JPS5830779B2 - optical transmitter - Google Patents
optical transmitterInfo
- Publication number
- JPS5830779B2 JPS5830779B2 JP54099334A JP9933479A JPS5830779B2 JP S5830779 B2 JPS5830779 B2 JP S5830779B2 JP 54099334 A JP54099334 A JP 54099334A JP 9933479 A JP9933479 A JP 9933479A JP S5830779 B2 JPS5830779 B2 JP S5830779B2
- Authority
- JP
- Japan
- Prior art keywords
- light source
- signal
- optical
- output
- light emitting
- 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
- H04B10/58—Compensation for non-linear transmitter output
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
- Led Devices (AREA)
Description
【発明の詳細な説明】 本発明は光通信方式に使用される光送信装置に関する。[Detailed description of the invention] The present invention relates to an optical transmitter used in an optical communication system.
特に入力電気信号に対して出力光信号の歪特性および雑
音特性の改良された光送信装置に関する。In particular, the present invention relates to an optical transmitter with improved distortion characteristics and noise characteristics of an output optical signal with respect to an input electrical signal.
発光ダイオードＬＥＤあるいは半導体レーザＬＤの電気
光変換特性の非直線性を補償するため、あるいは半導体
レーザの雑音特性を改良するために、第１図に示すよう
なフィードバックを用いる手法が知られている。In order to compensate for the nonlinearity of the electro-optical conversion characteristics of a light emitting diode LED or a semiconductor laser LD, or to improve the noise characteristics of a semiconductor laser, a method using feedback as shown in FIG. 1 is known.
すなわち第１図で、発光源駆動回路１は電気入力信号と
帰還信号の差を増幅し、発光源２を１駆動し、その出力
光は光ファイバ３により取出される。That is, in FIG. 1, a light emitting source driving circuit 1 amplifies the difference between an electrical input signal and a feedback signal, drives a light emitting source 2, and its output light is extracted through an optical fiber 3.
またこの出力光の一部はフォトダイオードにより電気信
号に変換され、増幅器５により増幅されて、帰還信号と
して発光源駆動回路１の入力に負帰還結合されている。Further, a part of this output light is converted into an electric signal by a photodiode, amplified by an amplifier 5, and coupled by negative feedback to the input of the light source driving circuit 1 as a feedback signal.
このような構成の装置では、光信号と電気入力信号との
間に、歪あるいは雑音などの原因で偏差が生じても、こ
の負帰還ループによって補償される優れた性質がある。A device with such a configuration has an excellent property that even if a deviation occurs between the optical signal and the electrical input signal due to causes such as distortion or noise, it is compensated for by the negative feedback loop.
しかしこの構成では次のような理由で高い周波数の信号
まで利用することは困難であった。However, with this configuration, it is difficult to utilize high frequency signals for the following reasons.
すなわち、（１）発光源２とフォトダイオード４との間
の電流変換効率が悪いので、増幅器５の増幅度を大きく
採らなければならない。That is, (1) since the current conversion efficiency between the light emitting source 2 and the photodiode 4 is poor, the amplification degree of the amplifier 5 must be increased.
このため増幅器５の内部の遅延時間が大きくなり、帰還
ループの位相余裕が小さくなる。Therefore, the internal delay time of the amplifier 5 increases, and the phase margin of the feedback loop decreases.
（２）大きな光出力を取り出すための光源は大電流で駆
動されるが、大電流駆動トランジスタの高周波特性はそ
の構造上あまり良好でなく高域での位相まわりが大きく
なる。(2) A light source for extracting a large optical output is driven with a large current, but the high frequency characteristics of a large current driven transistor are not very good due to its structure, and the phase rotation in the high range becomes large.
従って高い周波数での帰還ループの構成が困難になる。Therefore, it becomes difficult to construct a feedback loop at high frequencies.
