JPH0746187A - Optical communication system - Google Patents
Optical communication systemInfo
- Publication number
- JPH0746187A JPH0746187A JP5185333A JP18533393A JPH0746187A JP H0746187 A JPH0746187 A JP H0746187A JP 5185333 A JP5185333 A JP 5185333A JP 18533393 A JP18533393 A JP 18533393A JP H0746187 A JPH0746187 A JP H0746187A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- light
- sideband
- communication system
- carrier wave
- 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
Landscapes
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光多重通信に利用する。
特に、高密度の多重化ができ、しかも受信側で光ファイ
バの波長分散を容易に補償することのできる光通信方式
に関する。The present invention is used in optical multiplex communication.
In particular, it relates to an optical communication system capable of high-density multiplexing and easily compensating for chromatic dispersion of an optical fiber on the receiving side.
【０００２】[0002]
【従来の技術】一般に、ベースバンド信号により振幅変
調された信号スペクトルは、ベースバンド信号の２倍の
帯域を占有する。この信号スペクトルは搬送波を中心に
して上側波帯と下側波帯とを含み、そのどちらもが源信
号の完全な情報を含んでいる。上側波帯と下側波帯との
双方のスペクトル成分を伝送する方式は両側波帯（ＤＳ
Ｂ、Double Sideband)伝送と呼ばれ、一方のスペクトル
成分のみを伝送する方式は単側波帯（ＳＳＢ、Single S
ideband)伝送と呼ばれる。ＳＳＢ信号に必要な帯域幅は
ＤＳＢ信号の半分である。また、ＳＳＢ信号はマルチパ
スによる選択性フェージングの影響を受けにくいという
特長をもつ。このような利点により、単側波帯伝送方式
は無線通信、特にアマチュア無線などの音声の伝送に広
く利用されている。2. Description of the Related Art Generally, a signal spectrum amplitude-modulated by a baseband signal occupies twice the band of the baseband signal. This signal spectrum includes an upper sideband and a lower sideband about the carrier, both of which contain the complete information of the source signal. The method of transmitting the spectral components of both the upper sideband and the lower sideband is the double sideband (DS
B, Double Sideband) transmission, and the method of transmitting only one spectral component is single sideband (SSB, Single S).
ideband) transmission. The bandwidth required for SSB signals is half that of DSB signals. Further, the SSB signal has a feature that it is not easily affected by the selective fading due to multipath. Due to these advantages, the single sideband transmission system is widely used for wireless communication, particularly for voice transmission such as amateur radio.
【０００３】光ファイバ通信においては、単側波帯伝送
を行うことにより信号波形を歪ませる光ファイバの波長
分散を受信側で容易に補償できることが、逸見、特開平
５−３４５６号公報に示されている。ホモダイン検波そ
の他のベースバンド検波では、両側波帯信号が検波され
るときに上下側波帯がベースバンドに折り返される。光
ファイバの波長分散を受けた信号は、ベースバンドに折
り返されたときに、上側波帯と下側波帯とでその影響が
異なる。このため、波長分散の影響を補償することは困
難である。しかし、単側波帯信号では、検波のときのス
ペクトルの折り返しがないため、線形な等化器を用いて
分散補償が可能となる。In optical fiber communication, it is disclosed in Japanese Unexamined Patent Publication No. 5-3456 that the chromatic dispersion of an optical fiber which distorts a signal waveform can be easily compensated for by a receiving side by performing single sideband transmission. ing. In homodyne detection and other baseband detection, the upper and lower sidebands are folded back to the baseband when the double sideband signal is detected. When the signal subjected to the chromatic dispersion of the optical fiber is folded back to the baseband, the influences thereof are different between the upper sideband and the lower sideband. Therefore, it is difficult to compensate the influence of chromatic dispersion. However, with a single sideband signal, since there is no aliasing of the spectrum at the time of detection, it is possible to perform dispersion compensation using a linear equalizer.
【０００４】また、光周波数多重通信方式においては、
光増幅器の帯域その他により、使用可能な周波数帯域が
制限される。制限された周波数帯域内で伝送容量を増や
すためには周波数利用効率を上げなければならず、その
ためには単側波帯伝送を用いることが有効であると考え
られる。Further, in the optical frequency multiplex communication system,
The usable frequency band is limited by the band of the optical amplifier and the like. In order to increase the transmission capacity within the limited frequency band, it is necessary to increase the frequency utilization efficiency, and it is considered effective to use single sideband transmission for that purpose.
