JP3532099B2 - Optical transmission method and optical transmission apparatus for frequency multiplexed signal - Google Patents
Optical transmission method and optical transmission apparatus for frequency multiplexed signalInfo
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- JP3532099B2 JP3532099B2 JP17214398A JP17214398A JP3532099B2 JP 3532099 B2 JP3532099 B2 JP 3532099B2 JP 17214398 A JP17214398 A JP 17214398A JP 17214398 A JP17214398 A JP 17214398A JP 3532099 B2 JP3532099 B2 JP 3532099B2
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- signal
- optical
- optical transmission
- frequency
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Description
【０００１】[0001]
【発明の属する技術分野】この発明は周波数多重化され
た多チャンネル信号を、ＦＭ一括変調して光伝送する光
伝送方法及びこれに使用する光伝送装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission method for performing FM batch modulation of a frequency-multiplexed multi-channel signal for optical transmission, and an optical transmission apparatus used for the same.
【０００２】[0002]
【従来の技術】従来周波数多重化された多チャンネル信
号を、ＦＭ一括変調して伝送する装置としては、例えば
特開平８−２７４７１４号公報に記載されているものが
知られている。2. Description of the Related Art Conventionally, as a device for FM-modulating and transmitting a multi-channel signal which has been frequency-multiplexed, there is known one disclosed in, for example, Japanese Patent Laid-Open No. 8-274714.
【０００３】上記公報の光伝送装置は、図８に示すよう
に、周波数多重化された多チャンネル信号により搬送波
信号をＦＭ一括変調するＦＭ変調器ａと、得られたＦＭ
一括変調信号によって信号光を強度変調する光変調器ｂ
と、変調された光信号を伝送する光ファイバよりなる光
伝送路ｃと、伝送されてきた光信号を光／電気変換する
光受信器ｄと、ＦＭ一括変調信号をＦＭ復調して、周波
数多重化された多チャンネル信号を出力するＦＭ復調器
ｅとより構成されている。The optical transmission device of the above publication, as shown in FIG. 8, has an FM modulator a for FM-modulating a carrier signal by a frequency-multiplexed multi-channel signal, and an obtained FM modulator.
Optical modulator b for intensity-modulating the signal light by the collective modulation signal
, An optical transmission line c formed of an optical fiber for transmitting a modulated optical signal, an optical receiver d for optically / electrically converting the transmitted optical signal, FM demodulation of an FM collective modulation signal, and frequency multiplexing. It is composed of an FM demodulator e that outputs a converted multi-channel signal.
【０００４】そして次のように動作する。Then, it operates as follows.
【０００５】すなわち、ＦＭ変調器ａに入力された周波
数多重化された多チャンネル信号は、ＦＭ変調器ａによ
りＦＭ一括変調された後、光変調器ｂにより信号光が強
度変調され、光伝送路ｃにより伝送される。That is, the frequency-multiplexed multi-channel signal input to the FM modulator a is FM-modulated by the FM modulator a, and then the signal light is intensity-modulated by the optical modulator b. c.
【０００６】伝送された信号光は、光受信器ｄにより光
／電気変換され、得られたＦＭ一括変調信号は、ＦＭ復
調器ｅによりＦＭ復調することにより、周波数多重化さ
れた多チャンネル信号に再生される。The transmitted signal light is optically / electrically converted by the optical receiver d, and the obtained FM collective modulation signal is FM-demodulated by the FM demodulator e to be a frequency-multiplexed multi-channel signal. Is played.
【０００７】[0007]
【発明が解決しようとする課題】しかし上記従来の光伝
送装置では、光伝送路ｃによる光伝送距離が長くなっ
て、光受信器ｄにより受信される光電力が低下すると、
ＦＭ一括変調信号と、光ファイバｃや光受信器ｄ等で発
生する強度雑音との電力比（ＣＮＲ）が低下し、その結
果ＦＭ復調後の周波数多重化された多チャンネル信号と
雑音の電力比（ＳＮＲ）が劣化するなどの不具合があっ
た。However, in the above-mentioned conventional optical transmission device, when the optical transmission distance through the optical transmission line c becomes long and the optical power received by the optical receiver d decreases,
The power ratio (CNR) between the FM batch modulation signal and the intensity noise generated in the optical fiber c, the optical receiver d, etc. decreases, and as a result, the power ratio between the frequency-multiplexed multi-channel signal after FM demodulation and the noise. There was a problem such as deterioration of (SNR).
