JPH01302788A - Semiconductor laser driving system - Google Patents
Semiconductor laser driving systemInfo
- Publication number
- JPH01302788A JPH01302788A JP63055747A JP5574788A JPH01302788A JP H01302788 A JPH01302788 A JP H01302788A JP 63055747 A JP63055747 A JP 63055747A JP 5574788 A JP5574788 A JP 5574788A JP H01302788 A JPH01302788 A JP H01302788A
- Authority
- JP
- Japan
- Prior art keywords
- current
- optical output
- feedback loop
- semiconductor laser
- digital
- 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.)
- Granted
Links
- 239000004065 semiconductor Substances 0.000 title claims description 17
- 230000003287 optical effect Effects 0.000 claims description 32
- 238000010586 diagram Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 2
- 238000013139 quantization Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 235000013372 meat Nutrition 0.000 description 1
- 230000002123 temporal effect 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
- H01S5/062—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
-
- 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
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/10—Controlling the intensity of the light
- H05B45/12—Controlling the intensity of the light using optical feedback
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/10—Controlling the intensity of the light
- H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
-
- 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
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/042—Electrical excitation ; Circuits therefor
-
- 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
- H01S5/0617—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium using memorised or pre-programmed laser characteristics
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
この発明は、半導体レーザを駆動する方法に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for driving a semiconductor laser.
〈従来の技術〉
半導体レーザは、ある種のＰＮ接合に順方向電流■Ｆを
流子ことによりレーザ光を得るもので、■、と光出力Ｐ
Ｏとの関係はリニアでなく、ＩＦを増加していくと、あ
る電流Ｉ ｔｈでレーザ発振が始まり、以後はＩＦの増
加と共にレーザ光出力Ｐｏ も増加する。この特性を
第２図に示す。<Prior art> A semiconductor laser obtains laser light by passing a forward current F through a type of PN junction, and the optical output P is
The relationship with O is not linear; as IF is increased, laser oscillation begins at a certain current I th , and thereafter, as IF increases, laser light output Po also increases. This characteristic is shown in FIG.
ところが、７ ｔｈ＋微分効率ηと呼ばれるＩＰの変化
に対するＰＯの変化の割合は一定ではなく、周囲温度や
個体によって変化する。However, the ratio of the change in PO to the change in IP, called 7th+differential efficiency η, is not constant and changes depending on the ambient temperature and the individual.
このような半導体レーザを一定光出力で駆動するために
、第３図に示す方式が一般に用いられている。１は半導
体レーザで、増幅器３の出力で制御される電流源４によ
って駆動される。ｌた光出力はホトダイオード２によっ
てモニタされ、第３図では抵抗５によって電圧に父換さ
れる。この電圧は増幅器３に入力され、全体で負帰還ル
ープを構成している。増幅器３の一方の入力には、基準
電圧Ｖｒｅｆが印加されておフ、結局光出力は基準電圧
で規定される一定値になる。In order to drive such a semiconductor laser with a constant optical output, a method shown in FIG. 3 is generally used. 1 is a semiconductor laser, which is driven by a current source 4 controlled by the output of an amplifier 3; The optical output is monitored by a photodiode 2 and converted into a voltage by a resistor 5 in FIG. This voltage is input to the amplifier 3, and the whole constitutes a negative feedback loop. A reference voltage Vref is applied to one input of the amplifier 3, and the optical output eventually becomes a constant value defined by the reference voltage.
