JPH01252927A - Method of shaping phase modulating light waveform - Google Patents
Method of shaping phase modulating light waveformInfo
- Publication number
- JPH01252927A JPH01252927A JP8066288A JP8066288A JPH01252927A JP H01252927 A JPH01252927 A JP H01252927A JP 8066288 A JP8066288 A JP 8066288A JP 8066288 A JP8066288 A JP 8066288A JP H01252927 A JPH01252927 A JP H01252927A
- Authority
- JP
- Japan
- Prior art keywords
- light
- amplifier
- power
- optical
- modulation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 7
- 238000007493 shaping process Methods 0.000 title claims description 5
- 230000003287 optical effect Effects 0.000 claims abstract description 26
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 3
- 239000013307 optical fiber Substances 0.000 abstract description 9
- 230000002238 attenuated effect Effects 0.000 abstract description 2
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000010168 coupling process Methods 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- 238000004891 communication Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000002372 labelling Methods 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明はコヒーレント光通信で用いられる光位相変調方
式に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical phase modulation method used in coherent optical communication.
（従来の技術）
半導体光位相変調器は、低電圧で高速の変調が可能であ
るという点で従来用いられていたＬｔＮｂＯ３（ニオブ
酸リチウム）製光位相変調器よりも優れているがその反
面挿入損失と不要な振幅変調が問題である。この挿入損
失については変調器から出射された信号光をレーザダイ
オードアンプ（ＬＤアンプ）で増幅することによって補
償することが可能である。しかしながら不要な振幅変調
成分については、効果的な抑圧方法がこれまで示されて
いなかった。そして、この振幅変調成分は、ＰＳＫ光ヘ
テロダイン受信器の感度劣化を引き起こす要因となって
しまう。(Prior art) Semiconductor optical phase modulators are superior to conventionally used optical phase modulators made of LtNbO3 (lithium niobate) in that they can perform high-speed modulation with low voltage. Loss and unwanted amplitude modulation are problems. This insertion loss can be compensated for by amplifying the signal light emitted from the modulator with a laser diode amplifier (LD amplifier). However, no effective method of suppressing unnecessary amplitude modulation components has been demonstrated so far. This amplitude modulation component becomes a factor that causes sensitivity deterioration of the PSK optical heterodyne receiver.
（発明が解決しようとする問題点）
本発明は、前記光位相変調器によって生じていた不要な
振幅変調成分を、デバイスを変えることなく容易に抑圧
する方法を提供するものである。(Problems to be Solved by the Invention) The present invention provides a method for easily suppressing unnecessary amplitude modulation components generated by the optical phase modulator without changing the device.
（問題を解決するための手段）
本発明による位相変調光波形整形方法は、光位相変調器
で不要な振幅変調を受けた位相変調光をレーザダイオー
ドアンプに入射させ、利得飽和状態となるレベルまで前
記位相変調光のパワーを増大させることによって、前記
不要振幅変調成分を除去するものである。(Means for Solving the Problem) The phase-modulated light waveform shaping method according to the present invention makes phase-modulated light that has undergone unnecessary amplitude modulation in an optical phase modulator enter a laser diode amplifier until the gain saturates. The unnecessary amplitude modulation component is removed by increasing the power of the phase modulated light.
（作用）
本発明を特徴付けている点は従来リニアアンプとして用
いられていたＬＤアンプ（タダシサイトウアンドタカア
キムカイ“１．５１１ｍ ＧａＩｎＡｓＰ ）ラベリン
グウェーブセミコンダクタレーザアンプリファイア”
ＩＥＥＥジャーナルオブクオンタムエレクトロニクスＶ
ｏ１．ＱＥ−２３，Ｎｏ６．１９８７．ｐｐｌｏｌｏ−
１９）を、リミッタとして扱っている所である。リミッ
タは、電気回路においては波形整形に良く用いられてい
るものであるが本発明では、光に対して同様の作用を行
なわせるものである。これにより前述のごとく位相変調
器による挿入損失の補償と同時に波形整形も実現できる
点が大きな利点として掲げられる。(Function) The feature that characterizes the present invention is that the LD amplifier (Tadasi Saito & Takaakimkai "1.511m GaInAsP") labeling wave semiconductor laser amplifier which has been conventionally used as a linear amplifier.