【０００８】この発明はかかる従来の不具合を改善する
ためになされたもので、光伝送路による伝送距離が長く
なって、光受信器の受信光電力が低下した場合でも、良
質な周波数多重化された多チャンネル信号が再生できる
多チャンネル信号の光伝送方法及び光伝送装置を提供す
ることを目的とするものである。The present invention has been made in order to solve the above-mentioned conventional inconvenience. Even when the optical transmission line has a long transmission distance and the received optical power of the optical receiver is lowered, good frequency multiplexing is performed. Another object of the present invention is to provide an optical transmission method and an optical transmission device for a multi-channel signal that can reproduce the multi-channel signal.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成するた
め、この発明の光伝送方法及びこれに使用する光伝送装
置は、ＦＭ変調器の後段に、ＦＭ一括変調信号をパルス
信号に変換するパルス信号変換器を設けたもので、ＦＭ
一括変調信号をパルス信号変換器によりパルス信号に変
換し、ＦＭ一括変調信号の波形の立ち上り、立ち下りを
急峻にして伝送することで、フリップフロップやＡＮＤ
ゲートなどを用いて遅延検波しＦＭ復調することによ
り、強度雑音の影響により生じるパルスのジッタを低減
することができ、受信光電力が特に低くなり、ＦＭ一括
変調信号と光伝送路や光受信器等で発生する強度雑音と
の電力比（ＣＮＲ）が低下した場合でも、良質な周波数
多重化された多チャンネル信号を伝送することができる
光伝送方法及び光伝送装置を提供することができるよう
になる。In order to achieve the above object, an optical transmission method of the present invention and an optical transmission apparatus used for the same are provided with a pulse for converting an FM batch modulated signal into a pulse signal after an FM modulator. With a signal converter, FM
The batch modulation signal is converted into a pulse signal by a pulse signal converter, and the waveform of the FM batch modulation signal is transmitted with a sharp rise and fall, thereby enabling a flip-flop and an AND.
By performing delay detection and FM demodulation using a gate or the like, pulse jitter caused by the influence of intensity noise can be reduced, the received optical power becomes particularly low, and the FM collective modulation signal and optical transmission line or optical receiver can be reduced. Thus, it is possible to provide an optical transmission method and an optical transmission device capable of transmitting a high-quality frequency-multiplexed multi-channel signal even when the power ratio (CNR) to the intensity noise generated in the above-mentioned situation is reduced. Become.
【００１０】[0010]
【発明の実施の形態】この発明の請求項１に記載の発明
は、周波数多重化された多チャンネル信号をＦＭ一括変
調すると共に、得られたＦＭ一括変調信号によって信号
光を強度変調して光伝送し、この光信号を光／電気変換
して得られたＦＭ一括変調信号をＦＭ復調して周波数多
重化された多チャンネル信号を伝送する光伝送方法にお
いて、周波数多重化された多チャンネル信号をＦＭ変調
することにより得られたＦＭ一括変調信号をパルス信号
に変換して、ＦＭ一括変調信号の波形の立ち上りと立ち
下りを急峻にし、得られたパルス信号で信号光を強度変
調して光伝送するようにしたもので、受信光電力が小さ
く、強度雑音の影響が大きい場合でも、ＦＭ復調時の強
度雑音によるジッタを低減することができる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is to perform FM batch modulation of a frequency-multiplexed multi-channel signal, and intensity-modulate signal light with the obtained FM batch modulation signal to obtain an optical signal. An optical transmission method for transmitting a frequency-multiplexed multi-channel signal by FM demodulating an FM collective modulation signal obtained by optical-electrically converting this optical signal, and transmitting the frequency-multiplexed multi-channel signal. The FM batch modulated signal obtained by FM modulation is converted into a pulse signal, the rising and falling edges of the waveform of the FM batch modulated signal are made sharp, and the signal light is intensity-modulated with the obtained pulse signal to perform optical transmission. Therefore, even when the received optical power is low and the influence of the intensity noise is large, it is possible to reduce the jitter due to the intensity noise during FM demodulation.
【００１１】この発明の請求項２に記載の発明は、周波
数多重化された多チャンネル信号により搬送波信号をＦ
Ｍ一括変調するＦＭ変調器と、変調されたＦＭ一括変調
信号をパスル信号に変換して、ＦＭ一括変調信号の波形
の立ち上りと立ち下りを急峻にするパルス信号変換器
と、このパルス信号によって信号光を強度変調する光変
調器と、この変調された光信号を伝送する手段と、伝送
された光信号を光／電気変換する光受信器と、光／電気
変換により得られたＦＭ一括変調信号をＦＭ復調して周
波数多重化された多チャンネル信号を得るＦＭ復調器と
より構成したもので、受信光電力が小さく、強度雑音の
影響が大きい場合でも、ＦＭ復調時の強度雑音によるジ
ッタを低減することができる。According to a second aspect of the present invention, the carrier signal is F-channel by a frequency-multiplexed multi-channel signal.
An FM modulator that performs M batch modulation, a pulse signal converter that converts the modulated FM batch modulation signal into a pulse signal to make the rising and falling of the waveform of the FM batch modulation signal steep, and a signal using this pulse signal Optical modulator for intensity-modulating light, means for transmitting the modulated optical signal, optical receiver for optical / electrical conversion of the transmitted optical signal, and FM collective modulation signal obtained by optical / electrical conversion And an FM demodulator that obtains frequency-multiplexed multi-channel signals by performing FM demodulation, reduce jitter due to intensity noise during FM demodulation even when received optical power is small and intensity noise is large. can do.
【００１２】この発明の請求項３に記載の発明は、パル
ス信号変換器をリミッタアンプより構成したもので、こ
のリミッタアンプによりＦＭ一括変調信号を、波形の立
ち上りと立ち下りが急峻なパルス信号に変換することが
できる。According to a third aspect of the present invention, the pulse signal converter is constituted by a limiter amplifier, and the limiter amplifier converts the FM collective modulation signal into a pulse signal having sharp rising and falling edges. Can be converted.
【００１３】この発明の請求項４に記載の発明は、パル
ス信号変換器を論理回路より構成したもので、この論理
回路によりＦＭ一括変調信号を、波形の立ち上りと立ち
下りが急峻なパルス信号に変換することができる。According to a fourth aspect of the present invention, the pulse signal converter is constituted by a logic circuit, and the FM batch modulated signal is converted into a pulse signal having a sharp rise and fall of a waveform by this logic circuit. Can be converted.
