JP3324086B2 - Optical signal multiplexing method - Google Patents
Optical signal multiplexing methodInfo
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- JP3324086B2 JP3324086B2 JP33852694A JP33852694A JP3324086B2 JP 3324086 B2 JP3324086 B2 JP 3324086B2 JP 33852694 A JP33852694 A JP 33852694A JP 33852694 A JP33852694 A JP 33852694A JP 3324086 B2 JP3324086 B2 JP 3324086B2
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- optical signal
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Description
【０００１】[0001]
【産業上の利用分野】本発明は光ＣＡＴＶシステム、光
ＩＴＶシステム等の光信号通信において使用される複数
の光信号を多重化する方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for multiplexing a plurality of optical signals used in optical signal communication such as an optical CATV system and an optical ITV system.
【０００２】[0002]
【従来の技術】光ＣＡＴＶシステム、光ＩＴＶシステム
等の光通信方法には各種方法があり、その一つとして従
来は複数の光信号を光ファイバにより多重伝送し、その
多重信号を一つの受光器で同時に受光する光多重方法が
あった。このように多重信号を一つの受光器で同時に受
光すると、隣接する光信号の波長間隔（波長差）に応じ
たビート雑音がサブキャリア帯域に発生する。このビー
ト発生の周波数が搬送波の周波数帯域と一致した場合は
ビートにより光信号の品質が損なわれる。かかるビート
雑音の影響を抑制するためには伝送する光信号の所要品
質に応じて隣接波長間隔をある程度広くとる必要があ
る。また、全ての光信号を信号到達点で同一品質にする
ためには伝送する光信号のレべルを等しくする必要があ
る。また、同一のサブキャリアで変調された多数の光信
号に、異なったサブキャリアで変調された光信号を多重
化するためには、従来は上記のように光信号間の波長間
隔を広く保つ以外に、図６に示す様にその光信号（＋α
部分）を既存の光信号（ｘｎｍ部分）の配列の外側に配
列していた。2. Description of the Related Art There are various types of optical communication methods such as an optical CATV system and an optical ITV system. One of the conventional methods is to multiplex and transmit a plurality of optical signals through an optical fiber, and to multiplex the multiplexed signals into one optical receiver. There is an optical multiplexing method for receiving light simultaneously. When a multiplexed signal is received by one photodetector at the same time, beat noise corresponding to the wavelength interval (wavelength difference) between adjacent optical signals is generated in the subcarrier band. If the frequency of the beat generation matches the frequency band of the carrier, the beat degrades the quality of the optical signal. In order to suppress the influence of such beat noise, it is necessary to increase the interval between adjacent wavelengths to some extent in accordance with the required quality of the optical signal to be transmitted. Also, in order for all optical signals to have the same quality at the signal arrival point, the levels of the transmitted optical signals need to be equal. In addition, in order to multiplex optical signals modulated by different subcarriers on a large number of optical signals modulated by the same subcarrier, conventionally, as described above, a wavelength interval between optical signals must be kept wide. In addition, as shown in FIG.
Part) was arranged outside the arrangement of the existing optical signals (xnm part).
【０００３】[0003]
【発明が解決しようとする課題】従来の光通信方法にお
ける光多重化方法では次の様な問題があった。 ．光信号に変調をかける全てのサブキャリアを同一変
調方式にした場合は、全てのサブキャリアの品質を同一
にする際に、伝送する光信号のレベルも全て同一にする
必要がある。しかし、同一レベルの光信号の場合はそれ
に応じた光ビート雑音が受光部分で発生するため、ビー
ト雑音を解消して所要性能を確保するためにはある程度
以上の波長間隔が必要である。しかし波長間隔を広げる
と他方において実用上いくつかの問題が生じる。例えば
５０波の光信号を合波する光伝送装置で波長間隔を２ｎ
ｍに設定した場合は、１００ｎｍの幅で半導体レーザの
波長を制御する必要が生じる。しかし半導体レーザの製
造工程上、この様な広い幅で波長の異なる半導体レーザ
を作製するためには著しくコストが高くなる。従って、
上記の波長間隔はむやみに広くするのではなく、ビート
が信号の品質を劣化させない程度にできるだけ狭く設計
する必要がある。このため同一レベルの状態では光信号
多重度を上げるにも限度がある。また、光伝送帯域が広
くなるため広くなった分だけ雑音の影響を受け易くな
る。The optical multiplexing method in the conventional optical communication method has the following problems. . When all the subcarriers that modulate the optical signal are of the same modulation scheme, when the quality of all the subcarriers is the same, the level of the optical signal to be transmitted also needs to be the same. However, in the case of an optical signal of the same level, an optical beat noise corresponding thereto is generated in the light receiving portion. Therefore, in order to eliminate the beat noise and secure required performance, a certain wavelength interval is required. However, widening the wavelength spacing, on the other hand, causes some practical problems. For example, in an optical transmission device that multiplexes 50 optical signals, the wavelength interval is 2n.