IEEE Journal of Quantum Electronics V
o1. QE-23, No. 6.1987. pplolo-
19) is treated as a limiter. A limiter is often used for waveform shaping in electric circuits, and in the present invention, it is used to perform a similar effect on light. A major advantage of this is that, as described above, it is possible to compensate for insertion loss by the phase modulator and also realize waveform shaping at the same time.
（実施例）
第１図に本発明の第１の実施例の構成を示す。第１の実
施例は本発明を４相ＰＳＫ光位相変調装置に適用したも
のである。第１の光ファイバ１より送られてきたパワー
＋１０ｄＢｍの信号光は、第１のレンズ２を介して光位
相変調器３に入射される。この光位相変調器３の導波路
は多重量子井戸で形成されており、低半波長電圧が得ら
れている。また、信号電極は２分割されており、一方が
ｏ−ｎ変調領域他方が０−ｎ／２変調領域となっている
。これにより４相ＰＳＫ変調を行なうことができる。こ
の光位相変調器３の各電極光り半波長電圧は３ｖ、３ｄ
Ｂ力ツトオフ周波数は５ＧＨｚであり、高速のＦＥＴア
ンプで駆動可能となっている。ここで４相ＰＳＫ変調さ
れた信号光は、第２のレンズ４を介して再び第２の光フ
ァイバ５に集光される。このとき信号光のパワーは光位
相変調器３の導波路損失３ｄＢと第１第２の光ファイバ
１．５との結合損失１０ｄＢにより一３ｄＢｍまで減衰
している。(Embodiment) FIG. 1 shows the configuration of a first embodiment of the present invention. The first embodiment is an application of the present invention to a four-phase PSK optical phase modulation device. Signal light with a power of +10 dBm sent from the first optical fiber 1 is input to the optical phase modulator 3 via the first lens 2. The waveguide of this optical phase modulator 3 is formed of multiple quantum wells, and a low half-wavelength voltage is obtained. Further, the signal electrode is divided into two parts, one being an on modulation region and the other being an 0-n/2 modulation region. This allows four-phase PSK modulation to be performed. The half-wave voltage of each electrode of this optical phase modulator 3 is 3v, 3d
The B power cut-off frequency is 5 GHz, and can be driven by a high-speed FET amplifier. Here, the signal light subjected to four-phase PSK modulation is again focused on the second optical fiber 5 via the second lens 4. At this time, the power of the signal light is attenuated to -3 dBm due to the 3 dB waveguide loss of the optical phase modulator 3 and the 10 dB coupling loss between the first and second optical fibers 1.5.
また、変調光の振幅は第１図に示す様に、位相が変わる
ごとに変化している。この振幅変動は光ヘテロダイン検
波時に感度劣化を引き起こしてしまう。Further, as shown in FIG. 1, the amplitude of the modulated light changes every time the phase changes. This amplitude fluctuation causes sensitivity deterioration during optical heterodyne detection.
この信号光は続いて、第３のレンズ６によりＬＤアンプ
７に入射される。ＬＤアンプ７は、光入力レベル−１３
ｄＢｍでは出力飽和状態となっており＋ １０ｄＢｄＢ
ｍで出射光パワーはリミットされる。This signal light then enters the LD amplifier 7 through the third lens 6. The LD amplifier 7 has an optical input level of -13
At dBm, the output is saturated and +10dBdB
The output light power is limited by m.
従ってＬＤアンプ７の出力に現れる信号光は、第１図に
示す様に振幅一定で＋１０ｄＢｍのパワーのＰＳＫ変調
光となる。以上により、変調前と同一の光レベルのＰＳ
Ｋ変調光を波形歪無く低電力で得ることができる。Therefore, the signal light appearing at the output of the LD amplifier 7 becomes PSK modulated light with a constant amplitude and a power of +10 dBm, as shown in FIG. As a result of the above, the PS of the same optical level as before modulation
K modulated light can be obtained with low power without waveform distortion.
