JPS5860844A - Driving circuit for laser diode - Google Patents
Driving circuit for laser diodeInfo
- Publication number
- JPS5860844A JPS5860844A JP56159402A JP15940281A JPS5860844A JP S5860844 A JPS5860844 A JP S5860844A JP 56159402 A JP56159402 A JP 56159402A JP 15940281 A JP15940281 A JP 15940281A JP S5860844 A JPS5860844 A JP S5860844A
- Authority
- JP
- Japan
- Prior art keywords
- diode
- frequency
- laser diode
- transistor
- adjustment
- 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
- 230000000295 complement effect Effects 0.000 claims description 2
- 230000006866 deterioration Effects 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 230000005540 biological transmission Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000013307 optical fiber Substances 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 2
- 241000255925 Diptera Species 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 210000003813 thumb Anatomy 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
-
- 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
- H01S5/0427—Electrical excitation ; Circuits therefor for applying modulation to the laser
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
本発明はレーデダイオードの駆動回路に関する・近年の
光通信システムの進展に伴いレーデダイオードがその発
光源として広く用い、られるようになった。このレーデ
ダイオードよシ光信号を放射せしめる場合、該レーデメ
イオーＰＯ駆動回路にベースバンドの伝送信号を与え、
これをアナログ変調する。アナログ変調された光信号は
光フアイバー内を伝播し所定の受信装置に至る。この場
合、単にベースバンドのアナログ変調のみならず高周波
信号をも併せて重畳し丸形でアナログ変調する方法が試
みられている。このように高周波重量しなければならな
いのはレーデダイオードのコヒーレンシーの良さが逆に
悪影醤を与えているからである。りｔ〕、通常の発光ダ
イオードの如くコヒーレンシーが悪ければ光信号の輝度
は光７アイ／＃−〇端面において全頁に均一パターンを
形成する・七ζろがレーザダイオードはコヒーレンシー
が嵐いために、いわゆるス（ツクルノ譬ターンをその端
面に形成し、光信号の輝度にむらを生ずる。しか％、ソ
ノスペックルパターンは光ファイバーが動くのに応動し
て変化する。そうすると、光ファイバーを中継するコネ
クタ相互間で光の、伝達ロスを生ずることになる。つま
プコネクタの対れ両端面が常に完全に一致するように接
合することは稀であシ、コネクタ間で不完全に接合した
部分に光信号の高輝度部分が重なったとすると、光の伝
達ロスは極めて大となる。そこで、レーデダイオード０
持つ高速性（例えばＩ ＧＨｚ ）、高パワーという利
点を活かしつつコヒーレンシーを悪化させるために高周
波信号を重畳する。これは、レーデダイオードの光／母
ワ一対駆動電流特性に於て、レーデダイオードの発振閾
値電流以下からΔルス状の高周波電流で駆動するもので
、この方法にょシコヒーレンシーの悪さを持続させるも
のである。従って、重畳周波数が高い程コヒーレンシー
が悪くなる関係にある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive circuit for a Raded diode. With the recent development of optical communication systems, Raded diodes have come to be widely used as light emitting sources. When the radar diode emits an optical signal, a baseband transmission signal is given to the radar diode PO drive circuit,
This is analog modulated. The analog modulated optical signal propagates within the optical fiber and reaches a predetermined receiving device. In this case, a method has been attempted in which not only baseband analog modulation but also high frequency signals are superimposed and circular analog modulation is performed. The reason why it is necessary to increase the frequency at such high frequencies is that the good coherency of the radar diode has a negative effect. If the coherency is poor like a normal light emitting diode, the brightness of the optical signal will form a uniform pattern on all pages at the end face of the light. A so-called speckle pattern is formed on the end face of the optical fiber, causing uneven brightness of the optical signal. However, the speckle pattern changes in response to the movement of the optical fiber. It is rare for a pair of thumb connectors to be joined so that their end faces always match perfectly, and optical signal high If the brightness areas overlap, the transmission loss of light will be extremely large.Therefore, the radar diode 0
A high frequency signal is superimposed in order to deteriorate coherency while taking advantage of the high speed (for example, I GHz) and high power that it has. This is because the light/power pair driving current characteristics of the Raded diode are driven by a delta-like high-frequency current below the oscillation threshold current of the Raded diode, and this method maintains poor coherency. It is something. Therefore, the higher the superimposition frequency, the worse the coherency becomes.
