JPH0263179A - Temperature control system of semiconductor laser - Google Patents
Temperature control system of semiconductor laserInfo
- Publication number
- JPH0263179A JPH0263179A JP21453488A JP21453488A JPH0263179A JP H0263179 A JPH0263179 A JP H0263179A JP 21453488 A JP21453488 A JP 21453488A JP 21453488 A JP21453488 A JP 21453488A JP H0263179 A JPH0263179 A JP H0263179A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- semiconductor laser
- auxiliary
- heater
- temperature control
- 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
- 239000004065 semiconductor Substances 0.000 title claims abstract description 59
- 238000001514 detection method Methods 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims description 11
- 230000005855 radiation Effects 0.000 claims 1
- 238000010408 sweeping Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 21
- 230000010355 oscillation Effects 0.000 description 12
- 238000010586 diagram Methods 0.000 description 11
- 238000010521 absorption reaction Methods 0.000 description 3
- 239000003507 refrigerant Substances 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910000896 Manganin Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/02—Structural details or components not essential to laser action
- H01S5/024—Arrangements for thermal management
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/06804—Stabilisation of laser output parameters by monitoring an external parameter, e.g. temperature
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/06835—Stabilising during pulse modulation or generation
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
- Control Of Temperature (AREA)
Abstract
Description
【発明の詳細な説明】
〔概要〕
半導体レーザの発振波長を所定波長付近でｌ＋’ｆｌ弓
させるために、半導体レーザの素子温度を制御する温度
制御方式に関し、
半導体レーザの駆動電流を高周波数で変調した場合でも
、高速かつ高安定に半導体レー１１の素子温度を制御す
ることを目的とし、
半導体レーザの放熱用ヒートシンクの温度を温度センサ
で検出し、その検出信号に基づいて温度制御回路により
該ヒートシンクの加熱用ヒータの温度を制御することに
より、該ヒートシンク及び半導体レーザの温度を一定に
制御する半導体レーザの温度制御方式において、前記ヒ
ートシンク、温度センサ及びヒータによる熱抵抗、熱容
量より小なる熱抵抗、熱容量をもつ補助温度センサ及び
補助ヒータを前記半導体レーザの近傍に配置し、該補助
温度センサからの温度検出信号に基づいて該補助ヒータ
の温度を制御する補助温度制御回路を設けると共に、該
補助温度セン９からの温度検出信号の変動量が設定値以
上のときに該補助温度制御回路による該補助ヒータの温
度制御をオフにするリミット手段を設けるように構成す
る。[Detailed Description of the Invention] [Summary] This invention relates to a temperature control method for controlling the element temperature of a semiconductor laser in order to make the oscillation wavelength of the semiconductor laser bow l+'fl around a predetermined wavelength. The purpose is to control the element temperature of the semiconductor laser 11 quickly and with high stability even when modulated.The temperature of the heat sink for heat dissipation of the semiconductor laser is detected by a temperature sensor, and the temperature control circuit controls the temperature based on the detection signal. In a semiconductor laser temperature control method in which the temperatures of the heat sink and the semiconductor laser are kept constant by controlling the temperature of a heater for the heat sink, the thermal resistance is smaller than the thermal resistance and heat capacity of the heat sink, temperature sensor, and heater. , an auxiliary temperature control circuit is provided in which an auxiliary temperature sensor and an auxiliary heater having a heat capacity are arranged near the semiconductor laser, and the temperature of the auxiliary heater is controlled based on a temperature detection signal from the auxiliary temperature sensor; A limiter is provided for turning off the temperature control of the auxiliary heater by the auxiliary temperature control circuit when the amount of variation in the temperature detection signal from the temperature sensor 9 is equal to or greater than a set value.
その透過光の光強度の変化分に基づいて被測定ガスのガ
ス濃度を測定するレーザ方式ガスセンサなどのような、
半導体レーザの発振波長可変性を利用する装置において
は、通常、駆動電流の値により発振波長を可変している
ので、素子温度が所定の一定範囲内に収まるようにする
温度制御方式が必要となる（因みに、レーザ方式ガスセ
ンサでは目標のガススペクトル吸収線付近でレーザ光の
波長を掃引するために、半導体レーザの素子温度を数十
ミリケルビン（ｍＫ＞の精度で制御する必要がある）。Such as a laser gas sensor that measures the gas concentration of the gas to be measured based on the change in the light intensity of the transmitted light.
