JPS592392B2 - Laser equipment for optical communication - Google Patents
Laser equipment for optical communicationInfo
- Publication number
- JPS592392B2 JPS592392B2 JP52071744A JP7174477A JPS592392B2 JP S592392 B2 JPS592392 B2 JP S592392B2 JP 52071744 A JP52071744 A JP 52071744A JP 7174477 A JP7174477 A JP 7174477A JP S592392 B2 JPS592392 B2 JP S592392B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- signal
- semiconductor laser
- bias current
- 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.)
- Expired
Links
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
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Semiconductor Lasers (AREA)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】
この発明は光出力安定化機構を備えた光通信用レーザ装
置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser device for optical communication equipped with an optical output stabilization mechanism.
半導体レーザは、しきい値電流以上に電流を供給すると
発振し、通常は直流バイアス電流に信号電流を重畳した
変調電流で、駆動する。Semiconductor lasers oscillate when supplied with a current equal to or higher than a threshold current, and are normally driven with a modulation current obtained by superimposing a signal current on a DC bias current.
上記しきい値電流は、温度依存性が大きいため、変調電
流を一定にしておくと周囲温度の変化によつて、出射さ
れる光電力が変動する。The threshold current has a strong temperature dependence, so if the modulation current is kept constant, the emitted optical power will vary with changes in ambient temperature.
また、長時間使用するにつれ徐々に劣化が進み光出力電
力が減少する。Further, as it is used for a long time, it gradually deteriorates and the optical output power decreases.
このため、半導体レーザを光源として用いる光通信用レ
ーザ装置では信号伝送を安定に行う上から、送信光電力
を一定に保つ光出力安定化(以下APCと略す)機構に
よつて光出力を制御することが不可欠であり、通常は、
回路構成が簡単で制御が容易なバイアス電流制御方式が
用いられている。For this reason, in order to ensure stable signal transmission in optical communications laser devices that use semiconductor lasers as light sources, the optical output is controlled by an optical output stabilization (APC) mechanism that keeps the transmitted optical power constant. It is essential and usually
A bias current control method with a simple circuit configuration and easy control is used.
第1図は半導体レーザに対する保護機能を有する従来の
APC回路を備えた光通信用レーザ装置の構成を示すブ
ロック図である。FIG. 1 is a block diagram showing the configuration of a laser device for optical communication equipped with a conventional APC circuit having a protection function for a semiconductor laser.
第1図において、半導体レーザ1には直流バイアス回路
2からのバイアス電流に、駆動回路3からの信号電流を
重量した変調電流が印加され、半導体レーザ1からは、
前後両方向へ信号光が出射される。In FIG. 1, a modulation current obtained by weighting a bias current from a DC bias circuit 2 with a signal current from a drive circuit 3 is applied to a semiconductor laser 1, and from the semiconductor laser 1,
Signal light is emitted in both the front and rear directions.
いま、前方向へ出射される信号光4を伝送用に、後方向
へ出射される信号光5を制御用としてそれぞれ用いると
する。Now, it is assumed that the signal light 4 emitted in the forward direction is used for transmission, and the signal light 5 emitted in the rear direction is used for control.
このとき後方向へ出射される信号光5を受光素子6で受
光し、増幅器Tを通して出射光電力に比例した信号を得
る。At this time, the signal light 5 emitted in the backward direction is received by the light receiving element 6, and passed through the amplifier T to obtain a signal proportional to the power of the emitted light.
この検出信号と、出射光電力を設定する基準信号発生回
路8からの基準信号とを比較回路9を用いて比較し、そ
の比較信号に比例させて直流バイアス回路2のバイアス
電流を増減させ、前方向へ出射する信号光4の光電力を
一定に制御する。このとき、比較回路9と、直流バイア
ス回路2との間に、ツェナーダイオードと抵抗とで構成
した電流制限回路10を接続し、半導体レーザ1に最大
定格値以上の過電流が流れるのを防止している。This detection signal is compared with a reference signal from a reference signal generation circuit 8 that sets the emitted light power using a comparison circuit 9, and the bias current of the DC bias circuit 2 is increased or decreased in proportion to the comparison signal. The optical power of the signal light 4 emitted in the direction is controlled to be constant. At this time, a current limiting circuit 10 composed of a Zener diode and a resistor is connected between the comparator circuit 9 and the DC bias circuit 2 to prevent an overcurrent exceeding the maximum rated value from flowing into the semiconductor laser 1. ing.
