JPS60171778A - Driving device for semiconductor laser - Google Patents
Driving device for semiconductor laserInfo
- Publication number
- JPS60171778A JPS60171778A JP2723684A JP2723684A JPS60171778A JP S60171778 A JPS60171778 A JP S60171778A JP 2723684 A JP2723684 A JP 2723684A JP 2723684 A JP2723684 A JP 2723684A JP S60171778 A JPS60171778 A JP S60171778A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- signal
- detector
- control circuit
- time
- 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
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
- H01S5/06825—Protecting the laser, e.g. during switch-on/off, detection of malfunctioning or degradation
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】
本弁明は半導体レーザーの光強度を制御するために用い
る駆動装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present disclosure relates to a driving device used to control the light intensity of a semiconductor laser.
半導体レーザーの進歩により、小型で強力なコーヒレン
ト光発生装置として各種の半導体レーザーが広く使用さ
れてきており、その駆動装置にも種々の方式が提案され
ている。一般に、半導体レーザーは第4図に示・すよう
に駆動電流を増加していくと、持込の電流値(発振開始
電流値)を越えると急激に光強度が増加する特性を有し
ており、更に、この特性が温度によって大きく変化する
こと、および光強度があるレベルを越えると半導体レー
ザーが瞬間的に破壊すること等の現象が生ずるので、駆
動電流を適正に制御することは極めて重要である。With the advancement of semiconductor lasers, various types of semiconductor lasers have come into widespread use as compact and powerful coherent light generating devices, and various systems have been proposed for their driving devices. Generally, as shown in Figure 4, semiconductor lasers have the characteristic that when the driving current is increased, the light intensity increases rapidly when the current value exceeds the carry-in current value (oscillation starting current value). Furthermore, this characteristic changes greatly depending on temperature, and phenomena such as instantaneous destruction of the semiconductor laser occur when the light intensity exceeds a certain level, so it is extremely important to control the drive current appropriately. be.
駆動電流の制御方法として普通に行なわれている方法は
、半導体レーザーの光の一部をホトダイオードで検出し
、この出力電圧が一定になるように駆動電流を制御する
ものであるが、この方法では電源投入時に半導体レーザ
ーに過大な電流を流す心配があった。即ち、電源が瞬間
的に投入された場合、ホトダイオードの検出信号が駆動
電流をシリ御し始めるまでにあるR開を要するため、こ
の僅かな時間に無制御の過大電流が流れて半導体レーザ
ーを破壊することがある。また、半導体レーザーは光強
度を高周波変調して使用することも多いが、簡単で信頼
性の高い変調方式が必要であるし、更に、また、赤外発
光の半導体レーザーを使用した場合にはレーザー光の存
在が目視不可能であるため、適切な安全対策が必要であ
る。The commonly used method for controlling the drive current is to detect a portion of the light from the semiconductor laser with a photodiode and control the drive current so that the output voltage is constant. There was a concern that excessive current would flow through the semiconductor laser when the power was turned on. In other words, when the power is turned on instantaneously, a certain R-open is required before the photodiode detection signal begins to control the drive current, so an uncontrolled excessive current flows during this short period of time, destroying the semiconductor laser. There are things to do. In addition, semiconductor lasers are often used by modulating the light intensity with high frequency, but a simple and reliable modulation method is required. Since the presence of light is not visible to the naked eye, appropriate safety measures are required.
本発明は”、以上の問題潔を解決するためになされたも
ので、その目的は簡単で信頼性が高く、かつ安全性にも
優れた半導体レーザー駆動装置を提供することにあり、
以下に、本発明を添付図面に示した実施例を参照しなが
ら詳述する。The present invention has been made to solve the above problems, and its purpose is to provide a semiconductor laser drive device that is simple, highly reliable, and has excellent safety.
The invention will now be described in detail with reference to embodiments illustrated in the accompanying drawings.
