JPS61198934A - Optical transmitter - Google Patents
Optical transmitterInfo
- Publication number
- JPS61198934A JPS61198934A JP60039352A JP3935285A JPS61198934A JP S61198934 A JPS61198934 A JP S61198934A JP 60039352 A JP60039352 A JP 60039352A JP 3935285 A JP3935285 A JP 3935285A JP S61198934 A JPS61198934 A JP S61198934A
- Authority
- JP
- Japan
- Prior art keywords
- output
- current
- reference current
- current source
- laser diode
- 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
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
- H01S5/06—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
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野ｊ
この発明は光出力を容易に設定可能な光送信器に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application j] This invention relates to an optical transmitter whose optical output can be easily set.
〔従来の技術Ｊ
第４図に例えば昭和５６年度電子通信学会総合全国大会
２２４Ｂ 「キャリア検出回路材１００ ＭＤ／Ｓレー
ザダイオード光送信光送信器源れた従来の光送信器を示
す構成図であり、第１図において、（］）は送信データ
入力端子、（２）は入力端子（１）に接続でれた変調器
、（３１は発光素子としてのレーザダイオード、（４）
は送信データの平均値検出回路、 ＋５）Ｈ平均値検出
回路に接続された電圧増幅器、（６）は電圧増幅器の基
準電圧源、（７）は抵抗、（８）はレーザダイオードの
出力光の一部を受光する受光素子、 （９１＆−ｊこの
受光素子（８）に並列接続されたコンデンサ、 １１は
受光素子（８）のバイアス用電源、α１１は電流増幅器
である。[Prior art J] For example, Figure 4 is a configuration diagram showing a conventional optical transmitter, which was used as the source of the optical transmitter. , In Fig. 1, (]) is a transmission data input terminal, (2) is a modulator connected to input terminal (1), (31 is a laser diode as a light emitting element, (4)
is the average value detection circuit of the transmitted data, +5) is the voltage amplifier connected to the H average value detection circuit, (6) is the reference voltage source of the voltage amplifier, (7) is the resistor, and (8) is the output light of the laser diode. A light-receiving element that receives a portion of the light, (91&-j) a capacitor connected in parallel to the light-receiving element (8), 11 a power supply for biasing the light-receiving element (8), and α11 a current amplifier.
従来の光送信器は上記の様に構成されていて。A conventional optical transmitter is configured as described above.
送信データ入力端子ｆｉｌに加えられた送信データに対
応した電流が変調器（２）によって変調され、レーザダ
イオード（３）に印加される。また、送信データは平均
値検出回路（４）に加えられ、送信データの平均値に比
例した電圧が平均値検出回路（４）から出力され、Ｘ圧
増幅器（５）の一方の入力端に加えられる。A current corresponding to the transmission data applied to the transmission data input terminal fil is modulated by the modulator (2) and applied to the laser diode (3). In addition, the transmitted data is applied to the average value detection circuit (4), and a voltage proportional to the average value of the transmitted data is output from the average value detection circuit (4), and is applied to one input terminal of the X-pressure amplifier (5). It will be done.
電圧増幅器（５）の他方の入力端には、基準電圧源（６
）が接続されている。電圧増幅器（５）は平均値検出回
路（４）と基準電圧源（６）の差の電圧を増幅する。電
圧増幅器（５１の出力電圧と電流増幅器αυの入力電圧
の差を抵抗（７）で除した電流と受光素子（８）電流れ
る電流の平均値の差が電流増幅器Ｉで増幅され、レーザ
ダイオード（３）に印加される。変調器（２）と電流増
幅器αυの出力電流の和がレーザダイオード（３）を流
れ、光に変換され、その一部が光出力として取り出され
る。また一部の光が受光素子（８）に入射し。A reference voltage source (6) is connected to the other input terminal of the voltage amplifier (5).
) are connected. The voltage amplifier (5) amplifies the voltage difference between the average value detection circuit (4) and the reference voltage source (6). The difference between the average value of the current obtained by dividing the difference between the output voltage of the voltage amplifier (51) and the input voltage of the current amplifier αυ by the resistor (7) and the current flowing through the light receiving element (8) is amplified by the current amplifier I, and 3).The sum of the output currents of the modulator (2) and the current amplifier αυ flows through the laser diode (3) and is converted into light, part of which is taken out as optical output. enters the light receiving element (8).
それに比例した電流が上記の受光素子（８）を流れる電
流でろる。A current proportional to the current flows through the light receiving element (8).
