JPH06152565A - Coherent light transmitting device - Google Patents
Coherent light transmitting deviceInfo
- Publication number
- JPH06152565A JPH06152565A JP4302013A JP30201392A JPH06152565A JP H06152565 A JPH06152565 A JP H06152565A JP 4302013 A JP4302013 A JP 4302013A JP 30201392 A JP30201392 A JP 30201392A JP H06152565 A JPH06152565 A JP H06152565A
- Authority
- JP
- Japan
- Prior art keywords
- light
- signal
- amplitude
- optical
- semiconductor laser
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光ＣＡＴＶ、移動体無
線基地局間等の伝送システムとして、複数の変調信号か
らなる周波数分割多重信号を外部変調器を用いて半導体
レーザ光を振幅変調して伝送するコヒーレント光伝送装
置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a transmission system for optical CATV, mobile radio base stations, etc., in which a semiconductor laser beam is amplitude-modulated with a frequency division multiplexed signal composed of a plurality of modulated signals by using an external modulator. The present invention relates to a coherent optical transmission device for transmitting by transmission.
【０００２】[0002]
【従来の技術】従来のこの種の光伝送装置として、特開
平４−４８８３３号に開示された光ＦＭコヒーレント光
伝送装置が提案されている。このコヒーレント光伝送装
置は、送信装置で、複数の変調信号からなる周波数分割
多重信号を半導体レーザに入力して出力光に対し光周波
数変調を行い、信号光を受信装置に伝送する。ここで、
半導体レーザに入力する変調信号とは、映像信号やデー
タ等をＡＭ、ＦＭ、ＰＭ、ＱＡＭ等で変調した信号であ
る。受信装置では、光のヘテロダイン検波を行った後、
光周波数変調によって得られる搬送波成分の信号と第一
側波成分の信号との積を取り、半導体レーザ光が持つ位
相雑音を低減して元の周波数分割多重信号を得るように
構成されている。搬送波成分と第一側波成分に含まれる
光の位相雑音はお互い同じである。そこで、両信号の積
をとれば、光の位相雑音が相殺され、元の信号を復調す
ることができる。2. Description of the Related Art An optical FM coherent optical transmission device disclosed in Japanese Patent Laid-Open No. 4-48833 has been proposed as a conventional optical transmission device of this type. In this coherent optical transmission device, a transmitter transmits a frequency division multiplexed signal composed of a plurality of modulated signals to a semiconductor laser to perform optical frequency modulation on the output light, and transmits the signal light to the receiver. here,
The modulation signal input to the semiconductor laser is a signal obtained by modulating a video signal, data or the like with AM, FM, PM, QAM or the like. In the receiving device, after performing the heterodyne detection of the light,
The product of the carrier wave component signal and the first side wave component signal obtained by the optical frequency modulation is taken to reduce the phase noise of the semiconductor laser light to obtain the original frequency division multiplexed signal. The phase noises of light contained in the carrier wave component and the first side wave component are the same. Therefore, if the product of both signals is taken, the phase noise of the light is canceled and the original signal can be demodulated.
【０００３】[0003]
【発明が解決しようとする課題】上記従来のコヒーレン
ト光伝送装置のように光周波数変調して信号を伝送する
と、以下のような問題を生じる。When a signal is transmitted by optical frequency modulation as in the conventional coherent optical transmission device described above, the following problems occur.
【０００４】半導体レーザに周波数分割多重信号を入力
して光周波数変調したときの光のスペクトル分布は、無
変調時の光周波数を持つ搬送波を中心に入力信号の周波
数とその高調波の周波数だけ離れたところにスペクトル
が生じる。そのため、第一側波成分の周波数帯域内に３
次、５次などの高調波成分も含まれてしまう。これが復
調後に歪になり、過剰な歪の増加を招く。周波数分割多
重信号のチャンネル数を増やせば、この歪は更に増え
る。When the frequency division multiplexed signal is input to the semiconductor laser and the optical frequency is modulated, the spectrum distribution of the light is separated by the frequency of the input signal and the frequency of its harmonics centering on the carrier having the optical frequency in the non-modulated state. A spectrum is generated everywhere. Therefore, within the frequency band of the first side component, 3
Second and fifth harmonic components are also included. This becomes distortion after demodulation, which causes an excessive increase in distortion. This distortion is further increased by increasing the number of channels of the frequency division multiplexed signal.