先ず、第1図は駆動装置の全体構成図であって、1は半
導体レーザーであり、その駆動電流は電流制御回路2に
より制御される。レーザー光の一部3は光出力検出器(
以下単に検出器という)4に入射し、増幅器5で増幅さ
れて光強度信号6が得られる。しかして、増幅器5と電
流制御回路2との間には時限信号発生回路7を設けてあ
り、この時限信号発生回路7の出力電圧8と上記光強度
信号6が加算された信号9は光強度設定値10と比較さ
れ、誤差信号11となって電流制御回路2の出力電流を
制御する。なお、検出器4としてはホトダイオードが用
いられる。First, FIG. 1 is an overall configuration diagram of a driving device, in which reference numeral 1 denotes a semiconductor laser, the driving current of which is controlled by a current control circuit 2. As shown in FIG. Part 3 of the laser beam is transmitted to a light output detector (
The light enters a light beam (hereinafter simply referred to as a detector) 4 and is amplified by an amplifier 5 to obtain a light intensity signal 6. A time signal generation circuit 7 is provided between the amplifier 5 and the current control circuit 2, and a signal 9 obtained by adding the output voltage 8 of the time signal generation circuit 7 and the light intensity signal 6 is the light intensity. It is compared with a set value 10 and becomes an error signal 11 to control the output current of the current control circuit 2. Note that a photodiode is used as the detector 4.
上記構成において1時限信号発生回路7が無い場合を考
えると、電源が瞬間・的に投入された場合、増幅器5の
立上り特性等から決まる一定時間の間は光強度信号6が
発生しないため、電流制御回路2の出力電流はI?間的
に最大となり、半導体レーザー1を破壊する可能性があ
る。そこで、第2図のAあるいはBに示すような時限信
号を擬似的な光検出信号となし、これを光強度信号6に
加算する。第2図においてtoを増幅器5の立上り特性
等から決まる無制御時間、Vo を光強度設定値とする
と、少なくともto より長いFR間にVQ より大き
い擬似的な光検出信号を発生させれば、この間、電流制
御回路2の出力電流は零どなっている。Considering the case where the one-time signal generation circuit 7 is not provided in the above configuration, when the power is turned on momentarily, the light intensity signal 6 is not generated for a certain period of time determined by the rise characteristics of the amplifier 5, etc., so the current Is the output current of control circuit 2 I? There is a possibility that the damage will reach a maximum in time and destroy the semiconductor laser 1. Therefore, a time signal such as that shown at A or B in FIG. 2 is used as a pseudo light detection signal, and this is added to the light intensity signal 6. In FIG. 2, if to is the uncontrolled time determined from the rise characteristics of the amplifier 5, and Vo is the light intensity setting value, then if a pseudo photodetection signal larger than VQ is generated between at least FRs longer than to, then during this period , the output current of the current control circuit 2 has become zero.
口の時間以後は、擬似信号を漸次減少させれば、光検出
信号による電流制御が動作した状態で光強度設定値10
に向かつてレーザー光が強度を増し、設定値に達した所
で一定に制御される。After the opening time, if the pseudo signal is gradually decreased, the light intensity setting value is 10 while the current control based on the photodetection signal is activated.
The intensity of the laser beam increases as it approaches the target, and is controlled at a constant level when it reaches the set value.
したがって、時限信号発生回路7が付加されている本駆
動装置によれば、瞬間的な電源投入に対しても半導体レ
ーザー1を破壊する心配が全熱ない。Therefore, according to the present driving device to which the time signal generating circuit 7 is added, there is no risk of destroying the semiconductor laser 1 even when the power is turned on momentarily.
また、第1図において、検出器5の出力側、即ち光強度
信号6に餐告ランプ12の駆動回路13を接続し、レー
ザー光が発生Jれば直ちに警告ランプ12が点灯できる
ように構成する。この構成ににれば、特に赤外発光半導
体レーザーを使用する場合の安全性を高めることができ
る。Further, in FIG. 1, a drive circuit 13 for a warning lamp 12 is connected to the output side of the detector 5, that is, a light intensity signal 6, so that the warning lamp 12 can be turned on immediately if a laser beam is generated. . With this configuration, safety can be particularly improved when using an infrared-emitting semiconductor laser.
