JPS6248183B2 - - Google Patents
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- Publication number
- JPS6248183B2 JPS6248183B2 JP16522279A JP16522279A JPS6248183B2 JP S6248183 B2 JPS6248183 B2 JP S6248183B2 JP 16522279 A JP16522279 A JP 16522279A JP 16522279 A JP16522279 A JP 16522279A JP S6248183 B2 JPS6248183 B2 JP S6248183B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- wavelength
- measurement
- measured
- optical path
- 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.)
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Links
- 238000005259 measurement Methods 0.000 claims description 25
- 230000010355 oscillation Effects 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 13
- 238000010521 absorption reaction Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- 230000006641 stabilisation Effects 0.000 claims description 6
- 238000011105 stabilization Methods 0.000 claims description 6
- 239000007789 gas Substances 0.000 description 60
- 238000010586 diagram Methods 0.000 description 9
- 210000004027 cell Anatomy 0.000 description 8
- 238000000691 measurement method Methods 0.000 description 6
- 238000000862 absorption spectrum Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 210000002421 cell wall Anatomy 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000004451 qualitative analysis Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Optics & Photonics (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
【発明の詳細な説明】
この発明は、波長可変型のダイオードレーザを
用いた赤外線ガス分析装置における測定波長の安
定化方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stabilizing a measurement wavelength in an infrared gas analyzer using a wavelength tunable diode laser.
一般に各種のガス分子は、赤外域の光に対して
それぞれ固有の吸収スペクトルを有するので、特
定ガスの吸収スペクトルに波長を合わせた赤外線
を被測定ガス空間に照射してその透過光の吸収状
態を調べれば、当該被測定ガス空間における特定
ガスの検出ならびに定量、定性分析が可能とな
る。このような測定原理を利用した最近の赤外線
ガス分析装置では、赤外線の発光源として狭いバ
ンドギヤツプの多元半導体よりなる波長可変型の
ダイオードレーザが用いられるようになり、その
取扱い易さと、波長可変特性を利用した微分計測
法の適用による測定精度の向上等が相俟つて、大
気中の汚染ガスモニタシステムなどへの広範な応
用が進められている。 Generally, each type of gas molecule has its own unique absorption spectrum for light in the infrared region, so by irradiating the gas space to be measured with infrared rays whose wavelength matches the absorption spectrum of a specific gas, the absorption state of the transmitted light can be determined. If investigated, it becomes possible to detect, quantify, and qualitatively analyze the specific gas in the gas space to be measured. Recent infrared gas analyzers that utilize such measurement principles have begun to use wavelength tunable diode lasers made of narrow bandgap multi-component semiconductors as infrared light emission sources. Combined with improvements in measurement accuracy through the application of the differential measurement method, widespread application to atmospheric pollutant gas monitoring systems is progressing.
一方、上記のような波長可変型のダイオードレ
ーザを用いた赤外線ガス分析装置では、ダイオー
ドレーザからの発振波長の安定化が不可欠であ
り、従来種々の安定化方式が提案されている。と
ころが過去の波長安定化方式に共通する考え方
は、被測定ガスと同種のガスを基準ガスとして用
い、該基準ガスを透過したときの吸収量が最大と
なるようにレーザ電流を制御することによつて発
振波長を安定化するといういわゆるAFC方式を
基本としたもので、被測定ガスの種類によつて
は、AFC用基準ガスの安定性や取扱いに問題を
生じる欠点がある。すなわち、例えば被測定ガス
が放射性ガスであるような場合、同種の基準ガス
では保管や取扱いに危険が伴うし、また化学的、
物理的に不安定なガスを測定対象とするときも、
基準ガスが同種であると容器への吸着が反応によ
つてガス自体の安定性の維持が困難となる。 On the other hand, in an infrared gas analyzer using a wavelength tunable diode laser as described above, it is essential to stabilize the oscillation wavelength from the diode laser, and various stabilization methods have been proposed. However, the idea common to past wavelength stabilization methods is to use the same type of gas as the gas to be measured as a reference gas, and to control the laser current so that the amount of absorption when passing through the reference gas is maximized. This method is based on the so-called AFC method, in which the oscillation wavelength is stabilized by using the oscillation wavelength, and depending on the type of gas to be measured, there are drawbacks such as problems with the stability and handling of the reference gas for AFC. In other words, if the gas to be measured is a radioactive gas, storing and handling the same type of reference gas is dangerous, and there are chemical and
Even when measuring physically unstable gases,
If the reference gases are of the same type, it will be difficult to maintain the stability of the gas itself due to adsorption to the container and reaction.