【０００５】周波数分割多重信号の振幅を小さくするな
どして光周波数変調の変調指数を小さくすれば、上記の
歪は低減される。しかし、同時に第一側波成分も小さく
なって復調後のＣＮＲが劣化してしまう。The above distortion can be reduced by reducing the modulation index of the optical frequency modulation by reducing the amplitude of the frequency division multiplexed signal. However, at the same time, the first sideband component also decreases and the CNR after demodulation deteriorates.
【０００６】上述のように、光周波数変調方式では、Ｃ
ＮＲと歪特性の両方を満足させるためには周波数分割多
重信号のチャンネル数を制限しなければならない。これ
は変調方式に起因する課題である。また、光を外部変調
器を用いて位相変調する方式においても同様の課題を有
する。As described above, in the optical frequency modulation system, C
In order to satisfy both the NR and the distortion characteristic, the number of channels of the frequency division multiplexed signal must be limited. This is a problem caused by the modulation method. The same problem is also encountered in the method of phase-modulating light using an external modulator.
【０００７】[0007]
【課題を解決するための手段】上記問題点を解決するた
めに本発明のコヒーレント光伝送装置は、送信装置で、
光周波数変調して信号を伝送するのでは無く、半導体レ
ーザ光を振幅変調して信号光を伝送し、受信装置で、ヘ
テロダイン検波後、光の振幅変調した搬送波成分と第一
側波成分の積を取って復調する構成とした。In order to solve the above problems, a coherent optical transmission device of the present invention is a transmission device,
Rather than transmitting the signal by optical frequency modulation, the semiconductor laser light is amplitude-modulated and the signal light is transmitted, and after the heterodyne detection by the receiver, the product of the amplitude-modulated carrier component of the light and the first side wave component It is configured to take and demodulate.
【０００８】[0008]
【作用】上記構成にすることによって、半導体レーザ光
の位相雑音を低減すると共に、光を変調した際に高調波
成分を発生させずに第一側波成分を大きくすることがで
きる。これにより、周波数分割多重信号のチャンネル数
を増やしたり、ＣＮＲや歪特性を向上することが可能に
なる。With the above structure, the phase noise of the semiconductor laser light can be reduced and the first side wave component can be increased without generating a harmonic component when the light is modulated. This makes it possible to increase the number of channels of the frequency division multiplexed signal and improve CNR and distortion characteristics.
【０００９】[0009]
【実施例】以下、本発明の実施例を図面を用いて説明す
る。Embodiments of the present invention will be described below with reference to the drawings.
【００１０】（実施例１）図１は本発明の実施例１にお
けるコヒーレント光伝送装置のブロック図で、この実施
例は請求項１に対応している。このコヒーレント光伝送
装置は、送信装置１と受信装置２とにより構成されてい
る。送信装置１は、半導体レーザ１０と、外部変調器２
０とにより構成されており、受信装置２は、光結合器３
０と、局部発振用半導体レーザ４０と、受光回路５０
と、通過周波数がｆ0の帯域通過フィルタ６０と、通過
周波数がｆ0−ｆS、あるいはｆ0＋ｆSの帯域通過フィル
タ７０と、ミキサ８０とにより構成されている。伝送す
べき周波数分割多重信号の周波数は複数個あるが、ここ
では便宜上ｆSとする。信号光Ａは半導体レーザ１０の
出力光、信号光Ｂは光振幅変調後の信号光で、局部発振
用半導体レーザ４０は局部発振光Ｃを出力する。信号光
Ａと局部発振光Ｃのビートの周波数はｆ0とする。(Embodiment 1) FIG. 1 is a block diagram of a coherent optical transmission apparatus according to Embodiment 1 of the present invention, and this embodiment corresponds to claim 1. This coherent optical transmission device comprises a transmitter 1 and a receiver 2. The transmitter 1 includes a semiconductor laser 10 and an external modulator 2
0, and the receiving device 2 includes an optical coupler 3
0, the local oscillation semiconductor laser 40, and the light receiving circuit 50
When a band-pass filter 60 passes frequency f 0, bandpass filter 70 pass frequencies f 0 -f S or f 0 + f S,, it is constituted by a mixer 80. Although there are a plurality of frequencies of the frequency division multiplexed signal to be transmitted, it is assumed here as f S for convenience. The signal light A is output light of the semiconductor laser 10, the signal light B is signal light after optical amplitude modulation, and the semiconductor laser 40 for local oscillation outputs local oscillation light C. The beat frequency of the signal light A and the local oscillation light C is f 0 .
