JPS624899B2 - - Google Patents
Info
- Publication number
- JPS624899B2 JPS624899B2 JP56100597A JP10059781A JPS624899B2 JP S624899 B2 JPS624899 B2 JP S624899B2 JP 56100597 A JP56100597 A JP 56100597A JP 10059781 A JP10059781 A JP 10059781A JP S624899 B2 JPS624899 B2 JP S624899B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- optical
- analog signal
- laser diode
- electrical signal
- 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
- 230000003287 optical effect Effects 0.000 claims description 58
- 230000005540 biological transmission Effects 0.000 claims description 11
- 238000001228 spectrum Methods 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 230000000903 blocking effect Effects 0.000 claims 1
- 238000003786 synthesis reaction Methods 0.000 claims 1
- 239000013307 optical fiber Substances 0.000 description 16
- 238000010586 diagram Methods 0.000 description 9
- 230000006866 deterioration Effects 0.000 description 5
- 230000001427 coherent effect Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
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
Description
【発明の詳細な説明】
本発明はビデオ信号のようなアナログ信号をレ
ーザダイオードを用いて光フアイバを伝送する光
送受信装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical transmitter/receiver that transmits an analog signal such as a video signal through an optical fiber using a laser diode.
従来のこの種の光送受信装置は、あとに図面を
用いて説明するが、入力したアナログ信号を増幅
し、増幅した信号を変調信号としてレーザダイオ
ードを駆動して光信号を出射する送信部と、出射
した光信号を光フアイバで伝送する光線路部と、
光フアイバ出射光を光電素子で電気信号に変換
し、この電気信号を増幅してアナログ信号を再生
して出力する光受信部とから成つていた。 A conventional optical transmitter/receiver of this type, which will be explained later with reference to the drawings, includes a transmitter that amplifies an input analog signal and uses the amplified signal as a modulation signal to drive a laser diode to output an optical signal; an optical line section that transmits the emitted optical signal through an optical fiber;
It consisted of an optical receiver that converts the light emitted from the optical fiber into an electrical signal using a photoelectric element, amplifies this electrical signal, and reproduces and outputs an analog signal.
しかし乍ら上記のような装置においては、これ
又あとに詳しく説明するが、レーザダイオードの
電流−光出力特性（Ｉ−Ｌ特性）で示されるキン
ク或いは曲りなどの非直線性によりアナログ信号
に波形歪が生じるという欠点があつた。又、レー
ザダイオードのコヒーレントな出力光は光フアイ
バ伝播中に各モード間での伝播時間差がレーザダ
イオードのコヒーレント長よりも短い場合にモー
ド間干渉が起き、このモード間干渉に起因して伝
送損失は変動し、光フアイバ伝播光は信号レベル
に依存して波形歪を生じるが、歪んだ光波形は受
光器でそのまま光検波される。従つて、再生され
たアナログ信号は非直線性歪が劣化し、例えばビ
デオ信号のDG・DP特性に劣化が生じるという欠
点があつた。 However, in the above-mentioned device, as will be explained in detail later, the analog signal may have a waveform due to non-linearities such as kinks or bends shown in the current-light output characteristics (IL characteristics) of the laser diode. The drawback was that distortion occurred. In addition, when the coherent output light of a laser diode is propagated through an optical fiber, inter-mode interference occurs when the propagation time difference between each mode is shorter than the coherent length of the laser diode, and the transmission loss due to this inter-mode interference is The optical fiber propagating light causes waveform distortion depending on the signal level, but the distorted optical waveform is optically detected as is by the optical receiver. Therefore, the reproduced analog signal suffers from deterioration in non-linear distortion, which has the disadvantage that, for example, the DG/DP characteristics of the video signal deteriorate.
上記の従来装置の欠点の説明において、前者の
波形歪みは広く知られていることであり、これに
対しレーザダイオードの改良がなされているが、
まだ満足すべきものは得られていない。また後者
の波形歪みはR.E.Epworthが1978年９月の
Proc.4th European Conference on Optical
Fiber Communicationにおいて“アナログ・デ
イジタル光フアイバシステムにおけるモード雑音
現象”と題する論文において指摘したもので、併
せてその対策についても説明を行つているが、実
際の装置においてモード雑音を無視できるところ
まで小さくすることは容易ではないように思われ
る。 In explaining the drawbacks of the conventional devices above, the former waveform distortion is widely known, and improvements have been made to laser diodes to address this problem.
I haven't found anything satisfying yet. The latter waveform distortion was reported by REEpworth in September 1978.
