JPS61265884A - Drive for semiconductor laser - Google Patents
Drive for semiconductor laserInfo
- Publication number
- JPS61265884A JPS61265884A JP60108507A JP10850785A JPS61265884A JP S61265884 A JPS61265884 A JP S61265884A JP 60108507 A JP60108507 A JP 60108507A JP 10850785 A JP10850785 A JP 10850785A JP S61265884 A JPS61265884 A JP S61265884A
- Authority
- JP
- Japan
- Prior art keywords
- pulse
- semiconductor laser
- iop
- light emission
- current
- 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
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
- H01S5/06213—Amplitude modulation
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
- Dot-Matrix Printers And Others (AREA)
- Laser Beam Printer (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、半導体レーザの駆動方法に関し、特にレー
ザビームプリンタ、レーザファクシミリ、光ディスク等
の光情報機器の光源に用いるのに適した半導体レーザの
駆動方法に関する。Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for driving a semiconductor laser, and in particular to a method for driving a semiconductor laser suitable for use as a light source for optical information equipment such as a laser beam printer, a laser facsimile, and an optical disk. Regarding the driving method.
（従来の技術）
従来の屈折型、反射型の光学素子に対して、回折型の光
学素子は複製が容易で安価に量産できることから産業上
利用され始めている０例えば、スーパ・−マーケットの
バーフード読取装置やレーザビームプリンタに用いられ
ているホログラフィックレーザスキャナをあげることが
できる。レーザビームプリンタのレーザスキャナに用い
た一例として、岩岡秀人、塩沢隆広著の電子通信学会発
行の電子通信学会技術研究会報告第８４巻第１９３号（
１９８４年１１月１９日発行）の２５〜３２頁記載の論
文「直線・無収差ホログラム・スキャナ」（論文番号０
ＱＥ８４−８６）がある。回折型の光学素子を用いると
、光源であるレーザの波長が変化すると、光学素子の出
力光の方向が変わってしまう。上にあげたレーザビーム
プリンタのレーザスキャナの例では、走査線の位置変動
を生じる。半導体レーザの発振波長は、活性層の屈折率
の温度変化、及び活性層のバンドギャップの温度変化に
よって生じる。前者は０．５〜０．８人／にのゆるやか
な変化であるが、後者は２〜５人／にと大きく、又、縦
モードの３〜８人のとびを生じる。そこで、上にあげた
論文では、半導体レーザのバイアス電流と、パルスのデ
ユーティ比を制御して、発光時と非発光時とにかかわら
ず消費電力を一定にすることにより、半導体レーザの温
度を安定化し、発振波長を安定化する方法が述べられて
いる。(Prior Art) Compared to conventional refractive and reflective optical elements, diffractive optical elements are easier to replicate and can be mass-produced at a lower cost, so they are beginning to be used industrially. Examples include holographic laser scanners used in reading devices and laser beam printers. As an example of a laser scanner used in a laser beam printer, Hideto Iwaoka and Takahiro Shiozawa, IEICE Technical Study Group Report Vol. 84, No. 193, published by IEICE,
Published on November 19, 1984), pages 25-32 of the paper ``Linear, aberration-free hologram scanner'' (paper number 0).
QE84-86). When a diffractive optical element is used, when the wavelength of the laser that is the light source changes, the direction of the output light of the optical element changes. In the example of a laser scanner in a laser beam printer given above, variations in the position of the scan line occur. The oscillation wavelength of a semiconductor laser is caused by a temperature change in the refractive index of the active layer and a temperature change in the band gap of the active layer. The former has a gradual change of 0.5 to 0.8 people/person, but the latter has a large change of 2 to 5 people/person, and also causes a jump of 3 to 8 people/person in the vertical mode. Therefore, in the above-mentioned paper, the temperature of the semiconductor laser is stabilized by controlling the bias current of the semiconductor laser and the pulse duty ratio to keep the power consumption constant regardless of whether it is emitting light or not. A method for stabilizing the oscillation wavelength is described.