【００１１】次に動作を説明する。半導体レーザ１０か
らの信号光Ａは外部変調器２０に入る。外部変調器２０
では、周波数がｆSの周波数分割多重信号に応じて信号
光Ａを振幅変調し信号光Ｂを出力する。なお、周波数分
割多重信号とは、映像信号やデータ等をＡＭ、ＦＭ、Ｐ
Ｍ、ＱＡＭ等で変調した信号を周波数分割多重した信号
のことである。外部変調器２０は、光強度変調器に使用
されるマッハチェンダー型や吸収型などを使用すること
ができる。外部変調器２０が理想的な振幅変調器であれ
ば、信号光Ａの光周波数をνとすると信号光Ｂのスペク
トルは、光周波数がνの搬送波、ν−ｆSを中心にした
第一下側波とν＋ｆSを中心にした第一上側波のみから
なる。この光振幅変調された信号光Ｂが受信装置２に伝
送される。Next, the operation will be described. The signal light A from the semiconductor laser 10 enters the external modulator 20. External modulator 20
Then, the signal light A is amplitude-modulated according to the frequency division multiplexed signal having the frequency f S , and the signal light B is output. It should be noted that the frequency division multiplexed signal is a signal such as a video signal or data that is AM, FM,
It is a signal obtained by frequency division multiplexing a signal modulated by M, QAM, or the like. The external modulator 20 may be a Mach-Cender type or an absorption type used for the light intensity modulator. If the external modulator 20 is ideal amplitude modulator, the spectrum of the signal light B when the optical frequency and [nu signal light A, first under the optical frequency centered carrier, the [nu-f S of the [nu consisting only of a first upper sideband centered on the sideband and ν + f S. The signal light B whose optical amplitude has been modulated is transmitted to the receiving device 2.
【００１２】受信装置２に伝送されてきた信号光Ｂは、
光結合器３０に入る。光結合器３０は、信号光Ｂに局部
発振用半導体レーザ４０からの局部発振光Ｃを結合す
る。光結合器３０で結合された二つの信号光は、受光回
路５０に供給される。受光回路５０は、二つの信号光の
ビート、すなわち中間周波信号を電気信号として出力す
る。帯域通過フィルタ６０は、光振幅変調によって得ら
れる搬送波成分を抽出し、帯域通過フィルタ７０は、光
振幅変調によって得られる第一下側波成分あるいは第一
上側波成分を抽出する。ミキサ８０は、搬送波成分と第
一側波成分の積を取り、周波数がｆSの周波数分割多重
信号を出力する。搬送波成分と第一側波成分に含まれる
光の位相雑音はお互い同じである。そこで、両信号の積
をとれば、光の位相雑音が相殺され、元の信号を復調す
ることができる。The signal light B transmitted to the receiver 2 is
Enter the optical coupler 30. The optical coupler 30 couples the signal light B with the local oscillation light C from the local oscillation semiconductor laser 40. The two signal lights combined by the optical coupler 30 are supplied to the light receiving circuit 50. The light receiving circuit 50 outputs the beat of two signal lights, that is, an intermediate frequency signal as an electric signal. The band pass filter 60 extracts the carrier component obtained by the optical amplitude modulation, and the band pass filter 70 extracts the first lower side wave component or the first upper side wave component obtained by the optical amplitude modulation. The mixer 80 takes the product of the carrier wave component and the first side wave component and outputs a frequency division multiplexed signal having a frequency of f S. The phase noises of light contained in the carrier wave component and the first side wave component are the same. Therefore, if the product of both signals is taken, the phase noise of the light is canceled and the original signal can be demodulated.