【００１４】この発明の請求項５に記載の発明は、パル
ス信号変換器をＴフリップフロップ回路からなる分周回
路より構成したもので、この分周回路によりＦＭ一括変
調信号を、波形の立ち上りと立ち下りが急峻なパルス信
号に変換することができる。According to a fifth aspect of the present invention, the pulse signal converter is composed of a frequency dividing circuit composed of a T flip-flop circuit, and the FM batch modulation signal is generated by the frequency dividing circuit at the rising edge of the waveform. It can be converted into a pulse signal having a sharp fall.
【００１５】この発明の請求項６に記載の発明は、光変
調器を、半導体レーザと外部光強度変調器より構成した
もので、外部光強度変調器はパルス信号変換器でパルス
信号に変換されたＦＭ一括変調信号の波形を極力変化さ
せずに光伝送路に送信することができる。According to a sixth aspect of the present invention, the optical modulator comprises a semiconductor laser and an external light intensity modulator, and the external light intensity modulator is converted into a pulse signal by a pulse signal converter. The waveform of the FM batch modulated signal can be transmitted to the optical transmission line without changing the waveform as much as possible.
【００１６】以下この発明の実施の形態１ないし５を、
図１ないし図７に示す図面を参照して詳述する。Embodiments 1 to 5 of the present invention will be described below.
This will be described in detail with reference to the drawings shown in FIGS.
【００１７】（実施の形態１）図１は実施の形態１にな
る光伝送装置のブロック図、図２及び図３は作用を示す
線図で、光伝送装置は、周波数多重化された多チャンネ
ル信号をＦＭ一括変調するＦＭ変調器１と、得られたＦ
Ｍ一括変調信号をパルス信号に変換するパルス信号変換
器２と、得られたパルス信号により信号光を強度変調す
る光変調器３と、強度変調された光信号を伝送する光フ
ァイバよりなる光伝送路４と、伝送されてきた光信号を
光／電気変換する光受信器５と、ＦＭ一括変調信号をＦ
Ｍ復調して、周波数多重化された多チャンネル信号に再
生するＦＭ復調器６とより構成されている。(Embodiment 1) FIG. 1 is a block diagram of an optical transmission apparatus according to Embodiment 1, and FIGS. 2 and 3 are diagrams showing the operation. The optical transmission apparatus is a frequency-multiplexed multi-channel. An FM modulator 1 for performing FM batch modulation on a signal and the obtained F
Optical transmission comprising a pulse signal converter 2 for converting an M batch modulated signal into a pulse signal, an optical modulator 3 for intensity modulating signal light with the obtained pulse signal, and an optical fiber for transmitting the intensity modulated optical signal The path 4, the optical receiver 5 for converting the transmitted optical signal into an electrical signal, and the FM collective modulation signal to F
It is composed of an FM demodulator 6 which performs M demodulation and reproduces a frequency-multiplexed multi-channel signal.
【００１８】次に上記構成された光伝送装置の作用を図
２及び図３も参照して説明すると、ＦＭ変調器１に入力
された周波数多重化された多チャンネル信号は、ＦＭ変
調器１によりＦＭ一括変調された後、パルス信号変換器
２へ送られる。Next, the operation of the optical transmission apparatus having the above configuration will be described with reference to FIGS. 2 and 3 as well. The frequency-multiplexed multi-channel signal input to the FM modulator 1 is processed by the FM modulator 1. After being FM-modulated, it is sent to the pulse signal converter 2.
【００１９】そしてパルス信号変換器２によりパルス信
号に変換された後、光変調器３により信号光が強度変調
されて、光伝送路４へ光伝送される。After being converted into a pulse signal by the pulse signal converter 2, the signal light is intensity-modulated by the optical modulator 3 and is optically transmitted to the optical transmission line 4.
【００２０】また光伝送路４へ伝送された光信号は、光
受信器５により光／電気交換されて、ＦＭ一括変調信号
となり、得られたＦＭ一括変調信号は、ＦＭ復調器６に
よりＦＭ復調されて周波数多重化された多チャンネル信
号に再生されるが、ＦＭ変調器１によりＦＭ一括変調さ
れたＦＭ一括変調信号をパルス信号変換器２によりパル
ス信号に変換して光伝送することにより、光伝送路４
や、光受信器５で発生する強度雑音の影響を低減するこ
とができるため、ＦＭ復調器６によりＦＭ復調する際の
強度雑音によるジッタを低減することができ、これによ
ってＦＭ復調後の雑音レベルを低減することができる。The optical signal transmitted to the optical transmission line 4 is optically / electrically exchanged by the optical receiver 5 to become an FM collective modulation signal, and the obtained FM collective modulation signal is FM demodulated by the FM demodulator 6. The frequency-multiplexed multi-channel signal is regenerated, and the FM collective modulation signal FM-modulated by the FM modulator 1 is converted into a pulse signal by the pulse signal converter 2 and is optically transmitted. Transmission line 4
Also, since the influence of the intensity noise generated in the optical receiver 5 can be reduced, it is possible to reduce the jitter due to the intensity noise when performing FM demodulation by the FM demodulator 6, and thereby the noise level after FM demodulation. Can be reduced.