If it is set to m, it is necessary to control the wavelength of the semiconductor laser in a width of 100 nm. However, in the manufacturing process of the semiconductor laser, manufacturing a semiconductor laser having such a wide width and different wavelengths significantly increases the cost. Therefore,
It is necessary to design the above wavelength interval as narrow as possible so that the beat does not degrade the signal quality, instead of being unnecessarily wide. For this reason, there is a limit in increasing the optical signal multiplicity under the same level. Also, since the optical transmission band is widened, the wider the optical transmission band is, the more easily it is affected by noise.
【０００４】．ビート雑音は任意の光信号レベルを低
下させることによって低下させることができるが、光信
号レベルを低下させるとレベルが低下した光信号に変調
をかけているサブキャリアの受信レベルも低下してしま
い、伝送品質が劣化してしまう。 ．同一のサブキャリアで変調された多数の光信号に、
異なったサブキャリアで変調された光信号を多重化する
場合は、図６のようにその光信号を既存の光信号配列の
外側に配列するため光伝送帯域幅が広がり、その分だけ
雑音の影響を受け易くなる。[0004] Beat noise can be reduced by lowering any optical signal level, but lowering the optical signal level also lowers the reception level of the subcarrier that modulates the optical signal whose level has decreased, Transmission quality is degraded. . To many optical signals modulated by the same subcarrier,
When multiplexing optical signals modulated by different subcarriers, the optical signal is arranged outside the existing optical signal arrangement as shown in FIG. More easily.
【０００５】本発明の目的はビートによる信号の品質劣
化が生じない範囲で波長間隔を極力狭くすることがで
き、また、一定の伝送帯域内における光信号の多重度を
向上させることができる光信号多重方法を実現すること
にある。SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical signal capable of shortening the wavelength interval as far as possible without deteriorating the signal quality due to beats, and improving the multiplicity of the optical signal within a certain transmission band. It is to implement a multiplexing method.
【０００６】[0006]
【課題を解決するための手段】本発明のうち請求項１記
載の光信号多重方法は図１に示す様に、サブキャリアに
よって変調された複数の光信号を多重化して１本の光フ
ァイバにより伝送し、その多重信号を一つの受光器で同
時に受光する光信号通信方法において、高い受信レベル
のサブキャリアによって変調された隣接する光信号の波
長間に、低い受信レベルのサブキャリアによって変調さ
れた光信号を前記光信号よりも低いレベルで配列して一
つの受光器で受光されるようにした方法である。The optical signal multiplexing method according to claim 1 of the present invention multiplexes a plurality of optical signals modulated by subcarriers and uses a single optical fiber as shown in FIG. In an optical signal communication method for transmitting and simultaneously receiving the multiplexed signal with one optical receiver, the wavelength of an adjacent optical signal modulated by a high reception level subcarrier is modulated by a low reception level subcarrier. This is a method in which optical signals are arranged at a lower level than the optical signals and received by one light receiver.
【０００７】本発明のうち請求項２記載の光信号多重方
法は図１に示す様に、サブキャリアによって変調された
複数の光信号を個別の光ファイバにより伝送し、それら
の光信号を一つの受光器で同時に受光する光信号通信方
法において、高い受信レベルのサブキャリアによって変
調された隣接する光信号の波長間に、低い受信レベルの
サブキャリアによって変調された光信号を前記光信号よ
りも低いレベルで配列して一つの受光器で受光されるよ
うにした方法である。In the optical signal multiplexing method according to the second aspect of the present invention, as shown in FIG. 1, a plurality of optical signals modulated by subcarriers are transmitted through individual optical fibers, and those optical signals are converted into one optical signal. In an optical signal communication method of receiving light simultaneously by a light receiver, an optical signal modulated by a subcarrier having a low reception level is lower than an optical signal between wavelengths of adjacent optical signals modulated by a subcarrier having a high reception level. This is a method in which light is received by one light receiver by arranging the light at one level.
【０００８】本発明のうち請求項３記載の光信号多重方
法は図１に示す様に、請求項１又は請求項２記載の光信
号多重方法において、高い受信レベルのサブキャリアに
よって変調された光信号が０．２ｎｍ〜０．４ｎｍの波
長間隔で配列され、その中間周波数にそれらの光信号レ
ベルよりも低い受信レベルのサブキャリアによって変調
された光信号を配列するようにした方法である。In the optical signal multiplexing method according to the third aspect of the present invention, as shown in FIG. 1, in the optical signal multiplexing method according to the first or second aspect, the optical signal modulated by a subcarrier having a high reception level. This is a method in which signals are arranged at wavelength intervals of 0.2 nm to 0.4 nm, and an optical signal modulated by a subcarrier having a reception level lower than those optical signal levels is arranged at the intermediate frequency.
