JPH02307027A - Light frequency measuring instrument - Google Patents
Light frequency measuring instrumentInfo
- Publication number
- JPH02307027A JPH02307027A JP12813789A JP12813789A JPH02307027A JP H02307027 A JPH02307027 A JP H02307027A JP 12813789 A JP12813789 A JP 12813789A JP 12813789 A JP12813789 A JP 12813789A JP H02307027 A JPH02307027 A JP H02307027A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- light source
- output
- light
- photodetector
- 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.)
- Pending
Links
- 230000005540 biological transmission Effects 0.000 claims abstract description 13
- 230000003287 optical effect Effects 0.000 claims description 18
- 238000005259 measurement Methods 0.000 claims description 6
- 239000011324 bead Substances 0.000 claims description 5
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 abstract description 22
- 239000004576 sand Substances 0.000 abstract 1
- 238000004364 calculation method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Spectrometry And Color Measurement (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、光の絶対周波！（または波長）を測定する装
置の実現に関する。[Detailed Description of the Invention] <Industrial Application Field> The present invention is based on the absolute frequency of light! (or wavelength).
〈従来の技術〉
従来、光の絶対周波数を測定する一般的な手段としては
、回折格子を利用する分光測定（光スペクトラムアナラ
イザ）や、内部に基準光路差と基準光源を持ち、干渉信
号から波長を測定するもの等がある。<Conventional technology> Conventionally, general methods for measuring the absolute frequency of light include spectroscopic measurements using a diffraction grating (optical spectrum analyzer), and methods that have an internal reference optical path difference and a reference light source to determine the wavelength from the interference signal. There are some methods that measure .
〈発明が解決しようとする課題〉
しかしながら、上記のような測定手段の場合、その測定
精度が±５ｘｌＯ’程度であり、分光分析や光通信等の
ようにより高い測定精度が要求される分野では不十分で
ある。<Problem to be solved by the invention> However, in the case of the above-mentioned measuring means, the measurement accuracy is about ±5xlO', which is not suitable for fields that require higher measurement accuracy such as spectroscopic analysis and optical communication. It is enough.
本発明はこのような問題点を解決するために成されたも
ので、光の絶対周波数を高精度で測定することのできる
装置を実現することを目的とする。The present invention was made to solve these problems, and an object of the present invention is to realize a device that can measure the absolute frequency of light with high precision.
く課題を解決するための手段〉
本発明は被測定光の周波数を測定する光周波数測定装置
に係るもので、その特徴とするところは出力光の周波数
が安定化な周波数基準光源と、出力光の周波数が可変の
周波数可変光源と、前記周波数基準光源および前記周波
数可変光源の出力光を入射するエタロンと、前記周波数
基準光源および前記周波数可変光源からのエタロン透過
光をそれぞれ検出する第１および第２の光検出器と、前
記第１の光検出器の出力に基づいて前記エタロンの透過
周波数の１つを前記周波数基準光源の出力光の周波数に
制御する第１の制御手段と、前記第２の光検出器の出力
に基づいて前記周波数可変光源の出力光の周波数を前記
エタロンの各透過周波数に順次掃引制御する第２の制御
手段と、前記第２の光検出器の出力ピーク数を計数する
カウンタと、周波数可変光源の出力光と被測定光とを合
波する合波手段と、この合波手段の出力光からビード信
号を検出する第３の光検出器と、この第３の光検出器の
出力信号と前記カウンタの出力から被測定光の周波数を
演算する演算部とを備えた点にある。Means for Solving the Problems> The present invention relates to an optical frequency measuring device that measures the frequency of light to be measured, and its features include a frequency reference light source whose output light frequency is stabilized, and a frequency reference light source that stabilizes the frequency of the output light. a frequency variable light source whose frequency is variable; an etalon into which output light from the frequency reference light source and the frequency variable light source is incident; first and second etalons for detecting the etalon transmitted light from the frequency reference light source and the frequency variable light source, respectively; a first control means for controlling one of the transmission frequencies of the etalon to the frequency of the output light of the frequency reference light source based on the output of the first photodetector; a second control means that sequentially sweeps and controls the frequency of the output light of the variable frequency light source to each transmission frequency of the etalon based on the output of the photodetector; and counting the number of output peaks of the second photodetector. a counter for combining the output light of the frequency variable light source and the light to be measured; a third photodetector for detecting a bead signal from the output light of the multiplexing means; The present invention is characterized in that it includes a calculation section that calculates the frequency of the light to be measured from the output signal of the detector and the output of the counter.