【００２１】次にその理由を説明する。Next, the reason will be described.
【００２２】図２の（イ）ないし（ニ）は、ＦＭ一括変
調信号をリミッタとフリップフロップ及びＡＮＤゲート
などの回路を用いて遅延検波し、ＦＭ復調する場合の波
形図を示すもので、図２の（イ）に示すように、リミッ
タの識別レベルにおけるＦＭ一括変調信号の傾きαが小
さいと、強度雑音に対して発生するジッタは図２の
（ロ）に示すように大きいが、図２の（ハ）に示すよう
にリミッタの識別レベルにおけるＦＭ一括変調信号の傾
きαが大きくなると、同じ量の強度雑音に対して発生す
るジッタは、図２の（ニ）に示すように小さくなる。FIGS. 2A to 2D are waveform diagrams in the case where the FM collective modulation signal is subjected to the delay detection using the circuits such as the limiter, the flip-flop and the AND gate, and the FM demodulation is performed. As shown in FIG. 2B, if the slope α of the FM batch modulation signal at the limiter discrimination level is small, the jitter generated with respect to the intensity noise is large as shown in FIG. When the gradient α of the FM batch modulation signal at the limiter discrimination level becomes large as shown in (c) of (3), the jitter generated for the same amount of intensity noise becomes small as shown in (d) of FIG.
【００２３】この発明はこの点に着目したもので、実施
の形態１では、ＦＭ変調器１の後段に、パルス信号変換
器２を設けて、ＦＭ変調器１でＦＭ一括変調されたＦＭ
一括変調信号をパルス信号に変換して、ＦＭ一括変調信
号の立ち上り及び立ち下りを急峻にした後、光変調器３
を経て光伝送路４へ光伝送するようにしたものである。The present invention focuses on this point. In the first embodiment, the pulse signal converter 2 is provided after the FM modulator 1, and the FM signal is FM-modulated by the FM modulator 1.
After converting the collective modulation signal into a pulse signal to make the rising and falling edges of the FM collective modulation signal steep, the optical modulator 3
The optical transmission is carried out to the optical transmission line 4 via.
【００２４】これによって光伝送路４を経て光受信器５
により受信されたＦＭ一括変調信号を、ＦＭ復調器６が
復調すると、ＦＭ一括変調信号は予めパルス信号に変換
されて、立ち上り及び立ち下りの傾きが大きくなってい
るため、図２の（ハ）及び（ニ）に示すように、強度雑
音によるジッタが低減されるようになる。As a result, the optical receiver 5 passes through the optical transmission line 4.
When the FM demodulator 6 demodulates the FM batch modulated signal received by, the FM batch modulated signal is converted into a pulse signal in advance and the rising and falling slopes become large. As shown in (d) and (d), the jitter due to the intensity noise is reduced.
【００２５】図３は、パルス信号変換器２でパルス信号
に変換したＦＭ一括変調信号をＦＭ復調した後の雑音レ
ベルの受信光電力特性を示したもので、比較のためパル
ス信号に変換しない従来の受信光電力特性も併せて示し
ている。FIG. 3 shows the received optical power characteristic of the noise level after FM demodulation of the FM batch modulation signal converted into a pulse signal by the pulse signal converter 2, and is not converted into a pulse signal for comparison in the conventional case. The received optical power characteristics of are also shown.
【００２６】この図から明らかなように、ＦＭ一括変調
信号をパルス信号に変換して光伝送することにより、強
度雑音により発生するジッタが低減することができるた
め、ＦＭ復調後の雑音レベルも低減することができるよ
うになる。As is clear from this figure, by converting the FM batch modulated signal into a pulse signal and transmitting it optically, the jitter generated by the intensity noise can be reduced, so the noise level after FM demodulation is also reduced. You will be able to.
【００２７】以上のように上記実施の形態１によれば、
パルス信号変換器２によりＦＭ一括変調信号をパルス信
号に変換して光伝送することにより、受信光電力が小さ
く強度雑音の影響が大きい場合においても、ＦＭ復調時
の強度雑音によるジッタを低減することができ、良質な
周波数多重化された多チャンネル信号を伝送することが
できるという優れた周波数多重化された多チャンネル信
号の光伝送装置を提供することができるようになる。As described above, according to the first embodiment,
By converting the FM batch modulation signal into a pulse signal by the pulse signal converter 2 and optically transmitting it, it is possible to reduce the jitter due to the intensity noise during FM demodulation even when the received optical power is small and the influence of the intensity noise is large. Therefore, it is possible to provide an excellent optical transmission apparatus for frequency-multiplexed multi-channel signals that can transmit high-quality frequency-multiplexed multi-channel signals.
【００２８】（実施の形態２）図４はこの発明の実施の
形態２になる光伝送装置を示すブロックで、次にこれを
説明する。(Second Embodiment) FIG. 4 is a block diagram showing an optical transmission apparatus according to a second embodiment of the present invention, which will be described below.
【００２９】なお上記実施の形態１と同一部分は、同一
符号を付してその説明は省略する。The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
【００３０】この実施の形態２では、上記実施の形態１
で説明したパルス信号変換器２をリミッタアンプにより
構成したもので、その他は実施の形態１と同じである。In the second embodiment, the first embodiment described above is adopted.
The pulse signal converter 2 described in 1. is constituted by a limiter amplifier, and the other points are the same as those in the first embodiment.