【００１３】復調後の周波数分割多重信号のＣＮＲは、
光振幅変調で得られる第一側波成分のＣＮＲに大きく依
存する。従来例で述べたように、光周波数変調方式では
光の周波数変調指数を大きくして第一側波成分の振幅を
大きくしようとすると、高調波成分も増大するという課
題があった。光を振幅変調すれば、変調度を大きくして
も高調波成分を発生させずに第一側波成分の振幅を大き
くすることができる。The CNR of the frequency division multiplexed signal after demodulation is
It greatly depends on the CNR of the first side component obtained by the optical amplitude modulation. As described in the conventional example, in the optical frequency modulation method, there is a problem that when the frequency modulation index of light is increased to increase the amplitude of the first side wave component, the harmonic component also increases. If the light is amplitude-modulated, the amplitude of the first side-wave component can be increased without generating a harmonic component even if the modulation degree is increased.
【００１４】（実施例２）図２は本発明の実施例２にお
けるコヒーレント光伝送装置の受信装置のブロック図
で、この実施例は請求項２に対応している。受信装置
は、光結合器３０と、局部発振用半導体レーザ４０と、
受光回路５０と、通過周波数がｆ0の帯域通過フィルタ
６０と、通過周波数がｆ0−ｆS、あるいはｆ0＋ｆSの帯
域通過フィルタ７０と、ミキサ８０と、ピークディテク
タ１００と、利得可変増幅器１１０により構成されてい
る。(Second Embodiment) FIG. 2 is a block diagram of a receiver of a coherent optical transmission device according to a second embodiment of the present invention, and this embodiment corresponds to claim 2. The receiving device includes an optical coupler 30, a local oscillation semiconductor laser 40,
A light receiving circuit 50, a band-pass filter 60 passes frequency f 0, pass frequency f 0 -f S or a band pass filter 70 of f 0 + f S, and a mixer 80, a peak detector 100, a variable gain amplifier It is composed of 110.
【００１５】以下、動作の説明をする。実施例１と同様
に光結合器３０と局部発振用半導体レーザ４０、受光回
路５０で信号光Ｂを光のヘテロダイン検波する。受光回
路５０で得られた中間周波信号は、利得可変増幅器１１
０で増幅される。帯域通過フィルタ６０、７０とミキサ
８０の動作は実施例１と同様であり、周波数がｆSの周
波数分割多重信号が復調される。ピークディテクタ１０
０では、まず、中間周波信号から光の振幅変調によって
得られる搬送波成分をフィルタ等で抽出し、その信号振
幅を検出する。そして、検出した信号振幅が一定になる
ように、利得可変増幅器１１０の利得を制御する。The operation will be described below. As in the first embodiment, the optical coupler 30, the local oscillation semiconductor laser 40, and the light receiving circuit 50 perform heterodyne detection of the signal light B. The intermediate frequency signal obtained by the light receiving circuit 50 is supplied to the variable gain amplifier 11
It is amplified by 0. The operations of the band pass filters 60 and 70 and the mixer 80 are the same as those in the first embodiment, and the frequency division multiplexed signal having the frequency f S is demodulated. Peak detector 10
At 0, first, a carrier component obtained by amplitude modulation of light from the intermediate frequency signal is extracted by a filter or the like, and the signal amplitude is detected. Then, the gain of the variable gain amplifier 110 is controlled so that the detected signal amplitude becomes constant.
【００１６】なお、ピークディテクタ１００の入力は、
帯域通過フィルタ６０の出力側で、その信号振幅を検出
する構成であっても良い。The input of the peak detector 100 is
The signal amplitude may be detected on the output side of the bandpass filter 60.