【０００９】本発明のうち請求項４記載の光信号多重方
法は図１に示す様に、請求項１又は請求項２記載の光信
号多重方法において、高い所要受信レベルのサブキャリ
アによって変調された隣接する光信号の波長間に、６４
ｋＨｚ〜２ＭＨｚの帯域の位相シフト変調信号によって
強度変調された光信号を配列するようにした方法であ
る。In the optical signal multiplexing method according to the fourth aspect of the present invention, as shown in FIG. 1, in the optical signal multiplexing method according to the first or second aspect, the signal is modulated by a subcarrier having a high required reception level. Between the wavelengths of adjacent optical signals, 64
This is a method in which optical signals intensity-modulated by a phase shift modulation signal in a band of kHz to 2 MHz are arranged.
【００１０】本発明のうち請求項５記載の光信号多重方
法は図１に示す様に、請求項１又は請求項２記載の光信
号多重方法において、２７ＭＨｚ帯域のＦＭ変調信号
（ＦＭ映像を送る時の一般的帯域）によって強度変調さ
れ且つ０．２ｎｍ〜０．４ｎｍの波長間隔で配列された
光信号の中間周波数に、６４ｋＨｚ〜２ＭＨｚ（デジタ
ル信号を送る時のビットレ−ト）の帯域の位相シフト変
調信号によって強度変調された光信号（デジタル信号）
を配列するようにした方法である。In the optical signal multiplexing method according to the fifth aspect of the present invention, as shown in FIG. 1, in the optical signal multiplexing method according to the first or second aspect, an FM modulated signal (FM image is transmitted in a 27 MHz band). The phase of a band of 64 kHz to 2 MHz (bit rate when transmitting a digital signal) at the intermediate frequency of an optical signal which is intensity-modulated by a general band at the time and arranged at a wavelength interval of 0.2 nm to 0.4 nm. Optical signal (digital signal) intensity-modulated by the shift modulation signal
Are arranged.
【００１１】[0011]
【作用】本発明のうち請求項１及び請求項２記載の光信
号多重方法では、高い受信レベルのサブキャリアによっ
て変調された隣接する光信号の波長間に、低い受信レベ
ルのサブキャリアによって変調された光信号を前記光信
号よりも低いレベルで配列して一つの受光器で受光され
るようにしたので、波長間隔を狭めて多重度を上げて
も、全ての光信号を同一レベルで強度変調した場合より
もビートレベルの上昇が抑制され、全ての光信号に変調
をかけているサブキャリアの品質を所要品質に保った状
態で光信号の多重度を上げることができる。In the optical signal multiplexing method according to the first and second aspects of the present invention, a signal is modulated by a low-reception-level subcarrier between wavelengths of adjacent optical signals modulated by a high-reception-level subcarrier. The optical signals are arranged at a lower level than the optical signals so that they are received by one photodetector, so that even if the wavelength interval is reduced and the multiplicity is increased, all the optical signals are intensity-modulated at the same level. In this case, the rise of the beat level is suppressed more than in the case of the above-mentioned case, and the multiplicity of the optical signal can be increased while maintaining the required quality of the subcarriers on which all the optical signals are modulated.
【００１２】本発明のうち請求項３記載の光信号多重方
法では、高い受信レベルのサブキャリアによって変調さ
れた光信号が０．２ｎｍ〜０．４ｎｍの波長間隔で配列
するので、ビートによる信号の品質劣化が生じない範囲
で波長間隔を狭くすることができる。しかも、０．２ｎ
ｍ〜０．４ｎｍの波長間隔の中間波長に、それらの光信
号レベルよりも低い所要受信レベルのサブキャリアによ
って変調された光信号を配列するので、ビート雑音がよ
り一層少なくなる。In the optical signal multiplexing method according to the third aspect of the present invention, optical signals modulated by subcarriers having a high reception level are arranged at wavelength intervals of 0.2 nm to 0.4 nm. The wavelength interval can be narrowed in a range where quality deterioration does not occur. And 0.2n
Since an optical signal modulated by a subcarrier having a required reception level lower than the optical signal level is arranged at an intermediate wavelength at a wavelength interval of m to 0.4 nm, beat noise is further reduced.