この発明は、以上のような状況から、赤外線ガ
ス分析装置の発光源用ダイオードレーザに対する
新しい波長安定化方式を提供し、以つてこの種ガ
ス分析装置の応用範囲の拡大と、測定精度の向上
を図ろうとするものである。簡単に述べるとこの
発明は、発振波長安定化のためのフイードバツク
制御（AFC）の中心波長を、被測定ガスに対す
る測定波長から離れた点に設定し、AFC中心波
長を基準として測定用の別の波長の安定化を図る
ようにしたことを骨子とするものである。すなわ
ち、波長可変型ダイオードレーザの発振波長特性
は一般に既知であるので、この特性カーブから、
AFC動作によつて安定化された基準波長と、被
測定ガスの吸収スペクトルに対応した測定波長と
の差分に相当する波長変化を与えるための電流値
を求め、この電流を基準波長発振時のレーザ電流
に加算すれば、測定用波長点での安定な発振動作
が自動的に達成できることとなる。 In view of the above-mentioned circumstances, this invention provides a new wavelength stabilization method for the diode laser used as the light source of an infrared gas analyzer, thereby expanding the range of application of this type of gas analyzer and improving measurement accuracy. This is what we are trying to achieve. Briefly stated, this invention sets the center wavelength of feedback control (AFC) for stabilizing the oscillation wavelength at a point far from the measurement wavelength for the gas to be measured, and sets another point for measurement using the AFC center wavelength as a reference. The main idea is to stabilize the wavelength. In other words, since the oscillation wavelength characteristics of a wavelength tunable diode laser are generally known, from this characteristic curve,
The current value for giving a wavelength change corresponding to the difference between the reference wavelength stabilized by AFC operation and the measurement wavelength corresponding to the absorption spectrum of the gas under test is determined, and this current is applied to the laser when the reference wavelength is oscillated. By adding it to the current, stable oscillation operation at the measurement wavelength point can be automatically achieved.
この発明による波長安定化方式の原理につき第
１図を参照して今少し具体的に説明すると、第１
図は波長可変型赤外線ダイオードレーザの一般的
な発振波長特性を示す線図であつて、横軸にレー
ザ電流Ｉをとり、縦軸に波長λをとつてそれらの
間の関係を特性カーブａで表してある。この第１
図において、測定すべきガスの吸収ピーク波長が
λ２であるとすると、レーザ電流はI2の値に設定
すべきであるが、この発明においては、λ２での
波長の安定化を図るべく、まず波長λ１に吸収ピ
ークを有する基準ガスを用いて発振波長がλ１に
なるようレーザ電流I1を制御する。このレーザ電
流I1が定まつた後は、第１図の特定カーブａ上か
ら測定波長λ２に対するレーザ電流I2との差、す
なわちI2−I1が求まるので、この差分に相当する
電流を電流I1に加えてレーザに供給することによ
り、所望とする波長λ２の発振出力を得ることが
できる。従つて基準となる波長点λ１でのAFC
動作と、測定用波長点λ２でのガスの測定動作と
を、レーザ電流の切換えによつて交互になすこと
により、１種類の基準ガスを用意するだけで任意
多種類のガス測定が可能となり、発振波長安定化
制御のための基準ガスの選定と取扱いがきわめて
容易となる。 The principle of the wavelength stabilization method according to the present invention will be explained in more detail with reference to FIG.