In devices that utilize the oscillation wavelength tunability of semiconductor lasers, the oscillation wavelength is usually varied by the value of the drive current, so a temperature control method is required to keep the element temperature within a predetermined range. (Incidentally, in a laser-type gas sensor, in order to sweep the wavelength of the laser light near the target gas spectral absorption line, it is necessary to control the element temperature of the semiconductor laser with an accuracy of several tens of milliKelvin (mK>).
（産業上の利用分野〕
本発明は半導体レーザの温度制御方式に係り、特に半導
体レーザの発振波長を所定波長付近で掃引させるために
、半導体レーザの索Ｆｆ、度を制御する温度制御方式に
関する。(Industrial Application Field) The present invention relates to a temperature control method for a semiconductor laser, and more particularly to a temperature control method for controlling the temperature Ff of a semiconductor laser in order to sweep the oscillation wavelength of the semiconductor laser around a predetermined wavelength.
半導体レーザの発振波長は駆動電流やその素子温度によ
って変化する。従って、波長が順次可変されるレーザ光
を被測定ガス雰囲気中に透過させ、〔従来の技術〕
第６図は従来の半導体レーザの温度制御方式の一例の構
成図を示す。同図中、１は半導体レーザ、２はヒートシ
ンク、３は温度センサ、４はマウント台、５はヒータ、
６は冷媒である。The oscillation wavelength of a semiconductor laser changes depending on the driving current and the element temperature. Therefore, a laser beam whose wavelength is sequentially varied is transmitted into the gas atmosphere to be measured. [Prior Art] FIG. 6 shows a configuration diagram of an example of a conventional temperature control method for a semiconductor laser. In the figure, 1 is a semiconductor laser, 2 is a heat sink, 3 is a temperature sensor, 4 is a mount, 5 is a heater,
6 is a refrigerant.
半導体レーザ１は例えばＰｂ５ｎＴｅレーザで、赤外光
領域のレーザ光を放射する素子で、銅などからなるマウ
ント台４上に接着されており、これらはヒートシンク２
に対して一体的に交換自在の構成とされている。マウン
ト台４はアルミニウム又は銅など熱伝導率の良好な素材
から形成された板状のヒートシンク２の表面にネジ止め
されている。The semiconductor laser 1 is, for example, a Pb5nTe laser, which is an element that emits laser light in the infrared region, and is bonded on a mount 4 made of copper or the like, and these are attached to a heat sink 2.
It is configured so that it can be replaced integrally with the other parts. The mount base 4 is screwed onto the surface of a plate-shaped heat sink 2 made of a material with good thermal conductivity such as aluminum or copper.
ヒートシンク２は半導体レーザ１の駆動電流通電により
発生したジュール熱の放熱用であり、マウント台４側表
面と反対側の表面に温度センサ３が設けられており、ま
た半導体レーザ１と反対側の端部は大径の円柱状に形成
されている。The heat sink 2 is for dissipating Joule heat generated by the application of a driving current to the semiconductor laser 1, and a temperature sensor 3 is provided on the surface opposite to the surface on the mount base 4, and the end opposite to the semiconductor laser 1 is provided with a temperature sensor 3. The portion is formed in the shape of a cylinder with a large diameter.
ヒートシンク２の上記大径の円柱にｉの周囲に、例えば
マンガニン線が巻回されてヒータ５を形成している。ま
た、温度センサ３はヒートシンク２の温度検出用でシリ
コンダイオードからなり、その順方向降下電圧がヒート
シンク２の温度に応じて変化するので、この順方向降下
電圧が温度検出電圧として用いられる。For example, a manganin wire is wound around i around the large-diameter cylinder of the heat sink 2 to form the heater 5. Further, the temperature sensor 3 is made of a silicon diode for detecting the temperature of the heat sink 2, and since its forward voltage drop changes depending on the temperature of the heat sink 2, this forward voltage drop is used as the temperature detection voltage.
半導体レーザ１は通常低温に保持して動作させる必要が
あるため、第７図に示す如き真空容器７の内壁８ａと外
壁８ｂの間の真空空間９に、半導体レーザ１．ヒートシ
ンク２．温度センサ３．ヒータ５などが配設され、ヒー
トシンク２の大径の円柱部底面が、内！ｉ！８ａを介し
て冷媒６に接触されている。この冷媒６は例えば液体窒
素で、真空容器７内に収容されている。Since the semiconductor laser 1 normally needs to be operated while being kept at a low temperature, the semiconductor laser 1. Heat sink 2. Temperature sensor 3. The heater 5 etc. are arranged, and the bottom surface of the large diameter cylindrical part of the heat sink 2 is inside! i! It is in contact with the refrigerant 6 via 8a. This refrigerant 6 is, for example, liquid nitrogen, and is housed in a vacuum container 7.