Proc.4th European Conference on Optical
This was pointed out in a paper entitled "Modal Noise Phenomenon in Analog/Digital Optical Fiber Systems" in Fiber Communication, and also explains countermeasures, which include reducing modal noise to the point where it can be ignored in actual equipment. It seems that this is not easy.
従つて本発明の目的は、前述のようなアナログ
信号を光フアイバ信号を光フアイバ伝送する光送
受信装置において、レーザダイオードおよび光フ
アイバ伝送路自身の特性の改良とは別の形でレー
ザダイオードのＩ−Ｌ特性の非直線性および光フ
アイバ伝送の非直性の影響を緩和させて、非直線
性による波形の劣化を軽減させた光送受信装置を
提供しようとするものである。 Therefore, an object of the present invention is to improve the I of the laser diode, in addition to improving the characteristics of the laser diode and the optical fiber transmission line itself, in an optical transmitter/receiver that transmits an analog signal through an optical fiber as described above. An object of the present invention is to provide an optical transmitting/receiving device in which the effects of nonlinearity of -L characteristics and nonlinearity of optical fiber transmission are alleviated, and waveform deterioration due to nonlinearity is reduced.
本発明は上記の目的を達成するために、アナロ
グ信号に高周波信号を混合して波高値を平均化す
ることにより波形歪を除去するようにしたもので
ある。 In order to achieve the above object, the present invention removes waveform distortion by mixing a high frequency signal with an analog signal and averaging the peak values.
すなわち本発明によれば、入力アナログ信号に
基づく変調信号によりレーザダイオードを駆動し
て光信号を出射する光送信部と、前記出射された
光信号を伝送する光線路部と、この光線路部から
の光信号を光電素子により電気信号に変換しこの
電気信号から前記入力アナログ信号に対応する出
力アナログ信号を発生する光受信部とから成る光
送受信装置において、前記光送信部に、前記入力
アナログ信号の有する周波数成分より高い周波数
領域にスペクトラムを持ち且つ該入力アナログ信
号の波高値より低い波高値を持つ高周波電気信号
を発生する高周波発生回路と、前記高周波電気信
号および前記入力アナログ信号を合成し、合成し
た信号から前記入力アナログ信号に基づく変調信
号が得られるように配置された合成回路とを設
け、前記レーザダイオードのバイアス電流をその
閾値電流以上に設定し、前記光受信部の信号線路
に、前記高周波電気信号の周波数成分を阻止する
波器を設けて成ることを特徴とする光送受信装
置が得られる。 That is, according to the present invention, there is an optical transmitter that drives a laser diode with a modulation signal based on an input analog signal to output an optical signal, an optical line that transmits the emitted optical signal, and a an optical transmitter/receiver comprising: an optical receiver that converts an optical signal into an electrical signal using a photoelectric element and generates an output analog signal corresponding to the input analog signal from the electrical signal; a high frequency generation circuit that generates a high frequency electrical signal that has a spectrum in a frequency region higher than the frequency components of the input analog signal and has a peak value lower than the peak value of the input analog signal, and synthesizes the high frequency electrical signal and the input analog signal; a combining circuit arranged so that a modulated signal based on the input analog signal can be obtained from the combined signal, a bias current of the laser diode is set to a threshold current or more, and a signal line of the optical receiver is provided with a combining circuit arranged to obtain a modulated signal based on the input analog signal from the combined signal; An optical transmitting/receiving device is obtained, which is characterized in that it is provided with a transducer that blocks frequency components of the high-frequency electric signal.
次に図面を参照して詳細に説明する。 Next, a detailed explanation will be given with reference to the drawings.
第１図は従来のこの種の光送受信装置における
光通信系の構成例を示した図である。第１図の左
側の送信部において、入力端１に加えられるア
ナログ信号は、光送信回路２を経てレーザダイオ
ード３を駆動し、光強度変調された光信号に変換
する。このレーザダイオード３の光信号は光フア
イバ４により図の右側の受信部に光伝送され
る。この光フアイバ出射光は受光素子５により光
検波されて電気信号に変換され、変換された電気
信号は光受信回路６で増幅され、出力端７にアナ
ログ信号が再生される。 FIG. 1 is a diagram showing an example of the configuration of an optical communication system in a conventional optical transmitter/receiver of this type. In the transmission section on the left side of FIG. 1, an analog signal applied to an input terminal 1 passes through an optical transmission circuit 2, drives a laser diode 3, and is converted into a light intensity modulated optical signal. The optical signal from the laser diode 3 is optically transmitted through an optical fiber 4 to a receiving section on the right side of the figure. The light emitted from the optical fiber is optically detected by the light receiving element 5 and converted into an electrical signal.The converted electrical signal is amplified by the optical receiving circuit 6 and an analog signal is reproduced at the output end 7.