第２図に本発明の第２の実施例の構成を示す。第２の実
施例は、本発明をモノリシック構成によって実現したも
のである。信号光は第１の光ファイバ１により第１のレ
ンズ２を介してＬＤアンプ付光位相変調器１０に入射さ
れる。位相変調領域にてＰＳＫ変調された信号光は光増
幅領域にて増幅、波形整形される。FIG. 2 shows the configuration of a second embodiment of the present invention. The second embodiment implements the present invention in a monolithic configuration. The signal light is input to the optical phase modulator with LD amplifier 10 via the first lens 2 through the first optical fiber 1 . The signal light PSK-modulated in the phase modulation region is amplified and waveform-shaped in the optical amplification region.
以上により、パワー損失と波形歪の無いＰＳＫ変調光が
得られる。As described above, PSK modulated light without power loss and waveform distortion can be obtained.
（発明の効果）
以上詳しく述べた様に本発明を用いれば、低電力で高速
のＰＳＫ変調を信号光のパワー損失と不要な振幅変調無
しに実現することができる。これによって高速長距離Ｐ
ＳＫ光ヘテロダイン検波通信システムの構築が可能とな
る。(Effects of the Invention) As described above in detail, by using the present invention, low power and high speed PSK modulation can be realized without power loss of signal light and unnecessary amplitude modulation. This allows high-speed long-distance P
It becomes possible to construct an SK optical heterodyne detection communication system.
図の簡単な説明
第１図は本発明の第１の実施例を示す構成図、第２図は
本発明の第２の実施例を示す構成図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG. 2 is a block diagram showing a second embodiment of the present invention.
各図において、
１・・・第１の光ファイバ、２・・・第１のレンズ、３
・・・光位相変調器、４・・・第２のレンズ、５・・・
第２の光ファイバ、６・・・第３のレンズ、７・・・Ｌ
Ｄアンプ、８・・・第４のレンズ、９・・・第３の光フ
ァイバ、１０・・・ＬＤアンプ付光位相変調器
である。In each figure, 1... first optical fiber, 2... first lens, 3
... Optical phase modulator, 4... Second lens, 5...
Second optical fiber, 6...Third lens, 7...L
D amplifier, 8... fourth lens, 9... third optical fiber, 10... optical phase modulator with LD amplifier.
Claims (1)
続して信号光を増幅する光位相変調方式において、前記
光位相変調器で不要な振幅変調を受けた位相変調光を前
記レーザダイオードアンプに入射させ、利得飽和状態と
なるレベルまで前記位相変調光のパワーを増幅させるこ
とによって前記不要振幅変調成分を除去することを特徴
とする位相変調光波形整形方法。In an optical phase modulation method in which a laser diode amplifier is connected to the output side of an optical phase modulator to amplify signal light, the phase modulated light that has undergone unnecessary amplitude modulation in the optical phase modulator is made incident on the laser diode amplifier. . A phase modulated light waveform shaping method, characterized in that the unnecessary amplitude modulation component is removed by amplifying the power of the phase modulated light to a level at which gain is saturated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8066288A JPH01252927A (en) | 1988-03-31 | 1988-03-31 | Method of shaping phase modulating light waveform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8066288A JPH01252927A (en) | 1988-03-31 | 1988-03-31 | Method of shaping phase modulating light waveform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01252927A true JPH01252927A (en) | 1989-10-09 |
Family
ID=13724574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8066288A Pending JPH01252927A (en) | 1988-03-31 | 1988-03-31 | Method of shaping phase modulating light waveform |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01252927A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013040809A (en) * | 2011-08-12 | 2013-02-28 | Nikon Corp | Encoder device, and device |
-
1988
- 1988-03-31 JP JP8066288A patent/JPH01252927A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013040809A (en) * | 2011-08-12 | 2013-02-28 | Nikon Corp | Encoder device, and device |
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