したがって、レーザダイオード（３）の光出力が犬きく
なると受光素子（８）電流れる電流が増え、電流増幅器
αυの出力電流が少なくなり、レーザダイオード＋３１
の光出力が減少する。レーザダイオード（３）の光出力
が減少し７た場合は上記と逆の理由でレーザダイオード
（３）の光出力が大きくなる。この負帰還動作によって
、レーザダイオード＋３１の光出力がるる一定ｆｉに保
たれる。ディジタル信号全伝送する際の光信号のピーク
値に着目すると、レーザダイオード（３１の光出力のピ
ーク値Ｐ。ｕｔは次の様に表わされる。Therefore, when the optical output of the laser diode (3) becomes sharper, the current flowing through the light receiving element (8) increases, the output current of the current amplifier αυ decreases, and the laser diode +31
light output is reduced. When the optical output of the laser diode (3) decreases, the optical output of the laser diode (3) increases for the opposite reason to the above. By this negative feedback operation, the optical output of the laser diode +31 is kept constant fi. Focusing on the peak value of the optical signal when all digital signals are transmitted, the peak value P.ut of the optical output of the laser diode (31) is expressed as follows.
Ｐｏｕｔ ＝ Ａ （ＩＢ ＋ ＩＯＰ −Ｉｔｈ）
・・・・・・・・・・・・（１）ただし
ＩＢ＝β（Ｉｏ −ＩｐＤ） −−・”・（
２１１ｐ）） ＝ ｍ−ＩＬＬ、Ｐ ｏｕｔ
・・・・・・・・・・・・（３）■Ｂ：バイアス電
流（を流増幅器出力電流）Ｉｏｐ：変調電流（変調器出
力電流）
Ｉｚｈ ：レーザダイオードしきい値電流β：電流増幅
器増幅率
ＩＰＤ ：受光素子電流
Ｉｏ：基準電流
ｍ：ディジタル信号のマーク率（ｏ＜ｍ＝１）Ｌ：光出
力と受光素子電流変換効率
Ａ：レーザダイオード電・光変換効率
Ｄ：パルス占有率
なお、レーザダイオード（３）は第５図に示すように、
しきい値電流ｒｔｈ以下では発光しないものとする。Pout = A (IB + IOP - Ith)
・・・・・・・・・・・・(1) However, IB=β(Io −IpD) −−・”・(
211p)) = m-ILL, P out
・・・・・・・・・・・・(3) ■B: Bias current (amplifier output current) Iop: Modulation current (modulator output current) Izh: Laser diode threshold current β: Current amplifier amplification Rate IPD: Photodetector current Io: Reference current m: Mark rate of digital signal (o<m=1) L: Light output and photodetector current conversion efficiency A: Laser diode electric/light conversion efficiency D: Pulse occupancy rate The laser diode (3) is as shown in Figure 5.
It is assumed that no light is emitted below the threshold current rth.
第（１）式、第（２）式、第（３１式よりとなる。From Equation (1), Equation (2), and Equation (31).
第（４）式において、マーク率ｍが変化しても光出力Ｐ
。ｕｔが一定であるためにはマーク率に応じて基準電流
ＩＯを制御する必要がある。そこで。In equation (4), even if the mark rate m changes, the optical output P
. In order to keep ut constant, it is necessary to control the reference current IO according to the mark rate. Therefore.
Ｐｏｕｔ”Ｋ（一定）とおくと。If we set Pout”K (constant).
ＩＯ＝ Ｉｏｌ −）−ｍＩＯ２°０°°°００°−（
５１■ｏ２：＝に−Ｌ
となる。したかつ、て第（５１式に従って基準電流■０
を設定すれば、光出力Ｐ。ｕｔは一定となる。IO= Iol −)−mIO2°0°°°00°−(
51■o2:= becomes -L. Then, the reference current ■0 according to formula 51
If you set , the optical output P. ut remains constant.
第４図において基準電流は抵抗（７）？流れる電流でる
り、抵抗（７］？流れる電流ＩＯ′は次式で表わされる
。In Figure 4, the reference current is the resistance (7)? Flowing current R, resistance (7)?Flowing current IO' is expressed by the following equation.
ただし。however.
ｖＰ：平均値検出回路のｍ＝１のときの出力電圧
ｖｒｅｆ：基準電圧源電圧
Ｖｉ、：電流増幅器入力電圧
Ｇ：電圧増幅器の増幅率
Ｒ：抵抗（７）の抵抗値
所定の光出力を得るには、基準電圧源（６）と抵抗（７
） ｔｌ−調整することにＸり。vP: Output voltage of the average value detection circuit when m=1 vref: Reference voltage source voltage Vi,: Current amplifier input voltage G: Voltage amplifier amplification factor R: Resistance value of resistor (7) Obtain a predetermined optical output includes a reference voltage source (6) and a resistor (7).