第３図は、定常的に一定光出力を得るための構成である
が、ある種の応用においては、一定光出力を高速でオン
・オフする必要が生じる。その場合は例えば、第４図に
示す構成が用いられる。第４図は第３図の構成に、アナ
ログスイッチ７と静電容量８で構成されるサンプルホー
ルド回路と、高速電流スイッチ６、およびバッファアン
プ９を追加したものである。第４図の動作は次のような
ものである。まず、電流スイッチ６′ｆｆ：右側に、ス
イッチ７をオンにして、基準電圧Ｖｒｅｆで規定される
一定光出力を得る。次に７をオープンにする。Although FIG. 3 shows a configuration for constantly obtaining a constant light output, in certain applications, it becomes necessary to turn on and off the constant light output at high speed. In that case, for example, the configuration shown in FIG. 4 is used. FIG. 4 shows the configuration of FIG. 3 with the addition of a sample and hold circuit composed of an analog switch 7 and a capacitor 8, a high-speed current switch 6, and a buffer amplifier 9. The operation of FIG. 4 is as follows. First, the current switch 6'ff: on the right side, the switch 7 is turned on to obtain a constant optical output defined by the reference voltage Vref. Next, open 7.
このとき、ホールド容量８で電圧が保持されるので、半
導体レーザを駆動する電流は、変化しない。At this time, since the voltage is held by the hold capacitor 8, the current that drives the semiconductor laser does not change.
そうして電流スイッチ６を高速でオン・オフして、光出
力をオン・オフする。Then, the current switch 6 is turned on and off at high speed to turn on and off the optical output.
第４図の構成の場合、容量８でホールドされる電圧はア
ナログ量のため、長１守間一定値を保持するのは圏囃で
ある。長時間にわたって光出力を一定に保つことができ
るように考えられたのが次の第５図の駆動方法である。In the case of the configuration shown in FIG. 4, since the voltage held by the capacitor 8 is an analog quantity, it is the sound that maintains a constant value for the length of the length. The following driving method shown in FIG. 5 was designed to keep the optical output constant over a long period of time.
第５図は、第４肉のサンプルホールド部とバッファアン
プを除いて、アップ／ダウン・カウンタ１１とＤ／Ａ変
換器１０と発＠器１２を導入したもので、増幅器３はコ
ンパレータとして働く。アップ／ダウン・カウンタ１１
は、コンパレータ３の出力が“ＨＩＧＨ”の場合、発儀
器１２の出力パルスをカウントアツプして、逆に“ＬＯ
Ｗ“の場合カウントダウンする。カウント結果はＤ／Ａ
変換器１０でＩＦに変換され、レーザダイオードｌを駆
動する。＠５肉では、電流スイッチ６が右側に倒れた場
合に、全体として負帰還ループを構成して光出力は基準
電圧Ｖｒｅｆで規定される値になる。第５肉の場合１力
ウント分の誤差は生じるが、帰還ループ中にディジタル
コードとなる部分があるため、長時間ホールドについて
も問題ない。In FIG. 5, an up/down counter 11, a D/A converter 10, and an oscillator 12 are introduced, except for the fourth sample hold section and buffer amplifier, and the amplifier 3 functions as a comparator. Up/down counter 11
When the output of the comparator 3 is "HIGH", it counts up the output pulse of the trigger 12 and conversely becomes "LO".
If “W”, count down.The count result is D/A
It is converted into an IF by a converter 10 and drives a laser diode l. In @5 mode, when the current switch 6 falls to the right, a negative feedback loop is formed as a whole, and the optical output becomes a value defined by the reference voltage Vref. In the case of the fifth meat, an error equivalent to one force count occurs, but since there is a part that becomes a digital code in the feedback loop, there is no problem even when holding for a long time.
但し、前述のように半導体レーザのＩＦ−ｐｏ 特性
がリニアでないため、高精度で一定光出力を得るには、
高分解能のＤ／Ａ変換器が必要になる。However, as mentioned above, the IF-po characteristics of semiconductor lasers are not linear, so in order to obtain a constant optical output with high precision,
A high-resolution D/A converter is required.
