JPH0132678B2 - - Google Patents
Info
- Publication number
- JPH0132678B2 JPH0132678B2 JP56012236A JP1223681A JPH0132678B2 JP H0132678 B2 JPH0132678 B2 JP H0132678B2 JP 56012236 A JP56012236 A JP 56012236A JP 1223681 A JP1223681 A JP 1223681A JP H0132678 B2 JPH0132678 B2 JP H0132678B2
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- signal
- high frequency
- transistor
- drive circuit
- 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.)
- Expired
Links
- 239000004065 semiconductor Substances 0.000 claims description 31
- 230000005540 biological transmission Effects 0.000 claims description 4
- 239000013307 optical fiber Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006355 external stress Effects 0.000 description 1
- 239000000835 fiber Substances 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
- 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)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】
本発明は、半導体レーザの駆動回路に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor laser drive circuit.
従来半導体レーザ駆動回路は、第１図に示す様
な構成となつていた。ここで１は半導体レーザ、
２は信号入力端子、３は、バイアス電圧印加端
子、４，５はトランジスタである。ここでトラン
ジスタ５は半導体レーザの直流バイアスを設定す
るのに用いる。 A conventional semiconductor laser drive circuit has a configuration as shown in FIG. Here, 1 is a semiconductor laser,
2 is a signal input terminal, 3 is a bias voltage application terminal, and 4 and 5 are transistors. Here, the transistor 5 is used to set the DC bias of the semiconductor laser.
一方半導体レーザ光は、可干渉であるため、レ
ーザ光が多モード光フアイバを伝播すると、各伝
播モード間の干渉によりスペツクルが生じる。こ
のスペツクルのパターンは、半導体レーザの発振
波長の変動、光フアイバに加えられる外部応力の
変動等により大きく変動し、多モード光フアイバ
を伝播した信号波形を劣化させる要因となる。従
来の半導体レーザ駆動回路を用いて半導体レーザ
を駆動した場合は、半導体レーザの可干渉はそれ
程低下しないため、このスペツクルパタンの変動
により、多モード光フアイバを伝播した信号波形
の劣化が大きいという欠点があつた。 On the other hand, since semiconductor laser light is coherent, when the laser light propagates through a multimode optical fiber, speckles occur due to interference between each propagation mode. This speckle pattern varies greatly due to variations in the oscillation wavelength of the semiconductor laser, variations in external stress applied to the optical fiber, etc., and becomes a factor that deteriorates the signal waveform propagated through the multimode optical fiber. When a semiconductor laser is driven using a conventional semiconductor laser drive circuit, the coherence of the semiconductor laser does not decrease significantly, so this variation in speckle pattern significantly degrades the signal waveform propagated through the multimode optical fiber. There were flaws.
ところで、半導体レーザを変調信号に高周波を
重畳した信号で変調することにより半導体レーザ
光の可干渉性が低下するという現象が知られてい
る。この現象については、電子通信学会通信方式
研究会、研究技術報告CS−80−２（1980年４月17
日）「半導体レーザを用いたマルチモードフアイ
バアナログ伝送系の検討」に詳しい記述がある。 Incidentally, there is a known phenomenon in which the coherence of semiconductor laser light is reduced by modulating a semiconductor laser with a signal in which a high frequency is superimposed on a modulation signal. Regarding this phenomenon, the Institute of Electronics and Communication Engineers Communication Systems Study Group, Research and Technical Report CS-80-2 (April 17, 1980)
(Japanese) ``Study of multimode fiber analog transmission system using semiconductor laser'' has a detailed description.
本発明は、前記従来技術の欠点を除去し、半導
体レーザ光の可干渉性を低下させることを目的と
し、前記現象を利用し得る新規な半導体レーザの
駆動回路、即ち半導体レーザを変調信号と高周波
信号を重畳した信号で変調することのできる半導
体レーザの駆動回路を提供するものであり、以下
図面について詳細に説明する。 The present invention aims to eliminate the drawbacks of the prior art and reduce the coherence of semiconductor laser light, and provides a novel semiconductor laser drive circuit that utilizes the phenomenon described above. The present invention provides a semiconductor laser drive circuit that can modulate signals with a superimposed signal, and will be described in detail below with reference to the drawings.
第２図は、本発明の実施例であつて、６，８，
９はトランジスタ、７は高周波信号入力端子であ
る。２個のトランジスタ６，９のコレクタを共通
とし、その共通コレクタに半導体レーザ１が接続
され、かつ、一方のトランジスタ６のベースに高
周波入力端子７からの50MHz〜2GHz程度の高周
波信号が印加され、他方のトランジスタ９のベー
スに信号入力端子２からの伝送信号が印加される
よう構成されている。また前記共通コレクタには
半導体レーザに直流バイアス電流を供給するトラ
ンジスタ８が接続されている。 FIG. 2 shows an embodiment of the present invention, 6, 8,
9 is a transistor, and 7 is a high frequency signal input terminal. The collectors of the two transistors 6 and 9 are made common, the semiconductor laser 1 is connected to the common collector, and a high frequency signal of about 50 MHz to 2 GHz from a high frequency input terminal 7 is applied to the base of one transistor 6, The transmission signal from the signal input terminal 2 is applied to the base of the other transistor 9. Further, a transistor 8 is connected to the common collector for supplying a DC bias current to the semiconductor laser.