ところで、上記の高周波重畳方式によるレーデダイオー
ドの駆動回路は、後に述べるとおシ、レーデダイオード
を含み且つ高周波信号で駆動される差動増幅器（高周波
駆動［ｌ）と、蚊差動増幅器と掛算回路を構成する低周
波（ベースバンド）駆動部とからなる。このために不都
合な問題を伴うことがある。この不都合な問題とはレー
デダイオードの駆動電流の調整が困難となることである
。By the way, as will be described later, the drive circuit for the Raded diode using the above-mentioned high-frequency superimposition method is composed of a differential amplifier (high-frequency drive [l) that includes the Raded diode and is driven by a high-frequency signal, a mosquito differential amplifier, and a multiplier. It consists of a low frequency (baseband) drive section that makes up the circuit. This can lead to inconvenient problems. This disadvantageous problem is that it becomes difficult to adjust the drive current of the radar diode.
つま如、この調整のために前記差動増幅器における、レ
ーザダイオードに直列接続する側のトランジスタを調整
する。わけであるが、ζ０調整に伴りてもう一方の側の
トランジスタの動作点も一緒に低周波駆動部のトランジ
スタの動作点も変動して ′しまりのである。かくの如
く（一箇所の調整にとどまらず他の箇所の調整も連動し
て行なわなければならないから、メインテナンス等に非
常、に不利となる。For this adjustment, the transistor connected in series to the laser diode in the differential amplifier is adjusted. However, as the ζ0 is adjusted, the operating point of the transistor on the other side as well as the operating point of the transistor in the low frequency drive section changes. In this way, it is not only necessary to adjust one location, but also to adjust other locations, which is extremely disadvantageous in terms of maintenance, etc.
従って本発明の目的は前記、の不利点を解消すべく、高
周波駆動部における調整が低周波駆動部の動作点に変更
を及ばずことの少ないレーデダイオードの駆動回路を提
案することである・上記目的に従い本発明は、レーデ−
ダイオードに直列接続し且つ低周波変調信号によシ駆動
されるトランジスタと、前記レーデダイオードと前記ト
ランジスタの中間接続点に出力が並列接続し且つ高周波
変調信号によｐ駆動される鏝相補性ト２ンジスタから成
るカレントスイッチ回路とから構成したことを特徴とす
るものである。Therefore, an object of the present invention is to propose a drive circuit for a Raded diode in which adjustment in the high-frequency drive section does not change the operating point of the low-frequency drive section in order to eliminate the above-mentioned disadvantages. In accordance with the above object, the present invention
a transistor connected in series with the diode and driven by a low frequency modulation signal; and a complementary transistor whose output is connected in parallel to an intermediate connection point between the radar diode and the transistor and driven by a high frequency modulation signal. It is characterized by being constructed from a current switch circuit consisting of two transistors.
以下図面に従って本発明を説明する。The present invention will be explained below with reference to the drawings.
第１図はレーザダイオードの駆動回路における高周波重
畳方式の意味を説明するため０グツ７である。本図にお
いて横軸はレーデダイオードの駆動電流（Ｉ）、縦軸は
レーデダイオードの光出力（Ｐ）である。図示するとお
）、一般に光出力ｐと電流■は略逆り字形状をなす。こ
のＬ字０折点ム（発振閾値電Ｒ）近傍よ〕、電流の大な
る領域ではコヒーレンシーが良く通常はこの領域で低周
波信号（伝送信号）の変調を行なう。図中低周波変調信
号を８ｍで表わす。ところが、コヒーレンシーが良好で
あると前述したスベ、クル／４ターンを光ファイ”パー
のＭＡ直に生じ光の伝達ロスを生ずる。FIG. 1 is a diagram 7 for explaining the meaning of the high frequency superimposition method in a laser diode drive circuit. In this figure, the horizontal axis is the drive current (I) of the Raded diode, and the vertical axis is the optical output (P) of the Raded diode. (as shown in the figure), the optical output p and the current (2) generally form a substantially inverted shape. In the vicinity of this L-shaped 0-point point (oscillation threshold voltage R), coherency is good in a region where the current is large, and a low frequency signal (transmission signal) is usually modulated in this region. In the figure, the low frequency modulation signal is represented by 8 m. However, when the coherency is good, the above-mentioned smoothness/curve/four-turn occurs directly at the MA of the optical fiber, resulting in light transmission loss.
そこで、前述した如く、光出力Ｐが前記点ムよシ小さな
値から高周波の変調を加える。このために尋人されたの
が高周波の変調信号８Ｍで＃）シ、これを高周波重畳方
式と称している。Therefore, as described above, high frequency modulation is applied starting from a value where the optical output P is smaller than the above point. For this purpose, a high frequency modulation signal of 8M was used, and this is called the high frequency superimposition method.