〈発明が解決しようとする問題点〉
第５図の方式において、半導体レーザのＩＰ−ＰＯ特性
で、ＩＦがＩｔｈに満たない場合レーザ発振は起こらな
い。よって、ＩＦが１ｔｈ以下の領域は制御に用いるこ
とができない。そのために、ＩＦの量子化誤差に比べて
Ｐｏの量子化誤差は大きくなる。本発明は上述の問題点
を解決し、Ｐｏの制御精度を上げることを目的としてい
る。<Problems to be Solved by the Invention> In the system shown in FIG. 5, laser oscillation does not occur if IF is less than Ith due to the IP-PO characteristics of the semiconductor laser. Therefore, a region where the IF is 1th or less cannot be used for control. Therefore, the quantization error of Po becomes larger than the quantization error of IF. The present invention aims to solve the above-mentioned problems and improve the control accuracy of Po.
く問題点を解決するための手段〉
第１図は本発明のブロック図であって、第１図において
、１はレーザダイオード、２は光出力七二タ用のホトダ
イオード、３，１４１１コンパレータ、４，１３はそれ
ぞれ、Ｄ／Ａ変換器１０ 、１５で制御される電流源１
．５は抵抗、６は高速電流スイッチ、１１．１６はアッ
プ／ダウン・カウンタ、１２は発振器である。第１図は
、１，２，３．１１゜１０．４，６．１からなるフィー
ドバックループＡ１及びｌ、２．１４．１６，１５，１
３，６゜１からなるフィードバックループＢの２系統の
負帰還ループで構成されている。フィードバックループ
Ａで光出力の粗調整（大まかな調整）を行ない、フィー
ドバックループＢで微調整を行なう。1 is a block diagram of the present invention. In FIG. 1, 1 is a laser diode, 2 is a photodiode for optical output, 3, 1411 comparator, 4 , 13 are current sources 1 controlled by D/A converters 10 and 15, respectively.
．． 5 is a resistor, 6 is a high speed current switch, 11.16 is an up/down counter, and 12 is an oscillator. Figure 1 shows the feedback loop A1 and l, 2.14.16, 15,
It is composed of two negative feedback loops, feedback loop B consisting of 3.6°1. Feedback loop A performs coarse adjustment of the optical output, and feedback loop B performs fine adjustment.
〈作 用〉
第１因で、各負帰還ループの動作は第５図と同じである
が、基準電圧Ｉ Ｖｒｅｆ １は目的とする光出力ＰＯ
２より少し低い光出力Ｐｏｔを目標値として設定されて
おり、基準電圧２ Ｖｒｅｆ ２は目的とする光出力Ｐ
ｏ２を目標値として設定されている。<Function> For the first factor, the operation of each negative feedback loop is the same as in FIG. 5, but the reference voltage I Vref 1 is set to
The optical output Pot slightly lower than 2 is set as the target value, and the reference voltage 2 Vref 2 is the target optical output P.
o2 is set as the target value.
まず両方のカウンタ１１．１６’ｔ−リセットして、電
流源４．１３の電流をゼロにして、スイッチ６は右に倒
してフィードバックループＡを動作させる。このとき、
電流源４の電流は、光出力がＰｏｌになる電流ＩＦ１ｆ
、目標に増加して、やがて、ＩＦＩから±ΔＩ、□の範
囲で振動するようになる。ΔＩＦ□は（１）／Ａ変換器
１０がフルスケールにｌっ次場合の電流源４の電流）Ｘ
（Ｄ／Ａ変換器１０の分解能）、即ち、Ｄ／Ａ変換器１
０のＩＬＳＢに相当する電流源４の電流である。次にカ
ウンタ１１０カウントを停止して、その時点のカウント
値をホールドする。このとき電流源４の電流は、目標値
ＩＦＩから±ΔＩＦＩの範囲内の定電流ＩＦＩ’になる
。次にフィードバックループＢを動作さぜる。First, both counters 11.16't- are reset, the current of the current source 4.13 is made zero, and the switch 6 is turned to the right to operate the feedback loop A. At this time,
The current of the current source 4 is a current IF1f at which the optical output becomes Pol.