【０００５】[0005]
【発明が解決しようとする課題】このように、両側波帯
信号は単側波帯信号に比べて伝送帯域が２倍必要である
ため周波数の利用効率が悪く、また受信側で検波後に光
ファイバの波長分散を補償することが困難である。これ
に対し、単側波帯信号は、周波数利用効率が良く、受信
側で検波後に光ファイバの波長分散を補償することが容
易である。As described above, since the double sideband signal requires twice the transmission band as compared with the single sideband signal, the frequency utilization efficiency is poor, and the optical fiber after detection on the receiving side is not used. Is difficult to compensate. On the other hand, the single sideband signal has high frequency utilization efficiency, and it is easy to compensate the chromatic dispersion of the optical fiber after detection on the receiving side.
【０００６】しかし、従来はひとつの搬送波で１チャネ
ルしか伝送できず、複数の搬送波を用いた光周波数多重
伝送を考えた場合に、高密度の多重化は可能となるが、
それだけ多くの搬送波光発生手段（例えばレーザダイオ
ード）が必要となってしまう。However, conventionally, only one channel can be transmitted by one carrier, and when considering optical frequency multiplex transmission using a plurality of carriers, high-density multiplexing becomes possible.
Therefore, a large number of carrier wave light generation means (for example, laser diodes) are required.
【０００７】本発明は、このような課題を解決し、搬送
波の数を増やすことなく伝送容量を増やすことのできる
光通信方式を提供することを目的とする。An object of the present invention is to solve the above problems and provide an optical communication system capable of increasing the transmission capacity without increasing the number of carriers.
【０００８】[0008]
【課題を解決するための手段】本発明の光通信方式は、
ひとつの搬送波光に対して上側波帯と下側波帯とで異な
るデータを伝送することを特徴とする。The optical communication system of the present invention comprises:
It is characterized in that different data is transmitted in the upper sideband and the lower sideband with respect to one carrier light.
【０００９】具体的には、光送信機に、搬送波光を二つ
に分岐する光分岐手段と、分岐された二つの搬送波光を
それぞれ独立の信号で変調する二つの光変調手段と、こ
の二つの光変調手段の一方の出力から上側波帯を抽出す
る第一のフィルタ手段と、二つの光変調手段の他方の出
力から下側波帯を抽出する第二のフィルタ手段と、第一
および上記第二のフィルタ手段の出力を合波する光合波
手段とを備えたことを特徴とする。また、光受信機に
は、受信した信号光を上側波帯と下側波帯とに分離する
光分離手段と、分離された上側波帯と下側波帯とを各々
検波する検波手段とを備えることがよい。光受信機には
さらに、光送信機との間に設けられた光伝送路、特に光
ファイバの波長分散を検波手段の出力、すなわち電気領
域において等化する等化手段を含むことが望ましい。Specifically, the optical transmitter includes an optical branching unit for branching the carrier light into two, two optical modulators for modulating the two branched carrier lights with independent signals, respectively. First filter means for extracting the upper sideband from one output of the two light modulating means, second filter means for extracting the lower sideband from the other output of the two light modulating means, first and And an optical multiplexing means for multiplexing the output of the second filter means. Further, the optical receiver includes an optical separating unit that separates the received signal light into an upper sideband and a lower sideband, and a detecting unit that detects each of the separated upper sideband and lower sideband. Good to have. It is desirable that the optical receiver further includes an equalizer that is provided between the optical receiver and the optical transmitter to equalize the chromatic dispersion of the optical fiber, in particular, the optical fiber in the output of the detector, that is, in the electrical domain.
【００１０】この光通信方式を利用して光周波数分割多
重通信装置を実現できる。すなわち、上述した光送信機
および光受信機を複数組備え、これらの光送信機および
光受信機にはその組ごとに異なる搬送波光周波数を割り
当て、それぞれの組の光送信機と光受信機とを共通の光
ファイバにより接続する。An optical frequency division multiplex communication device can be realized by utilizing this optical communication system. That is, a plurality of sets of the optical transmitter and the optical receiver described above are provided, and different optical carrier frequencies are assigned to the sets, and the optical transmitter and the optical receiver of each set are assigned. Are connected by a common optical fiber.
