JPS62219680A - Constant-output drive circuit for semiconductor laser - Google Patents
Constant-output drive circuit for semiconductor laserInfo
- Publication number
- JPS62219680A JPS62219680A JP6059586A JP6059586A JPS62219680A JP S62219680 A JPS62219680 A JP S62219680A JP 6059586 A JP6059586 A JP 6059586A JP 6059586 A JP6059586 A JP 6059586A JP S62219680 A JPS62219680 A JP S62219680A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- temperature
- drive circuit
- case
- semiconductor
- 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 34
- 238000012544 monitoring process Methods 0.000 claims abstract description 4
- 150000001875 compounds Chemical class 0.000 claims abstract description 3
- 238000009413 insulation Methods 0.000 claims 1
- 239000003990 capacitor Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 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
- 238000010586 diagram Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 230000010355 oscillation Effects 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
- H01S5/06—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
-
- 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
- H01S5/02407—Active cooling, e.g. the laser temperature is controlled by a thermo-electric cooler or water cooling
- H01S5/02415—Active cooling, e.g. the laser temperature is controlled by a thermo-electric cooler or water cooling by using a thermo-electric cooler [TEC], e.g. Peltier element
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
[産業上の利用分野]
この種の回路として、第2図に示すような回路導体レー
ザLDとトランジスタTrのエミッターコレクタとを正
電源電圧+Vと大地電位Gとの間に接続する。増幅器A
tの一方の入力端子には正電源電圧+Vと大地電位Gと
の間に直列に接続した抵抗R1,可変抵抗VRおよび抵
抗R2の可変抵抗VRの可変出力端子から取り出した電
圧C−を印加し、同他方の入力端子には正電源電圧+V
と大地電位Gとの間に直列に接続した抵抗R3とサーミ
スタR4との接続点の電圧C+を印加する。増幅器A1
の出力を抵抗R5とR8を介してトランジスタTrのベ
ースに供給する。フォトダイオードPDの出力を増幅器
A1の他方の入力端子に供給する。抵抗R5とR6の接
続点と正電源電圧+Vとの間にコンデンサCを接続する
。[Detailed Description of the Invention] [Field of Industrial Application] As a circuit of this type, a circuit conductor laser LD and an emitter collector of a transistor Tr as shown in FIG. 2 are connected between a positive power supply voltage +V and a ground potential G. Connect to. Amplifier A
A voltage C- taken out from the variable output terminal of the variable resistor VR of the resistor R1, variable resistor VR, and resistor R2 connected in series between the positive power supply voltage +V and the ground potential G is applied to one input terminal of t. , the other input terminal is connected to the positive power supply voltage +V
A voltage C+ is applied at a connection point between a resistor R3 and a thermistor R4 connected in series between the ground potential G and the ground potential G. Amplifier A1
The output of the transistor Tr is supplied to the base of the transistor Tr via resistors R5 and R8. The output of the photodiode PD is supplied to the other input terminal of the amplifier A1. A capacitor C is connected between the connection point of resistors R5 and R6 and the positive power supply voltage +V.
この回路は以下のように動作する。This circuit operates as follows.
まず、増幅器A1の入力電圧6”、6−は次式でrt
+r2 ’可変抵抗VRの値、
i:半導体レーザLDの出力光量モニタ用フォトダイオ
ードPDの出力電流
増幅器A1の出力C0は増幅器AIのゲインをAとして
(3)式で示される。First, the input voltages 6'' and 6- of the amplifier A1 are expressed as rt
+r2' Value of variable resistor VR, i: Output C0 of the output current amplifier A1 of the photodiode PD for monitoring the output light amount of the semiconductor laser LD is expressed by equation (3) where A is the gain of the amplifier AI.