, increases to the target, and eventually begins to oscillate within the range of ±ΔI, □ from IFI. ΔIF□ is (1)/current of current source 4 when A converter 10 is at full scale)X
(Resolution of D/A converter 10), that is, D/A converter 1
This is the current of the current source 4 corresponding to an ILSB of 0. Next, the counter 110 stops counting and holds the count value at that point. At this time, the current of the current source 4 becomes a constant current IFI' within the range of ±ΔIFI from the target value IFI. Next, feedback loop B is activated.
レーザダイオード１の駆動電流は、ＩＦＩ’に電流源１
３の電流が加算され、電流源１３の電流は光出力がＰＯ
２になる値ＩＦ２を目標に増加して、フィードバックル
ープＡの場合と同様にＩＦ２から±ΔＩＦ２の範囲で振
動するようになる。ここにΔＩＦ２は、Ｄ／Ａ変換器１
５のＩＬＳＢ相当の電流源１３の電流である。ここで、
カウンタ１６のカウント動作を停止して、カウント値を
ホールドすると、電流源１３の電流は、その目標値ＩＦ
２から±ΔＩＦ２の範囲内の定’ＲＩＦ２’となる。結
局レーザダイオード１の駆動電流は、ＩＦ！’＋ＩＦ２
’になり、その目標値からの誤差は、フィードバックル
ープＡには依存せず、フィードバックループＢでの誤差
のみ、即ち、±ΔＩＦ２以内となる。Ｄ／Ａ変換器１５
がフルスケールになっ九場合の電流源１３の電流は、ｒ
ｐｔに比べて小さく選ぶことが可能なので、ΔＩＦ２Ｖ
ｉ、１系統で同一分解能のＤ／Ａ変換器を使用する場合
に比較して、非常に小さくすることができ、光出力Ｐｏ
を高精度で制仰できる。The driving current of laser diode 1 is supplied from current source 1 to IFI'.
3 are added, and the current of current source 13 is such that the optical output is PO
The value IF2 is increased to a value of 2, and as in the case of the feedback loop A, it comes to oscillate within the range of ±ΔIF2 from IF2. Here, ΔIF2 is D/A converter 1
This is the current of the current source 13 corresponding to ILSB of 5. here,
When the counting operation of the counter 16 is stopped and the count value is held, the current of the current source 13 increases to its target value IF.
2 to ±ΔIF2. In the end, the driving current of laser diode 1 is IF! '+IF2
', and the error from the target value does not depend on the feedback loop A, but only the error in the feedback loop B, that is, within ±ΔIF2. D/A converter 15
The current of current source 13 when is at full scale is r
Since it is possible to select a smaller value than pt, ΔIF2V
i.Compared to using D/A converters with the same resolution in one system, the optical output Po can be made very small.
can be controlled with high precision.
以上の様子は第６図を参照されたい。尚基準電圧ＩＶｒ
ｅｆを目的とする光出力ＰＯ２より少し高い値に設定し
て、１πい側から目的の光出力に接近させる場合と同様
である。Please refer to FIG. 6 for the above situation. Furthermore, the reference voltage IVr
This is similar to the case where ef is set to a value slightly higher than the target optical output PO2 and the target optical output is approached from the 1π smaller side.
〈実施例〉
第７図に本発明の実施例を示す。第１図の電流スイッチ
６を１０６で構成、電流源４．１３をそれぞれ１０４．
１１３で構成している。なお、′第ｘｌＤのコンパレー
タ３，１４および基準電圧１、基準電圧２は、第７図で
は、コンパレータ１０３と基準電圧Ｖｒｅｆ、および抵
抗Ｒ１＊ Ｒ２＊ Ｒｓと、トランジスタＱｌでまとめ
である。表１は、コントロールロジックと、カウンタ１
，２、Ｑｌおよび電流スイッチ１０６の動作の対応表で
ある。<Example> FIG. 7 shows an example of the present invention. The current switch 6 in FIG. 1 is composed of 106, and the current sources 4.13 are each composed of 104.