温度センサ３によりヒートシンク２の温度を検出して得
られた温度検出電圧（前記したように、これはダイオー
ドの順方向降下電圧である）は、公知の温度制御回路（
図示せず）を経由してヒータ５に供給されてその発熱層
を制御することにより、ヒートシンク２は常に一定温度
にあるように制御される。これにより、半導体レーザ１
も駆動電流によるジュール熱が放熱されて、所定の素子
温度で駆動されるように温度制御が行なわれる。The temperature detection voltage obtained by detecting the temperature of the heat sink 2 by the temperature sensor 3 (as mentioned above, this is the forward drop voltage of the diode) is controlled by a known temperature control circuit (
The heat sink 2 is controlled to always have a constant temperature by being supplied to the heater 5 via the heater 5 (not shown) and controlling its heat generating layer. As a result, the semiconductor laser 1
Temperature control is performed so that Joule heat caused by the drive current is radiated and the device is driven at a predetermined temperature.
レーザ方式ガスセンサでは上記の半導体レーザ１を光源
とし、被測定ガスのスペクトル吸収線及びその近傍の波
長領域で半導体レーザ１の発振波長を掃引する（実際に
は、数ＫＨｚ〜数汁ＫＨｚの微少変調も同時に行なって
いる）。しかし、この掃引周波数（すなわち駆動電流の
変調周波数）は通常数Ｈｚであるのに対し、ヒートシン
ク２゜ヒータ５の熱容量が大で、また温度センサ３の熱
抵抗も大きいために、温度制御の応答時定数が通常３０
秒以上と長く、温度制御が素子ａ度変化に追随すること
ができないため、ヒートシンク２の温度は波長掃引中、
変動してしまっていた。In a laser gas sensor, the above semiconductor laser 1 is used as a light source, and the oscillation wavelength of the semiconductor laser 1 is swept in the spectral absorption line of the gas to be measured and a wavelength region in the vicinity thereof (actually, the oscillation wavelength of the semiconductor laser 1 is swept in the spectral absorption line of the gas to be measured and the wavelength region in the vicinity thereof (actually, a slight modulation of several KHz to several KHz is used). are also carried out at the same time). However, while this sweep frequency (that is, the modulation frequency of the drive current) is usually several Hz, the heat sink 2 and the heater 5 have a large heat capacity, and the temperature sensor 3 has a large thermal resistance, so the response of the temperature control is Time constant is usually 30
During the wavelength sweep, the temperature control of the heat sink 2 is longer than 2 seconds, and the temperature control cannot follow the temperature change of the element a degree.
It was changing.
本発明は上記の点に鑑みてなされたもので、半導体レー
ザの駆動電流を高周波数で変調した場合でも、高速かつ
高安定に半導体レーザの素子温度をυ１１［ｌすること
ができる半導体レーザの温度制御方式を提供することを
目的とする。The present invention has been made in view of the above points, and is a semiconductor laser that can quickly and highly stably reduce the element temperature of the semiconductor laser by υ11[l even when the driving current of the semiconductor laser is modulated at a high frequency. The purpose is to provide a control method.
第１図は本発明の原理ブロック図を示す。同図中、１は
半導体レーザ、２はヒートシンク、３は温度センサ、５
はヒータで、これらは第６図に示した従来方式と同様の
構成である。温度センサ３によりヒートシンク２の温度
を検出して得た検出信号が温度制御回路１１を介してヒ
ータ５に印加され、ヒートシンク２の温度が設定温度に
保たれるように温度制御が行なわれる。これにより、半
導体レーザ１の素子温度も一定となるように制御される
。FIG. 1 shows a block diagram of the principle of the present invention. In the figure, 1 is a semiconductor laser, 2 is a heat sink, 3 is a temperature sensor, and 5
is a heater, which has the same structure as the conventional system shown in FIG. A detection signal obtained by detecting the temperature of the heat sink 2 by the temperature sensor 3 is applied to the heater 5 via the temperature control circuit 11, and temperature control is performed so that the temperature of the heat sink 2 is maintained at a set temperature. Thereby, the element temperature of the semiconductor laser 1 is also controlled to be constant.