6o=A(e+ −6−)+6− (3)すな
わち、(1)、(2)式で示される入力電圧O+と〇−
の差(e+−e−)は増幅器A1で増幅され、(e+−
e−)>oのときは増幅器A1の出力C0はC−よりも
大きくなり、(e” −e−)く0のときはC−よりも
小さくなる。6o=A(e+ -6-)+6- (3) That is, the input voltage O+ and 〇- shown in equations (1) and (2)
The difference (e+-e-) is amplified by amplifier A1, and the difference (e+-e-
When e-)>o, the output C0 of amplifier A1 is larger than C-, and when (e''-e-)>0, it is smaller than C-.
回路全体の発振防止用の抵抗RへとコンデンサCから成
る一次遅れ要素を経て増幅器A1の出力Coは平滑化さ
れ、抵抗R6を経由してトランジこれにより半導体レー
ザLDの発光量の変動は補償され、増幅器A1の出力C
0がC−になるように制御されることになる。すなわち
、可変抵抗で調整できる電圧O−を小さく(大きく)す
れば、C0も小さく(大きく)なりトランジスタTrの
ベース電流は大きく(小さく)なる、これにより半導体
レーザLDの発光量を調整できることが分る。The output Co of the amplifier A1 is smoothed by passing through a first-order delay element consisting of a capacitor C to a resistor R for preventing oscillation of the entire circuit, and is transferred to a transistor via a resistor R6, thereby compensating for fluctuations in the amount of light emitted by the semiconductor laser LD. , the output C of amplifier A1
It will be controlled so that 0 becomes C-. In other words, if the voltage O-, which can be adjusted by the variable resistor, is decreased (increased), C0 also decreases (increases), and the base current of the transistor Tr increases (decreases).This shows that the amount of light emitted by the semiconductor laser LD can be adjusted. Ru.
以上のような従来の半導体レーザの駆動回路には次のよ
うな問題点がある。The conventional semiconductor laser drive circuit as described above has the following problems.
増幅器A1のオフセット電圧の温度特性のために、(3
)式は正確には次の(4)式のようになる。Due to the temperature characteristics of the offset voltage of amplifier A1, (3
) is exactly as shown in the following equation (4).
Oo =A@ (e” −6−+6−* K@T)
+6−T:増幅器A1の発光光量(”O)
すなわち、増幅器AIを理想的なものとすれば、になる
、開式はC1・に−Tの項のために、増幅器A1の発光
光量Tの変化に伴い6oが変化することを意味している
。Oo = A@ (e” −6−+6−* K@T)
+6-T: Amount of light emitted from amplifier A1 ("O) In other words, if amplifier AI is ideal, the following equation is obtained. Because of the term -T in C1, the amount of light emitted from amplifier A1 T This means that 6o changes with the change.
換言すれば、(4)式は、半導体レーザLDの光量変動
がないにもかかわらず増幅器A1の出力OOはオフセッ
ト電圧C1の温度特性のために変化し、Kが正の値の場
合は温度上昇とともにCOが増大し、またKの値が負の
場合は温度上昇とともにCOが減少することを意味して
いる。In other words, equation (4) shows that even though there is no variation in the light intensity of the semiconductor laser LD, the output OO of the amplifier A1 changes due to the temperature characteristics of the offset voltage C1, and if K is a positive value, the temperature rises. A negative value of K means that CO decreases as the temperature increases.
このように、もともと半導体LDに光量変動がなかった
にもかかわらず、発光光量の変動によりトランジスタT
rのベース電流が変化し、半導体レーザLDに流す電流
を変化させ、LDの発光光量が変動してしまうという欠
点があった。In this way, even though the semiconductor LD originally had no fluctuation in the amount of light, due to the fluctuation in the amount of emitted light, the transistor T
There is a drawback that the base current of r changes, the current flowing through the semiconductor laser LD changes, and the amount of light emitted from the LD fluctuates.