【００１１】[0011]
【作用】ひとつの搬送波に対して上側波帯と下側波帯と
で異なるデータを伝送することにより、ひとつの搬送波
あたりの伝送容量を２倍にできる。さらに、受信側で分
離して単側波帯信号として検波することにより、光ファ
イバの波長分散を容易に補償できる。By transmitting different data for the upper sideband and the lower sideband to one carrier, the transmission capacity per carrier can be doubled. Further, the chromatic dispersion of the optical fiber can be easily compensated by separating on the receiving side and detecting as a single sideband signal.
【００１２】[0012]
【実施例】図１は本発明第一実施例の光通信装置を示す
ブロック構成図であり、図２ないし図５はその動作を説
明する図である。1 is a block diagram showing an optical communication apparatus according to a first embodiment of the present invention, and FIGS. 2 to 5 are diagrams for explaining the operation thereof.
【００１３】この実施例装置は、コヒーレントな搬送波
光を変調して送信する光送信機１と、光伝送路としての
光ファイバ２と、光送信機１からの光信号を受信して復
調する光受信機３とを備える。光送信機１には、コヒー
レントな搬送波光を生成するレーザダイオード１１を備
える。The apparatus of this embodiment comprises an optical transmitter 1 for modulating and transmitting coherent carrier light, an optical fiber 2 as an optical transmission line, and an optical signal for receiving and demodulating an optical signal from the optical transmitter 1. And a receiver 3. The optical transmitter 1 includes a laser diode 11 that generates coherent carrier light.
【００１４】ここで本実施例の特徴とするところは、光
送信機１に、搬送波光を二つに分岐する光分岐手段とし
て光分波器１２を備え、分岐された二つの搬送波光をそ
れぞれ独立の信号で変調する二つの光変調手段として光
変調器１３、１４を備え、光変調器１３の出力から上側
波帯を抽出する第一のフィルタ手段として光フィルタ１
５を備え、光変調器１４の出力から下側波帯を抽出する
第二のフィルタ手段として光フィルタ１６を備え、光フ
ィルタ１５、１６の出力を合波する光合波手段として光
合波器１７を備えたことにある。光受信機３には、受信
した信号光を上側波帯と下側波帯とに分離する光分離手
段として光フィルタ３３を備え、分離された上側波帯と
下側波帯とを各々検波する検波手段として光検波器３
４、３５を備える。Here, the feature of this embodiment is that the optical transmitter 1 is provided with an optical demultiplexer 12 as an optical branching unit for branching the carrier light into two, and the two branched carrier lights are respectively provided. The optical filter 1 is provided with the optical modulators 13 and 14 as two optical modulators for modulating with independent signals, and as the first filter means for extracting the upper sideband from the output of the optical modulator 13.
5, an optical filter 16 is provided as a second filter means for extracting the lower sideband from the output of the optical modulator 14, and an optical combiner 17 is provided as an optical combiner for combining the outputs of the optical filters 15 and 16. Be prepared. The optical receiver 3 is provided with an optical filter 33 as an optical separation means for separating the received signal light into an upper sideband and a lower sideband, and detects the separated upper sideband and lower sideband respectively. Optical detector 3 as the detection means
4, 35 are provided.
【００１５】光検波器３４の出力は低域通過フィルタ３
６を介して識別器３８に入力され、受信データが識別さ
れる。光検波器３５の出力は低域通過フィルタ３７を介
して識別器３９に入力され、受信データが識別される。
光受信機３にはまた、光ファイバ２からの信号光をホモ
ダイン検波するため、光フィルタ３３の前段に、レーザ
ダイオード３１および光合波器３２を備える。The output of the photodetector 34 is the low-pass filter 3
It is input to the discriminator 38 via 6 and the received data is discriminated. The output of the photodetector 35 is input to the discriminator 39 via the low pass filter 37, and the received data is discriminated.
The optical receiver 3 also includes a laser diode 31 and an optical multiplexer 32 in front of the optical filter 33 for homodyne detection of the signal light from the optical fiber 2.
【００１６】レーザダイオード１１はコヒーレントな搬
送波光を生成し、この搬送波光は光分波器１２により二
つに分岐される。この二つに分岐された搬送波光は、光
変調器１３、１４において、各々データＡ、Ｂにより振
幅変調される。データＡ、Ｂの二つの信号ａ（ｔ）、ｂ
（ｔ）を次の式で表す。The laser diode 11 produces coherent carrier light, and this carrier light is split into two by the optical demultiplexer 12. The carrier light branched into two is amplitude-modulated by the data A and B in the optical modulators 13 and 14, respectively. Two signals a (t) and b of data A and B
(T) is represented by the following formula.