【００３１】次に実施の形態２における光伝送装置の作
用を説明すると、ＦＭ変調器１に入力された周波数多重
化された多チャンネル信号は、ＦＭ変調器１によりＦＭ
一括変調された後、リミッタアンプよりなるパルス信号
変換器２へ送られる。Next, the operation of the optical transmission apparatus according to the second embodiment will be described. The frequency-multiplexed multi-channel signal input to the FM modulator 1 is FM-modulated by the FM modulator 1.
After being collectively modulated, it is sent to the pulse signal converter 2 including a limiter amplifier.
【００３２】そしてパルス信号変換器２によりパルス信
号に変換された後、光変調器３により信号光が強度変調
されて、光伝送路４へ光伝送される。After being converted into a pulse signal by the pulse signal converter 2, the signal light is intensity-modulated by the optical modulator 3 and is optically transmitted to the optical transmission line 4.
【００３３】また光伝送路４へ伝送された光信号は、光
受信器５により光／電気交換されて、ＦＭ一括変調信号
となり、得られたＦＭ一括変調信号は、ＦＭ復調器６に
よりＦＭ復調されて周波数多重化された多チャンネル信
号に再生される。The optical signal transmitted to the optical transmission line 4 is optically / electrically exchanged by the optical receiver 5 to become an FM collective modulation signal, and the obtained FM collective modulation signal is FM demodulated by the FM demodulator 6. It is reproduced as a multi-channel signal which has been frequency-multiplexed.
【００３４】以上のように上記実施の形態２によれば、
リミッタアンプより構成されるパルス信号変換器２によ
りＦＭ一括変調信号をパルス信号に変換して光伝送する
ことにより、受信光電力が小さく強度雑音の影響が大き
い場合においても、ＦＭ復調時の強度雑音によるジッタ
を低減することができ、良質な周波数多重化された多チ
ャンネル信号を伝送することができるという優れた周波
数多重化された多チャンネル信号の光伝送装置を提供す
ることができるようになる。As described above, according to the second embodiment,
Even if the received light power is small and the influence of the intensity noise is large, the intensity noise at the time of FM demodulation is converted by converting the FM collective modulation signal into a pulse signal by the pulse signal converter 2 including a limiter amplifier and optically transmitting the pulse signal. Therefore, it is possible to provide an excellent optical transmission device for frequency-multiplexed multi-channel signals, which can reduce jitter due to the above and can transmit high-quality frequency-multiplexed multi-channel signals.
【００３５】（実施の形態３）図５はこの発明の実施の
形態３になる光伝送装置を示すブロックで、次にこれを
説明する。(Embodiment 3) FIG. 5 is a block diagram showing an optical transmission apparatus according to Embodiment 3 of the present invention, which will be described below.
【００３６】なお上記実施の形態１と同一部分は、同一
符号を付してその説明は省略する。The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
【００３７】この実施の形態３では、上記実施の形態１
で説明したパルス信号変換器２を、論理回路により構成
したもので、その他は実施の形態１と同じである。In the third embodiment, the above-mentioned first embodiment is used.
The pulse signal converter 2 described in 1. is configured by a logic circuit, and the other points are the same as those in the first embodiment.
【００３８】次に実施の形態３における光伝送装置の作
用を説明すると、ＦＭ変調器１に入力された周波数多重
化された多チャンネル信号は、ＦＭ変調器１によりＦＭ
一括変調された後、論理回路よりなるパルス信号変換器
２へ送られる。Next, the operation of the optical transmission apparatus according to the third embodiment will be described. The frequency-multiplexed multi-channel signal input to the FM modulator 1 is FM-modulated by the FM modulator 1.
After being collectively modulated, it is sent to the pulse signal converter 2 formed of a logic circuit.
【００３９】そしてパルス信号変換器２によりパルス信
号に変換された後、光変調器３により信号光が強度変調
されて、光伝送路４へ光伝送される。After being converted into a pulse signal by the pulse signal converter 2, the signal light is intensity-modulated by the optical modulator 3 and is optically transmitted to the optical transmission line 4.
【００４０】また光伝送路４へ伝送された光信号は、光
受信器５により光／電気交換されて、ＦＭ一括変調信号
となり、得られたＦＭ一括変調信号は、ＦＭ復調器６に
よりＦＭ復調されて周波数多重化された多チャンネル信
号に再生される。The optical signal transmitted to the optical transmission line 4 is optically / electrically exchanged by the optical receiver 5 to become an FM collective modulation signal, and the obtained FM collective modulation signal is FM demodulated by the FM demodulator 6. It is reproduced as a multi-channel signal which has been frequency-multiplexed.
【００４１】以上のように上記実施の形態３によれば、
論理回路より構成されるパルス信号変換器２によりＦＭ
一括変調信号をパルス信号に変換して光伝送することに
より、受信光電力が小さく強度雑音の影響が大きい場合
においても、ＦＭ復調時の強度雑音によるジッタを低減
することができ、良質な周波数多重化された多チャンネ
ル信号を伝送することができるという優れた周波数多重
化された多チャンネル信号の光伝送装置を提供すること
ができるようになる。As described above, according to the third embodiment,
FM by the pulse signal converter 2 composed of a logic circuit
By converting the batch modulation signal into a pulse signal and transmitting the light, the jitter due to the intensity noise during FM demodulation can be reduced even when the received optical power is small and the influence of the intensity noise is large. Therefore, it is possible to provide an excellent optical transmission apparatus for frequency-multiplexed multi-channel signals capable of transmitting the converted multi-channel signals.