しかし、上記のような構成をもつ従来の光通信用レーザ
装置では、周囲温度が半導体レーザの許容動作温度範囲
を越えて上昇した場合、直流バイアス電流がその最大定
格値以下であると、バイアス電流はさらに増加し、半導
体レーザは熱的な損傷によつて劣化が急速に進み、半導
体レーザが破壊するという重大な欠点があつた。However, in conventional optical communication laser devices with the above configuration, when the ambient temperature rises beyond the permissible operating temperature range of the semiconductor laser and the DC bias current is below its maximum rated value, the bias current decreases. further increased, and semiconductor lasers rapidly deteriorated due to thermal damage, resulting in the serious drawback that the semiconductor lasers were destroyed.
この発明はこれらの欠点を除去するため、直流バイアス
回路の入力側に温度検出回路および差動増幅回路2段と
ツエナーダイオードとで構成した電流制限回路を接続す
5ることにより、周囲温度が設定動作温度を越えると自
動的に直流バイアス電流がカツト・オフ状態になるよう
にしたものであるO第2図は、この発明による光通信用
レーザ装置の一実施例を示したものである。In order to eliminate these drawbacks, the present invention connects a current limiting circuit consisting of a temperature detection circuit, two stages of differential amplifier circuits, and a Zener diode to the input side of the DC bias circuit, so that the ambient temperature can be set. The DC bias current is automatically cut off when the operating temperature is exceeded. FIG. 2 shows an embodiment of a laser device for optical communication according to the present invention.
第2図において、1〜10は、第1図と同じであり、半
導体レーザ1からは、前後両方向へ、信号光が出射する
が、このうち、後方向への出射信号光5の光電力を検出
し、その検出信号を用いて直流バイアス回路2を動作さ
せバイアス電流を増減し、前方向への出射信号光4の光
電力が一定になるように制御している。In FIG. 2, 1 to 10 are the same as in FIG. 1, and signal light is emitted from the semiconductor laser 1 in both forward and backward directions. Of these, the optical power of the signal light 5 emitted in the backward direction is The detection signal is used to operate the DC bias circuit 2 to increase or decrease the bias current, thereby controlling the optical power of the signal light 4 emitted in the forward direction to be constant.
このとき、比較回路9からの比較信号を、ツエナーダイ
オードと抵抗とで構成した電流制限回路10に通し、バ
イアス電流がその最大定格イ直を越えないように制限し
ている。At this time, the comparison signal from the comparison circuit 9 is passed through a current limiting circuit 10 composed of a Zener diode and a resistor to limit the bias current so that it does not exceed its maximum rating.
一方、サーミスタや熱電対などを温度センサとして用い
た温度検出回路11からの検出信号と許容動作温度値を
設定するための基準信号発生回路12からの設定信号と
を差動増幅回路13に入力する。On the other hand, a detection signal from a temperature detection circuit 11 using a thermistor, thermocouple, etc. as a temperature sensor and a setting signal from a reference signal generation circuit 12 for setting an allowable operating temperature value are input to a differential amplifier circuit 13. .
この差動増幅回路13からの出力信号を、差動増幅回路
13の出力端子と電源14との間に接続したツエナーダ
イオード15を通し、次段の差動増幅回路16に入力す
る。オペアンプ16からの出力信号と、上記電流制限回
路10からの信号とを演算回路17に入力し、その出力
信号を用いて直流バイアス回路2を動作させる装置構成
になつている。The output signal from the differential amplifier circuit 13 is input to the next stage differential amplifier circuit 16 through a Zener diode 15 connected between the output terminal of the differential amplifier circuit 13 and the power supply 14. The device is configured such that the output signal from the operational amplifier 16 and the signal from the current limiting circuit 10 are input to the arithmetic circuit 17, and the DC bias circuit 2 is operated using the output signal.
このような装置構成をもつ、この発明による光通信用レ
ーザ装置において、上記温度検出回路11からの検出信
号電圧をEtl基準信号発生回路12からの設定信号電
圧をErlツエナーダイオード15のツエナ一電圧をE
Zl電源14の電源電圧をEZlオフセツト電圧発生回
路18からのオフセツト電圧をEzとすると、差動増幅
回路16からの出力信号電圧EOは第(1)式で与えら
れる。In the optical communication laser device according to the present invention having such a device configuration, the detection signal voltage from the temperature detection circuit 11, the setting signal voltage from the Etl reference signal generation circuit 12, and the Zener voltage of the Erl Zener diode 15 are used. E
Assuming that the power supply voltage of the Zl power supply 14 is the offset voltage from the EZl offset voltage generation circuit 18 as Ez, the output signal voltage EO from the differential amplifier circuit 16 is given by equation (1).
このとき、周囲温度をT1許容動作温度をTcとすると
、検出信号電圧Etと設定信号電圧Erは、それぞれ第
(2)式、第(3)式で与えられる。At this time, when the ambient temperature is T1 and the allowable operating temperature is Tc, the detection signal voltage Et and the setting signal voltage Er are given by equations (2) and (3), respectively.
