JPH0456288A - Optical signal transmitting device - Google Patents
Optical signal transmitting deviceInfo
- Publication number
- JPH0456288A JPH0456288A JP2167454A JP16745490A JPH0456288A JP H0456288 A JPH0456288 A JP H0456288A JP 2167454 A JP2167454 A JP 2167454A JP 16745490 A JP16745490 A JP 16745490A JP H0456288 A JPH0456288 A JP H0456288A
- Authority
- JP
- Japan
- Prior art keywords
- light emitting
- emitting element
- circuit
- current
- threshold value
- 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
- 230000003287 optical effect Effects 0.000 title claims abstract description 26
- 238000010586 diagram Methods 0.000 description 14
- 239000004065 semiconductor Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 235000010724 Wisteria floribunda Nutrition 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
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- Semiconductor Lasers (AREA)
- Led Devices (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、電気信号を一旦光信号に変換して伝送を行な
う光信号送信装置に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical signal transmitting device that converts an electrical signal into an optical signal and then transmits the signal.
〈従来技術〉
一般に、光信号送信装置には、先出力−順電流特性にし
きい値を持つ発光素子を使用する例（従来例１）と、順
電流−先出力特性にしきい値を持たない発光索子を使用
する例（従来例２）とがある。<Prior art> In general, optical signal transmitters use a light-emitting element that has a threshold value in the forward current-forward current characteristic (conventional example 1), and a light-emitting element that does not have a threshold value in the forward current-forward current characteristic. There is an example (conventional example 2) in which a cord is used.
「従来例１コ
第４図は従来例１としての光信号送信装置の構成を示す
ブロック図、第５図はその発光素子の先出力−順電流特
性を示す図である。"Conventional Example 1" FIG. 4 is a block diagram showing the configuration of an optical signal transmitter as Conventional Example 1, and FIG. 5 is a diagram showing the forward output-forward current characteristics of the light emitting element.
このように、先出力−順電流特性にしきい値を持つ発光
素子（半導体レーザ月８を使用する場合には、一般にし
きい値付近までバイアス電流を流し、その上Ｚこ変調電
流を流している。この場合、温度の変化等によるしきい
値電流の変化に対応するため、第４図の如く、先出力を
受光素子３でモニタし、そのモニタ電流に応じてバイア
ス電流値を変化させるための回路（Ａｒｃ回路）４が必
要である。In this way, when using a light-emitting element (semiconductor laser 8) that has a threshold value in its forward output-forward current characteristic, a bias current is generally passed to near the threshold value, and then a Z modulation current is passed. In this case, in order to cope with changes in the threshold current due to changes in temperature, etc., the first output is monitored by the light receiving element 3, and the bias current value is changed according to the monitored current, as shown in Fig. 4. A circuit (Arc circuit) 4 is required.
なお、第４図中、２は発光素子駆動回路、５は抵抗であ
る。In addition, in FIG. 4, 2 is a light emitting element drive circuit, and 5 is a resistor.
［従来例２］
第６図は従来例２としての光信号送信装置の構成を示す
ブロック図、第７図はその発光素子の先出力−順電流特
性を示す図である。[Conventional Example 2] FIG. 6 is a block diagram showing the configuration of an optical signal transmitting device as Conventional Example 2, and FIG. 7 is a diagram showing the forward output-forward current characteristics of the light emitting element.
このように、先出力−順電流特性にしきい値を持たない
発光素子（発光ダイオード）ｌｂを使用する場合には、
従来例１のようなモニタ用受光素子３とＡＰＣ回路４と
が不必要であるので、第６図のように構成を簡略化でき
る。In this way, when using a light emitting element (light emitting diode) lb that does not have a threshold value in the forward output-forward current characteristic,
Since the monitor light receiving element 3 and the APC circuit 4 as in Conventional Example 1 are unnecessary, the configuration can be simplified as shown in FIG. 6.
なお、第６図中、６は定電流回路である。In addition, in FIG. 6, 6 is a constant current circuit.