以上のような構成により、半導体レーザを流れ
る電流波形は信号波形に高周波パルスが重畳され
た波形となる。一例として、第３図ａに入力信号
波形、第３図ｂに端子９に加えた高周波信号波
形、第３図ｃに半導体レーザを流れる電流波形を
示す。 With the above configuration, the current waveform flowing through the semiconductor laser becomes a waveform in which a high-frequency pulse is superimposed on a signal waveform. As an example, FIG. 3a shows the input signal waveform, FIG. 3b shows the high frequency signal waveform applied to the terminal 9, and FIG. 3c shows the current waveform flowing through the semiconductor laser.
なお、半導体レーザの発振閾値電流Ithと、半
導体レーザ駆動電流レベルとの相対関係は、第３
図ｃに示した１，２のどちらでも良い。 Note that the relative relationship between the oscillation threshold current I th of the semiconductor laser and the semiconductor laser drive current level is determined by the third
Either 1 or 2 shown in Figure c may be used.
本発明の駆動回路を用い、第３図ｃに示した様
な駆動電流により、半導体レーザ１を駆動する
と、前記刊行物記載の現象により、その半導体レ
ーザ１の発振スペクトルは多数本化し、レーザ光
の可干渉性を低下させる効果がある。したがつ
て、レーザ光の可干渉性に起因する信号波形の劣
化を低減させることができる。 When the semiconductor laser 1 is driven using the drive circuit of the present invention with a drive current as shown in FIG. This has the effect of reducing the coherence of Therefore, deterioration of the signal waveform due to the coherence of laser light can be reduced.
なお、高周波を重畳することにより生じた半導
体レーザ出射光の、所望信号以外の高周波成分
は、光フアイバあるいは受光回路の帯域制限によ
りカツトできるため、原信号を得ることができ
る。したがつて受光回路系は、従来の直接強度変
調の場合と同じものでよく、特別なものを要しな
い。 Note that high frequency components other than the desired signal of the semiconductor laser emitted light generated by superimposing the high frequency can be cut by band limiting of the optical fiber or the light receiving circuit, so that the original signal can be obtained. Therefore, the light receiving circuit system may be the same as in the case of conventional direct intensity modulation, and no special one is required.
以上述べたように、本発明の半導体レーザ駆動
回路を用いて、半導体レーザを駆動すれば、レー
ザ光の可干渉性が減少し、その結果、多モード光
フアイバを伝搬した時にスペツクル雑音によつて
生じる伝送波形劣化を低減することが可能とな
る。 As described above, when a semiconductor laser is driven using the semiconductor laser drive circuit of the present invention, the coherence of the laser light decreases, and as a result, when it propagates through a multimode optical fiber, it is affected by speckle noise. It becomes possible to reduce the transmission waveform deterioration that occurs.
また、本発明の半導体レーザ駆動回路は、トラ
ンジスタ１個を追加することにより、高周波重畳
変調回路の構成が可能であり、部品点数が少な
く、信頼性の点で有利であり、実用上低コスト化
を図れるという利点がある。 In addition, the semiconductor laser drive circuit of the present invention can configure a high frequency superimposition modulation circuit by adding one transistor, has a small number of parts, is advantageous in terms of reliability, and is practically cost-effective. It has the advantage of being able to
第１図は従来の半導体レーザ駆動回路、第２図
は本発明の一実施例の回路、第３図は本発明によ
る信号波形の例を示すものである。
１……半導体レーザ、２……信号入力端子、３
……バイアス電圧印加端子、４，５，６，８，９
……トランジスタ、７……高周波入力端子。
FIG. 1 shows a conventional semiconductor laser drive circuit, FIG. 2 shows a circuit according to an embodiment of the present invention, and FIG. 3 shows an example of a signal waveform according to the present invention. 1...Semiconductor laser, 2...Signal input terminal, 3
...Bias voltage application terminal, 4, 5, 6, 8, 9
...Transistor, 7...High frequency input terminal.
Claims (1)
その共通コレクタに半導体レーザを接続し、か
つ、一方のトランジスタのベースに50MHz〜2G
Hz程度の高周波信号を印加し、他方のトランジス
タのベースに伝送信号を印加し、半導体レーザを
高周波の重畳された信号により変調することを特
徴とする半導体レーザの駆動回路。1 The collectors of the two transistors are common,
A semiconductor laser is connected to the common collector, and 50MHz to 2G is connected to the base of one transistor.
A semiconductor laser drive circuit characterized in that a high frequency signal of approximately Hz is applied, a transmission signal is applied to the base of the other transistor, and the semiconductor laser is modulated by the high frequency superimposed signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56012236A JPS57128090A (en) | 1981-01-31 | 1981-01-31 | Driving circuit for semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56012236A JPS57128090A (en) | 1981-01-31 | 1981-01-31 | Driving circuit for semiconductor laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57128090A JPS57128090A (en) | 1982-08-09 |
| JPH0132678B2 true JPH0132678B2 (en) | 1989-07-10 |
Family
ID=11799729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56012236A Granted JPS57128090A (en) | 1981-01-31 | 1981-01-31 | Driving circuit for semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57128090A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60224134A (en) * | 1984-04-20 | 1985-11-08 | Yokogawa Hokushin Electric Corp | Semiconductor laser device |
| CN110112647B (en) * | 2015-07-28 | 2021-05-18 | 海信集团有限公司 | DLP projection system |
-
1981
- 1981-01-31 JP JP56012236A patent/JPS57128090A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57128090A (en) | 1982-08-09 |
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