば、第２図３に破線
２１で示すような出力となる。第２図３におい
て、横軸および縦軸は第２図２と同様であり、実
線は第２図２のエタロン特性が転記されたもので
ある。一方光源からの光の波長にゆらぎがある場
合は第２図３における破線２２のように振幅が帯
域制限効果を有するエタロン特性により制限され
る。すなわち波長の変化が振幅の変化に変換され
て出力される。変換された出力は光検出器１３に
おいて検出され、空気信号に変換される。該電気
信号は狭帯域レベルメータ、パワーメータ、およ
びスペクトラムアナライザ等でその電力が測定さ
れ、その結果により、光源からの光のAM・FM
雑音特性（中心波長のゆらぎ）が評価される。 Next, the operation of the above-mentioned apparatus will be explained with reference to FIG. FIG. 2 shows a spectrum of light from a light source (laser spectrum in this example), where the horizontal axis represents wavelength λ and the vertical axis represents optical power (LP). The center wavelength is expressed as λ 0 . FIG. 2 shows the characteristics of the fiber retunable etalon 12, where the horizontal axis represents the wavelength λ and the vertical axis represents the transmittance (TF). When light having a spectrum as shown in FIG. 2 passes through the fiber repeatable etalon 12,
If the center wavelength λ 0 of the light matches the wavelength showing the maximum transmittance in the etalon characteristics, the output will be as shown by the broken line 21 in FIG. 2 . In FIG. 2, the horizontal and vertical axes are the same as those in FIG. 2, and the solid line is a transcription of the etalon characteristics in FIG. 2. On the other hand, if the wavelength of the light from the light source fluctuates, the amplitude is limited by the etalon characteristics that have a band-limiting effect, as indicated by the broken line 22 in FIG. That is, a change in wavelength is converted into a change in amplitude and output. The converted output is detected by a photodetector 13 and converted into an air signal. The power of the electrical signal is measured using a narrowband level meter, power meter, spectrum analyzer, etc., and the results determine whether the light from the light source is AM or FM.
The noise characteristics (center wavelength fluctuation) are evaluated.
第３図は本装置に用いられるフアイバチユーナ
ブルエタロンの一例の外観を示す斜視図である。
図において、光フアイバ３３は途中で中断されて
おり、エアギヤツプ３４を有する。両端部の接続
部分はフエルール３２であり、外周はアダプタ３
１で囲まれている。図における矢印方向の圧力Ｐ
が加えられるとフエルール３２が伸縮し、共振波
長が変化する。第４図には、上述のフアイバチユ
ーナブルエタロンの長さの変化Ｌに対する減衰率
ATTが示される。本例では波長λが1.3マイクロ
メートルの場合である。 FIG. 3 is a perspective view showing the appearance of an example of a fiber retunable etalon used in this device.
In the figure, the optical fiber 33 is interrupted in the middle and has an air gap 34. The connecting parts at both ends are ferrules 32, and the outer periphery is an adapter 3.
It is surrounded by 1. Pressure P in the direction of the arrow in the figure
When the ferrule 32 is applied, the ferrule 32 expands and contracts, and the resonant wavelength changes. FIG. 4 shows the attenuation rate with respect to the change L in length of the fiber retunable etalon mentioned above.
ATT is indicated. In this example, the wavelength λ is 1.3 micrometers.
第５図には、本発明の他の実施例を行う測定装
置が示される。この測定装置においては、光源１
１とフアイバチユーナブルエタロン１２の間に局
部発振器（OSC）５２の出力により振幅変調を
行う光変調器５１を設け、かつ局部発振器５２の
発振周波数と同期のとれたロツクイン増幅器５３
を設け、その出力を前述の光信号から変換された
電気信号を測定する測定器に該電気信号と同時に
供給し、該測定器の測定機能の援助を行う。上述
した以外は第１図の装置と同様である。この実施
例によれば光源の静特性のみでなく、振幅変調時
の動特性も測定評価できる。 FIG. 5 shows a measuring device implementing another embodiment of the invention. In this measuring device, the light source 1
An optical modulator 51 that performs amplitude modulation using the output of a local oscillator (OSC) 52 is provided between the fiber-tunable etalon 1 and the fiber-tunable etalon 12, and a lock-in amplifier 53 that is synchronized with the oscillation frequency of the local oscillator 52.