く 発明が解決しようとする課題 〉
従来例１．２の光信号送信装置には、以下の問題点が指
摘されている。Problems to be Solved by the Invention The following problems have been pointed out in the optical signal transmitting device of Conventional Example 1.2.
（１）従来例１に使用されている発光素子１ａは、−船
釣なもので価格が安く、応答速度も充分であるが、第４
図のように、モニタ用受光素子３とＡＰＣ回路４とが必
要であるので、結果的に装置全体の価格が高くなり、し
かも信頼性の点でも難がある。(1) The light-emitting element 1a used in Conventional Example 1 is a boat-fished type, is inexpensive, and has sufficient response speed.
As shown in the figure, since a monitoring light-receiving element 3 and an APC circuit 4 are required, the cost of the entire device increases as a result, and there is also a problem in terms of reliability.
（２）従来例２に使用されている発光素子１ｂは、一般
には応答速度が遅く、高速伝送には使用できない。また
、一部に応答が速い特殊なものもあるが、これは価格が
非常に高いという欠点がある。(2) The light emitting element 1b used in Conventional Example 2 generally has a slow response speed and cannot be used for high-speed transmission. There are also some special types that have a fast response time, but they have the disadvantage of being very expensive.
本発明は、上記に鑑み、応答速度が充分速く、装置全体
のコストが安くなり、しかも信頼性のある光信号送信装
置の提供を目的とする。In view of the above, it is an object of the present invention to provide an optical signal transmitting device that has a sufficiently high response speed, reduces the cost of the entire device, and is reliable.
〈 課題を解決するための手段 〉
本発明による課題解決手段は、第１図ないし第３図の如
く、電気信号を一旦光信号に変換して伝送を行なうもの
であって、発光素子１ａと、該発光素子１ａを駆動させ
る発光素子駆動回路２とを備えた光信号送信装置におい
て、前記発光素子１ａは、先出力−順電流特性にしきい
値を持つものが使用され、前記発光素子駆動回路２は、
発光素子駆動電流値が発光素子１ａのしきい値よりも低
い範囲となるよう、回路定数が決定されたものである。<Means for Solving the Problems> As shown in FIGS. 1 to 3, the means for solving the problems according to the present invention is to convert an electrical signal into an optical signal and transmit it, and includes a light emitting element 1a, In an optical signal transmitting device including a light emitting element driving circuit 2 for driving the light emitting element 1a, the light emitting element 1a has a threshold value in the forward output-forward current characteristic, and the light emitting element driving circuit 2 is used as the light emitting element 1a. teeth,
The circuit constants are determined so that the light emitting element driving current value is in a range lower than the threshold value of the light emitting element 1a.
〈作用〉
上記課題解決手段において、発光素子駆動回路２に電気
信号が入力されると、発光素子１ａは発光素子駆動回路
２により駆動して、電気信号を一旦光信号に変換し伝送
する。<Operation> In the above problem solving means, when an electrical signal is input to the light emitting element drive circuit 2, the light emitting element 1a is driven by the light emitting element drive circuit 2, and the electrical signal is once converted into an optical signal and transmitted.
このとき、発光素子１ａは、先出力−順電流特性にしき
い値を持つが、発光素子駆動回路２の回路定数を、発光
素子駆動電流値が発光素子１ａのしきい値よりも低い範
囲となるよう決定することで、駆動電流値は、必ずしき
い値電流以下に設定されることになる。At this time, the light emitting element 1a has a threshold value in the forward output-forward current characteristic, but the circuit constant of the light emitting element drive circuit 2 is set such that the light emitting element drive current value is in a range lower than the threshold value of the light emitting element 1a. By making this determination, the drive current value is always set to be equal to or less than the threshold current.
これにより、温度変化等による発光素子１ａのしきい値
電流の変化にかかわらず、一定電流で駆動することがで
きる。Thereby, the light emitting element 1a can be driven with a constant current regardless of changes in the threshold current of the light emitting element 1a due to changes in temperature or the like.