It consists of 113. Note that the comparators 3, 14, reference voltage 1, and reference voltage 2 of the 'x1D are summarized in FIG. 7 by the comparator 103, the reference voltage Vref, the resistors R1*R2*Rs, and the transistor Ql. Table 1 shows the control logic and counter 1
, 2, Ql and the operation of the current switch 106.
カウンタ２は大まかな調整用、カウンタ１は微調整用で
、コントロール信号Ｒ及びＣが１０→１１→Ｏ１→００
で一連の光出力設定サイクルになっている。Counter 2 is for rough adjustment, counter 1 is for fine adjustment, and control signals R and C are 10 → 11 → O1 → 00.
This is a series of light output setting cycles.
表 １
その他の実施例を第８図に示す。溶９図は当該実施例に
おける調整動作の時間変化を示す図である。Table 1 Other examples are shown in FIG. Figure 9 is a diagram showing changes over time in the adjustment operation in this example.
第７図の前記実施例においてはフィードバックループＡ
（粗調整）の光出力目標値は最終的な光出力目標値以下
に設定されるが第８図の実施例ではフィードバックルー
プＡ（粗調整）の光出力目標値（ＰＯＩ ）は最終的な
光出力目標値（ＰＯ２）以上に設定される。In the embodiment of FIG. 7, the feedback loop A
The optical output target value (rough adjustment) is set to be less than the final optical output target value, but in the embodiment shown in FIG. It is set to be equal to or higher than the output target value (PO2).
表２は当該実施例における動作を表１に対応させて表わ
したものである。Table 2 shows the operation in this embodiment in correspondence with Table 1.
表 ２
更にその他の実施例を第１Ｏ図に示す。第１１図は当該
実施例の調整動作の時間変化を示す図である。表３は本
実施例における動作を表わしたものである。Table 2 Further examples are shown in FIG. 1O. FIG. 11 is a diagram showing changes over time in the adjustment operation in this embodiment. Table 3 shows the operation in this embodiment.
本実施例では粗調整時の光出力目標値は最終的な光出力
目標値と同値に設定する。この方式では８ｇ７図、！８
図の実施例に比べ基準電圧切換え回路（Ｒ１−Ｒ２，Ｒ
ｘ、Ｑｔ ）が不要となることなどの利点がある。In this embodiment, the optical output target value during rough adjustment is set to the same value as the final optical output target value. In this method, 8g7 figure,! 8
Compared to the embodiment shown in the figure, the reference voltage switching circuit (R1-R2, R
There are advantages such as no need for x, Qt).
なおフィードバックループＢ（微調整）を構成するカウ
ンタ１のイニシャライズＭはフルカウントのＨにセット
される。Note that the initialization M of the counter 1 constituting the feedback loop B (fine adjustment) is set to H, which is a full count.
表 ３
〈発明の効果〉
同一精度のシステムを、実現が容易な低分解能のＤ／Ａ
変換器で構成できるため、製品の低価格化が図れる。Table 3 <Effects of the invention> Low-resolution D/A system that is easy to realize with the same accuracy
Since it can be configured with a converter, it is possible to reduce the price of the product.
