JPS625495B2 - - Google Patents
Info
- Publication number
- JPS625495B2 JPS625495B2 JP55083923A JP8392380A JPS625495B2 JP S625495 B2 JPS625495 B2 JP S625495B2 JP 55083923 A JP55083923 A JP 55083923A JP 8392380 A JP8392380 A JP 8392380A JP S625495 B2 JPS625495 B2 JP S625495B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- light emitting
- emitting element
- signal
- optical fiber
- 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 17
- 239000013307 optical fiber Substances 0.000 claims description 17
- 230000010287 polarization Effects 0.000 claims description 17
- 238000004891 communication Methods 0.000 claims description 11
- 230000005540 biological transmission Effects 0.000 claims description 6
- 230000008859 change Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000005562 fading Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000005337 ground glass Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity 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
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】
本発明は光源としてレーザのようなコヒーレン
シのよい発光素子を用いた光送信回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical transmission circuit using a light emitting element with good coherency, such as a laser, as a light source.
第１図は光フアイバ通信に用いられている従来
の光送信回路を示す概略図であり、１は通信信号
を発信する信号源、２は駆動回路、３は半導体レ
ーザダイオード等の発光素子、４は伝送媒体であ
る光フアイバの如く構成されている。 FIG. 1 is a schematic diagram showing a conventional optical transmission circuit used in optical fiber communication, in which 1 is a signal source that transmits a communication signal, 2 is a drive circuit, 3 is a light emitting element such as a semiconductor laser diode, and 4 is constructed like an optical fiber which is a transmission medium.
この構成において、信号源１から発信された信
号は駆動回路２によつて増幅され、発光素子３を
発光させる。この光は該発光素子３に対向させた
光フアイバ４に効率よく入射し、伝送される。 In this configuration, a signal transmitted from the signal source 1 is amplified by the drive circuit 2, causing the light emitting element 3 to emit light. This light efficiently enters the optical fiber 4 facing the light emitting element 3 and is transmitted.
前記発光素子の発光出力は材質によつて決まる
特定の波長をもち、時間的にも空間的にもほぼ位
相が揃つている。このことは製造技術が向上する
につれて顕著になつてきている。このように発光
素子が単一キヤリアで発光した場合、いわゆる無
線伝送で問題となるフエージング現象に似た雑音
が発生する。これを光通信ではモーダル雑音と称
しているが、このモーダル雑音は時として伝送し
たい通信信号を無くしてしまうほどの大きさにな
ることがある。このことは無線におけるフエージ
ングを考えれば明らかである。 The light emitting output of the light emitting element has a specific wavelength determined by the material, and is substantially in phase both temporally and spatially. This is becoming more noticeable as manufacturing technology improves. When a light emitting element emits light using a single carrier in this way, noise similar to the fading phenomenon that is a problem in so-called wireless transmission occurs. In optical communications, this is called modal noise, and this modal noise can sometimes be so large as to eliminate the communication signal that is to be transmitted. This becomes clear when considering fading in radio.
このような雑音が発生する原因としては、発光
素子が単一キヤリア発光に近いこと、及び光フア
イバ内では光の通路が多くできるいわゆるマルチ
パスであること等が挙げられる。 The causes of such noise include the fact that the light emitting element is close to single-carrier light emission, and the fact that there are many light paths within the optical fiber, which is so-called multipath.
そこでこのモーダル雑音を無くすため、以下に
述べる対策が考えられている。 Therefore, in order to eliminate this modal noise, the following measures have been considered.
(イ) 単一キヤリア発光しない発光素子を選んで用
いる。(a) Select and use light-emitting elements that do not emit single-carrier light.
(ロ) 発光素子の動作点を下げ、単一キヤリア発光
しない領域を使用する。(b) Lower the operating point of the light-emitting element and use a region that does not emit single carrier light.
(ハ) 発光素子の動作点を高周波バイアスで振ら
し、なるべく単一キヤリア発光にならないよう
にする。(c) The operating point of the light emitting element is varied using a high frequency bias to prevent single carrier light emission as much as possible.