〈実施例〉
以下、本発明の一実施例を第［図ないし第３図に基づい
て説明する。<Example> Hereinafter, an example of the present invention will be described based on FIGS.
第１図は本発明の一実施例に係る光信号送信装置の構成
を示すブロック図、第２図は同じくその発光素子の構造
を示す図、第３図は発光素子のしきい値電流−温度特性
を示す図である。なお、第４．６図に示した従来技術と
同一機能部品については同一符号を付している。FIG. 1 is a block diagram showing the configuration of an optical signal transmitter according to an embodiment of the present invention, FIG. 2 is a diagram showing the structure of a light emitting device, and FIG. 3 is a diagram showing the threshold current vs. temperature of the light emitting device. FIG. 3 is a diagram showing characteristics. Note that the same reference numerals are given to the same functional parts as those of the prior art shown in FIG. 4.6.
本実施例の光信号送信装置は、第１図の如く、電気信号
を一旦光信号に変換して伝送を行なうものであって、発
光素子１ａと、該発光素子１ａを駆動さける発光素子駆
動回路２と、定電流回路６とを備えている。As shown in FIG. 1, the optical signal transmitting device of this embodiment is one that converts an electrical signal into an optical signal and then transmits it, and includes a light emitting element 1a and a light emitting element driving circuit that drives the light emitting element 1a. 2 and a constant current circuit 6.
府記発光素子１ａは、最近、光デイスクピックアップ用
光源として多く使用され、価格も安く、信頼性を高いＶ
ＳＩＳ（Ｖ−Ｃｈａｎｎｅ（ｌｅｄ ５ｕｂｓｔｒａ
ｔｅ Ｉ ｎｎｅｒ Ｓ ｔｒｉｐｅ）構造をもっ
たＧａＡρＡｓの半導体レーザ（λ−７８０ｔｎｍ）で
あり、先出力−順電流特性にしきい値を持ち、しきい値
電流が低く、横モードが安定などの特長がある。The Fuji light-emitting element 1a has recently been widely used as a light source for optical disk pickups, and is inexpensive and highly reliable.
SIS(V-Channel(led 5ubstra
It is a GaAρAs semiconductor laser (λ-780tnm) with a structure (te Inner Stripe), and has features such as a threshold in the forward output-forward current characteristic, a low threshold current, and a stable transverse mode. .
そして、発光素子１ａは、第２図の如く、ｐ−ｃＡｓ活
性層１３、ｎ−Ｇａ、ｘＡＱｘＡｓクラッド層１４、ｎ
−ＧａＡｓＪｉ １５、ｐ型電極１６およびｎ型電極
１７から構成されており、第１図の如く、カソードは定
電流回路６に接続され、アノードはグランドに接地され
ている。As shown in FIG. 2, the light emitting device 1a includes a p-cAs active layer 13, an n-Ga, xAQxAs cladding layer 14,
-GaAsJi 15, a p-type electrode 16, and an n-type electrode 17. As shown in FIG. 1, the cathode is connected to the constant current circuit 6, and the anode is grounded.
前記発光素子駆動回路２は、発光素子１ａと定電流回路
６との接続中間点ａに接続されており、発光素子駆動電
流値が発光素子１ａのしきい値よりも低い範囲となるよ
う、回路定数が決定されている。つまり、駆動電流は、
発光素子すの特性データに基づいて決定し、その値に固
定されている。The light emitting element driving circuit 2 is connected to the connection intermediate point a between the light emitting element 1a and the constant current circuit 6, and is configured to control the circuit so that the light emitting element driving current value is in a range lower than the threshold value of the light emitting element 1a. Constants have been determined. In other words, the drive current is
It is determined based on the characteristic data of the light emitting element and is fixed at that value.