このような温度制御方式において、本発明では補助温度
センサ１２及び補助ヒータ１３を夫々半導体レーザ１の
近傍に設け、また補助温度制御回路１４とリミット手段
１５とを設けたものである。In such a temperature control system, the present invention provides an auxiliary temperature sensor 12 and an auxiliary heater 13 in the vicinity of the semiconductor laser 1, as well as an auxiliary temperature control circuit 14 and a limit means 15.
補助温度センサ１２及び補助ヒータ１３の熱抵抗、熱容
量は温度センサ３及びヒータ５のそれに比し小なるよう
に構成されている。また、補助温度制御回路１４は補助
ヒータ１３の温度を制御し、半導体レーザ１の素子温度
が一定になるようにする。Thermal resistance and heat capacity of the auxiliary temperature sensor 12 and the auxiliary heater 13 are configured to be smaller than those of the temperature sensor 3 and the heater 5. Further, the auxiliary temperature control circuit 14 controls the temperature of the auxiliary heater 13 so that the element temperature of the semiconductor laser 1 is constant.
リミット手段１５は補助温度センサ１２の温度検出信号
の変動量が設定値以上のときに補助温度制御回路１４に
よる補助ヒータ１３の温度制御をオフにする。The limit means 15 turns off the temperature control of the auxiliary heater 13 by the auxiliary temperature control circuit 14 when the amount of variation in the temperature detection signal of the auxiliary temperature sensor 12 is equal to or greater than a set value.
従来、ヒートシンク２の温度が半導体レーザ１の素子温
度の速い変動に追随できないのは、ピー１〜シンク２と
冷媒との熱抵抗及びヒートシンク２などの熱容量で決ま
る熱時定数が大きいためである。しかし、ヒートシンク
２は構造上あまり小さくすることはできない。Conventionally, the reason why the temperature of the heat sink 2 cannot follow rapid fluctuations in the element temperature of the semiconductor laser 1 is because the thermal time constant determined by the thermal resistance between the P1 to the sink 2 and the coolant and the heat capacity of the heat sink 2 and the like is large. However, the heat sink 2 cannot be made very small due to its structure.
そこで、熱抵抗、熱容量の小なる補助温度センサ１２及
び補助ヒータ１３を設け、補助温度センサ１２より半導
体レーザ１の素子温度の速い変動にも十分に追随する温
度検出信号を取り出し、これを補助温度制御回路１４に
供給し、ここで制御信号に変換する。この制御信号は通
常はオンであるリミット手段１５を通して補助し−タ１
３に印加される。Therefore, an auxiliary temperature sensor 12 and an auxiliary heater 13 with small thermal resistance and heat capacity are provided, and a temperature detection signal that sufficiently follows the rapid fluctuations in the element temperature of the semiconductor laser 1 is extracted from the auxiliary temperature sensor 12, and this signal is sent to the auxiliary temperature. The signal is supplied to the control circuit 14, where it is converted into a control signal. This control signal is assisted through the limit means 15, which is normally on.
3 is applied.
前記したように補助ヒータ１３の熱抵抗は小さく、補助
温度センサ１２及び半導体レーザ１との熱時定数が小で
あり、高速に制御信号に応答し、また補助ヒータ１３の
発熱量は小であるのでハンチング現象は生じない。As described above, the auxiliary heater 13 has a small thermal resistance, a small thermal time constant with the auxiliary temperature sensor 12 and the semiconductor laser 1, responds quickly to control signals, and the amount of heat generated by the auxiliary heater 13 is small. Therefore, no hunting phenomenon occurs.
ところで、半導体レーザ１の発振波長調整時などのよう
に発振波長の変更に伴ってヒートシンク２の設定温度を
変更した時は、補助温度センサ１２からの温度検出信号
の変動量が設定値以上に大きく変化する。このような場
合にも、補助ヒータ１３の温度制御を行なうと、この場
合にはヒータ５も発熱量が大きく変化するので、補助ヒ
ータ１３とヒータ５に対する２つの温度制御のバランス
が合わず、安定しない。By the way, when the set temperature of the heat sink 2 is changed in conjunction with a change in the oscillation wavelength, such as when adjusting the oscillation wavelength of the semiconductor laser 1, the amount of variation in the temperature detection signal from the auxiliary temperature sensor 12 may be greater than the set value. Change. In such a case, if the temperature of the auxiliary heater 13 is controlled, the amount of heat generated by the heater 5 will also change greatly, so the two temperature controls for the auxiliary heater 13 and the heater 5 will not be balanced, resulting in a stable do not.