【００４２】（実施の形態４）図６はこの発明の実施の
形態４になる光伝送装置を示すブロックで、次にこれを
説明する。(Embodiment 4) FIG. 6 is a block diagram showing an optical transmission apparatus according to Embodiment 4 of the present invention, which will be described below.
【００４３】なお上記実施の形態１と同一部分は、同一
符号を付してその説明は省略する。The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
【００４４】この実施の形態４では、上記実施の形態１
で説明したパルス信号変換器２を、Ｔフリップフロップ
回路よりなる分周回路により構成したもので、その他は
実施の形態１と同じである。In the fourth embodiment, the above-mentioned first embodiment is used.
The pulse signal converter 2 described in 1 is configured by a frequency dividing circuit including a T flip-flop circuit, and the other points are the same as those in the first embodiment.
【００４５】次に実施の形態４における光伝送装置の作
用を説明すると、ＦＭ変調器１に入力された周波数多重
化された多チャンネル信号は、ＦＭ変調器１によりＦＭ
一括変調された後、Ｔフリップフロップ回路よりなる分
周回路で構成されたパルス信号変換器２へ送られる。Next, the operation of the optical transmission apparatus according to the fourth embodiment will be described. The frequency-multiplexed multi-channel signal input to the FM modulator 1 is FM-modulated by the FM modulator 1.
After being batch-modulated, it is sent to the pulse signal converter 2 which is composed of a frequency dividing circuit including a T flip-flop circuit.
【００４６】そしてパルス信号変換器２によりパルス信
号に変換された後、光変調器３により信号光が強度変調
されて、光伝送路４へ光伝送される。After being converted into a pulse signal by the pulse signal converter 2, the signal light is intensity-modulated by the optical modulator 3 and is optically transmitted to the optical transmission line 4.
【００４７】また光伝送路４へ伝送された光信号は、光
受信器５により光／電気交換されて、ＦＭ一括変調信号
となり、得られたＦＭ一括変調信号は、ＦＭ復調器６に
よりＦＭ復調されて周波数多重化された多チャンネル信
号に再生される。The optical signal transmitted to the optical transmission line 4 is optically / electrically exchanged by the optical receiver 5 to become an FM collective modulation signal, and the obtained FM collective modulation signal is FM demodulated by the FM demodulator 6. It is reproduced as a multi-channel signal which has been frequency-multiplexed.
【００４８】以上のように上記実施の形態３によれば、
論理回路より構成されるパルス信号変換器２によりＦＭ
一括変調信号をパルス信号に変換して光伝送することに
より、受信光電力が小さく強度雑音の影響が大きい場合
においても、ＦＭ復調時の強度雑音によるジッタを低減
することができ、良質な周波数多重化された多チャンネ
ル信号を伝送することができるという優れた周波数多重
化された多チャンネル信号の光伝送装置を提供すること
ができるようになる。As described above, according to the third embodiment,
FM by the pulse signal converter 2 composed of a logic circuit
By converting the batch modulation signal into a pulse signal and transmitting the light, the jitter due to the intensity noise during FM demodulation can be reduced even when the received optical power is small and the influence of the intensity noise is large. Therefore, it is possible to provide an excellent optical transmission apparatus for frequency-multiplexed multi-channel signals capable of transmitting the converted multi-channel signals.
【００４９】（実施の形態５）図７はこの発明の実施の
形態５になる光伝送装置を示すブロックで、次にこれを
説明する。(Fifth Embodiment) FIG. 7 is a block diagram showing an optical transmission apparatus according to a fifth embodiment of the present invention, which will be described below.
【００５０】なお上記実施の形態１と同一部分は、同一
符号を付してその説明は省略する。The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
【００５１】この実施の形態５では、上記実施の形態１
で説明した光変調器３を、半導体レーザ３ａと、外部光
強度変調器３ｂより構成したもので、その他は実施の形
態１と同じである。In the fifth embodiment, the above first embodiment is adopted.
The optical modulator 3 described in 1. is composed of a semiconductor laser 3a and an external light intensity modulator 3b, and the other points are the same as those in the first embodiment.
【００５２】次に実施の形態５における光伝送装置の作
用を説明すると、ＦＭ変調器１に入力された周波数多重
化された多チャンネル信号は、ＦＭ変調器１によりＦＭ
一括変調された後、パルス信号変換器２へ送られる。Next, the operation of the optical transmission apparatus according to the fifth embodiment will be described. The frequency-multiplexed multi-channel signal input to the FM modulator 1 is FM-modulated by the FM modulator 1.
After being collectively modulated, it is sent to the pulse signal converter 2.
【００５３】そしてパルス信号変換器２によりパルス信
号に変換された後、光変調器３へ入力されて、半導体レ
ーザ３ａを発光させる。After being converted into a pulse signal by the pulse signal converter 2, the pulse signal is input to the optical modulator 3 to cause the semiconductor laser 3a to emit light.
【００５４】半導体レーザ３ａより出力された光信号
は、外部光強度変調器３ｂにより強度変調された後、光
伝送路４へ光伝送される。The optical signal output from the semiconductor laser 3a is intensity-modulated by the external light intensity modulator 3b, and then optically transmitted to the optical transmission line 4.