【００１７】[0017]
【数１】 このとき、変調された光電界Ｅa （ｔ）、Ｅb （ｔ）は
次の式で表される。[Equation 1] At this time, the modulated optical electric fields E a (t) and E b (t) are expressed by the following equations.
【００１８】[0018]
【数２】 ただし、ω0 は基本各周波数である。光フィルタ１５は
データＡによって変調された光信号の上側波帯のみを抽
出し、光フィルタ１６はデータＢによって変調された光
信号の下側波帯のみを抽出する。ここで理想的な光フィ
ルタを仮定すると、単側波帯信号は、光電界Ｅ
a （ｔ）、Ｅb （ｔ）に対してそれぞれ次式のようにな
る。[Equation 2] However, ω 0 is each basic frequency. The optical filter 15 extracts only the upper sideband of the optical signal modulated by the data A, and the optical filter 16 extracts only the lower sideband of the optical signal modulated by the data B. Assuming an ideal optical filter here, the single sideband signal is
The following equations are obtained for a (t) and E b (t), respectively.
【００１９】[0019]
【数３】 ここで、ＵＳＢは上側波帯を表し、ＬＳＢは下側波帯を
表す。このようすを図２、図３に表す。この二つの単側
波帯信号を光合波器１７により合波する。これにより、
次式で表される信号光が得られる。[Equation 3] Here, USB represents the upper sideband and LSB represents the lower sideband. This is shown in FIGS. 2 and 3. These two single sideband signals are multiplexed by the optical multiplexer 17. This allows
The signal light represented by the following equation is obtained.
【００２０】[0020]
【数４】 すなわち、ひとつの搬送波に二つの単側波帯信号が重畳
された信号光が得られる。図４にこのようすを周波数軸
上で表す。この二つの単側波帯信号が多重化された両側
波帯信号が送信信号として送信される。以下、この信号
を二重単側波帯信号という。[Equation 4] That is, signal light in which two single sideband signals are superimposed on one carrier is obtained. This is shown in FIG. 4 on the frequency axis. A double sideband signal obtained by multiplexing these two single sideband signals is transmitted as a transmission signal. Hereinafter, this signal is referred to as a double single sideband signal.
【００２１】光受信機３では、ホモダイン検波を行うた
めに、レーザダイオード３１により局部発振光を発生
し、光合波器３２によりこの局部発振光を受信信号光に
合波する。この合波光を光フィルタ３３により上側波帯
と下側波帯とに分離する。これを図５に示す。分離され
た上側波帯については、光検波器３４、低域通過フィル
タ３６および識別器３８により検波および復調する。ま
た、下側波帯については、光検波器３５、低域通過フィ
ルタ３７および識別器３９により同様に検波および復調
する。In the optical receiver 3, in order to perform homodyne detection, the laser diode 31 generates local oscillation light, and the optical multiplexer 32 multiplexes the local oscillation light with the reception signal light. The combined light is separated into an upper sideband and a lower sideband by the optical filter 33. This is shown in FIG. The separated upper sideband is detected and demodulated by the photodetector 34, the low pass filter 36 and the discriminator 38. The lower sideband is similarly detected and demodulated by the photodetector 35, the low pass filter 37 and the discriminator 39.
【００２２】本実施例では光フィルタ３３が局部発振光
を透過するものとしたが、局部発振光を透過しないもの
を用いる場合には、光フィルタ３３の前段ではなく光検
波器３４、３５の直前で局部発振光を合波してホモダイ
ン検波を行えばよい。また、光検波器３４、３５と低域
通過フィルタ３６、３７との間に帯域通過フィルタと遅
延検波回路その他の中間周波数検波回路とを挿入するこ
とにより、ヘテロダイン検波を行うことができる。Although the optical filter 33 transmits local oscillation light in this embodiment, when the optical filter 33 does not transmit local oscillation light, the optical filter 33 is provided immediately before the optical detectors 34 and 35, not before the optical filter 33. The homodyne detection may be performed by combining the local oscillation light with. Further, a heterodyne detection can be performed by inserting a bandpass filter and a delay detection circuit or another intermediate frequency detection circuit between the photodetectors 34 and 35 and the low-pass filters 36 and 37.