ただしθは定数である。従つて差動増幅回路16からの
出力信号電圧EOは、第(4)式で与えられることにな
り、信号電圧EOの温度依存性は第3図aに示すように
なる。However, θ is a constant. Therefore, the output signal voltage EO from the differential amplifier circuit 16 is given by equation (4), and the temperature dependence of the signal voltage EO is as shown in FIG. 3a.
上記差動増幅回路16の出力信号を演算回路17を通し
て直流バイアス回路2に入力すると、直流バイアス電流
1Bは、第3図bに示すように周囲温度Tに応じて変化
する。ここで、周囲温度Tが許容動作温度Tcより低い
温度範囲における直流バイアス電流をIB(m)とする
と、周囲温度Tが許容動作温度Tcを越えるに従つてB
(m)θ/Ezの割合で直流バイアス電流が減少し自動
的にカツトオフ状態になり電流制限を行うことができる
。なお、演算回路17の出力信号は、T<Tcの温度範
囲では、半導体レーザの出射光電力の検出信号に比例し
て変化するのに対し、T≧Tcの温度範囲になると、上
記差動増幅回路16からの出力信号に比例して変化する
ことになる。When the output signal of the differential amplifier circuit 16 is input to the DC bias circuit 2 through the arithmetic circuit 17, the DC bias current 1B changes depending on the ambient temperature T as shown in FIG. 3B. Here, if the DC bias current in the temperature range where the ambient temperature T is lower than the allowable operating temperature Tc is IB (m), as the ambient temperature T exceeds the allowable operating temperature Tc, B
(m) The DC bias current decreases at a ratio of θ/Ez, and the cut-off state is automatically established, allowing current limitation. Note that in the temperature range of T<Tc, the output signal of the arithmetic circuit 17 changes in proportion to the detection signal of the emitted light power of the semiconductor laser, whereas in the temperature range of T≧Tc, the output signal of the arithmetic circuit 17 changes in proportion to the detection signal of the output power of the semiconductor laser. It will vary proportionally to the output signal from circuit 16.
すなわち、この発明による光通信用レーザ装置では、T
<Tcの温度範囲で、電流制限回路10が動作し直流バ
イアス電流を最大定格値以下に抑えるようになり、さら
にT≧Tcの温度範囲になると、差動増幅回路2段13
,16とツエナーダイオード15とで構成した回路が動
作し自動的に直流バイアス電流をカツトオフ状態にでき
るため、半導体レーザの熱的な損傷を防企できる利点が
ある。That is, in the optical communication laser device according to the present invention, T
In the temperature range <Tc, the current limiting circuit 10 operates to suppress the DC bias current below the maximum rated value, and when the temperature range becomes T>=Tc, the two-stage differential amplifier circuit 13 operates.
, 16 and the Zener diode 15 operates to automatically cut off the DC bias current, which has the advantage of preventing thermal damage to the semiconductor laser.
また、この発明による光通信用レーザ装置では、半導体
レーザの熱的な損傷により信号伝送の機能が停止してし
まうことがないので、直流バイアス電流の制限により半
導体レーザからの出射光電力がその設定値よりも減少し
ても信号伝送系のS/N比が低下するのみであり、この
場合、周囲温度を下げる手段を構することにより、元の
状態へ復帰させることができる利点がある。なお、以上
は、直流バイアス電流に、変調信号としてパルスまたは
アナログ信号電流を重畳して駆動する光通信用レーザ装
置の場合について説明したがこの発明はこれに限らずパ
ルスバイアス電流にパルス信号電流を重畳し駆動する場
合にも適用できることは言うまでもない。In addition, in the laser device for optical communication according to the present invention, the signal transmission function does not stop due to thermal damage to the semiconductor laser, so by limiting the DC bias current, the optical power emitted from the semiconductor laser can be adjusted to the set value. Even if it decreases below this value, the S/N ratio of the signal transmission system only decreases, and in this case, there is an advantage that the original state can be restored by providing means for lowering the ambient temperature. Although the above description has been made of the case of an optical communication laser device that is driven by superimposing a pulse or analog signal current as a modulation signal on a DC bias current, the present invention is not limited to this. Needless to say, it can also be applied to the case of superimposed driving.
以上のように、この発明に係る光通信用レーザ装置では
、半導体レーザから出射する信号光の一部を検出し、そ
の検出信号を用いて半導体レーザに供給するバイアス電
流を制御し、出射光電力の安定化を行つているが、この
バイアス回路の入力!側に、差動増幅回路2段を縦続接
続し、その前段のオペアンプの出力端子と電源との間の
ツエナーダイオードを接続した回路を設けることにより
、周囲温度が許容動差温度を越えると、バイアス電流が
自動的にカツト・オフ状態になるため、半導体レーザが
熱的に損傷し劣化が急速に進み、破損するのを防止でき
る利点がある。As described above, in the optical communication laser device according to the present invention, a part of the signal light emitted from the semiconductor laser is detected, the detection signal is used to control the bias current supplied to the semiconductor laser, and the emitted light power is The input of this bias circuit is being stabilized! By installing a circuit in which two stages of differential amplifier circuits are connected in cascade on the side, and a Zener diode is connected between the output terminal of the operational amplifier in the previous stage and the power supply, when the ambient temperature exceeds the allowable differential temperature, the bias Since the current is automatically cut off, there is an advantage that the semiconductor laser can be prevented from being thermally damaged, causing rapid deterioration and damage.
