JP2990713B2 - Light modulation circuit - Google Patents
Light modulation circuitInfo
- Publication number
- JP2990713B2 JP2990713B2 JP1319913A JP31991389A JP2990713B2 JP 2990713 B2 JP2990713 B2 JP 2990713B2 JP 1319913 A JP1319913 A JP 1319913A JP 31991389 A JP31991389 A JP 31991389A JP 2990713 B2 JP2990713 B2 JP 2990713B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- signal
- main signal
- auxiliary signal
- optical phase
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、光通信における補助信号伝送方式に関し、
特に光位相変調器を用い主信号に補助信号を重畳させる
光変調回路に関する。Description: TECHNICAL FIELD The present invention relates to an auxiliary signal transmission system in optical communication,
In particular, the present invention relates to an optical modulation circuit that superimposes an auxiliary signal on a main signal using an optical phase modulator.
従来、この種の光変調回路は主信号のデジタルパルス
列と補助信号（第２図（ａ））を伝送するため第２図
（ｂ）に示すように主信号のデジタルパルス列のパルス
振幅を補助信号の振幅に応じて変化させた電気信号を発
生し、その信号で半導体レーザ（以後LDと称す）を駆動
していた。Conventionally, this type of optical modulation circuit transmits a digital pulse train of a main signal and an auxiliary signal (FIG. 2 (a)) so that the pulse amplitude of the digital pulse train of the main signal is converted to an auxiliary signal as shown in FIG. 2 (b). An electrical signal changed according to the amplitude of the laser was generated, and the signal was used to drive a semiconductor laser (hereinafter referred to as an LD).
上述した従来の光変調回路は、主信号のデジタルパル
ス列に対しそのパルス振幅を変化させ補助信号を伝送す
るような構成、すなわち主信号を光の強度変調により伝
送するような方式なので、補助信号の伝送に伴い、主信
号の伝送劣化を起す。又、変調回路が複雑になるという
欠点がある。The above-described conventional optical modulation circuit is configured to transmit an auxiliary signal by changing the pulse amplitude of a digital pulse train of the main signal, that is, a method of transmitting the main signal by light intensity modulation. Along with the transmission, transmission degradation of the main signal occurs. Further, there is a disadvantage that the modulation circuit becomes complicated.
本発明によれば、半導体レーザ（以下LDと略す）と、
デジタル主信号によって前記LDを駆動するLD駆動回路
と、前記LDから出力された光を入力し、入力された光を
位相変調する光位相変調器と、前デジタル主信号に重畳
する補助信号で前記光位相変調器を駆動する光位相変調
器駆動回路とを有し、主信号の光の位相を変調すること
により補助信号の伝送を可能とする光変調回路が得られ
る。According to the present invention, there is provided a semiconductor laser (hereinafter abbreviated as LD),
An LD drive circuit that drives the LD with a digital main signal, an optical phase modulator that inputs light output from the LD, and modulates the input light with a phase, and an auxiliary signal that is superimposed on a previous digital main signal. An optical modulation circuit having an optical phase modulator driving circuit for driving the optical phase modulator and capable of transmitting an auxiliary signal by modulating the phase of light of the main signal is obtained.
次に、本発明の実施例について図面を参照して説明す
る。Next, embodiments of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例のブロック図である。 FIG. 1 is a block diagram of one embodiment of the present invention.