【００２３】図６は本発明の第二実施例を示すブロック
構成図であり、光受信機の構成を示す。光受信機以外の
構成は図１に示した第一実施例と同等である。この実施
例は、光検波器３４、３５の後段にそれぞれ光ファイバ
２の波長分散を補償する遅延等化器３１０、３１１が挿
入されたことが第一実施例と異なる。通常、光ホモダイ
ン検波では、光周波数帯における上下側波帯成分がベー
スバンドに折り返されて重なるために、ベースバンドで
の波長分散の補償が困難である。しかし、本発明は単側
波帯信号を用いているため、ホモダイン検波の際の上下
側波帯の折り返しがなく、ベースバンドでの分散補償を
容易に行うことができる。FIG. 6 is a block diagram showing the second embodiment of the present invention, showing the configuration of the optical receiver. The configuration other than the optical receiver is the same as that of the first embodiment shown in FIG. This embodiment differs from the first embodiment in that delay equalizers 310 and 311 for compensating the chromatic dispersion of the optical fiber 2 are inserted in the subsequent stages of the photodetectors 34 and 35, respectively. Normally, in optical homodyne detection, it is difficult to compensate for chromatic dispersion in the baseband because the upper and lower sideband components in the optical frequency band are folded and overlap with the baseband. However, since the present invention uses the single sideband signal, there is no aliasing of the upper and lower sidebands during homodyne detection, and dispersion compensation in the baseband can be easily performed.
【００２４】図７は光ファイバの波長分散の影響を受け
た二重単側波帯信号が受信側で分離されるようすを周波
数軸上で示したものであり、図８は光フィルタによって
分離された上下側波帯信号がホモダイン検波された後に
ベースバンドで分散補償されるようすを周波数軸上で示
したものである。これらの図において、破線は光ファイ
バの波長分散による相対遅延時間差、実線はそれを補償
する等化器の相対遅延時間差を示す。FIG. 7 shows on the frequency axis how the double single sideband signal affected by the chromatic dispersion of the optical fiber is separated on the receiving side, and FIG. 8 is separated by the optical filter. In addition, it shows on the frequency axis how the upper and lower sideband signals are homodyne-detected and then dispersion-compensated in the baseband. In these figures, the broken line shows the relative delay time difference due to the chromatic dispersion of the optical fiber, and the solid line shows the relative delay time difference of the equalizer that compensates for it.
【００２５】この実施例の場合にも第一実施例と同様
に、局部発振光を合波する位置を変更してもよく、ヘテ
ロダイン検波を用いてもよい。In the case of this embodiment as well, as in the first embodiment, the position at which the locally oscillated light is multiplexed may be changed, or heterodyne detection may be used.
【００２６】図９は本発明の利用例を示すブロック構成
図であり、図１０はその伝送信号スペクトルを示す。こ
の利用例は、第一実施例または第二実施例の光通信装置
を複数備え、これらの光通信装置にはそれぞれ異なる搬
送波周波数ｆ1 〜ｆN が割り当てられ、これらの光通信
装置のそれぞれの光送信機１−１〜１−Ｎと光受信機３
−１〜３−Ｎとが共通の光ファイバ２により接続され
る。光送信機１−１〜１−Ｎはそれぞれ図１に示した光
送信機１と同等であるが、互いに異なる搬送波周波数ｆ
1 〜ｆN が割り当てられる。光送信機１−１〜１−Ｎの
出力した二重単側波帯信号は光合波器４により合波さ
れ、１本の光ファイバ２に入力される。このとき周波数
軸上では、図１０に示すように、二重単側波帯信号がＮ
チャネル並び、全部で２Ｎチャネルの信号が伝送され
る。受信側では、光分波器５により各搬送波ごとに分波
し、図１または図６に示したと同等の光受信機３−１〜
３−Ｎで受信する。FIG. 9 is a block diagram showing an application example of the present invention, and FIG. 10 shows a transmission signal spectrum thereof. This application example includes a plurality of optical communication devices of the first embodiment or the second embodiment, and these optical communication devices are assigned different carrier wave frequencies f 1 to f N , respectively. Optical transmitters 1-1 to 1-N and optical receiver 3
-1 to 3-N are connected by a common optical fiber 2. The optical transmitters 1-1 to 1-N are the same as the optical transmitter 1 shown in FIG. 1, but have different carrier frequencies f.