（３）大出力用の半導体レーザあるいは発光ダイオード
などの端子インピーダンスの周波数特性は端子間容量が
大きく、高周波の位相余裕を減少させる。(3) The frequency characteristics of the terminal impedance of a high-output semiconductor laser or a light emitting diode have a large inter-terminal capacitance, which reduces the high frequency phase margin.
本発明はこれらの欠点を解決するもので、高周波まで利
用することのできる負帰還形の光送信装置を提供するこ
とを目的とする。The present invention solves these drawbacks, and aims to provide a negative feedback type optical transmitter that can be used up to high frequencies.
本発明は電気入力信号を直接光信号に変換する信号用光
源の他に、帰還ループを構成するためにもう一つの別の
光源を用いることを特徴とする特以下図面により実施例
を詳細に説明する。The present invention is characterized in that, in addition to a signal light source that directly converts an electrical input signal into an optical signal, another light source is used to configure a feedback loop. do.
第２図は本発明の実施例装置構成図である。FIG. 2 is a configuration diagram of an apparatus according to an embodiment of the present invention.
６は光源駆動用回路、γは光結合器、８は光分岐器、９
は光源駆動用回路、１０は光源である。6 is a light source driving circuit, γ is an optical coupler, 8 is an optical splitter, 9
1 is a light source driving circuit, and 10 is a light source.
電気入力信号は光源駆動用回路６を通して光源２を駆動
し、光出力信号に変換される。The electrical input signal drives the light source 2 through the light source driving circuit 6 and is converted into an optical output signal.
この光出力信号は、もう一つの光源１０からの光信号と
光結合器７で合成された後に、光分岐器８により、その
一部がモニタ信号として取出される。This optical output signal is combined with an optical signal from another light source 10 by an optical coupler 7, and then a part thereof is taken out by an optical splitter 8 as a monitor signal.
この光信号はフォトダイオード４で電気信号に変換され
、モニタ信号増幅器５で増幅される。This optical signal is converted into an electrical signal by a photodiode 4 and amplified by a monitor signal amplifier 5.
さらに光源駆動用回路９で電気入力信号と比較され、そ
の誤差分が増幅されて、光源１０に加えられる。Furthermore, it is compared with an electrical input signal in the light source driving circuit 9, and the error is amplified and applied to the light source 10.
このような構成の装置では、光源１０、フォトダイオー
ド４、モニタ増幅器５および光源駆動用回路９はフィー
ドバックループを構成し、光源２で発生した歪および雑
音を光源１０により補償することができる。In the device having such a configuration, the light source 10, the photodiode 4, the monitor amplifier 5, and the light source driving circuit 9 form a feedback loop, and the light source 10 can compensate for the distortion and noise generated in the light source 2.
しかも、この装置の光源１０は、光源２の歪および雑音
を補償するだけの光出力があればよいので、小出力の光
源で十分である。Furthermore, the light source 10 of this device only needs to have an optical output sufficient to compensate for the distortion and noise of the light source 2, so a small output light source is sufficient.
このために従来の実施例に比べて次のような特長がある
。For this reason, the present invention has the following features compared to conventional embodiments.
（１）光源が小出力でよいので半導体レーザを使う場合
には、電流対光出力比の大きいものを選ぶことができる
。(1) Since the light source requires only a small output, if a semiconductor laser is used, one with a large current-to-light output ratio can be selected.
従って帰還回路のオープンループゲインを大きくするこ
とができる。Therefore, the open loop gain of the feedback circuit can be increased.
（２）駆動電流が小さいため高速の光源駆動回路で駆動
することができる。(2) Since the drive current is small, it can be driven by a high-speed light source drive circuit.
また所要利得も小さくて良いので遅延時間を短くするこ
とができ、帰還ループの位相余裕を大きくとれる。Furthermore, since the required gain is small, the delay time can be shortened and the phase margin of the feedback loop can be increased.
（３）小出力の光源はその構造上２端子インピーダンス
の周波数特性が良いので、駆動時の位相まわりが少なく
ループの位相余裕を大きくすることができる。(3) Since a low-output light source has good frequency characteristics of two-terminal impedance due to its structure, the phase rotation during driving is small and the phase margin of the loop can be increased.