【００１７】実施例２の受信装置における利得可変増幅
器１１０とピークディテクタ１００は、受光回路５０の
出力である中間周波信号に含まれる振幅雑音を低減する
ためのものである。半導体レーザ１０の出力である信号
光Ａや局部発振用半導体レーザの出力である局部発振光
Ｃの振幅ゆらぎ、あるいは信号光Ｂと局部発振光Ｃの偏
波面の変化などによって、受光回路５０後の中間周波信
号に振幅雑音が生じる。この振幅雑音は、中間周波信号
における光振幅変調によって得られる搬送波成分と第一
側波成分に対して互いに同相である。そこで、中間周波
信号のうちの光振幅変調による搬送波成分の信号振幅を
一定にすれば、第一側波成分に含まれる振幅雑音を低減
することができる。The variable gain amplifier 110 and the peak detector 100 in the receiver of the second embodiment are for reducing the amplitude noise contained in the intermediate frequency signal output from the light receiving circuit 50. The amplitude of the signal light A output from the semiconductor laser 10 or the local oscillation light C output from the semiconductor laser for local oscillation is varied, or the polarization planes of the signal light B and the local oscillation light C are changed. Amplitude noise occurs in the intermediate frequency signal. This amplitude noise is in phase with the carrier wave component and the first side wave component obtained by the optical amplitude modulation in the intermediate frequency signal. Therefore, if the signal amplitude of the carrier component of the intermediate frequency signal due to the optical amplitude modulation is made constant, the amplitude noise included in the first side wave component can be reduced.
【００１８】[0018]
【発明の効果】以上説明したように本発明によれば、半
導体レーザと、複数の変調信号からなる周波数分割多重
信号に応じて半導体レーザの出力光を振幅変調する外部
変調器を備えた送信装置を設けるとともに、局部発振用
半導体レーザと、送信装置から送られてきた光信号と局
部発振用半導体レーザの光信号を結合する光結合器と、
二つの光信号の中間周波信号を得る受光回路と、受光回
路の出力信号から光の振幅変調によって得られる搬送波
成分および第一側波成分をそれぞれ抽出する帯域通過フ
ィルタと、それぞれの帯域通過フィルタから出力される
二つの信号の積を取るミキサを備えた受信装置を設ける
ことにより、半導体レーザ光の位相雑音を低減すると共
に、光を変調した際に高調波成分を発生させずに第一側
波成分を大きくすることができることから、周波数分割
多重信号のチャンネル数を増やしたり、ＣＮＲや歪特性
を向上することが可能になる。As described above, according to the present invention, a transmitter including a semiconductor laser and an external modulator for amplitude-modulating the output light of the semiconductor laser in accordance with a frequency division multiplexed signal composed of a plurality of modulated signals. And a semiconductor laser for local oscillation, an optical coupler that couples the optical signal sent from the transmitter and the optical signal of the semiconductor laser for local oscillation,
From the light receiving circuit that obtains the intermediate frequency signal of the two optical signals, the band pass filter that extracts the carrier component and the first side wave component obtained by the amplitude modulation of the light from the output signal of the light receiving circuit, and the respective band pass filter By providing a receiver equipped with a mixer that takes the product of the two output signals, the phase noise of the semiconductor laser light is reduced, and the first sideband without generating a harmonic component when the light is modulated. Since the component can be increased, it is possible to increase the number of channels of the frequency division multiplexed signal and improve CNR and distortion characteristics.