【００１３】本発明のうち請求項４記載の光信号多重方
法では図１に示す様に、請求項１又は請求項２記載の光
信号通信方法において、高い所要受信レベルのサブキャ
リアによって変調された隣接する光信号の波長間に、６
４ｋＨｚ〜２ＭＨｚの帯域の位相シフト変調信号によっ
て強度変調された光信号（デジタル信号）を配列するの
で、デジタル信号のレベルが低くとも、雑音があって
も、アナログ信号の場合よりもビート雑音の影響を受け
にくくなる。In the optical signal multiplexing method according to the fourth aspect of the present invention, as shown in FIG. 1, in the optical signal communication method according to the first or second aspect, the signal is modulated by a subcarrier having a high required reception level. 6 between the wavelengths of adjacent optical signals
An optical signal (digital signal) intensity-modulated by a phase shift modulation signal in a band of 4 kHz to 2 MHz is arranged, so that even if the level of the digital signal is low and there is noise, the influence of beat noise is greater than that of an analog signal. Hard to receive.
【００１４】本発明のうち請求項５の光信号多重方法で
は、２７ＭＨｚ帯域のＦＭ変調信号によって強度変調さ
れ且つ０．２ｎｍ〜０．４ｎｍの波長間隔で配列された
光信号の中間周波数に、６４ｋＨｚ〜２ＭＨｚの帯域の
位相シフト変調信号によって強度変調された光信号を配
列するので、狭い波長間隔でもビートの発生が少なくな
り、また、ビート雑音があってもその影響を受けにくく
なる。In the optical signal multiplexing method according to the fifth aspect of the present invention, the intermediate frequency of an optical signal which is intensity-modulated by an FM modulation signal in a 27 MHz band and is arranged at a wavelength interval of 0.2 nm to 0.4 nm is 64 kHz. Since the optical signals intensity-modulated by the phase shift modulation signal in the band of up to 2 MHz are arranged, the occurrence of a beat is reduced even at a narrow wavelength interval, and even if there is beat noise, it is hard to be affected by the beat noise.
【００１５】[0015]
【実施例１】本発明の光信号多重方法の一実施例を図１
〜図３に基づいて詳細に説明する。図１では端局１０に
おける複数の電気／光変換器（Ｅ／Ｏ変換器）１からの
光信号が変調器（ＭＯＤ）７からの信号（サブキャリ
ア）によって変調され、光カプラ５を介して１本の光フ
ァイバ（光伝送路）６へ送信されて多重化される。この
多重化された光信号はセンタ９の一つの受光器（ＰＤ：
フィトダイオード）２によって同時に検波され、分配器
８により復調器３へ分配され、復調器３で復調されてＴ
Ｖ等の受信装置４で受信される。Embodiment 1 FIG. 1 shows an embodiment of an optical signal multiplexing method according to the present invention.
This will be described in detail with reference to FIG. In FIG. 1, optical signals from a plurality of electric / optical converters (E / O converters) 1 in the terminal station 10 are modulated by signals (subcarriers) from a modulator (MOD) 7, The signal is transmitted to one optical fiber (optical transmission line) 6 and multiplexed. The multiplexed optical signal is supplied to one light receiver (PD:
The signal is simultaneously detected by the photodiode 2, distributed to the demodulator 3 by the distributor 8, demodulated by the demodulator 3, and
V and the like.
【００１６】この場合、受光器２において光の波長差分
に相当する周波数に光の相互干渉によるビート信号が発
生し、そのビート信号が変調器７から送出される信号の
周波数帯に発生すると、その影響により光信号の伝送品
質が著しく劣化する。ビートのピークレベルは干渉し合
う光のレベル及び偏波面の角度によって決定され、干渉
し合う光のレベルが低くなればビートレベルも抑制され
る。また、電気／光変換器１から送出される光信号を全
て同一のサブキャリアによって同一レベルで強度変調し
て、受光器２に到達する光信号レベルを図５に示すよう
に同一にすると、全てのサブキャリアが一致し、全ての
信号の伝送品質も同一になる。換言すれば、光信号のど
れかを低いレベルにするとその光信号に変調をかけてい
るサブキャリアレベルも他の信号より低下し、その信号
の品質だけが劣化してしまう。このため、本発明では光
信号の受光レベルと所要品質を考慮して、雑音レベル
（ビートレベル）が高まらないように波長間隔を設定す
る。波長間隔の一例としては例えば０．２〜０．４ｎｍ
にするのが望ましい。０．２ｎｍよりも狭いとビート雑
音が増え、０．４ｎｍよりも広くなると隣接光信号の間
隔が従来のもの（０．２ｎｍ）より広くなってしまい多
重度を上げることにならない。In this case, when a beat signal due to mutual interference of light is generated at a frequency corresponding to the wavelength difference of light in the light receiver 2 and the beat signal is generated in the frequency band of the signal transmitted from the modulator 7, Due to the influence, the transmission quality of the optical signal is significantly deteriorated. The peak level of the beat is determined by the level of the interfering light and the angle of the plane of polarization, and the lower the level of the interfering light, the lower the beat level. Further, when all the optical signals sent from the electrical / optical converter 1 are intensity-modulated at the same level by the same subcarrier and the optical signal levels reaching the light receiver 2 are made equal as shown in FIG. And the transmission qualities of all signals are the same. In other words, when one of the optical signals is set to a low level, the subcarrier level that modulates the optical signal is also lower than the other signals, and only the quality of the signal deteriorates. For this reason, in the present invention, the wavelength interval is set so that the noise level (beat level) does not increase in consideration of the light receiving level of the optical signal and the required quality. As an example of the wavelength interval, for example, 0.2 to 0.4 nm
It is desirable to make. If it is smaller than 0.2 nm, the beat noise increases, and if it is larger than 0.4 nm, the interval between adjacent optical signals becomes wider than that of the conventional one (0.2 nm), and the multiplicity does not increase.