The figure is a diagram showing the general oscillation wavelength characteristics of a wavelength-tunable infrared diode laser. The horizontal axis shows the laser current I, the vertical axis shows the wavelength λ, and the relationship between them is expressed by a characteristic curve a. It is shown. This first
In the figure, if the absorption peak wavelength of the gas to be measured is λ 2 , the laser current should be set to the value I 2 , but in this invention, in order to stabilize the wavelength at λ 2 , the laser current should be set to the value I 2. First, a reference gas having an absorption peak at wavelength λ 1 is used to control the laser current I 1 so that the oscillation wavelength is λ 1 . After this laser current I 1 is determined, the difference between the laser current I 2 and the measured wavelength λ 2 , that is, I 2 − I 1 , can be determined from the specific curve a in FIG. By adding this to the current I 1 and supplying it to the laser, an oscillation output of the desired wavelength λ 2 can be obtained. Therefore, the AFC at the reference wavelength point λ 1
By alternating the operation and the gas measurement operation at the measurement wavelength point λ 2 by switching the laser current, it is possible to measure any number of gases by simply preparing one type of reference gas. , it becomes extremely easy to select and handle a reference gas for oscillation wavelength stabilization control.
以下この発明の好ましい実施例につき、第２図
以下の図面を参照してさらに詳細に説明する。 Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings from FIG. 2 onwards.
第２図は、大気中の汚染ガス検知システムとし
て具体化した赤外線ガス分析装置の１例概略構成
を示すブロツク図で、プログラマブル定電流電源
１から所定のレーザ電流Ｉを供給されて発振する
波長可変型の赤外線ダイオードレーザ２の光軸上
には、ビームスプリツタ３を介して２分された測
定用の第１の光路LPMと、AFC用の第２の光路
LPCが設定されている。測定光路LPM中には、
この場合測定対象としての大気空間４が含まれて
いるほか、既知濃度の較正用ガスセル５も必要に
応じて当該光路に挿脱できるようになつており、
光路終端には光電変換用の赤外線検知器６が設け
られている。他方、ミラー７で反射されたAFC
光路LPC上には、AFC用の基準ガスセル８が置
かれ、終端には第２の赤外線検知器９が設けられ
ている。 FIG. 2 is a block diagram showing the schematic configuration of an example of an infrared gas analyzer embodied as an atmospheric pollutant gas detection system, in which a wavelength variable device oscillates when a predetermined laser current I is supplied from a programmable constant current power source 1. On the optical axis of the type infrared diode laser 2, there is a first optical path LPM for measurement, which is divided into two via a beam splitter 3, and a second optical path for AFC.
LPC is set. During measurement optical path LPM,
In this case, in addition to the atmospheric space 4 as the measurement target, a calibration gas cell 5 with a known concentration can also be inserted into and removed from the optical path as necessary.
An infrared detector 6 for photoelectric conversion is provided at the end of the optical path. On the other hand, AFC reflected by mirror 7
A reference gas cell 8 for AFC is placed on the optical path LPC, and a second infrared detector 9 is provided at the end.
ここで、この装置を大気中のNO2濃度の検出に
用いる場合について説明すると、従来であれば
AFC用の基準ガスとしても同じ吸収スペクトル
を有するNO2を用いていたのであるが、該NO2は
基準ガスセル８に充填したときセルの管壁に非常
に吸着され易く、一定濃度で長時間保持するのが
困難であるところから、この発明においては、測
定すべきガスとは別種のNH3を基準ガスとして用
いる。このNH3は、性状が安定で取扱いも容易で
ある。 Here, we will explain the case where this device is used to detect the NO 2 concentration in the atmosphere.
NO 2 , which has the same absorption spectrum, was used as the reference gas for AFC, but when it is filled into the reference gas cell 8, NO 2 is very easily adsorbed on the cell wall, and is kept at a constant concentration for a long time. Therefore, in the present invention, NH3 , which is a different type from the gas to be measured, is used as the reference gas. This NH 3 has stable properties and is easy to handle.