第２図は従来の半導体レーザ駆動方法における半導体レ
ーザの駆動電流波形を示す図である。本図に示すように
、この駆動方法は、Ｔ、が本来の発光時間であるが、Ｔ
、の内を高速変調する方法である。半導体レーザの非発
光時には、バイアス電流Ｉｂを流している。Ｉｎは発振
閾値電流である。半導体レーザの動作電圧ｖ、、はほぼ
一定であるから、発光時（パルス幅Ｔ、）と非発光時の
消費電力の差は
Ｐ＋ ＝Ｄ−Ｖ−・Ｉ−−−Ｖ−・Ｌ （
１）となる。ここにＬｐは半導体レーザの動作電流、Ｄ
は高速変調時の変調のデユーティ比である。FIG. 2 is a diagram showing a driving current waveform of a semiconductor laser in a conventional semiconductor laser driving method. As shown in this figure, in this driving method, T is the original light emission time, but T
, is a method of high-speed modulation. When the semiconductor laser is not emitting light, a bias current Ib is passed through the semiconductor laser. In is the oscillation threshold current. Since the operating voltage v,, of the semiconductor laser is almost constant, the difference in power consumption when emitting light (pulse width T,) and when not emitting light is P+ = D−V−・I−−−V−・L (
1). Here, Lp is the operating current of the semiconductor laser, and D
is the modulation duty ratio during high-speed modulation.
（１）式で、Ｄ・工、、ｍ１．と選ぶと、発光時と非発
光時との消費電力が等しくなり、半導体レーザの温度が
安定化され、一定した発振波長のレーザ光が得られる。In equation (1), D. Eng., m1. If this is selected, the power consumption during light emission and non-light emission becomes equal, the temperature of the semiconductor laser is stabilized, and laser light with a constant oscillation wavelength is obtained.
（発明が解決しようとする問題点）
上述の従来の技術には、次のような問題点がある。上に
あげた論文に開示されている定電力駆動方式では、例え
ば、画像記録装置で濃淡記録を行なうために発光パルス
幅変調の積分光エネルギを変えようとすると、Ｄ・工、
、は変化させられないので、発光幅即ちτ、を変えるＰ
ＷＭ （パルス幅変調）をとらざるを得ない。しかしこ
の場合、レーザビームプリンタやレーザファクシミリの
ようにレーザビームを走査しながら画像記録を行なうと
、記録ドツトが走査方向へ長円化してしまう。(Problems to be Solved by the Invention) The above-mentioned conventional techniques have the following problems. In the constant power driving method disclosed in the above-mentioned paper, for example, when trying to change the integrated optical energy of light emission pulse width modulation in order to record gradations in an image recording device, D.
, cannot be changed, so P changes the emission width, that is, τ.
WM (pulse width modulation) must be used. However, in this case, if an image is recorded while scanning with a laser beam as in a laser beam printer or a laser facsimile, the recorded dots become oval in the scanning direction.
そこで、本発明の目的は、このような従来技術の問題点
を解決し、発光幅Ｔ、を一定にして発光パルスの積分エ
ネルギを変えても安定な波長で半導体レーザが発振させ
られる半導体レーザの駆動方法の提供にある。SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a semiconductor laser that can oscillate at a stable wavelength even when the emission width T is constant and the integral energy of the emission pulse is changed. The purpose is to provide a driving method.