【００１７】前記のように複数の光信号を多重化して伝
送する場合、最小受信レベルが異なるサブキャリアによ
って変調がかけられている光信号が混在しているとき
は、最小受信レベルが低いキャリアによって変調されて
いる光信号の受信レベルは低くてもよい。そこで本発明
では最小受光レベルが高い光信号（図２の光信号１、
３：例えばアナログ映像のような信号）の波長間に、最
小受光レベルが低い信号（図２の光信号２：例えば低速
デジタルデータのような信号）を配列し、しかも、この
最小受光レベルが低い信号を最小受光レベルが高い光信
号よりも低いレベルで配列して多重化してある。When a plurality of optical signals are multiplexed and transmitted as described above, when optical signals modulated by subcarriers having different minimum reception levels are mixed, a carrier having a lower minimum reception level is used. The reception level of the modulated optical signal may be low. Therefore, in the present invention, an optical signal having a high minimum light receiving level (optical signal 1 in FIG.
3: A signal having a low minimum light reception level (optical signal 2: signal such as low-speed digital data in FIG. 2) is arranged between wavelengths of, for example, signals such as analog images, and the minimum light reception level is low. The signals are arranged and multiplexed at a lower level than an optical signal having a higher minimum light receiving level.
【００１８】最小受光レベルが低い光信号の受信レベル
を下げればビート雑音は減少するが下げ過ぎると光信号
の品質が劣化するので下げるにしても限度がある。そこ
で本実施例では所要性能を満たす領域内でレベルを下げ
て光信号を伝送するようにした。このようにすると複数
の光信号を全て同一レベルで伝送する場合に比して、伝
送波長帯域巾を増やすことなく多重数を上げることがで
きた。If the receiving level of an optical signal having a low minimum light receiving level is lowered, the beat noise is reduced, but if the level is lowered too much, the quality of the optical signal is deteriorated. Therefore, in the present embodiment, the optical signal is transmitted with the level lowered within a region satisfying the required performance. In this way, the number of multiplexed signals can be increased without increasing the transmission wavelength bandwidth, as compared with the case where all of a plurality of optical signals are transmitted at the same level.
【００１９】また、本実施例では最小受光レベルが高い
光信号と低い光信号を図２に示す様に交互に配列した。
この場合、本件発明者の実験によると、従来の多重度に
対してほぼ２倍の多重度が得られた。In this embodiment, optical signals having a high minimum light receiving level and optical signals having a low minimum light receiving level are alternately arranged as shown in FIG.
In this case, according to the experiment of the inventor of the present invention, the multiplicity almost doubled as compared with the conventional multiplicity was obtained.
【００２０】前記の様に最小受光レベルが高い光信号が
例えばＦＭ映像信号の場合は、その光信号はＦＭ映像信
号を伝送するときの一般的な帯域である２７ＭＨZ 帯域
のＦＭ変調信号により強度変調して伝送する。また、前
記の様に最小受光レベルが低い光信号がデジタル信号の
場合は、６４ｋＨｚ〜２ＭＨｚ（デジタル信号を送る時
のビットレート）の帯域の位相シフト変調信号によって
強度変調して伝送するのがよい。この場合、デジタル信
号はレベルが低くとも、雑音があってもアナログ信号よ
りも雑音の影響を受けにくいので、最小受光レベルが低
い光信号のレベルをある程度まで下げても光信号の最低
必要な品質は保持される。As described above, when the optical signal having the high minimum light receiving level is, for example, an FM video signal, the intensity of the optical signal is determined by an FM modulation signal in a 27 MHz Z band which is a general band for transmitting the FM video signal. Modulate and transmit. When an optical signal having a low minimum light receiving level is a digital signal as described above, it is preferable that the optical signal be intensity-modulated by a phase shift modulation signal in a band of 64 kHz to 2 MHz (bit rate when transmitting a digital signal) and transmitted. . In this case, even if the digital signal has a low level, even if there is noise, it is less susceptible to noise than an analog signal. Is retained.