路の発光光量に影響されないように構成した半導かかる
目的を達成するために、本発明は、半導駆動電流を少な
くシ、小さいときには半導体レーザの動電流を大きくす
るよう動作し、半導体レーザの発光光量が所定の値にな
るように制御する半導体レーザ駆動回路を、当該駆動回
路の温度を検出するためのサーミスタとともに熱伝導性
の良好なケース内に、電気絶縁性は高くかつ熱伝導性の
良好なサーマルコンパウンドで、埋めて一体化し、サー
ミスタにより検出される温度信号を設定温度と比較し、
その比較出力に基づいてケースに密着して配設したペル
チェ素子に流す電流を制御することにより、ケースの発
光光量が変化してもケース内の半導体レーザ駆動回路の
温度が一定になるようになしたことを特徴とする。In order to achieve the above object, the present invention operates to reduce the semiconductor drive current and increase the dynamic current of the semiconductor laser when it is small, thereby increasing the dynamic current of the semiconductor laser. A semiconductor laser drive circuit that controls the amount of emitted light to a predetermined value is housed in a case with good thermal conductivity, along with a thermistor that detects the temperature of the drive circuit. Fill and integrate with a good thermal compound, compare the temperature signal detected by the thermistor with the set temperature,
By controlling the current flowing through the Peltier element placed in close contact with the case based on the comparative output, the temperature of the semiconductor laser drive circuit inside the case can be kept constant even if the amount of light emitted by the case changes. It is characterized by what it did.
[作 用]
本発明では、半導体レーザ駆動回路をペルチェ素子を使
って発光光量の変化に関係なく定温制御することにより
、半導体レーザ駆動回路の温度時ザ定出力駆動回路を得
ることができる。[Function] In the present invention, by controlling the semiconductor laser drive circuit at a constant temperature using a Peltier element regardless of changes in the amount of emitted light, it is possible to obtain a constant output drive circuit depending on the temperature of the semiconductor laser drive circuit.
第1図は、本発明の実施例を示すものである。FIG. 1 shows an embodiment of the invention.
ここで、第2図と同様の個所には同一符号を付す。Here, the same parts as in FIG. 2 are given the same reference numerals.
第1図において、CAは第2図示の半導体駆動回路およ
び同ケース内の温度を検出するためのサーミスタR1′
を収納した銅ケースであり、その内部には、熱伝導が良
好で、かつ電気絶縁性の高いフンパウンドC0N(水谷
電機工業株式会社のCASTALL800など)を充填
して上記回路を埋めである。In FIG. 1, CA represents the semiconductor drive circuit shown in FIG. 2 and a thermistor R1' for detecting the temperature inside the case.
The inside of the case is filled with Funpound C0N (such as CASTALL 800 manufactured by Mizutani Electric Industry Co., Ltd.), which has good thermal conductivity and high electrical insulation properties, and the circuit is filled with the above-mentioned circuit.
抵抗R11〜R,うおよびサーミスタR1,から構成さ
れたブリッジ回路により、温度設定値(抵抗R11とR
11の接続点の電位)と測定温度(抵抗R11とサーミ
スタRとの接続点の電位)との差が抵抗R4〜R11お
よび増幅器A2とから成る差動増幅器により増幅される
。The temperature setting value (resistors R11 and R
The difference between the potential at the connection point of resistor R11 and the measured temperature (the potential at the connection point of resistor R11 and thermistor R) is amplified by a differential amplifier including resistors R4 to R11 and amplifier A2.
この出力は、パワトランジスタtr1およびtr2スC
A内の温度が高ければ、これを下げる方向に、””讐な
わち、設定温度よりケースCA内の温度が低ければ、抵
抗R11とR,□との接続点の電位は、サーミスタR1
4が温度に対して負性抵抗であることを考慮して、抵抗
RIBとサーミスタR1’+との接続点の電位よりも低
くなるようにブリッジ回路を設計しておく。This output is connected to the power transistors tr1 and tr2
If the temperature inside case CA is high, it will be lowered.In other words, if the temperature inside case CA is lower than the set temperature, the potential at the connection point between resistor R11 and R,
Considering that 4 is a negative resistance with respect to temperature, the bridge circuit is designed so that the potential is lower than the potential of the connection point between the resistor RIB and thermistor R1'+.