具体的には、発光素子１ａの動作温度範囲の下限（通常
は一２０８Ｃ，−１０℃など）におけるしきい値の最小
値を仕様書等で確認し、これ以下の値を駆動電流値とし
て決定する。そして、回路的に電流値がこの値になるよ
う回路定数を決定する。Specifically, the minimum value of the threshold value at the lower limit of the operating temperature range of the light emitting element 1a (usually -208C, -10C, etc.) is checked in the specifications, etc., and the value below this is determined as the drive current value. do. Then, circuit constants are determined so that the current value becomes this value in terms of the circuit.
この際に、回路の温度特性も計算に入れば良い。At this time, the temperature characteristics of the circuit should also be included in the calculation.
上記構成において、発光素子駆動回路２に電気信号が人
力されると、発光素子１ａは発光素子駆動回路２により
駆動して、電気信号を一旦光信号に変換し伝送する。In the above configuration, when an electric signal is manually applied to the light emitting element drive circuit 2, the light emitting element 1a is driven by the light emitting element drive circuit 2, and the electric signal is once converted into an optical signal and transmitted.
このとき、発光素子１ａは、先出力−順電流特性にしき
い値を持つが、発光素子駆動回路２の回路定数を、発光
素子駆動電流値が発光素子１ａのしきい値よりも低い範
囲となるよう決定することで、駆動電流値は、必ずしき
い値電流以下に設定されることになる。At this time, the light emitting element 1a has a threshold value in the forward output-forward current characteristic, but the circuit constant of the light emitting element drive circuit 2 is set such that the light emitting element drive current value is in a range lower than the threshold value of the light emitting element 1a. By making this determination, the drive current value is always set to be equal to or less than the threshold current.
ここで、発光素子（半導体レーザ）ｌａのしきい値電流
−温度特性が第訓図のような場合、温度が一２０℃以上
のときは、しきい値が３５ｍＡ以上であるので、例えば
ＨＩＧＨ駆動電流を３０＋ｎＡに設定すれば、通常の使
用条件においてレーザ発振は起こり得ない。Here, if the threshold current-temperature characteristic of the light emitting element (semiconductor laser) la is as shown in Figure 1, when the temperature is 120°C or higher, the threshold value is 35 mA or higher, so for example, HIGH drive If the current is set to 30+nA, no laser oscillation can occur under normal usage conditions.
このように、発光素子駆動電流を必ずしきい値電流以下
に設定することにより、先出力−順電流特性にしきい値
を持つ発光素子１ａを用いても、モニタ用受光素子およ
びＡＰＣ回路がなくても、温度変化等によるしきい値電
流の変化に対応することができる。In this way, by always setting the light-emitting element drive current below the threshold current, even if the light-emitting element 1a having a threshold value in the forward output-forward current characteristic is used, there is no need for a monitor light-receiving element and an APC circuit. Also, it is possible to cope with changes in threshold current due to temperature changes and the like.
したがって、本実施例によると、発光素子は応答速度が
充分速く、価格も安く、かつＡＰＣ回路やモニタ用受光
素子が不要となるために、装置全体のコストを下げるこ
とができ、また発光素子の寿命も、しきい値電流以下で
使用する場合に比べ、長くすることかできるので、信頼
性も向上する。Therefore, according to this embodiment, the light emitting element has a sufficiently fast response speed, is inexpensive, and does not require an APC circuit or a light receiving element for monitoring, so the cost of the entire device can be reduced. The lifespan can be extended compared to the case where the current is used below the threshold current, so the reliability is also improved.
なお、本発明は、上記実施例に限定されるものではなく
、本発明の範囲内で上記実施例に多くの修正および変更
を加え得ることは勿論である。It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.
〈発明の効果〉
以上の説明から明らかな通り、本発明によると、先出力
−順電流特性にしきい値を持つ発光素子を使用し、発光
素子電流値を必ず発光素子のしきい値電流よりも低い範
囲に設定しているので、温度変化等による発光素子のし
きい値電流の変化にかかわらず、使用することができる
。<Effects of the Invention> As is clear from the above description, according to the present invention, a light emitting element having a threshold value in the forward output-forward current characteristic is used, and the current value of the light emitting element is always set to be lower than the threshold current of the light emitting element. Since it is set in a low range, it can be used regardless of changes in the threshold current of the light emitting element due to changes in temperature or the like.