これらの特長により、帰還ループを従来の実施例に比べ
て高い周波数まで安定に動作させることができる。These features allow the feedback loop to operate stably up to higher frequencies than in conventional embodiments.
また、従来装置と同じ周波数範囲で動作させる場合には
、オーブンループゲインを大きくすることができるので
、歪、雑音特性の改善に効果がある。Furthermore, when operating in the same frequency range as the conventional device, the oven loop gain can be increased, which is effective in improving distortion and noise characteristics.
第２図では、光結合器７と光分岐器８は分離した形のも
のを示したが、これらは第３図に示すように、一つのま
とまった形で構成することも可能である。In FIG. 2, the optical coupler 7 and the optical splitter 8 are shown as being separated, but they can also be configured as one unit as shown in FIG. 3.
第３図で１１はハーフミラ−であって、光源２、光源１
０からの光電力のいを透過し、１／２を反射する。In Fig. 3, 11 is a half mirror, light source 2, light source 1
The optical power from 0 is transmitted and 1/2 is reflected.
このため出力光電力とフォトダイオード４への入力光電
力とは同一となるが、第２図と同様に負帰還ループを構
成することができ、同様の効果が得られる。Therefore, the output optical power and the input optical power to the photodiode 4 are the same, but a negative feedback loop can be constructed in the same way as in FIG. 2, and the same effect can be obtained.
以上説明したように本発明によれば、光信号出力用光源
と帰還用光源とが分離した構造になっているので、位相
回転の少ない負帰還ループを構成することができ、その
ために高い周波数まで歪特性および雑音特性の優れた光
送信装置を得ることができる。As explained above, according to the present invention, since the optical signal output light source and the feedback light source have a separate structure, it is possible to configure a negative feedback loop with little phase rotation. An optical transmitter with excellent distortion characteristics and noise characteristics can be obtained.
第１図は従来例装置の構成図。 第２図は本発明実施例装置の構成図。 第３図は光結合部の他の構成例を示す図。 FIG. 1 is a configuration diagram of a conventional device. FIG. 2 is a configuration diagram of an apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing another example of the configuration of the optical coupling section.
Claims (1)
この発光源とは別の第二の発光源１０と、この第一およ
び第二の発光源の出力光を合成する手段と、この合成さ
れた出力光の一部を電気信号に変換し出力モニタ信号を
得る手段と、この出力モニタ信号と前記入力電気信号と
の差を増幅し前記第二の発光源を駆動する手段とを備え
た光送信装置。1 a first light emitting source 2 driven by a human-powered electric signal;
A second light emitting source 10 different from this light emitting source, a means for combining the output lights of the first and second light emitting sources, and a means for converting a part of the combined output light into an electrical signal and output monitoring. An optical transmitter comprising: means for obtaining a signal; and means for amplifying the difference between the output monitor signal and the input electrical signal to drive the second light emitting source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54099334A JPS5830779B2 (en) | 1979-08-03 | 1979-08-03 | optical transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54099334A JPS5830779B2 (en) | 1979-08-03 | 1979-08-03 | optical transmitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5623047A JPS5623047A (en) | 1981-03-04 |
| JPS5830779B2 true JPS5830779B2 (en) | 1983-07-01 |
Family
ID=14244720
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP54099334A Expired JPS5830779B2 (en) | 1979-08-03 | 1979-08-03 | optical transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5830779B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57203349A (en) * | 1981-06-09 | 1982-12-13 | Nec Corp | Laser diode driving circuit |
| AU5949790A (en) * | 1989-06-23 | 1991-01-17 | At & E Corporation. | Optoelectronic test apparatus for communicating with a receiver |
| US5535039A (en) * | 1994-12-08 | 1996-07-09 | Harris Corporation | Divergence feedback in a linear fiber optic analog transmission system and method |
-
1979
- 1979-08-03 JP JP54099334A patent/JPS5830779B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5623047A (en) | 1981-03-04 |
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