２つの赤外線検知器６および９からの信号出力
は、それぞれ直流増幅器１０，１１ならびにAD
コンバータ１２，１３を経た後、例えば16ビツト
のデジタル信号の形でマイクロコンピユータを含
む制御ユニツト１４に入れられる。そしてこの制
御ユニツト１４における信号処理結果の一部が
AFC信号としてプログラマブル定電流電源１に
フイードバツクされる一方、測定データがXYレ
コーダ１５に記録されるようになつている。 The signal outputs from the two infrared detectors 6 and 9 are connected to DC amplifiers 10, 11 and AD
After passing through the converters 12, 13, it is fed, for example, in the form of a 16-bit digital signal to a control unit 14, which includes a microcomputer. A part of the signal processing result in this control unit 14 is
The measurement data is fed back to the programmable constant current power supply 1 as an AFC signal, while the measurement data is recorded on the XY recorder 15.
以上のような構成において、プログラマブル定
電流電源１は、ダイオードレーザ２に対して第３
図のようなパターンでレーザ電流Ｉを供給する。
すなわちAFC期間Ｔaにおいてレーザ電流は、基
準ガスセル８の既知の吸収ピーク波長λ１に対応
した発振波長が得られるようI1′の値に設定され
て所定周期T0でオン・オフされ、かつそのオン
時には当該レーザ電流に△Ｉの振幅で高周波変調
がかけられる。かくしてダイオードレーザ２から
発射された波長λ1′の赤外線がビームスプリツタ
３とミラー７を介してAFC光路LPCに入り、基
準ガスセル８を透過して赤外線検知器９に入射す
ると、上記レーザ電流に対する高周波変調の
“Ｈ”（ハイレベル）時と“Ｌ”（ローレベル）時
とで直流増幅器１１の検知方法に△P1の出力差が
生じる。 In the above configuration, the programmable constant current power supply 1 has a third
A laser current I is supplied in a pattern as shown in the figure.
That is, during the AFC period T a , the laser current is set to the value I 1 ' to obtain an oscillation wavelength corresponding to the known absorption peak wavelength λ 1 of the reference gas cell 8, and is turned on and off at a predetermined period T 0 , and When it is on, high frequency modulation is applied to the laser current with an amplitude of ΔI. Thus, when the infrared rays of wavelength λ 1 ' emitted from the diode laser 2 enter the AFC optical path LPC via the beam splitter 3 and mirror 7, pass through the reference gas cell 8, and enter the infrared detector 9, the There is an output difference of ΔP 1 in the detection method of the DC amplifier 11 between "H" (high level) and "L" (low level) of high frequency modulation.
第４図はこの関係を示す線図であつて、基準ガ
スセル８を透過した赤外線の検知パワーＰと当該
赤外線の波長、すなわちレーザ電流Ｉとの間には
カーブｂのような関係がある。ここでレーザ電流
がオフの時のバツクグランド輻射や直流バイアス
による検知器出力をP0とし、レーザ電流オン時の
検知器出力をP1として、前述の高周波変調による
検知出力差△P1に対する単位パワー当りの１次導
関数を求めると、第５図のような微分カーブｃが
得られる。この第５図のような微分出力から測定
対象ガスの濃度を定量するやり方が、いわゆる微
分計測法と呼ばれるもので、吸収スペクトルのゆ
るやかな気体の計測においても高精度の検出が可
能となる。 FIG. 4 is a diagram showing this relationship, and there is a relationship as shown by curve b between the detected power P of the infrared rays transmitted through the reference gas cell 8 and the wavelength of the infrared rays, that is, the laser current I. Here, let the detector output due to background radiation or DC bias when the laser current is off be P 0 , and let the detector output when the laser current is on be P 1 , and the unit for the detection output difference △P 1 due to the high frequency modulation mentioned above. When the first derivative per power is determined, a differential curve c as shown in FIG. 5 is obtained. The method of quantifying the concentration of the gas to be measured from the differential output as shown in FIG. 5 is called the differential measurement method, and it enables highly accurate detection even when measuring gases with gentle absorption spectra.