したがって、従来しきい値を持つ発光素子を用いた場合
には、必ずモニタ用受光素子とＡＰＣ回路とが必要であ
ったが、これらが不要となり、装置全体のコスト低減を
図れ、しかも信頼性が向上する。また、しきい値をもた
ない発光素子を用いた場合に比べると、応答速度が速く
なるために高速伝送を行なうことが可能となる。Therefore, conventionally, when using a light-emitting element with a threshold value, a monitor light-receiving element and an APC circuit were always required, but these are no longer necessary, reducing the cost of the entire device and improving reliability. improves. Furthermore, compared to the case where a light emitting element without a threshold is used, the response speed is faster, so high-speed transmission can be performed.
第１図は本発明の一実施例に係る光信号送信装置の構成
を示すブロック図、第２図は同じくその発光素子の構造
を示す図、第３図は発光素子のしきい値電流−温度特性
を示す図、第４図は従来例１としての光信号送信装置の
構成を示すブロック図、第５図はその発光素子の先出力
−順電流特性を示す図、第６図は従来例２としての光信
号送信装置の構成を示すブロック図、第７図はその発光
素子の先出力−順電流特性を示す図である。
１ａ：発光素子、２：Ｒ光素子駆動回路、６．定電流回
路。FIG. 1 is a block diagram showing the configuration of an optical signal transmitter according to an embodiment of the present invention, FIG. 2 is a diagram showing the structure of a light emitting device, and FIG. 3 is a diagram showing the threshold current vs. temperature of the light emitting device. FIG. 4 is a block diagram showing the configuration of an optical signal transmitter as conventional example 1, FIG. 5 is a diagram showing the forward output-forward current characteristics of the light emitting element, and FIG. 6 is conventional example 2. FIG. 7 is a block diagram showing the configuration of the optical signal transmitting device as shown in FIG. 1a: light emitting element, 2: R optical element drive circuit, 6. Constant current circuit.
Claims (1)
あって、発光素子と、該発光素子を駆動させる発光素子
駆動回路とを備えた光信号送信装置において、前記発光
素子は、先出力−順電流特性にしきい値を持つものが使
用され、前記発光素子駆動回路は、発光素子駆動電流値
が発光素子のしきい値よりも低い範囲となるよう、回路
定数が決定されたことを特徴とする光信号送信装置。In an optical signal transmitting device that transmits an electrical signal by first converting it into an optical signal, and includes a light emitting element and a light emitting element drive circuit that drives the light emitting element, the light emitting element has a first output - A circuit having a threshold value in forward current characteristics is used, and the circuit constants of the light emitting element driving circuit are determined so that the light emitting element driving current value is in a range lower than the threshold value of the light emitting element. Optical signal transmitter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2167454A JPH0456288A (en) | 1990-06-25 | 1990-06-25 | Optical signal transmitting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2167454A JPH0456288A (en) | 1990-06-25 | 1990-06-25 | Optical signal transmitting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0456288A true JPH0456288A (en) | 1992-02-24 |
Family
ID=15849991
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2167454A Pending JPH0456288A (en) | 1990-06-25 | 1990-06-25 | Optical signal transmitting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0456288A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9890883B2 (en) | 2010-06-08 | 2018-02-13 | Waterworks Technology Development Organization Co., Ltd. | Pipe joint, packing ring, and method for mounting pipe joint |
-
1990
- 1990-06-25 JP JP2167454A patent/JPH0456288A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9890883B2 (en) | 2010-06-08 | 2018-02-13 | Waterworks Technology Development Organization Co., Ltd. | Pipe joint, packing ring, and method for mounting pipe joint |
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