このよりな高周波重畳方式に基づく駆動回路は次のよう
に構成される。第２図は高周波重畳方式に基づ゛〈従来
のレーデダイオード駆゛動回路の一例を示゛す回路−で
ある。本図において、１１゛はレーデダイオードであシ
、高周波駆動部をなす差動増幅器（トランジスタ１２−
１．１２−２からなる）の一方のトランジスタ１２−１
に直列接続される。A drive circuit based on this higher frequency superimposition method is configured as follows. FIG. 2 is a circuit illustrating an example of a conventional radar diode driving circuit based on the high frequency superimposition method. In this figure, 11' is a radar diode, and a differential amplifier (transistor 12-
1.12-2), one of the transistors 12-1
connected in series.
そしてもう一方のトランジスタ１２−２のペースに高周
波変調信号ＳＮを印加する。この−差動増幅器にはさら
にトランジスタ′１３が直列接続し、そのベースには低
周波変調信号Ｓｌが印加される。すなわちこのトランジ
スタ１３が低周波駆動部を形成する。なお、ダイオード
１４はレーザダイオード１１を保１するためのもの、ト
ランジスタ１５゜はレーデダイオード１１の光出力を温
度変動に対し二定に維持するものであり、ＡＰＣ（Ａｔ
＋ｔｏｍａｔｉ＠Ｐｏｗ＠ｒ Ｃｏｎｔｒｏｌ ）信号
を入力とする。ただし、これらダイオード１４、トラン
ジスタ１５はレーザダイオードの駆動回路において一般
的な構成要素である。 ゛
ところで、使用に際し、レーデダイオード１１の駆動電
流を調整する必要があシ、例えばバイアス電源１６を調
整する。然しなから、既述のようにこの調整は単にトラ
ンジスタ１２−ＩＣ）調整に止まらず、差動増幅器の他
方のトランジスタ１２−２へもその変動が波及し、又、
高周波駆動部（１２−１゜１２−２）と掛算回路を形成
する低周波駆動のトランジスタ１３へも波及する。この
ために、従来は調整が困難であるという欠点を伴った。Then, a high frequency modulation signal SN is applied to the other transistor 12-2. A transistor '13 is further connected in series to this differential amplifier, and a low frequency modulation signal Sl is applied to its base. That is, this transistor 13 forms a low frequency drive section. Note that the diode 14 is used to maintain the laser diode 11, and the transistor 15° is used to maintain the optical output of the laser diode 11 constant against temperature fluctuations.
+tomati@Pow@r Control ) signal is input. However, these diode 14 and transistor 15 are common components in a laser diode drive circuit. By the way, in use, it is necessary to adjust the drive current of the radar diode 11, for example, adjust the bias power supply 16. However, as mentioned above, this adjustment is not limited to simply adjusting the transistor 12-IC), and the fluctuation also spreads to the other transistor 12-2 of the differential amplifier.
This also affects the low-frequency drive transistor 13 that forms a multiplication circuit with the high-frequency drive section (12-1 and 12-2). For this reason, the conventional method has had the disadvantage that adjustment is difficult.
そこで本発明はそのような欠点を排除すべく次のような
構成を提案する。第３図は本発明に基づくレーデダイオ
ードの駆動回路の一実施例を示す回路図である。本図中
第１図の構成要素と同一〇ものＫｔｉ同一の参照番号を
付して示す。本図から明らかなことは、本発明ではレー
デダイオード１１を中心にして高周波駆動部（カレント
スイッチ回路３１）と低周波駆動部（１３）とを分離し
九ことである。これによシ高周波駆動部の調整と低周波
駆動部の調整とが電気的に分離されるので一部の調整が
他に波及することがなくなる。この理由は２つある。第
１は、高周波変調信号８．に基づく駆動電流を、低周波
変調信号らに基づく駆動電流に対して流し込むような回
路形式（前記Ｏ掛算回路の形式でなりとじたこと。第２
にカレントスイッチ回路３１の出力（図中の０点に接続
する）のレベルが不動であることに基づく。Ｃ点Ｏ該レ
ベルはレーデダイオード１１の順方向電圧で規定される
からである。なおりレントスイッチ回路３１は、定電流
源３２、一対のトランジスタ３３−１゜３３−２からな
シ通常のカレントスイッチそのものである。Therefore, the present invention proposes the following configuration in order to eliminate such drawbacks. FIG. 3 is a circuit diagram showing an embodiment of a Raded diode drive circuit according to the present invention. In this figure, Kti that is the same as the component shown in FIG. 1 is indicated with the same reference numeral. What is clear from this figure is that in the present invention, the high frequency drive section (current switch circuit 31) and the low frequency drive section (13) are separated around the radar diode 11. This electrically separates the adjustment of the high-frequency drive section and the adjustment of the low-frequency drive section, so that one part of the adjustment will not affect other parts. There are two reasons for this. The first is a high frequency modulated signal 8. A circuit type in which a drive current based on
This is based on the fact that the level of the output of the current switch circuit 31 (connected to point 0 in the figure) remains unchanged. This is because the level at point C is defined by the forward voltage of the Raded diode 11. The current switch circuit 31 is an ordinary current switch consisting of a constant current source 32 and a pair of transistors 33-1 and 33-2.