これにより、この場合、増幅器A2の出力は大地電位G
よりも正の電位となり、パワートランジスタtr1がペ
ルチェ素子Pに電流を流し込む、ペルチェ素子は電流の
向きによって加熱、冷却ができるので、この場合には、
ペルチェ素子PはケースOA内の温度が設定温度よりも
低かったものが設定温度になるよう加熱するように配線
しておくものとする。Therefore, in this case, the output of amplifier A2 is at ground potential G
The potential becomes more positive than that, and the power transistor tr1 flows current into the Peltier element P. Since the Peltier element can be heated or cooled depending on the direction of the current, in this case,
The Peltier element P is wired so that the temperature inside the case OA, which is lower than the set temperature, is heated so that the temperature reaches the set temperature.
逆に設定温度よりケースCA内の温度が高ければ、抵抗
R4,とR12との接続点の電位が、抵抗Rとサーミス
タR11)との接続点の電位よりも高の比により、ケー
スCA内の設定温度を調整できる。Conversely, if the temperature inside case CA is higher than the set temperature, the potential at the connection point between resistors R4 and R12 is higher than the potential at the connection point between resistor R and thermistor R11). You can adjust the set temperature.
第1図において、ペルチェ素子PにはフィンFを取りつ
けておく、このフィンFは、ペルチェ素子PがケースC
Aを冷却する場合にそれに相当する熱を周囲に放散し、
またケースOAをペルチェ素子Pが加熱する場合にそれ
に相当する熱を周囲から奪う際の効率をよくするための
ものである。In FIG. 1, a fin F is attached to the Peltier element P.
When cooling A, the corresponding heat is dissipated to the surroundings,
Further, when the case OA is heated by the Peltier element P, the heat is removed from the surroundings more efficiently.
なお、第1図においては、第2図と比較し、半導体レー
ザ駆動回路の可変抵抗VRは簡素化のために省略しであ
る。これは、レーザ駆動回路の設計段階において、目標
とする半導体レーザの出力パワーが得られるように、抵
抗R1,R2の値を最初から決定しである場合の一例で
あるが、このようにする代わりに、可変抵抗VRを設け
てもよいことは勿論である。Note that in FIG. 1, as compared with FIG. 2, the variable resistor VR of the semiconductor laser drive circuit is omitted for the sake of simplicity. This is an example of a case where the values of resistors R1 and R2 are determined from the beginning in order to obtain the target output power of the semiconductor laser at the design stage of the laser drive circuit, but instead Of course, a variable resistor VR may also be provided.
路を得ることができる。You can get the road.
[発明の効果]
体レーザ駆動回路を温度検出用のサーミスタとともに埋
めて一体化し、そのサーミスタにより検出される温度信
号を設定温度と比較し、この差を電力増幅して上記銅ケ
ースに密着して設置されているペルチェ素子に流す電流
を、発光光量が変化しても銅ケース内の温度が一定にな
るように制御するようにしたので、発光光量が変化して
も差動増幅器のオフセット電圧は一定となり、このため
、従来のように発光光量が変わると半導体レーザの発光
光量が変化する欠点をなくすことができ、発光光量の変
化に対し、非常に安定した半導体レーザ定出力駆動回路
を得ることができる。[Effects of the invention] The body laser drive circuit is embedded and integrated with a thermistor for temperature detection, the temperature signal detected by the thermistor is compared with the set temperature, and this difference is amplified in power. The current flowing through the installed Peltier element is controlled so that the temperature inside the copper case remains constant even if the amount of emitted light changes, so the offset voltage of the differential amplifier remains unchanged even if the amount of emitted light changes. Therefore, it is possible to eliminate the conventional drawback that the amount of emitted light of the semiconductor laser changes when the amount of emitted light changes, and to obtain a semiconductor laser constant output drive circuit that is extremely stable against changes in the amount of emitted light. I can do it.