第１図は、２系統の負帰還ループで構成した半導体レー
ザ駆動回路を示す図。第２図は、レーザダイオードの順
方向電流ＩＦと光出力ＰＯとの関係を示す図。第３図は
、一定光出力を得るための半導体レーザ駆動ロ路ブロッ
ク例を示す図。第４図は、サンプルホールド回路を用い
た、一定光出力の高速スイッチングを行なうための半導
体レーザ駆動回路ブロック例を示す図。第５面は、光出
力設定フィードバックル−プにＤ／Ａｆ換器を挿入した
、一定光出力の高速スイッチングを行なうための半導体
レーザ駆動回路ブロック例を示す図。
第６図は、半導体レーザのドライブ電流の時間変化及び
ＩＦ ＰＯ特性（２系統）を示す図。第７図は、本発
明の実施例を示す図。第８図は、本発明による他の実施
例を示す図。第９図は同他の実施例における半導体レー
ザのドライブ電流の時間変化及びＩＦ ＰＯ特性（２
系統）を示す図。第１Ｏ図は本発明による更に他の実施
例を示す図。
＠１１図は同更に他の実施例における半導体レーザのド
ライブ電流の時間変化及びＩｐ Ｐｏ 特性図であ
る。
１．１０１・・・半導体レーザ（レーザダイオード〕、
２．１０２・・・光出力モニタ用ホトダイオード、３．
１０３・・・増幅器（コンパレータ）、４．１０４・・
・電流源、 ５，１０５・・・抵抗、６．１０６・・・
ａ速電流スイッチ、 ７・・・アナログスイッチ、 ８
・・・電圧ホールド用静電容量、９・・・バッファアン
プ、 １０，１１０・・・Ｄ／Ａ変換器、 １１．１
１１・・・アップ／ダウン・カウンタ、 １２．１１２
・・・発振器、 １３゜１１３・・・電流源、 １４・
・・増幅器（コンパレータ）、１５．１１５・・・Ｄ／
、Ａ変換器、 １６゜１１６・・・アップ／ダウン・カ
ウンタ。
代理人 弁理士 杉 山 毅 至（他１名）第２図
第３図
！
第４図
Ｊｚ
第５図
むυＰ。FIG. 1 is a diagram showing a semiconductor laser drive circuit configured with two negative feedback loops. FIG. 2 is a diagram showing the relationship between the forward current IF of the laser diode and the optical output PO. FIG. 3 is a diagram showing an example of a semiconductor laser drive path block for obtaining a constant optical output. FIG. 4 is a diagram showing an example of a semiconductor laser drive circuit block for performing high-speed switching with a constant optical output using a sample-and-hold circuit. The fifth side is a diagram showing an example of a semiconductor laser drive circuit block for performing high-speed switching of constant optical output, in which a D/Af converter is inserted in the optical output setting feedback loop. FIG. 6 is a diagram showing temporal changes in drive current of a semiconductor laser and IF PO characteristics (two systems). FIG. 7 is a diagram showing an embodiment of the present invention. FIG. 8 is a diagram showing another embodiment according to the present invention. FIG. 9 shows the time variation of the drive current of the semiconductor laser and the IF PO characteristics (2
Diagram showing the system. FIG. 1O is a diagram showing still another embodiment according to the present invention. Figure @11 is a diagram showing the time change of the drive current of the semiconductor laser and the Ip Po characteristics in the same still another example. 1.101...Semiconductor laser (laser diode),
2.102...Photodiode for optical output monitor, 3.
103...Amplifier (comparator), 4.104...
・Current source, 5,105...Resistance, 6.106...
A-speed current switch, 7...analog switch, 8
...Capacitance for voltage hold, 9...Buffer amplifier, 10,110...D/A converter, 11.1
11...Up/down counter, 12.112
...Oscillator, 13゜113...Current source, 14.
...Amplifier (comparator), 15.115...D/
, A converter, 16°116...up/down counter. Agent: Patent attorney Takeshi Sugiyama (and 1 other person) Figure 2
Figure 3! Figure 4 Jz Figure 5 MuυP.