第1図は出力安定化機構を備えた従来の光通信用レーザ
装置の構成を示すプロツク図、第2図はこの発明による
光通信用レーザ装置の一実施例の構成図、第3図A,b
はこの発明の動作特性を説明するための特性図である。
図中、1は半導体レーザ、2はバイアス回路、3は1駆
動回路、4は前方向へ出射する信号光、5は後方向へ出
射する信号光、6は受光素子、7は増幅器、7は基準信
号発生回路、9は比較回路、10は電流制限回路、11
は温度検出回路、12は基準信号発生回路、13,16
は差動増幅回路、14は電源、15はツエナーダイオー
ド、17は演算回路である。FIG. 1 is a block diagram showing the configuration of a conventional optical communications laser device equipped with an output stabilization mechanism, FIG. 2 is a configuration diagram of an embodiment of the optical communications laser device according to the present invention, and FIGS. b
FIG. 2 is a characteristic diagram for explaining the operating characteristics of the present invention. In the figure, 1 is a semiconductor laser, 2 is a bias circuit, 3 is a 1 drive circuit, 4 is a signal light emitted in the forward direction, 5 is a signal light emitted in the rear direction, 6 is a light receiving element, 7 is an amplifier, 7 is a Reference signal generation circuit, 9 a comparison circuit, 10 a current limit circuit, 11
12 is a temperature detection circuit, 12 is a reference signal generation circuit, 13, 16
1 is a differential amplifier circuit, 14 is a power supply, 15 is a Zener diode, and 17 is an arithmetic circuit.
Claims (1)
とともに、その検出信号を用いて半導体レーザに供給す
るバイアス電流を制御し、上記半導体レーザから出射す
る信号光の電力を一定になす光出力安定化機構を備えた
光通信用レーザ装置において、バイアス電流供給回路に
、温度検出回路と、ツェナーダイオードと、差動増幅回
路とで構成した電流制御回路を設け、周囲温度が設定動
作温度を越えた時には上記半導体レーザに流れるバイア
ス電流がカット・オフ(Cut−Off)状態になるよ
うにしたことを特徴とする光通信用レーザ装置。1 Optical output stabilization that detects a part of the signal light emitted from the semiconductor laser and uses the detection signal to control the bias current supplied to the semiconductor laser to keep the power of the signal light emitted from the semiconductor laser constant. In a laser device for optical communications equipped with a switching mechanism, a current control circuit consisting of a temperature detection circuit, a Zener diode, and a differential amplifier circuit is installed in the bias current supply circuit, so that when the ambient temperature exceeds the set operating temperature, A laser device for optical communication, characterized in that a bias current flowing through the semiconductor laser is sometimes in a cut-off state.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP52071744A JPS592392B2 (en) | 1977-06-17 | 1977-06-17 | Laser equipment for optical communication |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP52071744A JPS592392B2 (en) | 1977-06-17 | 1977-06-17 | Laser equipment for optical communication |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS546703A JPS546703A (en) | 1979-01-19 |
JPS592392B2 true JPS592392B2 (en) | 1984-01-18 |
Family
ID=13469329
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP52071744A Expired JPS592392B2 (en) | 1977-06-17 | 1977-06-17 | Laser equipment for optical communication |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS592392B2 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58151081A (en) * | 1982-03-04 | 1983-09-08 | Matsushita Electric Ind Co Ltd | Laser power source circuit |
JPS5984491A (en) * | 1982-11-05 | 1984-05-16 | 電気化学工業株式会社 | Method of producing etched metal foil-bonded laminated board |
JPS6022747A (en) * | 1983-07-19 | 1985-02-05 | Fujitsu Ten Ltd | Protecting circuit of laser pickup |
JPS6065659A (en) * | 1983-09-21 | 1985-04-15 | Hitachi Ltd | Semiconductor laser light source device |
JP5842622B2 (en) * | 2012-01-12 | 2016-01-13 | 富士通株式会社 | Optical transmission apparatus and optical transmission method |
JP5567176B1 (en) * | 2013-03-25 | 2014-08-06 | ミハル通信株式会社 | Semiconductor light emitting device controller |
-
1977
- 1977-06-17 JP JP52071744A patent/JPS592392B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS546703A (en) | 1979-01-19 |
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