and supplies its output simultaneously with the electrical signal to a measuring device that measures the electrical signal converted from the aforementioned optical signal, thereby assisting the measuring function of the measuring device. The apparatus is similar to the apparatus shown in FIG. 1 except as described above. According to this embodiment, not only the static characteristics of the light source but also the dynamic characteristics during amplitude modulation can be measured and evaluated.
(6) 発明の効果
本発明によれば、光源のAM・FM雑音を高感
度で測定することができ、より詳細な光源の特性
評価をすることができる。またフアイバチユーナ
ブルエタロンを用いることは、小杉、軽量、低価
格であるほか、レンズ等が不要である等多くの利
点を有する。(6) Effects of the Invention According to the present invention, AM/FM noise of a light source can be measured with high sensitivity, and more detailed characteristics of the light source can be evaluated. Furthermore, the use of a fiber reusable etalon has many advantages, such as being lightweight, low cost, and eliminating the need for lenses.
第１図は本発明の一実施例としての光源の
AM・FM雑音の特性評価方法を行う測定装置の
ブロツク図、第２図は第１図の装置の動作を説明
するための特性図、第３図は第１図の装置に用い
られるフアイバチユーナブルエタロンの概略的な
外観を示す斜視図、第４図は第３図のフアイバチ
ユーナブルエタロンの特性を示す特性図、および
第５図は本発明の他の実施例を行う測定装置を示
すブロツク図である。
１１…光源、１２…フアイバチユーナブルエタ
ロン、１３…光検出器、１４…測定器、３１…ア
ダプタ、３２…フエルール、３３…光フアイバ、
３４…エアギヤツプ、５１…光変調器、５２…局
部発振器、５３…ロツクイン増幅器。
Figure 1 shows a light source as an embodiment of the present invention.
A block diagram of a measuring device that performs a method for evaluating the characteristics of AM/FM noise, Figure 2 is a characteristic diagram to explain the operation of the device in Figure 1, and Figure 3 is a diagram of the fiber characteristics used in the device in Figure 1. FIG. 4 is a characteristic diagram showing the characteristics of the flexible etalon shown in FIG. 3, and FIG. 5 is a block diagram showing a measuring device for carrying out another embodiment of the present invention. It is. DESCRIPTION OF SYMBOLS 11... Light source, 12... Fiber retunable etalon, 13... Photodetector, 14... Measuring device, 31... Adapter, 32... Ferrule, 33... Optical fiber,
34... Air gap, 51... Optical modulator, 52... Local oscillator, 53... Lock-in amplifier.