そこで、本発明ではこのような場合にはリミット手段１
５により、補助温度制御回路１４の出力温度検出信号に
よる補助ヒータ１３への温度制御をオフとし、上記の不
安定さを防止する。Therefore, in the present invention, in such a case, the limit means 1
5 turns off the temperature control to the auxiliary heater 13 based on the output temperature detection signal of the auxiliary temperature control circuit 14, thereby preventing the above instability.
（実施例）
第２図は本発明方式の要部の一実施例の構成図で、同図
（Ａ）は側面図、同図（Ｂ）は正面図を示す。同図中、
第１図及び第６図と同一構成部分には同一符号を付し、
その説明を適宜省略する。(Embodiment) FIG. 2 is a configuration diagram of an embodiment of the main part of the system of the present invention, in which FIG. 2(A) shows a side view and FIG. 2(B) shows a front view. In the same figure,
Components that are the same as those in FIGS. 1 and 6 are designated by the same reference numerals.
The explanation will be omitted as appropriate.
第２図（Ａ）、（Ｂ）において、補助温度センサ１２と
補助ヒータ１３とは夫々半導体レーザ１と同じマウント
台４上に設けられている。In FIGS. 2A and 2B, the auxiliary temperature sensor 12 and the auxiliary heater 13 are each provided on the same mount base 4 as the semiconductor laser 1.
補助温度センサ１２はチップダイオードからなり、その
サイズは例えば２００μｍ角で、温度センサ３よりも小
である。また、補助ヒータ１３は例えばチップ抵抗で、
縦３ｍ！、横１ｍ＋＋＋、高さ０．５履程度の小さな発
熱体である。The auxiliary temperature sensor 12 is made of a chip diode, and its size is, for example, 200 μm square, which is smaller than the temperature sensor 3. Further, the auxiliary heater 13 is, for example, a chip resistor,
3m long! It is a small heating element with a width of 1 m+++ and a height of about 0.5 shoes.
第３図は本発明方式の他の要部の一実施例のブロック図
を示す。同図中、第１図及び第２図と同一構成部分には
同一符号を付し、その説明を省略する。第３図は本実施
例の温度制ａ回路系を示しており、差動器１７と第１の
温度制御器１８により温度１１１１１１１回路１１が構
成され、差動器１９と第２の温度制御方式２０により補
助温度制御回路１４が構成されている。また、差動器２
１とリミット回路２２によりリミット手段１５が構成さ
れている。差動器１７，１９及び２１には夫々設定電圧
源２３より設定電圧Ｖｏが夫々供給される。FIG. 3 shows a block diagram of an embodiment of another essential part of the system of the present invention. In the figure, the same components as in FIGS. 1 and 2 are denoted by the same reference numerals, and their explanations will be omitted. FIG. 3 shows the temperature control a circuit system of this embodiment, in which a temperature 1111111 circuit 11 is configured by a differential device 17 and a first temperature controller 18, and a differential device 19 and a second temperature control method are configured. 20 constitutes an auxiliary temperature control circuit 14. Also, differential 2
1 and the limit circuit 22 constitute a limit means 15. A set voltage Vo is supplied to the differential devices 17, 19, and 21 from a set voltage source 23, respectively.
温度センサ３からの温度検出電圧Ｖ１は差動器１７によ
り設定電圧Ｖｏとの差分がとられた後第１の温度制御器
１８に供給され、ここで上記差分（Ｖ＋ Ｖｏ）を小
さくするような制御電流に変換されてからヒータ５に供
給され、その発熱量を制御する。ここで、半導体レーザ
１の駆動電流（レーザ電ｉ ＞が第４図（Ａ）に示す如
く時間と共に増大していくような波長昂引が行なわれて
いるときには、上記温度検出電圧ｖ１はそれに高速に追
随して第４図（Ｂ）に実線工で示す如く変化するのに対
し、前記したように熱時定数が大きいためにヒータ５の
温度（発熱量）はこれに追随できず第４図（Ｄ）に示す
如く殆ど変化しない。The temperature detection voltage V1 from the temperature sensor 3 is supplied to the first temperature controller 18 after the difference between it and the set voltage Vo is calculated by the differential device 17. After being converted into a control current, it is supplied to the heater 5, and its heat generation amount is controlled. Here, when the driving current of the semiconductor laser 1 (laser electric current i > increases with time as shown in FIG. 4(A)), the temperature detection voltage v1 increases rapidly. As shown by the solid line in Fig. 4 (B), the temperature of the heater 5 cannot follow this change due to the large thermal time constant as described above, and the temperature (heat amount) changes as shown in Fig. 4 (B). As shown in (D), there is almost no change.