次に、半導体レーザー1の光強度を高周波変調する構成
を説明すると、第1図において、14は変調信号源、1
5は変調信号源14のインピーダンス、1Gは高周波同
軸ケーブル、17は抵抗、18はコンデンサであって、
ごれらの部材によって111周波変調信号を前述した電
流制御回路2の出力側に供給する伝送回路系19が構成
される。しかして、高周波信号を伝送する場合には、一
般に入出力のインピーダンスをケーブルのインピーダン
スに一致させる必要がある。半導体レーザー1の電圧−
電流特性は第3図のように非線形であるから、RL−Δ
V/ΔIとして、このRLとの和が同軸ケーブルの特性
インピーダンスとなるような抵抗17及び直流分をカッ
トするためのフンデンサ18を接続する。このような回
路イに成によって、高周波変調信号に比例して半導体レ
ーザー1の1lffi流が変化することになる。また、
平均的な光強度は検出器4と電流制御回路2によって光
強度設定値に制御されているため、過大な変調信号が印
加された場合でも半導体レーザー1を破壊する心配は殆
んどない。Next, to explain the configuration for high-frequency modulating the light intensity of the semiconductor laser 1, in FIG. 1, 14 is a modulation signal source;
5 is the impedance of the modulation signal source 14, 1G is a high frequency coaxial cable, 17 is a resistor, 18 is a capacitor,
These members constitute a transmission circuit system 19 that supplies the 111 frequency modulation signal to the output side of the current control circuit 2 described above. Therefore, when transmitting high frequency signals, it is generally necessary to match the input and output impedance to the impedance of the cable. Voltage of semiconductor laser 1 -
Since the current characteristics are nonlinear as shown in Figure 3, RL-Δ
As V/ΔI, a resistor 17 such that the sum with this RL becomes the characteristic impedance of the coaxial cable and a capacitor 18 for cutting the DC component are connected. By constructing such a circuit A, the 1lffi current of the semiconductor laser 1 changes in proportion to the high frequency modulation signal. Also,
Since the average light intensity is controlled to the light intensity setting value by the detector 4 and the current control circuit 2, there is almost no fear that the semiconductor laser 1 will be destroyed even if an excessive modulation signal is applied.
本発明は上記の如くであって、半導体レーザーを破II
る心配がなく、光強度を制御できることは勿論のこと、
簡単に高周波変調することが可能であつ−C1更に、使
用時の安全性も十分に確保できる駆動装置を提供できる
ものであって、半導体レーザーの普及に大きく貢献でき
る等、その実用的価値(よ極めて多大である。The present invention is as described above, and the semiconductor laser is
Of course, you can control the light intensity without worrying about
It is possible to provide a drive device that can easily perform high-frequency modulation, and also ensures sufficient safety during use, and its practical value (such as greatly contributing to the spread of semiconductor lasers) It is extremely large.
第1匍は本発明の一実施例の構成図、第2図は時限信号
の説明図、第3図は半導体レーザーの電圧−電流の特性
図、第4図は半導体レーザーの電流−光強度の特性図で
ある。
図中、1は半導体レーザー、2は電流制御回路、4は光
出力検出器、7は時限信号発生回路、12は警告ランプ
、13は駆動回路、19は伝送回路系である。
特許出願人 山 1)英 彦
第1図
Q
ュ 第2図
第3図 第4図The first figure is a configuration diagram of an embodiment of the present invention, the second figure is an explanatory diagram of a time signal, the third figure is a voltage-current characteristic diagram of a semiconductor laser, and the fourth figure is a diagram of a semiconductor laser current-light intensity characteristic. It is a characteristic diagram. In the figure, 1 is a semiconductor laser, 2 is a current control circuit, 4 is an optical output detector, 7 is a time signal generation circuit, 12 is a warning lamp, 13 is a drive circuit, and 19 is a transmission circuit system. Patent applicant Yama 1) Hidehiko Figure 1 Q Figure 2 Figure 3 Figure 4
Claims (3)
出力が一定になるように半導体レーザーに流れる電流を
制御する電流制御回路から構成される半導体レーザー駆
動装置において、上記検出器と電流制御回路どの間には
電源投入から一定時間に亘って擬似的な光検出信号を発
生させる時限信号発生回路を付加して成ることを特徴と
する半導体レーザー駆動装置。(1) In a semiconductor laser drive device consisting of a semiconductor laser optical output detector and a current control circuit that controls the current flowing through the semiconductor laser so that the output of the detector is constant, 1. A semiconductor laser driving device characterized in that a time-limited signal generation circuit is added between the circuits to generate a pseudo photodetection signal for a certain period of time after power is turned on.