く作用〉
演算部において、周波数基準光源の出力周波数と、エタ
ロンの透過ピーク間隔と、カウンタで計数される透過ピ
ーク数と、第３の光検出器の出力から求められるビード
周波数とから被測定光源の絶対周波数を高精度に測定す
ることができる。In the calculation section, the light source to be measured is determined from the output frequency of the frequency reference light source, the transmission peak interval of the etalon, the number of transmission peaks counted by the counter, and the bead frequency determined from the output of the third photodetector. The absolute frequency of can be measured with high precision.
〈実施例〉 以下本発明を図面を用いて詳しく説明する。<Example> The present invention will be explained in detail below using the drawings.
第１図は本発明に係る光周波数測定装置の一実施例を示
す構成ブロック図である０図において、３０はレーザ等
からなる被測定光源、４０は被測定光源３０の出力光の
周波数を測定する光周波数測定装置である。光周波数測
定装置４０において、ｌは例えばＲｂ等の原子吸収線に
半導体レーザの波長を制御する等により周波数を非常に
安定にした周波数基準光源、２はこの周波数基準光源１
の出力光を入射するファブリ・ペロー・エタロン、３は
周波数基準光源１の出力光がエタロン２を透過した光を
検出するフォトダイオード等の第１の光検出器、４はロ
ックインアンプ等で構成され光検出器３の出力を入力し
てエタロン２の面間距離（ミラー間の距離）を制御する
第１の制御手段、２３は制御手段４の出力によりエタロ
ン２の面間距離を変化させる圧電素子等のトランスジュ
ーサ、５は制御信号により出力光の周波数を変化できる
周波数可変光源で、例えば位相制御領域を持つＤＢＲ型
半導体レーザで位相制御領域へ流す電流を可変するもの
、６は周波数可変光源５の出力光を２つの方向に分離す
る第１のハーフミラ−１７はハーフミラ−６の透過光が
エタロン２を透過した光を検出するフォトダイオード等
の第２の光検出器、８はロックインアンプ等で構成され
光検出器７の出力を入力して周波数可変光源５の出力周
波数を変化させる第２の制御手段、９は被測定光源ｌＯ
の出力光とハーフミラ−６の反射光を合波する合波手段
を構成する第２のハーフミラ−５１０はハーフミラ−９
で合波された光を検出するフォトダイオード等の第３の
光検出器、１１は光検出器１０の出力を増幅する増幅器
で、その周波数帯域がＦＳＲ以上であるもの、１２は光
検出器７の出力パルス数を計数するカウンタ、１３は増
幅器１１およびカウンタ１２の出力を入力して被測定光
源３０の出力光の絶対周波数を演算する演算部である。FIG. 1 is a block diagram showing an embodiment of the optical frequency measuring device according to the present invention. In FIG. This is an optical frequency measuring device. In the optical frequency measuring device 40, 1 is a frequency reference light source whose frequency is made very stable by controlling the wavelength of a semiconductor laser to an atomic absorption line such as Rb, and 2 is this frequency reference light source 1.