一方、補助温度センサ１２からの温度検出電圧ｖ２は第
３図に示す差動器１９に供給され、ここで設定電圧Ｖｏ
との差分ΔＶをとられた後、第２の温度制御器２０に供
給され、ここで所定の特性に従ってＩＩｌ ｍ ｇ流に
変換されてがらりミツト回路２２に供給される。On the other hand, the temperature detection voltage v2 from the auxiliary temperature sensor 12 is supplied to the differential gear 19 shown in FIG.
After taking the difference ΔV from the current, the current is supplied to the second temperature controller 20, where it is converted into an IIl mg flow according to a predetermined characteristic, and is supplied to the GARIMIT circuit 22.
リミット回路２２は差動器２１よりの温度検出電圧ｖ２
と設定電圧Ｖｏとの差分ΔＶにより、その動作が制御さ
れるよう構成されており、差分ΔＶが予め設定した値（
これは通常の波長停引時では生じないような、波長変更
時等のように温度検出電圧ｖ２が大きく変動した時に初
めて得られるような値であ、る）以上にならない限り、
第２の温度制御器２０からの制ｍ＋電流をそのまま通過
出力し、他方、差分ΔＶが上記予め設定した値以上とな
ったときには、上記制御電流の通過を遮断（オフ）する
ように構成されている。The limit circuit 22 is the temperature detection voltage v2 from the differential device 21.
The operation is controlled by the difference ΔV between and the set voltage Vo, and the difference ΔV is a preset value (
This is a value that is only obtained when the temperature detection voltage v2 fluctuates greatly, such as when changing the wavelength, which does not occur when the wavelength is stopped normally.
The control m+ current from the second temperature controller 20 is passed through and output as is, and on the other hand, when the difference ΔV exceeds the preset value, the passage of the control current is cut off (turned off). There is.
従って、補助ヒータ１３は通常の波長昂引時にはリミッ
ト回路２２を通過した上記制御電流により発熱し、半導
体レーザ１の素子温度を変化させ設定電圧Ｖｏに応じた
一定値になるようにする。Therefore, during normal wavelength excitation, the auxiliary heater 13 generates heat due to the control current passing through the limit circuit 22, and changes the element temperature of the semiconductor laser 1 to a constant value corresponding to the set voltage Vo.
ここで、上記の温度検出電圧ｖ２は第４図（Ｃ）に実線
■で示す如く、同図（Ａ）のレーザ電流の変化に高速に
追随して変化し、また補助ヒータ１３の熱抵抗が前記し
たように小さいので、補助ヒータ１３の温度も第４図（
Ｅ）に示す如く高速に応答して変化する。Here, the above-mentioned temperature detection voltage v2 changes rapidly following the change in the laser current in FIG. 4(A), as shown by the solid line ■ in FIG. 4(C), and the thermal resistance of the auxiliary heater 13 changes. Since the temperature of the auxiliary heater 13 is small as described above, the temperature of the auxiliary heater 13 is also as shown in FIG.
As shown in E), it responds quickly and changes.
これにより、半導体レーザ１の素子湿度が一定値になる
ように高速に制御されるため、前記温度検出電圧Ｖ＋
、Ｖ２は本実施例による温度制御が行なわれないときは
第４図（［３）、（Ｃ）に実線１、ＩＩｌで示す如く変
化するが、本実施例の温度制御により同図（Ｂ）、（Ｃ
）に夫々−点ｔＡ線■。As a result, since the element humidity of the semiconductor laser 1 is controlled at high speed to a constant value, the temperature detection voltage V+
, V2 change as shown by the solid lines 1 and IIl in FIG. 4 ([3) and (C) when the temperature control according to this embodiment is not performed, but when the temperature control according to this embodiment is performed, the values change as shown in FIG. 4 (B). , (C
) respectively - point tA line■.
ＩＶで示す如くに変化する。It changes as shown by IV.