第1図は本発明の一実施例を示す回路図、第2図は従来
の半導体レーザ定出力駆動回路の一例を示す回路図であ
る。
R1〜 R3、R5・R6・R11〜 R+5・RIB
〜R+9・・・固定抵抗、
R4、R17・・・サーミスタ、
At、A2・・・増幅器、
Tr、 trl 、 tr2・・・パワートランジス
タC1・・・コンデンサ、
CPM・・・サーマルコンバウンド、
OA・・・銅ケース、
PD・・・半導体レーザ光量モニタ用
フォトダイオード、
LD・・・半導体レーザ、
P・・・ペルチェ素子、
F・・・フィン。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of a conventional semiconductor laser constant output drive circuit. R1~R3, R5・R6・R11~R+5・RIB
~R+9...Fixed resistance, R4, R17...Thermistor, At, A2...Amplifier, Tr, trl, tr2...Power transistor C1...Capacitor, CPM...Thermal combine, OA・...Copper case, PD...Photodiode for semiconductor laser light intensity monitoring, LD...Semiconductor laser, P...Peltier element, F...Fin.
Claims (1)
ダイオードを設け、該フォトダイオードの電流が設定値
と比較して大きいときには前記半導体レーザの駆動電流
を少なくし、小さいときには前記半導体レーザの動電流
を大きくするよう動かし、前記半導体レーザの発光光量
が所定の値になるように制御する半導体レーザ駆動回路
を、当該駆動回路の温度を検出するためのサーミスタと
ともに熱伝導性の良好なケース内に、電気絶縁性は高く
かつ熱伝導性の良好なサーマルパウンドで、埋めて一体
化し、前記サーミスタにより検出される温度信号を設定
温度と比較し、その比較出力に基づいて前記ケースに密
着して配設したペルチェ素子に流す電流を制御すること
により、前記ケースの周囲温度が変化しても前記ケース
内の前記半導体レーザ駆動回路の温度が一定になるよう
になしたことを特徴とする半導体レーザ定出力駆動回路
。A photodiode for monitoring the amount of emitted light is provided close to the semiconductor laser, and when the current of the photodiode is large compared to a set value, the driving current of the semiconductor laser is reduced, and when it is small, the dynamic current of the semiconductor laser is reduced. A semiconductor laser drive circuit that controls the amount of light emitted by the semiconductor laser to a predetermined value is housed in a case with good thermal conductivity, along with a thermistor for detecting the temperature of the drive circuit. A thermal compound with high insulation properties and good thermal conductivity is embedded and integrated, and the temperature signal detected by the thermistor is compared with the set temperature, and based on the comparison output, it is placed in close contact with the case. A semiconductor laser constant output drive characterized in that the temperature of the semiconductor laser drive circuit inside the case is kept constant even if the ambient temperature of the case changes by controlling the current flowing through the Peltier element. circuit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6059586A JPS62219680A (en) | 1986-03-20 | 1986-03-20 | Constant-output drive circuit for semiconductor laser |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6059586A JPS62219680A (en) | 1986-03-20 | 1986-03-20 | Constant-output drive circuit for semiconductor laser |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS62219680A true JPS62219680A (en) | 1987-09-26 |
Family
ID=13146745
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6059586A Pending JPS62219680A (en) | 1986-03-20 | 1986-03-20 | Constant-output drive circuit for semiconductor laser |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS62219680A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63265480A (en) * | 1987-04-23 | 1988-11-01 | Nec Corp | Optical transmission equipment |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5914362B2 (en) * | 1980-02-26 | 1984-04-04 | 横浜ゴム株式会社 | tire filling |
-
1986
- 1986-03-20 JP JP6059586A patent/JPS62219680A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5914362B2 (en) * | 1980-02-26 | 1984-04-04 | 横浜ゴム株式会社 | tire filling |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63265480A (en) * | 1987-04-23 | 1988-11-01 | Nec Corp | Optical transmission equipment |
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