3 is a first photodetector such as a photodiode that detects the light output from the frequency reference light source 1 transmitted through the etalon 2, and 4 is a lock-in amplifier. 23 is a piezoelectric device that changes the inter-plane distance of the etalon 2 according to the output of the control means 4; A transducer such as an element, 5 is a variable frequency light source that can change the frequency of output light according to a control signal, for example, a DBR type semiconductor laser having a phase control region that changes the current flowing to the phase control region, 6 is a variable frequency light source 5 The first half mirror 17 that separates the output light into two directions is a second photodetector such as a photodiode that detects the light transmitted by the half mirror 6 and the etalon 2, and 8 is a lock-in amplifier or the like. 9 is a light source to be measured lO which inputs the output of the photodetector 7 and changes the output frequency of the variable frequency light source 5;
The second half mirror 510 constituting a combining means for combining the output light of the half mirror 6 and the reflected light of the half mirror 6 is a half mirror 9.
11 is an amplifier that amplifies the output of the photodetector 10 and its frequency band is equal to or higher than the FSR; 12 is the photodetector 7; A counter 13 counts the number of output pulses of the light source 30, and a calculation section 13 inputs the outputs of the amplifier 11 and the counter 12 to calculate the absolute frequency of the output light of the light source 30 to be measured.
次に上記構成の装置の動作を第２図を用いて説明する。Next, the operation of the apparatus having the above configuration will be explained using FIG. 2.
第２図において５１は周波数基準光源１の出力光の周波
数スペクトル、５２はエタロン２の透過強度の周波数特
性、５３は被測定光源３０の出力光の周波数スペクトル
である。In FIG. 2, 51 is the frequency spectrum of the output light of the frequency reference light source 1, 52 is the frequency characteristic of the transmitted intensity of the etalon 2, and 53 is the frequency spectrum of the output light of the light source 30 to be measured.
（１）まず制御手段４により、エタロン２の透過光のピ
ーク（第２図のＰ、、Ｐ２・・・）の１つを周波数基準
光源１の出力光周波数ｆＲｂに制御する。(1) First, the control means 4 controls one of the peaks of the transmitted light of the etalon 2 (P, P2, . . . in FIG. 2) to the output optical frequency fRb of the frequency reference light source 1.
ここではエタロン２の透過ピークＰ、がｆＲｂにロック
される。Here, the transmission peak P of the etalon 2 is locked to fRb.
（２）次に制御手段８により、周波数可変光８５の出力
光周波数ｆＹを掃引させて、エタロン２の透過ピークＰ
＋ 、Ｐ２・・・に順次制御する０周波数可変光源５の
出力周波数はｆＲｂ、ｆＲｂ十ＦｓＲ，ｆＲｂ＋２ＦＳ
Ｒ，・・・と変化するが、このときの透過ピークの数は
カウンタ１２で計数される（ＦＳＲ：Ｆｒｅｅ Ｓｐ
ｅｃｔｒｕｍ Ｒａｎｇｅ：エタロンの透過ピーク周
波数の間隔）０周波数可変光源５の出力光周波数ｆＶと
被測定光源３０の出力光周波数ｆｒ＋との差の周波数ｆ
ａを有するビード信号が増幅器１１の出力から検出され
ると、演算部１３が掃引制御信号により制御手段８の周
波数挿引を停止し、最終のピーク（ＰＮ ）まで周波数
を戻し、そこで安定化する。そのときのビード周波数ｆ
Ｂを用いて次に述べる演算を行なう。(2) Next, the control means 8 sweeps the output optical frequency fY of the frequency variable light 85 to reach the transmission peak P of the etalon 2.
The output frequencies of the 0-frequency variable light source 5, which are sequentially controlled to +, P2..., are fRb, fRb+FsR, fRb+2FS
The number of transmission peaks at this time is counted by the counter 12 (FSR: Free Sp
ectrum Range: interval of transmission peak frequencies of the etalon) 0 Frequency f of the difference between the output optical frequency fV of the frequency variable light source 5 and the output optical frequency fr+ of the light source under test 30
When a bead signal with a is detected from the output of the amplifier 11, the arithmetic unit 13 uses a sweep control signal to stop the frequency addition of the control means 8, returns the frequency to the final peak (PN), and stabilizes there. . Bead frequency f at that time
The following calculation is performed using B.