第２図は先に簡単に説明したレーザダイオード
の駆動電流Ｉと出力光Ｌの関係の一例を示した図
で、キンク或いは曲りなどの非直線が明確にあら
われており、アナログ信号をこの特性のまま光強
度変調すれば波形歪を生じることを示している。
なおこの特性は最近のレーザダイオードでは相当
改善されているが、まだそのままで使用した場合
好ましくない波形歪が残つている。また実際にレ
ーザタイドに印加する電流には、この波形の直線
に近い部分の中央に近いI0に相当するバイアス電
流を附加している。なおＩthは閾値電流を示す。 Figure 2 is a diagram showing an example of the relationship between the drive current I of the laser diode and the output light L, which was briefly explained earlier. Non-linearity such as kinks or bends is clearly visible, and the analog signal is This shows that if the light intensity is modulated as is, waveform distortion will occur.
Although this characteristic has been considerably improved in recent laser diodes, undesirable waveform distortion still remains when used as is. Furthermore, a bias current corresponding to I 0 near the center of the near-straight line portion of this waveform is added to the current actually applied to the laser tide. Note that I th indicates a threshold current.
第３図は本発明によるアナログ信号の光通信シ
ステム構成の一実施例を示した図である。第３図
においては前記第１図を参照して説明した構成要
素に共通した部分があるので、第３図中第１図と
同一部分の構成要素については同一符号を付して
説明を省略し、以下異なる部分について説明す
る。１１は高周波雑音発生回路であり、アナログ
信号の有する周波数成分よりも高い周波数領域に
スペクトラムをもつ雑音状電気信号Ｂを発生す
る。１２は混合器であり、アナログ信号Ａと高周
波雑音発生回路１１の雑音状電気信号Ｂとを合成
し、合成した電気信号Ｃを発する。１３は低域
波器であり、光受信回路６の出力電気信号Ｆに含
まれる雑音状電気信号を分離し、アナログ信号Ｇ
のみを取り出すものである。 FIG. 3 is a diagram showing an embodiment of the configuration of an analog signal optical communication system according to the present invention. In Fig. 3, there are parts common to the constituent elements explained with reference to Fig. 1 above, so the constituent elements in Fig. 3 that are the same as those in Fig. 1 are given the same reference numerals and explanations are omitted. , the different parts will be explained below. Reference numeral 11 denotes a high frequency noise generation circuit, which generates a noise-like electrical signal B having a spectrum in a frequency region higher than the frequency components of the analog signal. A mixer 12 combines the analog signal A and the noise-like electrical signal B from the high-frequency noise generating circuit 11, and generates a synthesized electrical signal C. Reference numeral 13 denotes a low frequency filter, which separates the noise-like electrical signal contained in the output electrical signal F of the optical receiver circuit 6 and converts it into an analog signal G.
It is for taking out only.
第４図および第５図には第３図の各部に対応す
る信号波形の交流成分およびスペクトラムをそれ
ぞれ示す図である。以下第３図〜第５図を併用し
て説明すると、入力端１に加えられるアナログ信
号Ａと高周波雑音発生回路１１からの前記信号Ａ
に比して波高値の相当低い雑音状電気信号Ｂとを
混合器１２で合成し、この合成した電気信号Ｃで
光送信回路２によりバイアスされたレーザダイオ
ード３を光強度変調する。レーザダイオード３の
出力光Ｄは光フアイバ４により光伝送される。こ
の光フアイバ４の出射光Ｅは受光素子５により光
検波されて電気信号に変換される。この電気信号
は光受信回路６で増幅され、増幅された電気信号
Ｆは低域波器１３により雑音状電気信号成分を
分離して、アナログ信号Ｇが出力端７に再生され
る。 FIGS. 4 and 5 are diagrams showing AC components and spectra of signal waveforms corresponding to each part of FIG. 3, respectively. The following explanation will be given with reference to FIGS. 3 to 5: the analog signal A applied to the input terminal 1 and the signal A from the high frequency noise generation circuit 11.
The mixer 12 synthesizes the noise-like electrical signal B, which has a considerably lower peak value than the noise-like electrical signal B, and modulates the optical intensity of the biased laser diode 3 by the optical transmission circuit 2 with the synthesized electrical signal C. The output light D of the laser diode 3 is optically transmitted through an optical fiber 4. The emitted light E from the optical fiber 4 is optically detected by the light receiving element 5 and converted into an electrical signal. This electrical signal is amplified by the optical receiving circuit 6, and the amplified electrical signal F is separated into noise-like electrical signal components by the low frequency filter 13, and an analog signal G is reproduced at the output terminal 7.