なお、前記差分ΔＶが設定値以上となり、リミット回路
２２がオフとされたときには、補助ヒータ１３は制御さ
れないから従来と同じ温度制御が行なわれることになる
。Note that when the difference ΔV exceeds the set value and the limit circuit 22 is turned off, the auxiliary heater 13 is not controlled, so that the same temperature control as in the prior art is performed.
かかる温度制御方式によって素子湿度が制御１１される
半導体レーザ１は第５図に示ず如き公知のレーザガスセ
ンナに用いられる。同図中、２５は第３図に示した温度
！ｉｌ１ｗＪ系、２６は第２図に示した半導体レーザ源
である。半導体レーザ源２６中の半導体レーザ１より放
射された赤外光領域のレーザ光はハーフミラ−２７によ
り光路を２分岐され、一方は被測定ガスが充満している
測定側ガスセル２８を透過して赤外検知器２９に入射さ
れ、他方は被測定ガスと同種で濃度が既知の基準ガスが
充満している基準ガスセル３ｏを透過して赤外検知器３
１に入射される。A semiconductor laser 1 whose element humidity is controlled 11 by such a temperature control method is used in a known laser gas sensor as shown in FIG. In the figure, 25 is the temperature shown in Figure 3! il1wJ system, 26 is the semiconductor laser source shown in FIG. Laser light in the infrared region emitted by the semiconductor laser 1 in the semiconductor laser source 26 is split into two optical paths by a half mirror 27, one of which passes through the measurement side gas cell 28 filled with the gas to be measured, and the infrared laser beam is emitted by the semiconductor laser 1 in the semiconductor laser source 26. The other gas enters the infrared detector 3 through the reference gas cell 3o filled with a reference gas of the same type as the gas to be measured and whose concentration is known.
1.
赤外検知器２９．３１により夫々光電変換されて得られ
た、透過光強度に応じたレベルの信号は信号処理装置３
２に供給され、ここで公知の手段により被測定ガスの濃
度が算出される。また、信号処理袋Ｍ３２の出力信号は
レーザ電諒３３を制御し、半導体レーザ１の駆動電流を
高速に変調し、レーザ発振波長が釦用されるようにする
。Signals of a level corresponding to the transmitted light intensity obtained by photoelectric conversion by the infrared detectors 29 and 31 are sent to the signal processing device 3.
2, where the concentration of the gas to be measured is calculated by known means. Further, the output signal of the signal processing bag M32 controls the laser power generator 33 to modulate the drive current of the semiconductor laser 1 at high speed so that the laser oscillation wavelength is controlled.
このような構成のレーザ方式ガスセンサにおいて、半導
体レーザ源２６中の半導体レーザ１の素子温度は、館記
したように温度制御系２５により高速かつ高安定に制御
されるので、レーザ発振波長が駆動電流に正確に追随し
、高精度の濃度測定ができる。In the laser type gas sensor having such a configuration, the element temperature of the semiconductor laser 1 in the semiconductor laser source 26 is controlled quickly and highly stably by the temperature control system 25 as described above, so that the laser oscillation wavelength is controlled by the drive current. It follows accurately and can measure concentration with high precision.
上述の如く、本発明によれば、熱抵抗、熱容量の小なる
補助ヒータ、補助温度センサを設けて半導体レーザの素
子温度に高速に追随して温度制御できるようにしたため
、半導体レーザの駆１７Ｊｆｆｉ流を高周波数で変調し
て波長掃引を行なう場合でも、高速かつ高安定に半導体
レーザの素子温度が一定になるように制御することがで
き、従ってレーザ発振波長が駆動電流に正確に追随させ
ることができるので、レーザ方式ガスセンサの濃度測定
精度を向上することができる等の特長を有するものであ
る。As described above, according to the present invention, the auxiliary heater with small thermal resistance and heat capacity, and the auxiliary temperature sensor are provided to enable temperature control by rapidly following the element temperature of the semiconductor laser. Even when performing wavelength sweeping by modulating the laser diode at a high frequency, it is possible to control the semiconductor laser element temperature to be constant at high speed and with high stability, and therefore the laser oscillation wavelength can be made to accurately follow the drive current. Therefore, it has features such as being able to improve the concentration measurement accuracy of the laser type gas sensor.