1 to f N are assigned. The double single sideband signals output from the optical transmitters 1-1 to 1-N are multiplexed by the optical multiplexer 4 and input to one optical fiber 2. At this time, on the frequency axis, as shown in FIG. 10, the double single sideband signal is N
A total of 2N channels of signals are transmitted in a channel arrangement. On the receiving side, the optical demultiplexer 5 demultiplexes each carrier wave, and the optical receivers 3-1 to 3-1 equivalent to those shown in FIG.
Receive at 3-N.
【００２７】[0027]
【発明の効果】以上説明したように、本発明の光通信方
式は、ひとつの搬送波で２チャネルの信号を伝送できる
効果がある。また、光ファイバの波長分散をベースバン
ドで容易に補償することができる効果がある。さらに、
光周波数分割多重通信に利用することにより、従来と同
じ搬送波周波数間隔および同じ伝送帯域で２倍の伝送容
量を得ることができる効果がある。As described above, the optical communication system of the present invention has an effect of being able to transmit signals of two channels with one carrier. Further, there is an effect that the chromatic dispersion of the optical fiber can be easily compensated in the base band. further,
When used for optical frequency division multiplexing communication, there is an effect that a double transmission capacity can be obtained with the same carrier frequency interval and the same transmission band as the conventional one.
【図１】本発明第一実施例の光通信装置を示すブロック
構成図。FIG. 1 is a block configuration diagram showing an optical communication device of a first embodiment of the present invention.
【図２】第一実施例における上側波帯信号の発生を説明
する図。FIG. 2 is a diagram for explaining generation of an upper sideband signal in the first embodiment.
【図３】第一実施例における下側波帯信号の発生を説明
する図。FIG. 3 is a diagram for explaining generation of a lower sideband signal in the first embodiment.
【図４】第一実施例における二つの単側波帯信号の合波
を説明する図。FIG. 4 is a diagram for explaining combining of two single sideband signals in the first embodiment.
【図５】第一実施例における二つの単側波帯信号の分離
を説明する図。FIG. 5 is a diagram for explaining separation of two single sideband signals in the first embodiment.
【図６】本発明第二実施例の光受信機を示すブロック構
成図。FIG. 6 is a block diagram showing an optical receiver according to a second embodiment of the present invention.
【図７】光ファイバの波長分散を受けた二つの単側波帯
信号の分離を説明する図。FIG. 7 is a diagram for explaining separation of two single sideband signals that have undergone chromatic dispersion of an optical fiber.
【図８】光ファイバの波長分散の補償を説明する図。FIG. 8 is a diagram illustrating compensation of chromatic dispersion of an optical fiber.
【図９】本発明の利用例を示すブロック構成図。FIG. 9 is a block diagram showing a usage example of the present invention.
【図１０】周波数多重された信号スペクトルを示す図。FIG. 10 is a diagram showing a frequency-multiplexed signal spectrum.
１、１−１〜１−Ｎ 光送信機 ２ 光ファイバ ３、３−１〜３−Ｎ 光受信機 ４、１７、３２ 光合波器 ５、１２ 光分波器 １１、３１ レーザダイオード １３、１４ 光変調器 １５、１６、３３ 光フィルタ ３４、３５ 光検波器 ３６、３７ 低域通過フィルタ ３８、３９ 識別器 ３１０、３１１ 遅延等化器 1, 1-1 to 1-N Optical transmitter 2 Optical fiber 3, 3-1 to 3-N Optical receiver 4, 17, 32 Optical multiplexer 5, 12 Optical demultiplexer 11, 31 Laser diode 13, 14 Optical modulator 15, 16, 33 Optical filter 34, 35 Optical detector 36, 37 Low-pass filter 38, 39 Discriminator 310, 311 Delay equalizer
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０４Ｂ 10/06 Ｈ０４Ｊ 14/00 14/04 14/06 1/00 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location H04B 10/06 H04J 14/00 14/04 14/06 1/00
Claims (5)
する光通信方式において、ひとつの搬送波光に対して上
側波帯と下側波帯とで異なるデータを伝送することを特
徴とする光通信方式。1. An optical communication system for modulating and transmitting coherent carrier light, wherein different data is transmitted in the upper sideband and the lower sideband with respect to one carrier light. .