出力が一定になるように半導体レーザーに流れる電流を
制御する電流制御回路がら構成される半導体レーザー駆
動装置において、上記検出器と電流i!fi11回路と
の間には電源投入から一定時間に亘って擬似的な光検出
信号を発生させる時限信号発生回路を、また上記検出器
の出力側には警告ランプを点灯させる駆動回路をそれぞ
れ付加して成ることを特徴とする半導体レーザー駆動装
置。(2) In a semiconductor laser drive device that includes a semiconductor laser optical output detector and a current control circuit that controls the current flowing through the semiconductor laser so that the output of the detector is constant, the detector and the current i ! A time signal generation circuit that generates a pseudo light detection signal for a certain period of time after the power is turned on is connected to the fi11 circuit, and a drive circuit that lights up a warning lamp is added to the output side of the detector. A semiconductor laser drive device characterized by comprising:
出力が一定になるように半導体レーザーに流れる電流を
制御する電流制御回路から構成される半導体レーザー駆
動装置において、上記検出器と電流制御回路との間には
電源投入から一定時間に亘って擬似的な光検出信号を発
生させる時限信号発生回路を、また上記電流制御回路の
出力側には該出力に高周波変調信号を供給する伝送回路
系をそれぞれ付加して成ることを特徴とする半導体レー
ザー駆動装置。(3) In a semiconductor laser drive device consisting of a semiconductor laser optical output detector and a current control circuit that controls the current flowing through the semiconductor laser so that the output of the detector is constant, the detector and the current control circuit are provided. A time-limited signal generation circuit that generates a pseudo photodetection signal for a certain period of time after power-on is connected between the circuit and the output side of the current control circuit, and a transmission circuit that supplies a high-frequency modulation signal to the output. A semiconductor laser drive device characterized in that it is formed by adding systems.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2723684A JPS60171778A (en) | 1984-02-17 | 1984-02-17 | Driving device for semiconductor laser |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2723684A JPS60171778A (en) | 1984-02-17 | 1984-02-17 | Driving device for semiconductor laser |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS60171778A true JPS60171778A (en) | 1985-09-05 |
Family
ID=12215433
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2723684A Pending JPS60171778A (en) | 1984-02-17 | 1984-02-17 | Driving device for semiconductor laser |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS60171778A (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS543661U (en) * | 1977-06-10 | 1979-01-11 | ||
JPS54142987A (en) * | 1978-04-28 | 1979-11-07 | Hitachi Ltd | Protecting method from overdrive of semiconductor laser |
JPS5543898A (en) * | 1978-09-22 | 1980-03-27 | Siemens Ag | Method of adjusting laser diode bias current |
-
1984
- 1984-02-17 JP JP2723684A patent/JPS60171778A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS543661U (en) * | 1977-06-10 | 1979-01-11 | ||
JPS54142987A (en) * | 1978-04-28 | 1979-11-07 | Hitachi Ltd | Protecting method from overdrive of semiconductor laser |
JPS5543898A (en) * | 1978-09-22 | 1980-03-27 | Siemens Ag | Method of adjusting laser diode bias current |
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