【００２１】[0021]
【実施例２】実施例１では図２に示す様に隣接する最小
受光レベルが高い光信号（図２の光信号１、３）間に、
最小受光レベルが低い信号（図２の光信号２）を一つだ
け配列してあるが、この実施例では図３に示す様に隣接
する最小受光レベルが高い光信号（図３の光信号１、
３）間に、最小受光レベルが低い信号（図３の光信号
２）を二つ配列したものである。この場合も実施例１と
同様の効果が得られた。隣接する最小受光レベルが高い
光信号（図３の光信号１、３）間に配列する最小受光レ
ベルが低い信号（図３の光信号２）の数はビート障害が
生じなければ３以上でもよい。Embodiment 2 In Embodiment 1, as shown in FIG. 2, between adjacent optical signals having high minimum light receiving levels (optical signals 1 and 3 in FIG. 2).
Although only one signal having a low minimum light receiving level (optical signal 2 in FIG. 2) is arranged, in this embodiment, as shown in FIG. 3, an adjacent optical signal having a high minimum light receiving level (optical signal 1 in FIG. 3). ,
Between 3), two signals (light signal 2 in FIG. 3) having a low minimum light receiving level are arranged. In this case, the same effect as in the first embodiment was obtained. The number of signals (optical signal 2 in FIG. 3) having a low minimum light receiving level arranged between adjacent optical signals (optical signals 1 and 3 in FIG. 3) having a high minimum light receiving level may be three or more as long as no beat failure occurs. .
【００２２】[0022]
【実施例３】図１は光伝送路６が１本の場合であるが、
本実施例は図４に示す様に光伝送路６を複数本にし、各
送信装置からの光信号を夫々の光伝送路６により個別に
伝送し、それをカプラ５で合波し、更に、図２、図３に
示す様に最小受光レベルが高い光信号間に最小受光レベ
ルが低い信号を配列して多重化し、この多重化された複
数の光信号を１つの受光器２で同時に受光するようにし
たものである。この場合も実施例１と同様の効果が得ら
れた。なお、図４の９はセンタ、１０は端局である。Embodiment 3 FIG. 1 shows a case where the number of optical transmission lines 6 is one.
In the present embodiment, as shown in FIG. 4, a plurality of optical transmission lines 6 are provided, optical signals from each transmitting device are individually transmitted through the respective optical transmission lines 6, and multiplexed by the coupler 5, and As shown in FIGS. 2 and 3, a signal having a low minimum light receiving level is arranged and multiplexed between optical signals having a high minimum light receiving level, and a plurality of multiplexed optical signals are simultaneously received by one light receiver 2. It is like that. In this case, the same effect as in the first embodiment was obtained. In FIG. 4, 9 is a center, and 10 is a terminal station.
【００２３】[0023]
【発明の効果】本発明のうち請求項１及び請求項２記載
の光信号多重方法では、高い受信レベルのサブキャリア
によって変調された隣接する光信号の波長間に、低い受
信レベルのサブキャリアによって変調された光信号を前
記光信号よりも低いレベルで配列したので、波長帯域幅
を広げずに光信号の多重度を高めることができ、またビ
ートの影響による光信号の品質劣化も殆どない。According to the optical signal multiplexing method according to the first and second aspects of the present invention, a low receiving level subcarrier is used between adjacent optical signals modulated by a high receiving level subcarrier. Since the modulated optical signal is arranged at a lower level than the optical signal, the multiplicity of the optical signal can be increased without widening the wavelength bandwidth, and the quality of the optical signal is hardly deteriorated due to the influence of the beat.
【００２４】本発明のうち請求項３記載の光信号多重方
法では、高い受信レベルのサブキャリアによって変調さ
れた光信号の波長間隔を０．２ｎｍ〜０．４ｎｍとし、
その中間波長にレベルの低い光信号を配列するので、狭
い波長間隔に多くの信号を多重化でき、多重度が高ま
り、ビートの影響による光信号の品質劣化も少ない。In the optical signal multiplexing method according to the third aspect of the present invention, the wavelength interval of the optical signal modulated by the subcarrier having a high reception level is set to 0.2 nm to 0.4 nm,
Since an optical signal having a low level is arranged at the intermediate wavelength, many signals can be multiplexed at a narrow wavelength interval, the degree of multiplexing increases, and the deterioration of the optical signal quality due to the influence of beat is small.