する光送信機と、この光送信機からの光信号を受信して
復調する光受信機とを備えた光通信方式において、 上記光送信機は、 搬送波光を二つに分岐する光分岐手段と、 分岐された二つの搬送波光をそれぞれ独立の信号で変調
する二つの光変調手段と、 この二つの光変調手段の一方の出力から上側波帯を抽出
する第一のフィルタ手段と、 上記二つの光変調手段の他方の出力から下側波帯を抽出
する第二のフィルタ手段と、 上記第一および上記第二のフィルタ手段の出力を合波す
る光合波手段とを含むことを特徴とする光通信方式。2. An optical communication system comprising an optical transmitter for modulating and transmitting coherent carrier wave light and an optical receiver for receiving and demodulating an optical signal from the optical transmitter, wherein the optical transmitter Is an optical branching unit that splits the carrier wave light into two, two optical modulators that modulate the two branched carrier waves with independent signals, and an upper side wave from one output of these two optical modulators. The first filter means for extracting the band, the second filter means for extracting the lower sideband from the other output of the two light modulating means, and the output of the first and second filter means are combined. An optical communication system comprising: an optical multiplexing means for oscillating.
波帯と下側波帯とに分離する光分離手段と、 分離された上側波帯と下側波帯とを各々検波する検波手
段とを含む請求項１記載の光通信方式。3. The optical receiver comprises optical demultiplexing means for separating the received signal light into an upper sideband and a lower sideband, and detection for detecting the separated upper sideband and lower sideband respectively. The optical communication system according to claim 1, further comprising:
けられた光伝送路の波長分散を上記検波手段の出力にお
いて等化する等化手段を含む請求項３記載の光通信方
式。4. The optical communication system according to claim 3, wherein the optical receiver includes equalizing means for equalizing chromatic dispersion of an optical transmission line provided between the optical receiver and the optical transmitter at an output of the detecting means. .
信方式における光送信機および光受信機を複数組備え、
これらの光送信機および光受信機にはその組ごとに異な
る搬送波光周波数が割り当てられ、それぞれの組の光送
信機と光受信機とが共通の光ファイバにより接続された
ことを特徴とする光周波数分割多重通信装置。5. A plurality of sets of optical transmitters and optical receivers in the optical communication system according to claim 2,
These optical transmitters and optical receivers are assigned different carrier optical frequencies for each set, and the optical transmitter and optical receiver of each set are connected by a common optical fiber. Frequency division multiplex communication device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5185333A JPH0746187A (en) | 1993-07-27 | 1993-07-27 | Optical communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5185333A JPH0746187A (en) | 1993-07-27 | 1993-07-27 | Optical communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0746187A true JPH0746187A (en) | 1995-02-14 |
Family
ID=16168979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5185333A Pending JPH0746187A (en) | 1993-07-27 | 1993-07-27 | Optical communication system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0746187A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7149434B2 (en) * | 2001-03-30 | 2006-12-12 | Mission Research Corporation | System and method for optical communication |
| US7209660B1 (en) * | 1999-12-29 | 2007-04-24 | Forster Energy Llc | Optical communications using heterodyne detection |
| JP2008158133A (en) * | 2006-12-22 | 2008-07-10 | Nippon Telegr & Teleph Corp <Ntt> | Optical modulator circuit and method |
| JP2008219255A (en) * | 2007-03-01 | 2008-09-18 | Kddi R & D Laboratories Inc | Optical transmission device and method |
| JP2008261979A (en) * | 2007-04-11 | 2008-10-30 | Nippon Telegr & Teleph Corp <Ntt> | Optical ssb (single sideband) modulator |
| JP2009512285A (en) * | 2005-10-12 | 2009-03-19 | モナシュ、ユニバーシティ | Method and apparatus for optical transmission of digital signals |
| JP2009201099A (en) * | 2008-02-21 | 2009-09-03 | Nec Lab America Inc | Method and apparatus for 100 gbit/s ofdm optical signal generation |
| JP2009273109A (en) * | 2008-05-01 | 2009-11-19 | Nec Lab America Inc | Centralized lightwave wdm-pon employing intensity modulated downstream and upstream data signals |
| JP2010041707A (en) * | 2008-07-31 | 2010-02-18 | Nec Lab America Inc | Production method of optical transmission channel with 100 g bit/sec or more |