【００５５】また光伝送路４へ伝送された光信号は、光
受信器５により光／電気交換されて、ＦＭ一括変調信号
となり、得られたＦＭ一括変調信号は、ＦＭ復調器６に
よりＦＭ復調されて周波数多重化された多チャンネル信
号に再生される。The optical signal transmitted to the optical transmission line 4 is optically / electrically exchanged by the optical receiver 5 to become an FM collective modulation signal, and the obtained FM collective modulation signal is FM demodulated by the FM demodulator 6. It is reproduced as a multi-channel signal which has been frequency-multiplexed.
【００５６】すなわち従来の半導体レーザをパルス化さ
れたＦＭ一括変調信号により直接強度変調した場合では
レーザの緩和共振の影響でパルス化されたＦＭ一括変調
信号の波形変形が生じ、結果としてＦＭ復調器で識別レ
ベルでのＦＭ一括変調信号の傾きを劣化させるのに対し
て、上記実施の形態５のように、半導体レーザ３ａと外
部光強度変調器３ｂから構成される光変調器３を用いて
パルス化されたＦＭ一括変調信号により光信号を強度変
調することにより、パルス化されたＦＭ一括変調信号の
波形をパルス信号変換器出力に近い状態に保ったまま光
送信することができるという優れた周波数多重化された
多チャンネル信号の光伝送装置を提供することができる
ようになる。That is, when the conventional semiconductor laser is directly intensity-modulated by the pulsed FM collective modulation signal, the pulsed FM collective modulation signal is deformed due to the effect of relaxation resonance of the laser, resulting in the FM demodulator. On the other hand, while the inclination of the FM batch modulation signal at the discrimination level is deteriorated, the pulse is generated by using the optical modulator 3 including the semiconductor laser 3a and the external light intensity modulator 3b as in the fifth embodiment. By modulating the intensity of the optical signal with the modulated FM batch modulation signal, it is possible to perform optical transmission while maintaining the waveform of the pulsed FM batch modulation signal close to the output of the pulse signal converter. It becomes possible to provide an optical transmission apparatus for multiplexed multi-channel signals.
【００５７】[0057]
【発明の効果】この発明は以上詳述したように、ＦＭ一
括変調信号をパルス信号に変換してＦＭ一括変調信号の
波形の立ち上り立ち下りを急峻にして光伝送するように
したことから、強度雑音の影響により生じるパルスのジ
ッタを低減することができ、これによって受信光電力が
特に低くなり、ＦＭ一括変調信号と光伝送路や光受信器
等で発生する強度雑音との電力比（ＣＮＲ）が低下した
場合でも、良質な周波数多重化された多チャンネル信号
を伝送することができるという優れた周波数多重化され
た多チャンネル信号の光伝送方法及びこれに使用する光
伝送装置を提供することができる。As described in detail above, according to the present invention, the FM collective modulation signal is converted into a pulse signal and the rising and falling edges of the waveform of the FM collective modulation signal are made steep to perform optical transmission. It is possible to reduce the pulse jitter generated by the influence of noise, which makes the received optical power particularly low, and the power ratio (CNR) between the FM batch modulation signal and the intensity noise generated in the optical transmission line, the optical receiver, or the like. It is possible to provide an excellent optical transmission method for a frequency-multiplexed multi-channel signal, which can transmit a high-quality frequency-multiplexed multi-channel signal, and an optical transmission device used for the method. it can.
【図１】この発明の実施の形態１になる光伝送装置を示
すブロック図FIG. 1 is a block diagram showing an optical transmission device according to a first embodiment of the present invention.
【図２】（イ）ないし（ニ）はこの発明の実施の形態１
になる光伝送装置の作用を示す説明図2A to 2D are the first embodiment of the present invention.
Explanatory diagram showing the operation of the optical transmission device
【図３】この発明の実施の形態になる光伝送装置の作用
を示す説明図FIG. 3 is an explanatory diagram showing an operation of the optical transmission device according to the embodiment of the present invention.
【図４】この発明の実施の形態２になる光伝送装置を示
すブロック図FIG. 4 is a block diagram showing an optical transmission device according to a second embodiment of the present invention.
【図５】この発明の実施の形態３になる光伝送装置を示
すブロック図FIG. 5 is a block diagram showing an optical transmission device according to a third embodiment of the present invention.
【図６】この発明の実施の形態４になる光伝送装置を示
すブロック図FIG. 6 is a block diagram showing an optical transmission device according to a fourth embodiment of the present invention.
【図７】この発明の実施の形態５になる光伝送装置を示
すブロック図FIG. 7 is a block diagram showing an optical transmission device according to a fifth embodiment of the present invention.
【図８】従来の光伝送装置を示すブロック図FIG. 8 is a block diagram showing a conventional optical transmission device.