【００２５】本発明のうち請求項４記載の光信号多重方
法では、高い所要受信レベルのサブキャリアによって変
調された隣接する光信号の波長間に、６４ｋＨｚ〜２Ｍ
Ｈｚの帯域の位相シフト変調信号によって強度変調され
た光信号（デジタル信号）を配列するので、デジタル信
号のレベルが低くとも、雑音があっても、アナログ信号
の場合よりもビート雑音の影響を受けにくくなり、光信
号の品質劣化が少なくなる。In the optical signal multiplexing method according to the fourth aspect of the present invention, the frequency between adjacent optical signals modulated by subcarriers having a high required reception level is 64 kHz to 2M.
Since an optical signal (digital signal) intensity-modulated by the phase shift modulation signal in the Hz band is arranged, even if the level of the digital signal is low, even if there is noise, it is more affected by beat noise than in the case of an analog signal. And the quality of the optical signal is less deteriorated.
【００２６】本発明のうち請求項５の光信号多重方法で
は、２７ＭＨｚ帯域のＦＭ変調信号によって強度変調さ
れ且つ０．２ｎｍ〜０．４ｎｍの波長間隔で配列された
光信号の中間周波数に６４ｋＨｚ〜２ＭＨｚの帯域の位
相シフト変調信号によって強度変調された光信号を配列
するので、ビートの発生が少なく、ビート雑音があって
もその影響を受けにくく、信号の品質劣化が少ない。In the optical signal multiplexing method according to the fifth aspect of the present invention, the intermediate frequency of an optical signal which is intensity-modulated by an FM modulation signal in a 27 MHz band and is arranged at a wavelength interval of 0.2 nm to 0.4 nm is 64 kHz to 64 kHz. Since the optical signals that are intensity-modulated by the phase shift modulation signal of the 2 MHz band are arranged, the occurrence of beats is small, and even if there is beat noise, the influence of the beat noise is small, and the signal quality is hardly deteriorated.
【図１】本発明の光信号多重方法の第１の実施例を示す
バス型システムの構成図。FIG. 1 is a configuration diagram of a bus type system showing a first embodiment of an optical signal multiplexing method of the present invention.
【図２】本発明の光信号多重方法における光信号レベル
の第１の例を示す説明図。FIG. 2 is an explanatory diagram showing a first example of an optical signal level in the optical signal multiplexing method of the present invention.
【図３】本発明の光信号多重方法における光信号レベル
の第２の例を示す説明図。FIG. 3 is an explanatory diagram showing a second example of the optical signal level in the optical signal multiplexing method of the present invention.
【図４】本発明の光信号多重方法の第２の実施例を示す
スター型システムの構成図。FIG. 4 is a configuration diagram of a star type system showing a second embodiment of the optical signal multiplexing method of the present invention.
【図５】多重化される全ての光信号が同一レベルの場合
の説明図FIG. 5 is an explanatory diagram when all multiplexed optical signals have the same level.
【図６】異なったサブキャリアで変調された光信号を多
重化する場合の従来の光信号配列の説明図。FIG. 6 is an explanatory diagram of a conventional optical signal arrangement when multiplexing optical signals modulated by different subcarriers.
１は電気光変換器 ２は受光器 ３は復調器 ４は表示装置 ５は光カプラ ６は光伝送路 ７は変調器 ８は分配器 ９はセンタ １０は端局 1 is an electro-optical converter 2 is a light receiver 3 is a demodulator 4 is a display device 5 is an optical coupler 6 is an optical transmission line 7 is a modulator 8 is a distributor 9 is a center 10 is a terminal station
フロントページの続き (72)発明者 川口 武志 東京都千代田区丸の内２丁目６番１号 古河電気工業株式会社内 (72)発明者 高島 伸一 東京都千代田区丸の内２丁目６番１号 古河電気工業株式会社内 (72)発明者 篠田 雪久 神奈川県横浜市鶴見区江ケ崎町４番１号 東京電力株式会社システム研究所内 (56)参考文献 特開 平７−283787（ＪＰ，Ａ) 特開 平７−231300（ＪＰ，Ａ) 特開 平６−342952（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H04B 10/00 - 10/28 H04J 14/00 - 14/08 Continued on the front page (72) Inventor Takeshi Kawaguchi 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Shinichi Takashima 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. In-company (72) Inventor Yukihisa Shinoda 4-1 Egasaki-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Tokyo Electric Power Company System Research Laboratory (56) References JP-A-7-283787 (JP, A) JP-A-7-283 231300 (JP, A) JP-A-6-3422952 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H04B 10/00-10/28 H04J 14/00-14/08
Claims (5)
信号を多重化して１本の光伝送路により伝送し、その多
重信号を一つの受光器で同時に受光するようにした光信
号通信方法において、高い所要受信レベルのサブキャリ
アによって変調された隣接する光信号の波長間に、低い
所要受信レベルのサブキャリアによって変調された光信
号を前記光信号よりも低いレベルで配列して多重化する
ことを特徴とする光信号多重方法。An optical signal communication method comprising multiplexing a plurality of optical signals modulated by subcarriers, transmitting the multiplexed signals through one optical transmission line, and simultaneously receiving the multiplexed signals with one optical receiver. Arranging and multiplexing an optical signal modulated by a sub-carrier of a low required reception level at a lower level than the optical signal between wavelengths of adjacent optical signals modulated by a sub-carrier of a high required reception level. Characteristic optical signal multiplexing method.