【００１９】また、半導体レーザと、複数の変調信号か
らなる周波数分割多重信号に応じて半導体レーザの出力
光を振幅変調する外部変調器を備えた送信装置を設ける
とともに、局部発振用半導体レーザと、送信装置から送
られてきた光信号と局部発振用半導体レーザの光信号を
結合する光結合器と、二つの光信号の中間周波信号を得
る受光回路と、受光回路の出力信号を増幅する利得可変
増幅器と、利得可変増幅器の出力信号から光の振幅変調
によって得られる搬送波成分および第一側波成分をそれ
ぞれ抽出する帯域通過フィルタと、それぞれの帯域通過
フィルタから出力される二つの信号の積を取るミキサ
と、利得可変増幅器の出力信号から光の振幅変調によっ
て得られる搬送波成分の信号振幅を検知するピークディ
テクタを備えた受信装置を設けることにより、周波数分
割多重信号のチャンネル数を増やしたり、ＣＮＲや歪特
性を向上することが可能になるとともに、半導体レーザ
光の振幅ゆらぎ、偏波面の変化等による振幅雑音を低減
することができるという優れた効果を奏する。Further, the semiconductor laser and a transmitter equipped with an external modulator for amplitude-modulating the output light of the semiconductor laser according to a frequency division multiplexed signal composed of a plurality of modulation signals are provided, and a semiconductor laser for local oscillation is provided, An optical coupler that combines the optical signal sent from the transmitter with the optical signal of the local oscillation semiconductor laser, a light receiving circuit that obtains an intermediate frequency signal of the two optical signals, and a variable gain that amplifies the output signal of the light receiving circuit. The product of the amplifier, the band-pass filter that extracts the carrier component and the first side component obtained by the amplitude modulation of light from the output signal of the variable gain amplifier, and the two signals output from each band-pass filter Reception with a mixer and a peak detector that detects the signal amplitude of the carrier component obtained by amplitude modulation of light from the output signal of the variable gain amplifier By disposing the above arrangement, it is possible to increase the number of channels of the frequency division multiplexed signal, improve CNR and distortion characteristics, and reduce the amplitude noise of the semiconductor laser light and the amplitude noise due to changes in the polarization plane. It has an excellent effect that
【図１】本発明の実施例１におけるコヒーレント光伝送
装置のブロック図FIG. 1 is a block diagram of a coherent optical transmission device according to a first embodiment of the present invention.
【図２】本発明の実施例２におけるコヒーレント光伝送
装置に設けられた受信装置のブロック図FIG. 2 is a block diagram of a receiving device provided in a coherent optical transmission device according to a second exemplary embodiment of the present invention.
１ 送信装置 ２ 受信装置 １０ 半導体レーザ ２０ 外部変調器 ３０ 光結合器 ４０ 局部発振用半導体レーザ ５０ 受光回路 ６０ 帯域通過フィルタ ７０ 帯域通過フィルタ ８０ ミキサ １００ ピークディテクタ １１０ 利得可変増幅器 1 transmitter 2 receiver 10 semiconductor laser 20 external modulator 30 optical coupler 40 local oscillation semiconductor laser 50 light receiving circuit 60 band pass filter 70 band pass filter 80 mixer 100 peak detector 110 gain variable amplifier
Claims (2)
号を外部変調器に入力し前記外部変調器で半導体レーザ
の出力光を振幅変調するように少なくとも構成された送
信装置と、 局部発振用半導体レーザと、前記の送信装置から送られ
てきた光信号と前記局部発振用半導体レーザの光信号を
結合する光結合器と、前記二つの光信号の中間周波信号
を得る受光回路と、前記受光回路の出力信号から光の振
幅変調によって得られる搬送波成分を抽出する第一の帯
域通過フィルタと、前記受光回路の出力信号から光の振
幅変調によって得られる第一側波成分を抽出する第二の
帯域通過フィルタと、前記第一及び第二の帯域通過フィ
ルタから出力される二つの信号の積を取るミキサで少な
くとも構成された受信装置とからなるコヒーレント光伝
送装置。1. A transmission device at least configured to input a frequency division multiplexed signal composed of a plurality of modulation signals to an external modulator and amplitude-modulate the output light of a semiconductor laser by the external modulator, and a semiconductor for local oscillation. A laser, an optical coupler for coupling an optical signal sent from the transmitter and an optical signal of the local oscillation semiconductor laser, a light receiving circuit for obtaining an intermediate frequency signal of the two optical signals, and the light receiving circuit A first band-pass filter for extracting a carrier component obtained by amplitude modulation of light from the output signal of the second band, and a second band for extracting a first side wave component obtained by amplitude modulation of light from the output signal of the light receiving circuit. A coherent optical transmission device including a pass filter and a receiving device including at least a mixer for taking a product of two signals output from the first and second band pass filters. .