（３）演算部１３において次式により被測定光周波数ｆ
Ｍの絶対値を演算する。(3) In the calculation unit 13, the measured optical frequency f is determined by the following formula:
Calculate the absolute value of M.
ｆｒ＋ ＝ｔａ ｂ 十Ｎ−ＦＳＲ十ｆａ ・・・
（１）ここでＮはカウンタ１２で計数される透過ピーク
の数である。また次式を用いて波長λｉの絶対値を演算
することもできる。fr+ =ta b 1N-FSR1fa...
(1) Here, N is the number of transmission peaks counted by the counter 12. Furthermore, the absolute value of the wavelength λi can also be calculated using the following equation.
λＭ ＝ＣＯ／ｆＭ −（２＞ただし
Ｃｏは真空中の光の速度である。なおエタロン２の面間
距離をＬとすると、ＦＳＲは次式で表されるが、この値
は例えばルビジウムの異なる吸収線間の周波数差等を利
用してあらかじめキャリブレーションが行なわれる。λM = CO/fM - (2> where Co is the speed of light in vacuum. If the distance between the surfaces of the etalon 2 is L, then the FSR is expressed by the following formula, but this value is different from that of rubidium, for example. Calibration is performed in advance using frequency differences between absorption lines.
Ｆ Ｓ Ｒ＝ ｃ ／ ２ ｆ、
−（３）このような構成の光周波数測定装置によれば、
周波数または波長の絶対値を高精度で測定するこ・とが
できる、上記装置の精度は周波数基準光源１の安定度で
決定されるため、例えば周波ｆ＆基準光源１としてルビ
ジウム光源を用いた場合、その安定度は１０４オーダな
ので、このオークの測定精度が実現できる。FSR=c/2f,
-(3) According to the optical frequency measuring device having such a configuration,
The accuracy of the above device, which can measure the absolute value of frequency or wavelength with high precision, is determined by the stability of the frequency reference light source 1. For example, if a rubidium light source is used as the frequency f & reference light source 1, Since its stability is on the order of 104, the measurement accuracy of this oak can be achieved.
また周波数可変光源５の周波数可変幅の範囲内で任意の
周波数を測定することができる。Moreover, any frequency can be measured within the frequency variable range of the variable frequency light source 5.
なお上記の実施例では光の分離・合波にハーフミラ−を
用いていているが、これに限らず光ファイバやファイバ
カグラを用いて行なってもよい。In the above embodiment, a half mirror is used to separate and combine light, but the invention is not limited to this, and an optical fiber or a fiber converter may also be used.
またファブリ・ベロー・エタロン２の共振器長を変える
なめに圧電素子を用いる代りに、エタロン２のミラー間
に電気光学素子を配置してその電圧に帰還してもよい。Furthermore, instead of using a piezoelectric element to change the resonator length of the Fabry-Bello etalon 2, an electro-optical element may be placed between the mirrors of the etalon 2 and the voltage may be fed back.
また周波数可変光源として半導体レーザの注入電流や温
度により出力周波数を制御するものを用いてもよい。Further, as the variable frequency light source, one whose output frequency is controlled by the injection current or temperature of a semiconductor laser may be used.
〈発明の効果〉
以上述べたように本発明によれば、光の絶対周波数を高
精度で測定することのできる光周波数測定装置を簡単な
構成で実現することができる。<Effects of the Invention> As described above, according to the present invention, an optical frequency measuring device capable of measuring the absolute frequency of light with high precision can be realized with a simple configuration.