信号を個別の光ファイバにより別々に伝送し、それらの
光信号を多重化して一つの受光器で同時に受光する光信
号通信方法において、高い所要受信レベルのサブキャリ
アによって変調された隣接する光信号の波長間に、低い
所要受信レベルのサブキャリアによって変調された光信
号を前記光信号よりも低いレベルで配列して一つの受光
器で同時に受光されるようにしたことを特徴とする光信
号多重方法。2. An optical signal communication method in which a plurality of optical signals modulated by subcarriers are separately transmitted by individual optical fibers, and these optical signals are multiplexed and simultaneously received by one optical receiver. An optical signal modulated by a subcarrier of a low required reception level is arranged at a lower level than the optical signal between wavelengths of adjacent optical signals modulated by the subcarrier of the reception level, and is simultaneously received by one light receiver. An optical signal multiplexing method.
法において、高い所要受信レベルのサブキャリアによっ
て変調された光信号が０．２ｎｍ〜０．４ｎｍの波長間
隔で配列され、その中間周波数にそれらの光信号レベル
よりも低い所要受信レベルのサブキャリアによって変調
された光信号を配列することを特徴とする光信号多重方
法。3. The optical signal multiplexing method according to claim 1, wherein the optical signals modulated by the subcarriers having a high required reception level are arranged at a wavelength interval of 0.2 nm to 0.4 nm, and an intermediate signal is arranged between the optical signals. An optical signal multiplexing method, comprising arranging optical signals modulated by subcarriers having a required reception level lower than those optical signal levels in frequency.
法において、高い所要受信レベルのサブキャリアによっ
て変調された隣接する光信号の波長間に、６４ｋＨｚ〜
２ＭＨｚの帯域の位相シフト変調信号によって強度変調
された光信号を配列することを特徴とする光信号多重方
法。4. The optical signal multiplexing method according to claim 1 or 2, wherein the frequency between 64 kHz and 64 kHz is adjusted between adjacent optical signals modulated by subcarriers having a high required reception level.
An optical signal multiplexing method, comprising arranging optical signals that are intensity-modulated by a phase shift modulation signal of a 2 MHz band.
法において、２７ＭＨｚ帯域のＦＭ変調信号によって強
度変調され且つ０．２ｎｍ〜０．４ｎｍの波長間隔で配
列された光信号の中間周波数に、６４ｋＨｚ〜２ＭＨｚ
の帯域の位相シフト変調信号によって強度変調された光
信号を配列することを特徴とする光信号多重方法。5. The optical signal multiplexing method according to claim 1, wherein the intermediate frequency of the optical signal is intensity-modulated by a 27-MHz band FM modulation signal and arranged at a wavelength interval of 0.2 nm to 0.4 nm. , 64kHz-2MHz
An optical signal multiplexing method, comprising arranging optical signals that have been intensity-modulated by a phase shift modulation signal in the band of (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33852694A JP3324086B2 (en) | 1994-12-29 | 1994-12-29 | Optical signal multiplexing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33852694A JP3324086B2 (en) | 1994-12-29 | 1994-12-29 | Optical signal multiplexing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08186535A JPH08186535A (en) | 1996-07-16 |
| JP3324086B2 true JP3324086B2 (en) | 2002-09-17 |
Family
ID=18318998
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33852694A Expired - Lifetime JP3324086B2 (en) | 1994-12-29 | 1994-12-29 | Optical signal multiplexing method |
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| Country | Link |
|---|---|
| JP (1) | JP3324086B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004120694A (en) * | 2002-09-30 | 2004-04-15 | Synclayer Inc | Optical transmitting apparatus, repeating apparatus, and optical transmitting system using the same |
| JP5735309B2 (en) * | 2011-03-07 | 2015-06-17 | シンクレイヤ株式会社 | CATV system and optical tap |
-
1994
- 1994-12-29 JP JP33852694A patent/JP3324086B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08186535A (en) | 1996-07-16 |
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