この発明の１実施例に従うと、AFC期間Ｔaに
おいては、レーザ電流I1′を直流的にaI分変化させ
ながら、上述のような微分計測法によつて検出出
力が最大となる点をサーチする。すなわちレーザ
電流を、I1′±dI変化させると、第６図のカーブｄ
のように微分出力が変化するので、その最大とな
る点I1にレーザ電流を設定すると、発振波長λ
1′が基準ガスの吸収波長λ１に一致したことにな
る。従つてAFC期間Ｔaにおいてはこのような
AFC動作を行つて発振波長をλ１に固定し、引
続く測定期間Ｔbにおいては、第１図に示したダ
イオードレーザ２の特性カーブａからあらかじめ
求まる測定波長λ２との差分に相当する波長シフ
トを与えるよう、I2−I1の電流がAFC時の設定電
流I1に上乗せされて、波長λ２での発振が行われ
る。 According to one embodiment of the present invention, during the AFC period T a , the point at which the detected output is maximum is searched for by the above-mentioned differential measurement method while changing the laser current I 1 ' by aI in a direct current manner. do. In other words, when the laser current is changed by I 1 ′±dI, the curve d in Figure 6
Since the differential output changes as follows, if the laser current is set at the maximum point I1 , the oscillation wavelength λ
1 ' coincides with the absorption wavelength λ1 of the reference gas. Therefore, in the AFC period T a , such
The oscillation wavelength is fixed at λ 1 by performing AFC operation, and during the subsequent measurement period T b , the wavelength corresponds to the difference from the measurement wavelength λ 2 determined in advance from the characteristic curve a of the diode laser 2 shown in FIG. To provide a shift, a current of I 2 −I 1 is added to the set current I 1 during AFC, and oscillation at wavelength λ 2 is performed.
測定期間Ｔbでの大気空間４に対する測定も、
上記AFC期間と同様に微分計測法を用いて行わ
れ、AFC動作と測定動作が所定の周期で繰返さ
れる。このような計測法自体は既に周知の手法で
あるが、この発明は、AFC期間Ｔaにおいて求め
られた基準ガスに対しての最適レーザ電流I1を基
準として、所定の値はなれたレーザ電流I2による
発振波長λ２を安定化するようにしたものであ
る。AFC期間Ｔaにおけるレーザ電流の制御や、
AFC期間Ｔaから測定期間Ｔbへのレーザ電流の切
換えは、マイクロコンピユータを内蔵した制御ユ
ニツト１４からの演算結果と制御プログラムに基
づいてプログラマブル定電流電源１により実行さ
れることになる。 The measurement for the atmospheric space 4 during the measurement period T b is also
Similar to the AFC period described above, the differential measurement method is used, and the AFC operation and measurement operation are repeated at a predetermined period. Although such a measurement method itself is already well-known, the present invention is capable of measuring a laser current I that deviates from a predetermined value based on the optimum laser current I 1 for the reference gas determined in the AFC period T a . This is to stabilize the oscillation wavelength λ 2 due to 2 . Control of laser current during AFC period T a ,
Switching of the laser current from the AFC period T a to the measurement period T b is executed by the programmable constant current power supply 1 based on the calculation result and control program from the control unit 14 having a built-in microcomputer.
さて以上の説明から明らかなように、この発明
によれば、測定すべきガスとは異なる種類のガス
を基準ガスとして測定波長点でのダイオードレー
ザの発振波長を安定化するようにしているので、
基準ガスの選定が容易であり、安定で取扱い易い
ガスを用いて、危険なガスや、不安定なガス、あ
るいは大気のように多種類のガスが混じり合つて
吸収特性が複雑に広がつたようなガスの定量およ
び定性分析が可能となる。従つてこの発明は、波
長可変型のダイオードレーザを発光源として用い
た赤外線ガス分析装置に適用して、その応用範囲
の拡張と測定精度の向上に多大の効果を発揮す
る。 As is clear from the above explanation, according to the present invention, the oscillation wavelength of the diode laser at the measurement wavelength point is stabilized by using a gas of a different type than the gas to be measured as a reference gas.
It is easy to select a reference gas, and by using a stable and easy-to-handle gas, it is possible to prevent dangerous gases, unstable gases, or mixtures of many types of gases such as the atmosphere, with complex absorption characteristics. Quantitative and qualitative analysis of gases becomes possible. Therefore, the present invention can be applied to an infrared gas analyzer using a wavelength tunable diode laser as a light emitting source, and has great effects in expanding its application range and improving measurement accuracy.