第１図は本発明の原理ブロック図、
第２図は本発明方式の要部の一実施例の構成図、第３図
は本発明方式の他の要部の一実施例のブロック図、
第４図は第２図、第３図の各部の信号の時間変化を示す
図、
第５図はレーザ方式ガスセンサの一例のブロック図、
第６図は従来方式の一例の構成図、
第７図は真空容器の一例の構造図である。
図にＪ５いて、
１は半導体レーザ、
２はヒートシンク、
３は温度センサ、
５はヒータ、
１１は温度制御回路、
１２は補助温度センサ、
１３は補助ヒータ、
１４は補助温度制御回路、
１５はリミット手段
をホす。
ｍ１図
特許出願人 富 士 通 株式会社
第２図
第３図Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a configuration diagram of an embodiment of the main part of the system of the invention, and Fig. 3 is a block diagram of an embodiment of the other main parts of the system of the invention. Figure 4 is a diagram showing the time change of signals in each part of Figures 2 and 3, Figure 5 is a block diagram of an example of a laser type gas sensor, Figure 6 is a configuration diagram of an example of a conventional type gas sensor, Figure 7 is FIG. 2 is a structural diagram of an example of a vacuum container. In the figure, J5 includes 1 a semiconductor laser, 2 a heat sink, 3 a temperature sensor, 5 a heater, 11 a temperature control circuit, 12 an auxiliary temperature sensor, 13 an auxiliary heater, 14 an auxiliary temperature control circuit, and 15 a limit. Take the means. Figure m1 patent applicant Fujitsu Ltd. Figure 2 Figure 3
Claims (1)
を温度センサ（３）で検出し、その検出信号に基づいて
温度制御回路（１１）により該ヒートシンク（２）の加
熱用ヒータ（５）の温度を制御することにより、該ヒー
トシンク（２）及び半導体レーザ（１）の温度を一定に
制御する半導体レーザの温度制御方式において、 前記ヒートシンク（２）、温度センサ（３）及びヒータ
（５）による熱抵抗、熱容量より小なる熱抵抗、熱容量
をもつ補助温度センサ（１２）及び補助ヒータ（１３）
を前記半導体レーザ（１）の近傍に配置し、該補助温度
センサ（１２）からの温度検出信号に基づいて該補助ヒ
ータ（１３）の温度を制御する補助温度制御回路（１４
）を設けると共に、該補助温度センサ（１２）からの温
度検出信号の変動量が設定値以上のときに該補助温度制
御回路（１４）による該補助ヒータ（１３）の温度制御
をオフにするリミット手段（１５）を設けたことを特徴
とする半導体レーザの温度制御方式。[Claims] The temperature of the heat sink (2) for heat radiation of the semiconductor laser (1) is detected by the temperature sensor (3), and the heat sink (2) is heated by the temperature control circuit (11) based on the detection signal. In a semiconductor laser temperature control method that controls the temperature of the heat sink (2) and the semiconductor laser (1) to be constant by controlling the temperature of the heater (5), the heat sink (2) and the temperature sensor (3) and an auxiliary temperature sensor (12) and an auxiliary heater (13) having a thermal resistance and a thermal capacity smaller than the thermal resistance and thermal capacity of the heater (5).
is arranged near the semiconductor laser (1), and controls the temperature of the auxiliary heater (13) based on the temperature detection signal from the auxiliary temperature sensor (12).
), and a limit that turns off the temperature control of the auxiliary heater (13) by the auxiliary temperature control circuit (14) when the amount of variation in the temperature detection signal from the auxiliary temperature sensor (12) is equal to or greater than a set value. A temperature control method for a semiconductor laser, characterized in that a means (15) is provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21453488A JPH0263179A (en) | 1988-08-29 | 1988-08-29 | Temperature control system of semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21453488A JPH0263179A (en) | 1988-08-29 | 1988-08-29 | Temperature control system of semiconductor laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0263179A true JPH0263179A (en) | 1990-03-02 |
Family
ID=16657324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21453488A Pending JPH0263179A (en) | 1988-08-29 | 1988-08-29 | Temperature control system of semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0263179A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018098391A (en) * | 2016-12-14 | 2018-06-21 | ファナック株式会社 | Laser equipment |
-
1988
- 1988-08-29 JP JP21453488A patent/JPH0263179A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018098391A (en) * | 2016-12-14 | 2018-06-21 | ファナック株式会社 | Laser equipment |
| US10277004B2 (en) | 2016-12-14 | 2019-04-30 | Fanuc Corporation | Laser device |
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