) tl-I'm sorry for the adjustment.
に設定する。第（７１式はｍ＝０のときの基準電流であ
る。Set to . The 71st formula is the reference current when m=0.
〔発明が解決しようとする問題点〕
以上の様に従来の光送信器は構成されていたので、第（
６）式において、抵抗（７）の値Ｒが、マーク率ｍの影
響を受ける項と受けない項の両方に含まれている。抵抗
（７）により Ｉｏ２を設定する場合、 Ｉｏｌも変化
するので−ＶＨｎ’ｘ再度調整し１両者が目標値に達す
るまで繰り返し設定する必要があり、光出力の設定方法
が複雑であるという問題点があった。[Problems to be solved by the invention] Since the conventional optical transmitter was configured as described above,
In Equation 6), the value R of resistance (7) is included in both the term affected by the mark rate m and the term not affected. When setting Io2 using the resistor (7), since Iol also changes, it is necessary to readjust -VHn'x and set it repeatedly until both reach the target value, and the problem is that the method for setting the optical output is complicated. was there.
この発明は、この様な問題点全解決するためになされた
もので、光出力の設定、すなわち基準電流の設定が容易
な光送信器？得ることを目的としている。This invention was made to solve all of these problems, and is an optical transmitter that allows easy setting of optical output, that is, setting of reference current. The purpose is to obtain.
この発明による光送信器は、基準電流源を、第１の基準
電流源と、第２の基準を流源と、上記第２の基準電流源
の出力端に接続され送信データに対応してオン・オフす
るスイッチ回路と、上記第１の基準電流源の出力と上記
スイッチ回路の出力とを合成する合成手段とにより構成
したものである。The optical transmitter according to the present invention includes a reference current source, a first reference current source, a second reference current source, and an output terminal of the second reference current source that is connected to the output terminal and turned on in response to transmission data. - It is composed of a switch circuit that turns off, and a synthesizing means that synthesizes the output of the first reference current source and the output of the switch circuit.
〔作用Ｊ
この発明においては、使用する２個の基準電流源の出力
音それぞれ独立に設定できるため、マーク率変動に対す
る光出力設定が容易になる。[Function J] In this invention, since the output sounds of the two reference current sources used can be independently set, it becomes easy to set the light output in response to mark rate fluctuations.
第１図はこの発明の一実施例を示す光送信器の構成図で
ｉＪ、（ｌｌは送信データ入力端子、（２）は入力端子
ｆｉ＋に接続された変調器、（３）はレーザダイオード
、（８１Ｈレーザダイオード（３）の出力光の一部を受
光する受光素子、（９）はこの受光素子（８）に並列接
続すれたコンデンサ、ａυは受光素子ｆ８） （７）ハ
（７、＜用電源、（Ｉυは電流増幅器、α邊は第１の基
準電流源。FIG. 1 is a configuration diagram of an optical transmitter showing an embodiment of the present invention, in which iJ, (ll is a transmission data input terminal, (2) is a modulator connected to the input terminal fi+, (3) is a laser diode, (A light-receiving element that receives part of the output light of the 81H laser diode (3), (9) is a capacitor connected in parallel to this light-receiving element (8), aυ is the light-receiving element f8) (7) C (7, < (Iυ is a current amplifier, and α is the first reference current source.
α：Ｉは第２の基準電流源、α４は第２の基準電流源α
ｊの出力端に接続され、２値送信データに対応して切換
えるスイッチ回路である。いま、送信データが′１“
のとき、レーザダイオード（１）が発光するように変調
器（２）は動作し、スイッチ回路Ｉは導通状態になるも
のとする。α: I is the second reference current source, α4 is the second reference current source α
This is a switch circuit that is connected to the output terminal of j and switches in response to binary transmission data. Now, the transmitted data is ``1''
At this time, the modulator (2) operates so that the laser diode (1) emits light, and the switch circuit I becomes conductive.