(ニ) 発光素子と光フアイバとの間にすりガラス等
のような光の散乱を発生させる物体を配設して
マルチパスを十分多くする。(d) An object that causes light scattering, such as ground glass, is placed between the light emitting element and the optical fiber to sufficiently increase the number of multipaths.
(ホ) 単一モードフアイバを使う。(e) Use single mode fiber.
しかしこれらの対策はいずれも次のような欠
点を有している。すなわち、(イ)，(ロ)，(ハ)，(ニ)は
抜本的対策とはいえず(イ)の単一キヤリア発光し
ない発光素子を選ぶということは、良質でない
発光素子を選ぶことであり、従つて非線形の問
題が発生する。また、(ロ)，(ハ)，(ニ)の対策は発光
素子の光出力を減らすことにつながり、かつ(ロ)
と(ハ)は効果がある場合とない場合がある。(ホ)の
単一モードフアイバを使う方法は抜本的な対策
といえるが、発光素子と光フアイバとの結合効
率やフアイバコネクタの結合の問題があり、綜
合的にみて得策ではない。 However, all of these measures have the following drawbacks. In other words, (a), (b), (c), and (d) cannot be said to be fundamental measures, and choosing a light emitting element that does not emit single carrier light in (a) means choosing a light emitting element that is not of high quality. Therefore, a nonlinear problem occurs. In addition, measures (b), (c), and (d) lead to a reduction in the light output of the light emitting element, and (b)
and (c) may or may not be effective. The method (e) of using a single mode fiber can be said to be a drastic countermeasure, but it is not a good idea from an overall perspective because it has problems with the coupling efficiency between the light emitting element and the optical fiber and the coupling of the fiber connector.
本発明はこれらの欠点を解決することを目的と
し、この目的を達成するため、電気信号によつて
駆動される光偏波素子を発光素子と光フアイバと
の間に配置したことを特徴とする。 The present invention aims to solve these drawbacks, and in order to achieve this purpose, an optical polarization element driven by an electric signal is disposed between a light emitting element and an optical fiber. .
以下図面により説明すると、第２図は本発明の
一実施例を示す概略図で、１は通信信号を発信す
る信号源、２は駆動回路、３は発光素子、４は光
フアイバ、５は発光素子３と光フアイバ４との間
に配置した光偏波素子、６は該光偏波素子５を駆
動する信号源の如く構成してある。 To explain the following with reference to the drawings, FIG. 2 is a schematic diagram showing an embodiment of the present invention, in which 1 is a signal source that transmits a communication signal, 2 is a drive circuit, 3 is a light emitting element, 4 is an optical fiber, and 5 is a light emitting device. An optical polarization element 6 disposed between the element 3 and the optical fiber 4 is configured as a signal source for driving the optical polarization element 5.
この構成では、発光素子３からの光は光偏波素
子５を通つて光フアイバ４に入射する。そこで信
号源６によつて光偏波素子５に信号を与えると、
ほぼ直線偏波である前記光は光偏波素子５によつ
て偏波面の回転を受け、光フアイバ４に発光素子
３から直接入射する場合とは異つた入射の仕方を
するため、フエージング現象も異つてくる。従つ
て信号源６からの信号を高周波とすれば、発光素
子３からの光は、この高周波信号に従つた偏波面
の回転を受けて光フアイバ４に入射することにな
り、等価的にマルチパスが増加したことになる。
この高周波信号を信号源１からの通信信号の帯域
と十分離れた所に周波数配置すれば、通信信号を
妨害することなくモーダル雑音を無くすことがで
きる。 In this configuration, light from the light emitting element 3 passes through the optical polarization element 5 and enters the optical fiber 4. Therefore, when a signal is given to the optical polarization element 5 by the signal source 6,
The light, which is almost linearly polarized, undergoes rotation of its plane of polarization by the optical polarization element 5 and enters the optical fiber 4 in a different manner than when it enters directly from the light emitting element 3, resulting in a fading phenomenon. It will also be different. Therefore, if the signal from the signal source 6 is a high frequency signal, the light from the light emitting element 3 will undergo rotation of the plane of polarization according to this high frequency signal and enter the optical fiber 4, equivalently becoming a multipath. has increased.
By placing this high frequency signal at a frequency sufficiently apart from the band of the communication signal from the signal source 1, modal noise can be eliminated without interfering with the communication signal.