第１図はこの発明の原理を説明するためのダイ
オードレーザの一般的な発振波長特性を示す線
図、第２図はこの発明を適用した赤外線ガス分析
装置の１例概略構成を示すブロツク図、第３図は
レーザ電流のパターンを示す図、第４図および第
５図は微分計測法によるガス検出の手法を説明す
るための吸収特性線図、第６図はAFC動作を説
明するための線図である。
１：プログラマブル定電流電源、２：ダイオー
ドレーザ、３：ビームスプリツタ、４：被測定大
気空間、５：較正用ガスセル、６：赤外線検知
器、７：ミラー、８：AFC用基準ガスセル、
９：赤外線検知器、１０および１１：直流増幅
器、１２および１３：ADコンバータ、１４：制
御ユニツト、１５：XYレコーダ。
FIG. 1 is a diagram showing general oscillation wavelength characteristics of a diode laser to explain the principle of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of an example of an infrared gas analyzer to which the present invention is applied. Figure 3 is a diagram showing the laser current pattern, Figures 4 and 5 are absorption characteristic diagrams to explain the gas detection method using the differential measurement method, and Figure 6 is a diagram to explain the AFC operation. It is a diagram. 1: Programmable constant current power supply, 2: Diode laser, 3: Beam splitter, 4: Atmospheric space to be measured, 5: Calibration gas cell, 6: Infrared detector, 7: Mirror, 8: AFC reference gas cell,
9: infrared detector, 10 and 11: DC amplifier, 12 and 13: AD converter, 14: control unit, 15: XY recorder.
Claims (1)
として被測定ガス空間を通る第１の光路と、基準
ガス空間を通る第２の光路を設定するとともに、
該第２の光路の基準ガスを、第１の光路中の測定
すべきガスとは異なる既知の吸収特性をもつたガ
スに選定し、第２の光路を通過した赤外線光の該
基準ガスによる吸収が最大となるように前記ダイ
オードレーザの発振波長を制御した後、当該基準
波長と被測定ガスに対する測定波長との差分に応
じて被測定ガス測定時のレーザ電流を制御するよ
うにしたことを特徴とする赤外線ガス分析装置に
おけるダイオードレーザの波長安定化方式。1 Setting a first optical path passing through the measured gas space and a second optical path passing through the reference gas space using a wavelength tunable diode laser as a common light source, and
The reference gas in the second optical path is selected as a gas with known absorption characteristics different from the gas to be measured in the first optical path, and the infrared light passing through the second optical path is absorbed by the reference gas. After controlling the oscillation wavelength of the diode laser so that the wavelength is maximized, the laser current during measurement of the gas to be measured is controlled according to the difference between the reference wavelength and the measurement wavelength for the gas to be measured. A wavelength stabilization method for diode lasers in infrared gas analyzers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16522279A JPS5687845A (en) | 1979-12-18 | 1979-12-18 | Stabilizing system for wavelength of diode laser in infrared gas analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16522279A JPS5687845A (en) | 1979-12-18 | 1979-12-18 | Stabilizing system for wavelength of diode laser in infrared gas analyzer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5687845A JPS5687845A (en) | 1981-07-16 |
| JPS6248183B2 true JPS6248183B2 (en) | 1987-10-13 |
Family
ID=15808165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16522279A Granted JPS5687845A (en) | 1979-12-18 | 1979-12-18 | Stabilizing system for wavelength of diode laser in infrared gas analyzer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5687845A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5314301B2 (en) * | 2008-03-14 | 2013-10-16 | 三菱重工業株式会社 | Gas concentration measuring method and apparatus |
| JP2012108156A (en) * | 2012-02-29 | 2012-06-07 | Mitsubishi Heavy Ind Ltd | Gas concentration measurement method and device |
-
1979
- 1979-12-18 JP JP16522279A patent/JPS5687845A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5687845A (en) | 1981-07-16 |
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