（問題点を解決するための手段）
前述の問題点を解決するために本発明が提供する手段は
、パルス発光をする半導体レーザの駆動方法であって、
前記半導体レーザの非発光時にはバイアス電流Ｉｂを流
し、発光時にはデユーティ比りのパルス電流で高速変調
し、そのパルス電流の波高値及びオフセット値をそれぞ
れ工、、及びＬａとするとき、 Ｄ−Ｉ、、＋ （１−
Ｄ）・１．、−１．をほぼ零にし、Ｄ・１．、＋（１−
Ｄ）・１０．を一定にすることを特徴とする。(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems is a method of driving a semiconductor laser that emits pulsed light, comprising:
When the semiconductor laser is not emitting light, a bias current Ib is passed through it, and when it is emitting light, it is modulated at high speed with a pulse current corresponding to the duty ratio, and the peak value and offset value of the pulse current are respectively expressed as D-I, , + (1-
D)・1. , -1. to almost zero, D.1. , +(1-
D)・10. It is characterized by keeping constant.
（作用）
本発明の作用・原理は次の通りである０発光パルス内を
高速変調する時に、従来方法では電流値を０と１．、と
の間で変調していたが、本発明では、オフセット電流Ｌ
ｍと１．、との間で変調している。(Operation) The operation and principle of the present invention is as follows.When performing high-speed modulation within a 0 emission pulse, the conventional method changes the current value between 0 and 1. , but in the present invention, the offset current L
m and 1. , it modulates between.
従って、発光時の消費電力Ｐ、は、
Ｐｇ−Ｄ−Ｖ、、−１，、＋（１−Ｄ）Ｖ、−１，、（
２）となる、この電力Ｐ、はもちろん非発光時の消費電
力
Ｐ畠−Ｖｅｐ・１、 （３）と
等しくなければならないが、Ｄ ｆ ｘ＊、 ｌ Ｉｓ
・を調整すればＰ、を変化することなく、発光時の積分
光エネルギを変え得る。従って、半導体レーザの消費電
力を一定のまま、ＰＷＭによらずとも、即ち発光幅Ｔ、
を一定にしたままで、濃淡記録に必要な光エネルギの変
調ができる。Therefore, the power consumption P during light emission is Pg-D-V,,-1,,+(1-D)V,-1,,(
2), this power P must of course be equal to the power consumption during non-emission P Hatake-Vep・1, (3), but D f x *, l Is
By adjusting P, the integrated optical energy at the time of light emission can be changed without changing P. Therefore, without using PWM while keeping the power consumption of the semiconductor laser constant, that is, the emission width T,
It is possible to modulate the light energy necessary for gradation recording while keeping the value constant.
（実施例）
次に、本発明の実施例について図面を参照して説明する
。第１図は本発明の一実施例における駆動電流波形を示
す図である。本実施例では、（２）、（３）式のＰ ｔ
−Ｐ ｓの条件のパルス波形で駆動している。第１図
の右側のパルス電流波高値１０．′の発光パルスは、左
側のパルス電流波高値工、、の発光パルスよりも積分光
エネルギの小さい発光パルスであり、（２）式のＰ、が
一定の条件Ｄ−Ｖ、、 −１，、＋ （１−Ｄ） −Ｖ
、、 −Ｉ、、−Ｄ−Ｖ、、−１，、’＋ （１−Ｄ）
−Ｖ、、−１，、ｉ （４）を満たすようにＤを一定
のまま電流波高値を１．、′に、オフセット電流を１０
．′に変化させている。この結果、Ｐ、は一定となり、
発光パルスの積分エネルギを、定消費電力の条件下に変
え得る。そこで、本実施例を適用すれば、発光幅Ｔ、を
一定にして発光パルスの積分エネルギを変えても安定な
波長で半導体レーザを発振させることができる。(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a drive current waveform in an embodiment of the present invention. In this example, P t in equations (2) and (3)
It is driven with a pulse waveform under the condition of -Ps. Pulse current peak value 10 on the right side of Figure 1. The light emitting pulse ′ has a smaller integrated optical energy than the light emitting pulse with the pulse current peak value on the left, , and under the condition that P in equation (2) is constant DV, , −1, , + (1-D) -V
,, -I,, -D-V,, -1,,'+ (1-D)
-V, , -1,,i The current peak value is set to 1.D while keeping D constant so as to satisfy (4). ,', the offset current is set to 10
．． ’. As a result, P becomes constant,
The integrated energy of the emission pulse can be varied under conditions of constant power consumption. Therefore, by applying this embodiment, the semiconductor laser can be oscillated at a stable wavelength even if the emission width T is kept constant and the integral energy of the emission pulse is changed.