従つて、伝送するアナログ信号をそのままレー
ザダイオードで光強度変調して光伝送中にアナロ
グ信号が直接に波形歪の影響を受ける第１図の従
来の光送受信装置とは異なり、本発明では伝送す
るアナログ信号よりももつと周期の速い雑音状電
気信号で変調した電気信号をレーザダイオードで
光強度変調することにより、レーザダイオードの
Ｉ−Ｌ特性の非直線性および光フアイバ伝送の非
直線性による波形歪が平均化される。この平均化
された光波形を受光器で電気信号に変換して低域
波器で波されて取り出されたアナログ信号の
波形は、歪が平均化されているので波形歪の劣化
を軽減することができる。 Therefore, unlike the conventional optical transmitter/receiver shown in FIG. 1, in which the analog signal to be transmitted is directly modulated in optical intensity with a laser diode and the analog signal is directly affected by waveform distortion during optical transmission, the present invention By using a laser diode to modulate the optical intensity of an electrical signal modulated with a noise-like electrical signal with a faster period than an analog signal, a waveform due to the nonlinearity of the I-L characteristic of the laser diode and the nonlinearity of optical fiber transmission is generated. The distortion is averaged out. This averaged optical waveform is converted into an electrical signal by a photoreceiver, and the waveform of the analog signal is taken out by a low-frequency wave generator. Since the distortion is averaged, the deterioration of waveform distortion can be reduced. I can do it.
以上述べたように、レーザダイオードを用いた
アナログ信号の光送受信装置による光通信システ
ムにおいて、レーザダイオード及び光フアイバの
非直線性による波形歪劣化を軽減でき、例えばビ
デオ信号のDG・DP特性における改善がなされ、
高品質のアナログ信号伝送を実現することができ
る。 As described above, in an optical communication system using an optical transmitter/receiver for analog signals using a laser diode, it is possible to reduce waveform distortion deterioration due to nonlinearity of the laser diode and optical fiber, and improve the DG/DP characteristics of video signals, for example. was done,
High quality analog signal transmission can be achieved.
なお、上記例においてはアナログ信号をこれよ
り速い周期の雑音状電気信号で変調した電気信号
でレーザダイオードを光強度変調したが、アナロ
グ信号をこれより周期の速いパルス信号で変調し
た電気信号でレーザダイオードを光強度変調し
て、高品質のアナログ信号と本来歪劣化の影響が
比較的少ないデイジタル信号とを同時に伝送する
ハイブリツド光伝送を実施することも可能であ
る。なお、この場合はアナログ信号のみ波形歪劣
化の改善がなされる。また受信部において、混
合器１２を光送信回路２の増幅回路の途中に配置
してもよく、同様な意味で受信部において低域
波器１３を光受信回路６の増幅器の中段に配置
してもよい。 Note that in the above example, the laser diode was modulated in light intensity by an electrical signal obtained by modulating an analog signal with a noise-like electrical signal with a faster period, but it It is also possible to carry out hybrid optical transmission in which a high-quality analog signal and a digital signal, which is originally relatively unaffected by distortion degradation, are simultaneously transmitted by modulating the optical intensity of the diode. Note that in this case, only the analog signal is improved in waveform distortion deterioration. Further, in the receiving section, the mixer 12 may be placed in the middle of the amplifier circuit of the optical transmitting circuit 2, and in the same sense, the low frequency amplifier 13 may be placed in the middle of the amplifier of the optical receiving circuit 6 in the receiving section. Good too.
第１図は従来のアナログ信号光送受信装置を用
いた光通信システムの構成図、第２図はレーザダ
イオードの非直線性を示すＩ−Ｌ特性図、第３図
は本発明を用いた光通信システムの構成図、第４
図は本発明各部を説明するための信号波形図、第
５図は第４図の信号波形に対応するスペクトラム
図である。
記号の説明：２は光送信回路、３はレーザダイ
オード、４は光フアイバ、５は受光素子、６は光
受信回路、１１は高周波雑音発生回路、１２は混
合器、１３は低域波器をそれぞれあらわしてい
る。
Figure 1 is a configuration diagram of an optical communication system using a conventional analog signal optical transmitter/receiver, Figure 2 is an I-L characteristic diagram showing the nonlinearity of a laser diode, and Figure 3 is an optical communication system using the present invention. System configuration diagram, 4th
The figure is a signal waveform diagram for explaining each part of the present invention, and FIG. 5 is a spectrum diagram corresponding to the signal waveform of FIG. 4. Explanation of symbols: 2 is an optical transmitting circuit, 3 is a laser diode, 4 is an optical fiber, 5 is a light receiving element, 6 is an optical receiving circuit, 11 is a high frequency noise generation circuit, 12 is a mixer, 13 is a low frequency amplifier Each is represented.