第１図は本発明に係る光周波数測定装置の１実施例を示
す構成ブロック図、第２図は第１図装置の動作を説明す
るための特性曲線図である。
１・・・周波数基準光源、２・・・エタロン、３・・・
第１の光検出器、４・・・第１の制御手段と、５・・・
周波数可変光源、７・・・第２の光検出器、８・・・第
２の制御手段、９・・・合波手段、１０・・・第３の光
検出器、１２・・・カウンタ、１３・・・演算部、３０
・・・被測定光源、４０・・・光周波数測定装置。FIG. 1 is a configuration block diagram showing one embodiment of the optical frequency measuring device according to the present invention, and FIG. 2 is a characteristic curve diagram for explaining the operation of the device shown in FIG. 1... Frequency reference light source, 2... Etalon, 3...
a first photodetector, 4...a first control means, and 5...
Frequency variable light source, 7... Second photodetector, 8... Second control means, 9... Multiplexing means, 10... Third photodetector, 12... Counter, 13... Arithmetic unit, 30
. . . Light source to be measured, 40 . . . Optical frequency measuring device.
Claims (1)
、出力光の周波数が安定な周波数基準光源と、出力光の
周波数が可変の周波数可変光源と、前記周波数基準光源
および前記周波数可変光源の出力光を入射するエタロン
と、前記周波数基準光源および前記周波数可変光源から
のエタロン透過光をそれぞれ検出する第１および第２の
光検出器と、前記第１の光検出器の出力に基づいて前記
エタロンの透過周波数の１つを前記周波数基準光源の出
力光の周波数に制御する第１の制御手段と、前記第２の
光検出器の出力に基づいて前記周波数可変光源の出力光
の周波数を前記エタロンの各透過周波数に順次掃引制御
する第２の制御手段と、前記第２の光検出器の出力ピー
ク数を計数するカウンタと、周波数可変光源の出力光と
被測定光とを合波する合波手段と、この合波手段の出力
光からビード信号を検出する第３の光検出器と、この第
３の光検出器および前記カウンタの出力から被測定光の
周波数を演算する演算部とを備えたことを特徴とする光
周波数測定装置。An optical frequency measurement device that measures the frequency of light to be measured includes a frequency reference light source whose output light has a stable frequency, a frequency variable light source whose output light has a variable frequency, and output lights of the frequency reference light source and the frequency variable light source. first and second photodetectors that detect the etalon-transmitted light from the frequency reference light source and the frequency variable light source, respectively; a first control means for controlling one of the transmission frequencies to the frequency of the output light of the frequency reference light source; and a first control means for controlling the frequency of the output light of the frequency variable light source based on the output of the second photodetector. a second control means that sequentially performs sweep control for each transmission frequency; a counter that counts the number of output peaks of the second photodetector; and a multiplexer that multiplexes the output light of the frequency variable light source and the light to be measured. and a third photodetector that detects a bead signal from the output light of the multiplexing means, and an arithmetic unit that calculates the frequency of the light to be measured from the output of the third photodetector and the counter. An optical frequency measurement device characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12813789A JPH02307027A (en) | 1989-05-22 | 1989-05-22 | Light frequency measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12813789A JPH02307027A (en) | 1989-05-22 | 1989-05-22 | Light frequency measuring instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02307027A true JPH02307027A (en) | 1990-12-20 |
Family
ID=14977318
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12813789A Pending JPH02307027A (en) | 1989-05-22 | 1989-05-22 | Light frequency measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02307027A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011053457A (en) * | 2009-09-02 | 2011-03-17 | Nec Corp | Optical wavelength controller and optical wavelength control method |
| JP2011249389A (en) * | 2010-05-24 | 2011-12-08 | Nec Corp | Wavelength controller and control method |
-
1989
- 1989-05-22 JP JP12813789A patent/JPH02307027A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011053457A (en) * | 2009-09-02 | 2011-03-17 | Nec Corp | Optical wavelength controller and optical wavelength control method |
| JP2011249389A (en) * | 2010-05-24 | 2011-12-08 | Nec Corp | Wavelength controller and control method |
| US8634680B2 (en) | 2010-05-24 | 2014-01-21 | Nec Corporation | Wavelength control device and wavelength control method |
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