（発明の効果）
以上に詳しく説明したように、本発明の半導体レーザの
駆動方法を用いることにより、発光幅を一定にしたまま
で発光パルスの積分エネルギを変えても、半導体レーザ
のチップ内温度が一定化され、回折型光学素子の光源に
使用できる安定した発振波長のレーザ光が得られる。(Effects of the Invention) As explained in detail above, by using the semiconductor laser driving method of the present invention, even if the integral energy of the light emission pulse is changed while keeping the light emission width constant, the temperature inside the semiconductor laser chip remains constant. is made constant, and a laser beam with a stable oscillation wavelength that can be used as a light source for a diffractive optical element is obtained.
第１図は本発明の一実施例における駆動電流波形を示す
図、第２図の従来の半導体レーザ駆動方法における駆動
電流波形を示す図である。
ＬｐｔＬｔｏ・・・パルス電流波高値、１８．・・・発
振閾値電流、■、・・・非発光時バイアス電流、Ｌａ
Ｆ Ｌａ゛・・・・・・オフセット電流、τ、・・・発
光パルス幅。
第１図
時Ｐ−
第２図
Ｂ守聞FIG. 1 is a diagram showing a driving current waveform in an embodiment of the present invention, and FIG. 2 is a diagram showing a driving current waveform in a conventional semiconductor laser driving method. LptLto...Pulse current peak value, 18. ...Oscillation threshold current, ■, ...Bias current when not emitting light, La
F La゛...Offset current, τ,...Emission pulse width. Figure 1 Time P - Figure 2 B Shumon
Claims (1)
記半導体レーザの非発光時にはバイアス電流Ｉ＿ｂを流
し、発光時にはデューティ比Ｄのパルス電流で高速変調
し、そのパルス電流の波高値及びオフセット値をそれぞ
れＩ＿ｏ＿ｐ及びＩ＿ｏ＿ａとするとき、Ｄ・Ｉ＿ｏ＿
ｐ＋（１−Ｄ）・Ｉ＿ｏ＿ａ−Ｉ＿ｂをほぼ零にし、Ｄ
・Ｉ＿ｏ＿ｐ＋（１−Ｄ）・Ｉ＿ｏ＿ａを一定にするこ
とを特徴とする半導体レーザの駆動方法。In a method for driving a semiconductor laser that emits pulsed light, a bias current I_b is passed through the semiconductor laser when it is not emitting light, and when it is emitting light, it is modulated at high speed with a pulsed current having a duty ratio D, and the peak value and offset value of the pulsed current are set to I_o_p and offset value, respectively. When I_o_a, D・I_o_
Let p+(1-D)・I_o_a-I_b be almost zero, and D
- A semiconductor laser driving method characterized by keeping I_o_p+(1-D)·I_o_a constant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60108507A JPS61265884A (en) | 1985-05-20 | 1985-05-20 | Drive for semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60108507A JPS61265884A (en) | 1985-05-20 | 1985-05-20 | Drive for semiconductor laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61265884A true JPS61265884A (en) | 1986-11-25 |
Family
ID=14486531
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60108507A Pending JPS61265884A (en) | 1985-05-20 | 1985-05-20 | Drive for semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61265884A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100871057B1 (en) | 2007-07-10 | 2008-11-27 | 김정수 | Method for driving of a crystal laser diode |
-
1985
- 1985-05-20 JP JP60108507A patent/JPS61265884A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100871057B1 (en) | 2007-07-10 | 2008-11-27 | 김정수 | Method for driving of a crystal laser diode |
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