１ ＦＭ変調器 ２ パルス信号変換器 ３ 光変調器 ３ａ 半導体レーザ ３ｂ 外部光強度変調器 ４ 光伝送路 ５ 光受信器 ６ ＦＭ復調器 1 FM modulator 2 pulse signal converter 3 Optical modulator 3a Semiconductor laser 3b External light intensity modulator 4 Optical transmission line 5 Optical receiver 6 FM demodulator
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｈ０４Ｂ 10/152 10/18 Ｈ０４Ｊ 14/02 (72)発明者 川島 勢一郎 神奈川県横浜市港北区綱島東四丁目３番 １号 松下通信工業株式会社内 (72)発明者 桜井 尚也 東京都新宿区西新宿三丁目19番２号 日 本電信電話株式会社内 (56)参考文献 特開 平８−274714（ＪＰ，Ａ) 特開 平10−65618（ＪＰ，Ａ) 特開 平８−18537（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H04B 10/00 - 10/28 H04J 14/00 - 14/08 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI H04B 10/152 10/18 H04J 14/02 (72) Inventor Seiichiro Kawashima 4-3 Tsunashima Higashi, Kohoku Ward, Yokohama City, Kanagawa Prefecture No. Matsushita Communication Industry Co., Ltd. (72) Inventor Naoya Sakurai 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) Reference JP-A-8-274714 (JP, A) Kaihei 10-65618 (JP, A) JP-A-8-18537 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H04B 10/00-10/28 H04J 14/00- 14/08
Claims (6)
ＦＭ一括変調すると共に、得られたＦＭ一括変調信号に
よって信号光を強度変調して光伝送し、この光信号を光
／電気変換して得られたＦＭ一括変調信号をＦＭ復調し
て周波数多重化された多チャンネル信号を伝送する光伝
送方法において、周波数多重化された多チャンネル信号
をＦＭ一括変調することにより得られたＦＭ一括変調信
号をパルス信号に変換して、ＦＭ一括変調信号の波形の
立ち上りと立ち下りを急峻にし、得られたパルス信号で
信号光を強度変調して光伝送することを特徴とする周波
数多重信号の光伝送方法。1. An FM batch modulation of a frequency-multiplexed multi-channel signal, intensity modulation of signal light by the obtained FM batch modulation signal, optical transmission, and optical / electric conversion of this optical signal. In the optical transmission method of FM demodulating the FM batch modulated signal thus obtained and transmitting the frequency-multiplexed multi-channel signal, the FM batch modulated signal obtained by FM batch-modulating the frequency-multiplexed multi-channel signal is obtained. An optical transmission method of a frequency-multiplexed signal, which is characterized by converting the pulse signal to a pulse signal to make the rising and falling edges of the waveform of the FM batch modulation signal steep, and intensity-modulating the signal light with the obtained pulse signal. .
より搬送波信号をＦＭ一括変調するＦＭ変調器と、変調
されたＦＭ一括変調信号をパスル信号に変換して、ＦＭ
一括変調信号の波形の立ち上りと立ち下りを急峻にする
パルス信号変換器と、このパルス信号によって信号光を
強度変調する光変調器と、この変調された光信号を伝送
する手段と、伝送された光信号を光／電気変換する光受
信器と、光／電気変換により得られたＦＭ一括変調信号
をＦＭ復調して周波数多重化された多チャンネル信号を
得るＦＭ復調器とを具備したことを特徴とする周波数多
重信号の光伝送装置。2. An FM modulator that FM-modulates a carrier signal by a frequency-multiplexed multi-channel signal, and an FM modulator that converts the modulated FM batch-modulated signal into a pulse signal.
A pulse signal converter that makes the rising and falling of the waveform of the batch modulation signal steep, an optical modulator that intensity-modulates the signal light by this pulse signal, a means for transmitting this modulated optical signal, and transmitted An optical receiver for optically / electrically converting an optical signal, and an FM demodulator for FM-demodulating an FM batch modulated signal obtained by the optical / electrical conversion to obtain a frequency-multiplexed multi-channel signal. Optical transmission equipment for frequency-multiplexed signals.
プから構成されていることを特徴とする請求項２記載の
周波数多重信号の光伝送装置。3. The optical transmission device for frequency-division-multiplexed signals according to claim 2, wherein the pulse signal converter comprises a limiter amplifier.
構成されていることを特徴とする請求項２記載の周波数
多重信号の光伝送装置。4. The optical transmission device for frequency-multiplexed signals according to claim 2, wherein the pulse signal converter is composed of a logic circuit.
ロップ回路からなる分周回路から構成されていることを
特徴とする請求項２記載の周波数多重信号の光伝送装
置。5. The optical transmission apparatus for frequency-division-multiplexed signals according to claim 2, wherein the pulse signal converter is composed of a frequency dividing circuit including a T flip-flop circuit.
強度変調器から構成されていることを特徴とする請求項
２，３，４，５の何れか１項に記載の周波数多重信号の
光伝送装置。6. The frequency multiplexed signal according to claim 2, wherein the optical modulator comprises a semiconductor laser and an external light intensity modulator. Optical transmission equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17214398A JP3532099B2 (en) | 1998-06-05 | 1998-06-05 | Optical transmission method and optical transmission apparatus for frequency multiplexed signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17214398A JP3532099B2 (en) | 1998-06-05 | 1998-06-05 | Optical transmission method and optical transmission apparatus for frequency multiplexed signal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11355250A JPH11355250A (en) | 1999-12-24 |
| JP3532099B2 true JP3532099B2 (en) | 2004-05-31 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17214398A Expired - Fee Related JP3532099B2 (en) | 1998-06-05 | 1998-06-05 | Optical transmission method and optical transmission apparatus for frequency multiplexed signal |
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| Country | Link |
|---|---|
| JP (1) | JP3532099B2 (en) |
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1998
- 1998-06-05 JP JP17214398A patent/JP3532099B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH11355250A (en) | 1999-12-24 |
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