図において、LD駆動回路２は、端子１から供給された
デジタル主信号を増幅してLD3を駆動する。LD3より発光
した光は光位相変調器４に入力される。この光位相変調
器にはリチウムナイオベート（LiNbO3）やリチウムタン
タレート（LiTaO3）などの周知の光変調素子が使用され
る。一方、光位相変調器駆動回路５には端子６を介して
補助信号が入力され、補助信号を増幅して前述の光位相
変調器４の電極に印加して駆動し、主信号の光の位相変
調を行う。すなわち、駆動回路５の出力電圧に応じて光
位相変調器４が入力光信号の位相を変調し光ファイバケ
ーブル７に出射する。光ファイバケーブル７の受信側
（図示せず）で補助信号を検出する場合には、周知の光
ヘテロダイン検波を行なって光信号の位相を検出し補助
信号を再生すればよい。In the figure, an LD driving circuit 2 amplifies a digital main signal supplied from a terminal 1 and drives an LD 3. Light emitted from the LD 3 is input to the optical phase modulator 4. A well-known light modulation element such as lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ) is used for the optical phase modulator. On the other hand, an auxiliary signal is input to the optical phase modulator driving circuit 5 via the terminal 6, and the auxiliary signal is amplified and applied to the electrodes of the optical phase modulator 4 to drive the optical signal. Perform modulation. That is, the optical phase modulator 4 modulates the phase of the input optical signal in accordance with the output voltage of the drive circuit 5 and emits the signal to the optical fiber cable 7. When an auxiliary signal is detected on the receiving side (not shown) of the optical fiber cable 7, a known optical heterodyne detection may be performed to detect the phase of the optical signal and reproduce the auxiliary signal.
以上説明したように本発明は、補助信号の伝送に光位
相変調を用いることにより、補助信号の伝送に伴う主信
号の伝送劣化を防ぐ効果がある。As described above, the present invention has an effect of preventing main signal transmission deterioration accompanying transmission of an auxiliary signal by using optical phase modulation for transmission of the auxiliary signal.
第１図は本発明の実施例を示すブロック図、第２図
（ａ），（ｂ）は従来の光変調器の動作を説明する波形
図である。 １……デジタル主信号入力端子、２……LD駆動回路、３
……LD、４……光位相変調器、５……光位相変調器駆動
回路、６……補助信号入力端子、７……光ファイバケー
ブル。FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2A and 2B are waveform diagrams for explaining the operation of a conventional optical modulator. 1 ... Digital main signal input terminal 2 ... LD drive circuit 3
… LD, 4… optical phase modulator, 5… optical phase modulator drive circuit, 6… auxiliary signal input terminal, 7… optical fiber cable.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｈ０４Ｂ 10/152 Ｈ０４Ｊ 14/04 14/06 (58)調査した分野(Int.Cl.6，ＤＢ名) H04B 10/00 - 10/28 H01S 3/096 G02F 1/03 502 ──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. 6 identification code FI H04B 10/152 H04J 14/04 14/06 (58) Field surveyed (Int.Cl. 6 , DB name) H04B 10/00- 10/28 H01S 3/096 G02F 1/03 502
Claims (1)
と、 前記LDから出力された光を入力し、入力された光を位相
変調する光位相変調器と、 前記デジタル主信号に重畳する補助信号で前記光位相変
調器を駆動する光位相変調駆動回路と を有し、 前記主信号の光の位相を変調して前記補助信号の伝送を
行うことを特徴とする光変調回路。A semiconductor laser (hereinafter abbreviated as LD); an LD drive circuit for driving the LD with a digital main signal; and an optical phase for inputting light output from the LD and phase modulating the input light. A modulator, and an optical phase modulation drive circuit that drives the optical phase modulator with an auxiliary signal superimposed on the digital main signal, and modulates a phase of light of the main signal to transmit the auxiliary signal. An optical modulation circuit, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1319913A JP2990713B2 (en) | 1989-12-08 | 1989-12-08 | Light modulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1319913A JP2990713B2 (en) | 1989-12-08 | 1989-12-08 | Light modulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03181240A JPH03181240A (en) | 1991-08-07 |
| JP2990713B2 true JP2990713B2 (en) | 1999-12-13 |
Family
ID=18115632
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1319913A Expired - Lifetime JP2990713B2 (en) | 1989-12-08 | 1989-12-08 | Light modulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2990713B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2661574B2 (en) * | 1994-12-28 | 1997-10-08 | 日本電気株式会社 | LN modulator DC bias circuit |
-
1989
- 1989-12-08 JP JP1319913A patent/JP2990713B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03181240A (en) | 1991-08-07 |
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