以上説明したように本発明によれは、レーデダイオード
の駆動電流の調整が従来に比して寝具になる。As explained above, according to the present invention, the adjustment of the drive current of the radar diode is more effective than in the past.
縞１図はレーデダイオードの駆動回路における高周波重
畳方式の意味を説明するためのグラフ。
第２図は高周波重畳方式に基づ〈従来のレーデダイオー
ド駆動回路の一例を示す回路図、第３図は本発明に基づ
くレーデダイオードの駆動回路の一実施例を示す回路図
である。
１１・・・レーデダイオード、１３−）ツンゾスタ、３
１・・・カレントスイッチ回路、Ｓ１１・・・高周波変
調信号、Ｓ、−・・低周波変調信号。Figure 1 of the stripes is a graph for explaining the meaning of the high frequency superimposition method in the drive circuit of the Raded diode. FIG. 2 is a circuit diagram showing an example of a conventional Raded diode drive circuit based on a high frequency superimposition method, and FIG. 3 is a circuit diagram showing an example of a Raded diode driving circuit according to the present invention. 11... Rede diode, 13-) Tunzosta, 3
1... Current switch circuit, S11... High frequency modulation signal, S, -... Low frequency modulation signal.
Claims (1)
号によ動駆動されるトランジスタと、前記レーデダイオ
ードと前記トランジスタの中間接続点に出力が並列接続
し且つ高局波羨調信号によ動駆動される相補性トランジ
スタから成るカレントスイッチ回路とから構成したこと
を特徴とするレーデダイオードの駆動回路。1. A transistor connected in series to the laser diode and driven by a low frequency modulation signal, and an output connected in parallel to an intermediate connection point between the laser diode and the transistor and driven by a high frequency harmonic signal. and a current switch circuit consisting of complementary transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56159402A JPS5860844A (en) | 1981-10-08 | 1981-10-08 | Driving circuit for laser diode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56159402A JPS5860844A (en) | 1981-10-08 | 1981-10-08 | Driving circuit for laser diode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5860844A true JPS5860844A (en) | 1983-04-11 |
Family
ID=15692982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56159402A Pending JPS5860844A (en) | 1981-10-08 | 1981-10-08 | Driving circuit for laser diode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5860844A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04352660A (en) * | 1991-05-30 | 1992-12-07 | Taiyo Packaging Kk | Support member for packing |
-
1981
- 1981-10-08 JP JP56159402A patent/JPS5860844A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04352660A (en) * | 1991-05-30 | 1992-12-07 | Taiyo Packaging Kk | Support member for packing |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5325225A (en) | Method of optical transmission and optical transmitter used in the same | |
| US5187713A (en) | Nonlinear device control methods and apparatus | |
| JPS5860844A (en) | Driving circuit for laser diode | |
| JPH0511672B2 (en) | ||
| US4819240A (en) | Light modulator | |
| EP0325394A3 (en) | Transmitter having pll circuit | |
| US20210203124A1 (en) | High power and high quality laser system and method | |
| CN107947865A (en) | A kind of optical module | |
| JP3008677B2 (en) | Optical transmitter | |
| JPS5825735A (en) | Analog modulating and driving circuit for semiconductor laser | |
| JP2990698B2 (en) | Light modulation circuit | |
| JPS5928396A (en) | Semiconductor laser drive device | |
| JPH0327633A (en) | Laser diode driving system | |
| US2017520A (en) | Glow discharge device such as is used in the recording of sound | |
| JP3101833B2 (en) | Transmission output waveform control circuit | |
| JPS5914936B2 (en) | Analog modulation method of semiconductor laser | |
| JPH0132678B2 (en) | ||
| JPH02246632A (en) | Laser diode driving circuit | |
| SU57450A1 (en) | Device for automatic control of average power of a radio transmitter | |
| JPS6320388B2 (en) | ||
| JPH0541555A (en) | Automatic optical output control circuit | |
| US2825028A (en) | Pulse time modulation signal transmission system | |
| JPS6160622B2 (en) | ||
| JP2629455B2 (en) | Light modulation method | |
| JPS5921138A (en) | Transmitting system having amplitude-frequency characteristic variation compensating circuit |