Claims (1)
アイバチユーナブルエタロン中を通過させること
により、該光源の中心波長のゆらぎを振幅変調に
変換し、前記振幅変調された光を光検出器に加え
て検出し、電力信号に変換し、該変換された電力
信号により、光源のAM・FM雑音の特性評価を
行うことを特徴とする光源のAM・FM雑音の特
性評価方法。 ２ 被測定光源よりの光を変調用発振器の出力で
振幅変調して帯域制限効果のあるフアイバチユー
ナブルエタロン中を通過させ、該変調用発振器の
発振周波数と同期のとれたロツクイン増幅器から
の出力と該変換された電力信号により、光源の
AM・FM雑音の特性評価を行うことを特徴とす
る光源のAM・FM雑音の特性評価方法。[Claims] 1. By passing the light from the light source to be measured through a fiber-tunable etalon that has a band-limiting effect, fluctuations in the center wavelength of the light source are converted into amplitude modulation, and the amplitude-modulated light is A method for evaluating the characteristics of AM/FM noise of a light source, characterized in that the characteristics of AM/FM noise of the light source are evaluated by adding it to a photodetector, detecting it, converting it into a power signal, and evaluating the characteristics of the AM/FM noise of the light source using the converted power signal. . 2. The light from the light source to be measured is amplitude-modulated with the output of a modulation oscillator, passed through a fiber-tunable etalon that has a band-limiting effect, and the output from a lock-in amplifier synchronized with the oscillation frequency of the modulation oscillator. The converted power signal allows the light source to
A method for evaluating characteristics of AM/FM noise of a light source, characterized by evaluating characteristics of AM/FM noise.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16751382A JPS5957136A (en) | 1982-09-28 | 1982-09-28 | Method for evaluating characteristics of am-fm noise of light source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16751382A JPS5957136A (en) | 1982-09-28 | 1982-09-28 | Method for evaluating characteristics of am-fm noise of light source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5957136A JPS5957136A (en) | 1984-04-02 |
| JPH0363008B2 true JPH0363008B2 (en) | 1991-09-27 |
Family
ID=15851072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16751382A Granted JPS5957136A (en) | 1982-09-28 | 1982-09-28 | Method for evaluating characteristics of am-fm noise of light source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5957136A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2507790B2 (en) * | 1988-12-20 | 1996-06-19 | 富士通株式会社 | Semiconductor laser FM modulation characteristic measuring device |
| JP2802390B2 (en) * | 1989-06-02 | 1998-09-24 | 日本電信電話株式会社 | Optical frequency modulation characteristics measurement device |
| JPH0359428A (en) * | 1989-07-28 | 1991-03-14 | Fujitsu Ltd | Method and device for measuring frequency modulation characteristic of semiconductor laser |
| JPH0620333U (en) * | 1992-06-12 | 1994-03-15 | 有限会社九州生技研 | Chain guide rail structure |
-
1982
- 1982-09-28 JP JP16751382A patent/JPS5957136A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5957136A (en) | 1984-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6289143B1 (en) | Fiber optic acoustic emission sensor | |
| CA2007190C (en) | Laser optical ultrasound detection | |
| US4758087A (en) | Fiber optic transducer | |
| EP0147251B1 (en) | Method and apparatus for measuring chromatic dispersion coefficient | |
| EP0092369B1 (en) | Light frequency change detecting method and apparatus | |
| US5619326A (en) | Method of sample valuation based on the measurement of photothermal displacement | |
| CN114018171B (en) | A high-resolution strain sensor based on differential optical fiber resonator | |
| GB2146123A (en) | Apparatus for monitoring displacement | |
| CN111829981A (en) | A gas heterodyne detection device and detection method based on TDLAS | |
| JP2744742B2 (en) | Gas concentration measuring method and its measuring device | |
| JPH0240512A (en) | Optical fiber type monitoring apparatus for measuring vibration and acceleration of load object | |
| JP2703835B2 (en) | Gas concentration measuring method and its measuring device | |
| JPH0363008B2 (en) | ||
| JPH05256769A (en) | Method and apparatus for measuring gas concentration | |
| JP2540670B2 (en) | Multi-type gas detector using optical fiber | |
| JPH05256768A (en) | Gas concentration measuring method and measuring apparatus therefor | |
| JPS58120146A (en) | Measuring method for polarization characteristic of optical fiber | |
| GB2233087A (en) | Apparatus for monitoring a gas or a flame | |
| KR100335244B1 (en) | An apparatus and a method for the measurement of phase fluctuation of optical fiber | |
| JP2507790B2 (en) | Semiconductor laser FM modulation characteristic measuring device | |
| JPH037253B2 (en) | ||
| JPS6147534A (en) | Method and apparatus for measuring light loss characteristic of optical fiber | |
| JPS63188704A (en) | High-sensitivity optical fiber sensor | |
| JPS5917771B2 (en) | Optical fiber frequency characteristic measurement method | |
| Miles et al. | Low Frequency Noise in Fiber Coupled Diode Lasers |