上記のように構成された光送信器において第２の基準電
流源αｊの出力は送信データに対応してスイッチ回路Ｉ
でオン・オフされた電流として出力され、第１の基準電
流源住ｚの出力と加算合成される。レーザダイオード（
３）の出力光の一部が受光素子（８）に入射し、それに
比例した電流が受光素子（８）を流れる。受光素子（８
）電流れる電流と上記合成された電流の差がコンデンサ
（９）で平均化され電流増幅器αυで増幅されレーザダ
イオード＋３１に印加される。In the optical transmitter configured as described above, the output of the second reference current source αj is applied to the switch circuit I in response to the transmitted data.
The current is outputted as a current that is turned on and off, and is added and synthesized with the output of the first reference current source Z. Laser diode (
A part of the output light of step 3) is incident on the light receiving element (8), and a current proportional to the amount enters the light receiving element (8). Light receiving element (8
) The difference between the flowing current and the above-mentioned combined current is averaged by the capacitor (9), amplified by the current amplifier αυ, and applied to the laser diode +31.
ここで、第１の基準電流源ａ７Ｊの電流値を式（５）の
Ｉｏｌ、第２の基準電流源Ｑｊの電流値を第（５）式の
１ｏ２に対応させることができる。そこで、マーク″４
ｍ二〇のときにＩｏ１’を設定し、しかる後に適当なマ
ーク率ｍにて１０２を設定すれば、基準電流ＩＯが決定
できる。したがって＋ Ｉｏｌ、Ｉｏ２が独立に設定
することができ、容易に基準電流、すなわち光出力が設
定できる。Here, the current value of the first reference current source a7J can be made to correspond to Iol in equation (5), and the current value of the second reference current source Qj can be made to correspond to 1o2 in equation (5). Therefore, mark "4"
By setting Io1' when m20 and then setting 102 at an appropriate mark rate m, the reference current IO can be determined. Therefore, +Iol and Io2 can be set independently, and the reference current, that is, the optical output, can be easily set.
第２図は第１図に示したこの発明の一実施例の回路図で
ある。第２図では、スイッチ回路α４を論理ゲートＧお
よびトランジスタＴｒ？備えてなる電流切換スイッチで
構成している。スイッチ回路に電流切換スイッチ回路を
用いることで高速のスイッチングが可能となり、高ビッ
トレートの光送信器が構成できる。また第２図では第１
．第２の基準電流源０３αｊをトランジスタＴｒおよび
抵抗ｒ１でそれぞれ構成し、又電流増幅器ａ１１ｆｔト
ランジスタＴｒ、抵抗ｒ２で構成している例を示してい
る。FIG. 2 is a circuit diagram of one embodiment of the invention shown in FIG. In FIG. 2, the switch circuit α4 is connected to the logic gate G and the transistor Tr? It consists of a current selector switch. By using a current changeover switch circuit for the switch circuit, high-speed switching becomes possible, and a high bit rate optical transmitter can be configured. Also, in Figure 2, the first
．． An example is shown in which the second reference current source 03αj is composed of a transistor Tr and a resistor r1, and the current amplifier a11ft is composed of a transistor Tr and a resistor r2.
なおここでは第１の基準電流源ａａと、第２の基準電流
源α３が加算される構成としたが減算される構成した場
合の実施例全第３図に示す。第３図において、スイッチ
回路Ｉが、送信データゝゝ０“に対して導通状態とする
と、マーク率ｍ＝１で■。１を設定すれば同様の効果が
得られる。Here, the first reference current source aa and the second reference current source α3 are configured to be added, but FIG. 3 shows an embodiment in which the first reference current source aa and the second reference current source α3 are configured to be subtracted. In FIG. 3, if the switch circuit I is in a conductive state for the transmission data "0", the same effect can be obtained by setting the mark rate m=1 and 1.
〔発明の効果１
この発明は以上説明したとおり、基準電流源とし、て第
１の基準電流源の出力と、別の第２の基準電流源に接続
した送信データと対応して切換える切換回路の出力との
合成出力を用いているため。[Effects of the Invention 1] As explained above, the present invention uses a switching circuit which serves as a reference current source and switches between the output of a first reference current source and the transmission data connected to another second reference current source. Because it uses a composite output with the output.
使用する２個の基準電流源の出力がそれぞれ独立に設定
できるため、光出力の設定が容易になる効果がおる。Since the outputs of the two reference current sources used can be set independently, the optical output can be easily set.