号を外部変調器に入力し前記外部変調器で半導体レーザ
の出力光を振幅変調するように少なくとも構成された送
信装置と、 局部発振用半導体レーザと、前記の送信装置から送られ
てきた光信号と前記局部発振用半導体レーザの光信号を
結合する光結合器と、前記二つの光信号の中間周波信号
を得る受光回路と、受光回路の出力信号を増幅する利得
可変増幅器と、前記利得可変増幅器の出力信号から光の
振幅変調によって得られる搬送波成分を抽出する第一の
帯域通過フィルタと、前記利得可変増幅器の出力信号か
ら光の振幅変調によって得られる第一側波成分を抽出す
る第二の帯域通過フィルタと、前記第一及び第二の帯域
通過フィルタから出力される二つの信号の積を取るミキ
サと、前記利得可変増幅器の出力信号から光の振幅変調
によって得られる搬送波成分の信号の振幅を検知するピ
ークディテクタで少なくとも構成された受信装置とから
なり、 前記ピークディテクタで光の振幅変調によって得られる
搬送波成分の信号振幅が一定になるように前記利得可変
増幅器の利得を制御することを特徴としたコヒーレント
光伝送装置。2. A transmission device at least configured to input a frequency division multiplexed signal composed of a plurality of modulation signals to an external modulator and amplitude-modulate the output light of a semiconductor laser by the external modulator, and a semiconductor for local oscillation. A laser, an optical coupler for coupling an optical signal sent from the transmitter and an optical signal of the local oscillation semiconductor laser, a light receiving circuit for obtaining an intermediate frequency signal of the two optical signals, and a light receiving circuit A variable gain amplifier for amplifying an output signal, a first band-pass filter for extracting a carrier component obtained by amplitude modulation of light from an output signal of the variable gain amplifier, and an amplitude modulation of light from an output signal of the variable gain amplifier A second bandpass filter for extracting the first sideband component obtained by, and a mixer that takes the product of the two signals output from the first and second bandpass filters, A receiver comprising at least a peak detector that detects the amplitude of a carrier component signal obtained by amplitude modulation of light from the output signal of the variable gain amplifier, and the carrier component obtained by amplitude modulation of light by the peak detector. The coherent optical transmission device is characterized in that the gain of the variable gain amplifier is controlled so that the signal amplitude is constant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30201392A JP3168735B2 (en) | 1992-11-12 | 1992-11-12 | Coherent optical transmission equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30201392A JP3168735B2 (en) | 1992-11-12 | 1992-11-12 | Coherent optical transmission equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06152565A true JPH06152565A (en) | 1994-05-31 |
| JP3168735B2 JP3168735B2 (en) | 2001-05-21 |
Family
ID=17903845
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30201392A Expired - Fee Related JP3168735B2 (en) | 1992-11-12 | 1992-11-12 | Coherent optical transmission equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3168735B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996027928A1 (en) * | 1995-03-06 | 1996-09-12 | Northern Telecom Limited | Wavelength control of data-modulated lasers |
| AU782389B2 (en) * | 2000-06-22 | 2005-07-21 | National Institute Of Information And Communications Technology | Method and apparatus for transmitting high-frequency signals in optical communication system |
| GB2514073A (en) * | 2010-09-09 | 2014-11-19 | Univ Dublin City | An optical measurement method and system |
-
1992
- 1992-11-12 JP JP30201392A patent/JP3168735B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996027928A1 (en) * | 1995-03-06 | 1996-09-12 | Northern Telecom Limited | Wavelength control of data-modulated lasers |
| AU782389B2 (en) * | 2000-06-22 | 2005-07-21 | National Institute Of Information And Communications Technology | Method and apparatus for transmitting high-frequency signals in optical communication system |
| US7006772B2 (en) | 2000-06-22 | 2006-02-28 | National Institute Of Information And Communications Technology | Method and apparatus for transmitting high-frequency signals in optical communication system |
| US7149435B2 (en) | 2000-06-22 | 2006-12-12 | National Institute Of Information And Communications Technology | Method and apparatus for transmitting high-frequency signals in optical communication system |
| AU782389C (en) * | 2000-06-22 | 2007-02-01 | National Institute Of Information And Communications Technology | Method and apparatus for transmitting high-frequency signals in optical communication system |
| GB2514073A (en) * | 2010-09-09 | 2014-11-19 | Univ Dublin City | An optical measurement method and system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3168735B2 (en) | 2001-05-21 |
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