尚、本発明における光偏波素子５としては、
LiTaO3等の電気光学効果素子、近傍に電磁石を
もつたフアラデー効果素子又は電歪効果素子等を
用いることができる。 Note that the optical polarization element 5 in the present invention includes:
An electro-optic effect element such as LiTaO 3 , a Faraday effect element having an electromagnet nearby, an electrostrictive effect element, etc. can be used.
また、信号源６の信号としては、高周波正弦波
の他、通信信号と干渉しないだけ周波数が十分離
れていれば雑音的信号でも問題はなく、むしろ雑
音の方がマルチパスのできかたがランダムなので
品質の向上が期待できる。 In addition to high-frequency sine waves, the signal from the signal source 6 may be a noise signal as long as the frequency is far enough away from the communication signal to avoid interference.In fact, noise has a more random multipath pattern. Therefore, we can expect an improvement in quality.
以上説明したように本発明は、発光素子と光フ
アイバとの間に光偏波素子を配置し、該光偏波素
子に通信信号と干渉しないように十分周波数的に
離した信号を与えることにより発光素子からの光
を偏波して光フアイバと結合させているため、通
信信号を妨害することなくモーダル雑音を取除く
ことができ、発光素子の出力を有効に利用できる
という効果がある。また、光偏波素子としては、
単に光の偏波面を変えるだけでよいので、線形性
がよくかつ感度のよいものは必要としない利点が
ある。 As explained above, the present invention is achieved by arranging an optical polarization element between a light emitting element and an optical fiber, and providing a signal that is sufficiently separated in frequency so as not to interfere with a communication signal to the optical polarization element. Since the light from the light emitting element is polarized and coupled to the optical fiber, modal noise can be removed without interfering with communication signals, and the output of the light emitting element can be used effectively. In addition, as an optical polarization element,
Since it is sufficient to simply change the plane of polarization of the light, there is an advantage that a device with good linearity and high sensitivity is not required.
第１図は従来例を示す概略図、第２図は本発明
の一実施例を示す概略図である。
１……信号源、２……駆動回路、３……発光素
子、４……光フアイバ、５……光偏波素子、６…
…信号源。
FIG. 1 is a schematic diagram showing a conventional example, and FIG. 2 is a schematic diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Signal source, 2... Drive circuit, 3... Light emitting element, 4... Optical fiber, 5... Optical polarization element, 6...
...signal source.
Claims (1)
させ、その光を光フアイバに入射させて伝送する
光送信回路において、前記発光素子と光フアイバ
との間に、電気信号によつて光の偏波面を変える
ことのできる光偏波素子を配置したことを特徴と
する光送信回路。1. In an optical transmission circuit that causes a light emitting element to emit light in response to a communication signal from a signal source and transmits the light by inputting the light into an optical fiber, the polarization plane of the light is determined between the light emitting element and the optical fiber by an electrical signal. An optical transmission circuit characterized by having an optical polarization element arranged to change the polarization.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8392380A JPS5710550A (en) | 1980-06-23 | 1980-06-23 | Optical transmission circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8392380A JPS5710550A (en) | 1980-06-23 | 1980-06-23 | Optical transmission circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5710550A JPS5710550A (en) | 1982-01-20 |
| JPS625495B2 true JPS625495B2 (en) | 1987-02-05 |
Family
ID=13816115
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8392380A Granted JPS5710550A (en) | 1980-06-23 | 1980-06-23 | Optical transmission circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5710550A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8515499D0 (en) * | 1985-06-19 | 1985-07-24 | British Telecomm | Digital information transmission system |
| JP3543727B2 (en) | 2000-04-24 | 2004-07-21 | 住友電装株式会社 | ID terminal fitting |
| JP3546815B2 (en) | 2000-06-28 | 2004-07-28 | 住友電装株式会社 | ID terminal fitting |
| JP2002015787A (en) | 2000-06-29 | 2002-01-18 | Sumitomo Wiring Syst Ltd | Metal fitting for insulation displacement terminal |
-
1980
- 1980-06-23 JP JP8392380A patent/JPS5710550A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5710550A (en) | 1982-01-20 |
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