Claims (1)
２個のＤ／Ａ変換器を有するシステムに於いて、１つの
Ｄ／Ａ変換器で光出力の粗調整を行ない、別のＤ／Ａ変
換器で微調整を行なって高精度の光出力を得ることを特
徴とする半導体レーザ駆動方式。1. In a system having at least two D/A converters in a feedback loop to obtain a constant optical output, one D/A converter performs coarse adjustment of the optical output, and another D/A converter performs coarse adjustment of the optical output. A semiconductor laser drive system characterized by fine adjustment using a converter to obtain highly accurate optical output.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63055747A JPH067614B2 (en) | 1987-04-13 | 1988-03-09 | Semiconductor laser drive system |
| EP92201060A EP0497431B1 (en) | 1987-04-13 | 1988-04-13 | An apparatus for driving a semiconductor laser device |
| DE3854202T DE3854202T2 (en) | 1987-04-13 | 1988-04-13 | Apparatus for operating a semiconductor laser device. |
| DE3854094T DE3854094T2 (en) | 1987-04-13 | 1988-04-13 | Apparatus for operating a semiconductor laser device. |
| DE8888303348T DE3879250T2 (en) | 1987-04-13 | 1988-04-13 | CONTROL DEVICE FOR A SEMICONDUCTOR LASER. |
| EP92201061A EP0497432B1 (en) | 1987-04-13 | 1988-04-13 | An apparatus for driving a semiconductor laser device |
| EP88303348A EP0287360B1 (en) | 1987-04-13 | 1988-04-13 | An apparatus for driving a semiconductor laser device |
| US07/368,106 US4912714A (en) | 1987-04-13 | 1989-06-19 | Apparatus for driving a semiconductor laser device |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9017187 | 1987-04-13 | ||
| JP62-90171 | 1988-02-05 | ||
| JP2588688 | 1988-02-05 | ||
| JP63-25886 | 1988-02-05 | ||
| JP63055747A JPH067614B2 (en) | 1987-04-13 | 1988-03-09 | Semiconductor laser drive system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01302788A true JPH01302788A (en) | 1989-12-06 |
| JPH067614B2 JPH067614B2 (en) | 1994-01-26 |
Family
ID=27285189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63055747A Expired - Fee Related JPH067614B2 (en) | 1987-04-13 | 1988-03-09 | Semiconductor laser drive system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH067614B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5568464A (en) * | 1993-11-18 | 1996-10-22 | Olympus Optical Co., Ltd. | Semiconductor laser driving apparatus utilizing three current sources to control read and write light power |
| US6975813B1 (en) | 1999-02-19 | 2005-12-13 | Fujitsu Limited | Light output control device |
| US7522494B2 (en) | 2003-08-27 | 2009-04-21 | Ricoh Company, Ltd | Control of laser emission power for recording information on optical disc |
| JP2018041938A (en) * | 2016-09-09 | 2018-03-15 | 株式会社リコー | Light source driving device, image forming apparatus, and light intensity control method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5821386A (en) * | 1981-07-30 | 1983-02-08 | Fujitsu Ltd | Controller for semiconductor laser |
| JPS6230466A (en) * | 1985-07-31 | 1987-02-09 | Ricoh Co Ltd | Regulating method for output of semiconductor laser |
| JPS6376572A (en) * | 1986-09-19 | 1988-04-06 | Ricoh Co Ltd | Optical scanning method |
-
1988
- 1988-03-09 JP JP63055747A patent/JPH067614B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5821386A (en) * | 1981-07-30 | 1983-02-08 | Fujitsu Ltd | Controller for semiconductor laser |
| JPS6230466A (en) * | 1985-07-31 | 1987-02-09 | Ricoh Co Ltd | Regulating method for output of semiconductor laser |
| JPS6376572A (en) * | 1986-09-19 | 1988-04-06 | Ricoh Co Ltd | Optical scanning method |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5568464A (en) * | 1993-11-18 | 1996-10-22 | Olympus Optical Co., Ltd. | Semiconductor laser driving apparatus utilizing three current sources to control read and write light power |
| US6975813B1 (en) | 1999-02-19 | 2005-12-13 | Fujitsu Limited | Light output control device |
| US7266308B2 (en) | 1999-02-19 | 2007-09-04 | Fujitsu Limited | Light output control circuit |
| US7522494B2 (en) | 2003-08-27 | 2009-04-21 | Ricoh Company, Ltd | Control of laser emission power for recording information on optical disc |
| JP2018041938A (en) * | 2016-09-09 | 2018-03-15 | 株式会社リコー | Light source driving device, image forming apparatus, and light intensity control method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH067614B2 (en) | 1994-01-26 |
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