Claims (1)
ーザダイオードを駆動して光信号を出射する光送
信部と、前記出射された光信号を伝送する光線路
部と、この光線路部からの光信号を光電素子によ
り電気信号に変換しこの電気信号から前記入力ア
ナログ信号に対応する出力アナログ信号を発生す
る光受信部とから成る光送受信装置において、前
記光送信部に、前記入力アナログ信号の有する周
波数成分より高い周波数領域にスペクトラムを持
ち且つ該入力アナログ信号の波高値より低い波高
値を持つ高周波電気信号を発生する高周波発生回
路と、前記高周波電気信号および前記入力アナロ
グ信号を合成し、合成した信号から前記入力アナ
ログ信号に基づく変調信号が得られるように配置
された合成回路とを設け、前記レーザダイオード
のバイアス電流をその閾値電流以上に設定し、前
記光受信部の信号線路に、前記高周波電気信号の
周波数成分を阻止する波器を設けて成ることを
特徴とする光送受信装置。1. An optical transmission section that drives a laser diode to output an optical signal using a modulation signal based on an input analog signal, an optical line section that transmits the emitted optical signal, and an optical transmission section that transmits the optical signal from this optical path section to a photoelectric element. and an optical receiver that converts the electrical signal into an electrical signal and generates an output analog signal corresponding to the input analog signal from the electrical signal, wherein the optical transmitter includes a frequency component higher than that of the input analog signal. A high frequency generation circuit that generates a high frequency electrical signal having a spectrum in the frequency domain and a peak value lower than the peak value of the input analog signal; a synthesis circuit arranged to obtain a modulated signal based on an analog signal, a bias current of the laser diode is set to be equal to or higher than its threshold current, and a frequency of the high-frequency electric signal is connected to the signal line of the optical receiver. An optical transmitting/receiving device characterized by being provided with a wave device for blocking components.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56100597A JPS583431A (en) | 1981-06-30 | 1981-06-30 | Optical transmitter and receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56100597A JPS583431A (en) | 1981-06-30 | 1981-06-30 | Optical transmitter and receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS583431A JPS583431A (en) | 1983-01-10 |
| JPS624899B2 true JPS624899B2 (en) | 1987-02-02 |
Family
ID=14278271
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56100597A Granted JPS583431A (en) | 1981-06-30 | 1981-06-30 | Optical transmitter and receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS583431A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01107648A (en) * | 1987-07-24 | 1989-04-25 | Nippon Denso Co Ltd | Three position rotation actuator |
| JPH04133653A (en) * | 1990-09-25 | 1992-05-07 | Nippondenso Co Ltd | Actuator for multistage position control |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH054369Y2 (en) * | 1985-10-28 | 1993-02-03 | ||
| JPS6432768A (en) * | 1987-07-29 | 1989-02-02 | Nippon Chemicon | Fly-back line erasing circuit for cathode ray tube |
| JPH039627A (en) * | 1989-06-06 | 1991-01-17 | Nec Corp | Optical transmission equipment |
| FR2683401B1 (en) * | 1991-10-31 | 1993-12-31 | Alcatel Nv | OPTICAL GENERATOR, PARTICULARLY FOR THE TRANSPORT OF A MICROWAVE SIGNAL. |
| DE4234599A1 (en) * | 1992-08-22 | 1994-02-24 | Sel Alcatel Ag | Optical transmitter |
| NL9300347A (en) * | 1993-02-24 | 1994-09-16 | Nederland Ptt | Optical noise source. |
| US5598288A (en) * | 1995-07-31 | 1997-01-28 | Northrop Grumman Corporation | RF fiber optic transmission utilizing dither |
| JP2006352848A (en) | 2005-05-17 | 2006-12-28 | Toshiba Corp | Light signal transmission device and signal processing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57135535A (en) * | 1981-02-13 | 1982-08-21 | Mitsubishi Electric Corp | Analog modulation system of semiconductor laser |
-
1981
- 1981-06-30 JP JP56100597A patent/JPS583431A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57135535A (en) * | 1981-02-13 | 1982-08-21 | Mitsubishi Electric Corp | Analog modulation system of semiconductor laser |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01107648A (en) * | 1987-07-24 | 1989-04-25 | Nippon Denso Co Ltd | Three position rotation actuator |
| JPH04133653A (en) * | 1990-09-25 | 1992-05-07 | Nippondenso Co Ltd | Actuator for multistage position control |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS583431A (en) | 1983-01-10 |
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