| KR101012853B1 (en) * | 2004-02-06 | 2011-02-08 | 주식회사 케이티 | System and method for fire transfering |
-
1993
- 1993-07-27 JP JP5185333A patent/JPH0746187A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7209660B1 (en) * | 1999-12-29 | 2007-04-24 | Forster Energy Llc | Optical communications using heterodyne detection |
| US7149434B2 (en) * | 2001-03-30 | 2006-12-12 | Mission Research Corporation | System and method for optical communication |
| KR101012853B1 (en) * | 2004-02-06 | 2011-02-08 | 주식회사 케이티 | System and method for fire transfering |
| JP2009512285A (en) * | 2005-10-12 | 2009-03-19 | モナシュ、ユニバーシティ | Method and apparatus for optical transmission of digital signals |
| JP4786714B2 (en) * | 2005-10-12 | 2011-10-05 | オフィディウム、プロプライエタリー、リミテッド | Method and apparatus for optical transmission of digital signals |
| JP2008158133A (en) * | 2006-12-22 | 2008-07-10 | Nippon Telegr & Teleph Corp <Ntt> | Optical modulator circuit and method |
| JP2008219255A (en) * | 2007-03-01 | 2008-09-18 | Kddi R & D Laboratories Inc | Optical transmission device and method |
| JP2008261979A (en) * | 2007-04-11 | 2008-10-30 | Nippon Telegr & Teleph Corp <Ntt> | Optical ssb (single sideband) modulator |
| JP2009201099A (en) * | 2008-02-21 | 2009-09-03 | Nec Lab America Inc | Method and apparatus for 100 gbit/s ofdm optical signal generation |
| JP2009273109A (en) * | 2008-05-01 | 2009-11-19 | Nec Lab America Inc | Centralized lightwave wdm-pon employing intensity modulated downstream and upstream data signals |
| JP2010041707A (en) * | 2008-07-31 | 2010-02-18 | Nec Lab America Inc | Production method of optical transmission channel with 100 g bit/sec or more |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1760911B1 (en) | Optical-wireless hybrid communication system and optical-wireless hybrid communication method | |
| JP3183685B2 (en) | Optical communication system | |
| US9729229B2 (en) | Optical spatial-division multiplexed transmission system and transmission method | |
| US20100086303A1 (en) | High speed polmux-ofdm using dual-polmux carriers and direct detection | |
| US8831441B2 (en) | Optical communication system, optical receiver, optical transponder, wavelength multiplexing optical communication system, wavelength multiplexing receiving device, and wavelength multiplexing optical transponder | |
| EP0772314A2 (en) | SCM optical communication system | |
| CN104410462B (en) | Polarization-multiplexing-based method and device for modulating and directly detecting optical signals | |
| JP5707981B2 (en) | Sampling clock synchronization apparatus, digital coherent reception apparatus, and sampling clock synchronization method | |
| JP2018526842A (en) | System for improving frequency utilization efficiency in a multi-carrier communication system | |
| JP2000124876A (en) | Optical transmission system for frequency multiple signal | |
| EP2229742A1 (en) | Method and arrangement for transmitting signals in a point to multipoint network | |
| JPH0385834A (en) | Optical frequency multiplexer and optical frequency multiplex transmitter | |
| US20130121706A1 (en) | Signal transmission and reception device and method | |
| US20070134001A1 (en) | Polarization division multiplexed optical transmission system | |
| US6392770B1 (en) | Multi-point optical transmission system | |
| EP2204928B1 (en) | Method and device for receiving OPFDM-DQPSK signal | |
| JPH0746187A (en) | Optical communication system | |
| US6362903B1 (en) | Use of higher order modulation techniques to transmit information on passbands of a dispersion-limited fiber link | |
| JP4730560B2 (en) | Optical transmission system, optical transmission method, and optical transmitter | |
| JP2838839B2 (en) | Optical communication system | |
| US20010021047A1 (en) | Optical transmission system and optical receiver | |
| EP1408631B1 (en) | Optical transmitter | |
| CN115276810A (en) | Signal sending device, signal receiving device and communication system | |
| US20070134000A1 (en) | Polarization division multiplexed optical transmission system | |
| US6407837B1 (en) | Use of bandwidth efficient modulation techniques in a wavelength division multiplexed optical link |