第１図はこの発明の一実施例を示す光送信器の構成図、
第２図は、第１図に示したこの発明の一実施例の具体的
な回路を示す図、第３図σこの発明の他の実施例を示す
構成図、第４図は従来の光送信器を示す構成図、第５図
はレーザダイオードの電流・光出力の関係を示す図であ
る。
図において、（１）は送信データ入力端子、（２）は変
調器、 ｆ３１ｉレーザダイオード、（４）は平均値検
出回路、（５）は電圧増幅器、（６）は基準電圧源、（
７）は抵抗。
（８）は受光素子、（９）はコ／デンサ、α〔は受光素
子バイアス用電源、Ｕは電流増幅器、ａａ、α３は第１
゜第２の基準電流源、幀にスイッチ回路である。
なお、各図中同一符号は同一ま念は相当部分を示す。FIG. 1 is a configuration diagram of an optical transmitter showing an embodiment of the present invention;
Fig. 2 is a diagram showing a specific circuit of one embodiment of the present invention shown in Fig. 1, Fig. 3 is a block diagram showing another embodiment of the invention, and Fig. 4 is a conventional optical transmission. FIG. 5 is a diagram showing the relationship between the current and optical output of the laser diode. In the figure, (1) is the transmission data input terminal, (2) is the modulator, f31i laser diode, (4) is the average value detection circuit, (5) is the voltage amplifier, (6) is the reference voltage source, (
7) is resistance. (8) is the photodetector, (9) is the co/capacitor, α[ is the photodetector bias power supply, U is the current amplifier, aa, α3 is the first
゜The second reference current source is a switch circuit. Note that the same reference numerals in each figure indicate corresponding parts.
Claims (2)
印加する変調器と、上記発光素子の出力光の一部を受光
する受光素子と、上記受光素子を流れる信号電流と基準
電流源の電流の差に比例した電流を上記発光素子に印加
する手段とを備えた光送信器において、上記基準電流源
を、第１の基準電流源と、第２の基準電流源と、上記第
２の基準電流源の出力端に接続され２値送信データに応
じてオン・オフするスイッチ回路と、上記第１の基準電
流源の出力と上記スイッチ回路の出力とを合成する合成
手段とにより構成したことを特徴とする光送信器。(1) A modulator that applies a binary current to a light emitting element in response to binary transmission data, a light receiving element that receives part of the output light of the light emitting element, and a signal current and a reference current that flow through the light receiving element. an optical transmitter comprising: means for applying a current to the light emitting element that is proportional to a difference in current between sources; A switch circuit connected to the output terminal of the second reference current source and turned on/off according to the binary transmission data, and a synthesizing means for synthesizing the output of the first reference current source and the output of the switch circuit. An optical transmitter characterized by:
とを特徴とする特許請求範囲第１項記載の光送信器。(2) The optical transmitter according to claim 1, characterized in that a current changeover switch is used as the switch circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60039352A JPS61198934A (en) | 1985-02-28 | 1985-02-28 | Optical transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60039352A JPS61198934A (en) | 1985-02-28 | 1985-02-28 | Optical transmitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61198934A true JPS61198934A (en) | 1986-09-03 |
| JPH0244420B2 JPH0244420B2 (en) | 1990-10-03 |
Family
ID=12550680
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60039352A Granted JPS61198934A (en) | 1985-02-28 | 1985-02-28 | Optical transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61198934A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107362A (en) * | 1989-01-20 | 1992-04-21 | Mitsubishi, Denki Kabushiki Kaisha | Optical transmission apparatus |
| EP0725462A1 (en) * | 1995-02-02 | 1996-08-07 | Siemens Aktiengesellschaft | Two level laserdiode power control using a single control circuit |
| JP2005064001A (en) * | 2003-08-08 | 2005-03-10 | Fuji Xerox Co Ltd | Light quantity controller and image forming device using it |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1093170A (en) * | 1996-09-10 | 1998-04-10 | Fuji Xerox Co Ltd | Laser diode drive circuit, semiconductor integrated circuit for driving laser diode, and image recorder |
-
1985
- 1985-02-28 JP JP60039352A patent/JPS61198934A/en active Granted
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107362A (en) * | 1989-01-20 | 1992-04-21 | Mitsubishi, Denki Kabushiki Kaisha | Optical transmission apparatus |
| EP0725462A1 (en) * | 1995-02-02 | 1996-08-07 | Siemens Aktiengesellschaft | Two level laserdiode power control using a single control circuit |
| JP2005064001A (en) * | 2003-08-08 | 2005-03-10 | Fuji Xerox Co Ltd | Light quantity controller and image forming device using it |
| JP4655457B2 (en) * | 2003-08-08 | 2011-03-23 | 富士ゼロックス株式会社 | Light quantity control device and image forming apparatus using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0244420B2 (en) | 1990-10-03 |
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