JP2990698B2 - Light modulation circuit - Google Patents
Light modulation circuitInfo
- Publication number
- JP2990698B2 JP2990698B2 JP1182529A JP18252989A JP2990698B2 JP 2990698 B2 JP2990698 B2 JP 2990698B2 JP 1182529 A JP1182529 A JP 1182529A JP 18252989 A JP18252989 A JP 18252989A JP 2990698 B2 JP2990698 B2 JP 2990698B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- main signal
- analog
- semiconductor laser
- digital main
- 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
Landscapes
- Optical Communication System (AREA)
- Optical Couplings Of Light Guides (AREA)
- Optical Integrated Circuits (AREA)
- Semiconductor Lasers (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は分岐干渉型光変調器を用いた光変調回路に関
し，特に，光デジタル主信号に低周波アナログ補助信号
を重畳する光変調回路に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulation circuit using a branch interference optical modulator, and more particularly to an optical modulation circuit for superimposing a low-frequency analog auxiliary signal on an optical digital main signal. .
〔従来の技術〕 従来，この種の光変調回路として第２図に示す光変調
回路が知られている。[Prior Art] Conventionally, an optical modulation circuit shown in FIG. 2 is known as this type of optical modulation circuit.
第２図を参照して，従来の光変調回路は，エミッタ結
合型差動トランジスタ21及び22と，トランジスタ21及び
22のエミッタにコレクタが接続され，半導体レーザ（L
D）24による変調パルスのパルス振幅を制御するトラン
ジスタ23とを備えており,LD24はトランジスタ22のコレ
クタに接続されている。Referring to FIG. 2, the conventional light modulation circuit comprises emitter-coupled differential transistors 21 and 22, and transistors 21 and 22.
The collector is connected to the emitter of 22 and the semiconductor laser (L
D) a transistor 23 for controlling the pulse amplitude of the modulation pulse by 24, and the LD 24 is connected to the collector of the transistor 22.
そして，トランジスタ21及び22のベース（主信号入力
端子29及び30）にデジタル主信号を与え，トランジスタ
23のベース（補助信号入力端子31）にアナログ補助信号
を与えて，デジタル主信号のパルス列のパルス振幅に対
して低周波アナログ信号を重畳し,LD24から光信号とし
て出力している。A digital main signal is applied to the bases of the transistors 21 and 22 (main signal input terminals 29 and 30).
An analog auxiliary signal is given to the base (auxiliary signal input terminal 31) of 23, a low-frequency analog signal is superimposed on the pulse amplitude of the pulse train of the digital main signal, and an optical signal is output from the LD 24.
〔発明が解決しようとする問題点〕 上述した従来の光変調回路はエミッタ結合型差動トラ
ンジスタ及びパルス振幅を制御するトランジスタを備え
ており，特にデジタル主信号が高いビットレートの場
合，パルス振幅に補助信号を重畳すると，主信号のパル
ス波形に劣化起こし，パルス振幅が小さい時LDの変調が
充分に行えないという問題点がある。[Problems to be Solved by the Invention] The above-mentioned conventional optical modulation circuit includes an emitter-coupled differential transistor and a transistor for controlling the pulse amplitude. Particularly, when the digital main signal has a high bit rate, the pulse amplitude is reduced. When the auxiliary signal is superimposed, the pulse waveform of the main signal deteriorates, and there is a problem that the LD cannot be sufficiently modulated when the pulse amplitude is small.
さらに，回路規模が大きくなるばかりでなく複雑であ
るという問題点がある。Further, there is a problem that not only the circuit scale is increased but also the circuit is complicated.
本発明の目的は，デジタル主信号が高いビットレート
の際にも波形劣化を起こすことがなくしかも回路構成が
簡単な光変調回路を提供することにある。An object of the present invention is to provide an optical modulation circuit which does not cause waveform deterioration even when a digital main signal has a high bit rate and has a simple circuit configuration.
本発明によれば，半導体レーザと，デジタル主信号が
入力され前記半導体レーザを前記デジタル主信号に基づ
いて駆動するデジタル主信号駆動回路と，前記半導体レ
ーザの出射光を強度変調する分岐干渉型光変調器と，低
周波アナログ主信号がアナログ補助信号として与えられ
前記分岐干渉型光変調器を前記アナログ補助信号に応じ
て駆動するアナログ信号駆動回路とを有することを特徴
とする光変調回路が得られる。According to the present invention, a semiconductor laser, a digital main signal driving circuit that receives a digital main signal and drives the semiconductor laser based on the digital main signal, and a branch interference type light that intensity-modulates the emission light of the semiconductor laser An optical modulation circuit comprising: a modulator; and an analog signal driving circuit to which the low-frequency analog main signal is supplied as an analog auxiliary signal and drives the branch interference optical modulator in accordance with the analog auxiliary signal. Can be
次に，本発明について実施例によって説明する。 Next, the present invention will be described with reference to examples.
第１図を参照して，デジタル主信号がデジタル主信号
駆動回路11に入力され，デジタル主信号駆動回路11はこ
のデジタル主信号に基づいてLD12を駆動する。つまり、
LD12をオンオフする。この結果,LD12からは第３図
（ａ）に示す光出力が出力される。そして，この光出力
は分岐干渉型光変調器13に入力される。Referring to FIG. 1, a digital main signal is input to digital main signal drive circuit 11, and digital main signal drive circuit 11 drives LD 12 based on the digital main signal. That is,
Turn LD12 on and off. As a result, an optical output shown in FIG. 3A is output from the LD 12. Then, this optical output is input to the branch interference optical modulator 13.
一方，第３図（ｂ）に示す低周波アナログ主信号がア
ナログ補助信号駆動回路14に入力され，アナログ補助信
号駆動回路14はアナログ補助信号を分岐干渉型光変調器
13に与える。分岐干渉型光変調器13はアナログ補助信号
によって駆動される。その結果，第３図（ｃ）に示すよ
うに、デジタル主信号にアナログ補助信号が重畳された
光出力が得られる。On the other hand, the low-frequency analog main signal shown in FIG. 3 (b) is input to the analog auxiliary signal drive circuit 14, which converts the analog auxiliary signal into a branch interference optical modulator.
Give to 13. The branch interference optical modulator 13 is driven by an analog auxiliary signal. As a result, as shown in FIG. 3 (c), an optical output is obtained in which the analog auxiliary signal is superimposed on the digital main signal.
以上説明したように本発明では，分岐干渉型光変調器
を用いることにより高いビットレートにおいても波形劣
化がなく，デジタル主信号のパルス列のパルス振幅に低
周波アナログ補助信号を重畳し伝送できる。また回路構
成が簡単である。As described above, in the present invention, the use of the branching interference type optical modulator does not cause waveform deterioration even at a high bit rate, and can superimpose the low frequency analog auxiliary signal on the pulse amplitude of the pulse train of the digital main signal and transmit the signal. Further, the circuit configuration is simple.
第１図は本発明による光変調回路の一実施例を示すブロ
ック図である。第２図は従来の光変調回路を示す図，第
３図（ａ）〜（ｃ）はそれぞれ半導体レーザの出力，ア
ナログ補助信号及び分岐干渉型光変調器の出力を示す図
である。 11……デジタル主信号駆動回路,12……半導体レーザ,13
……分岐干渉型光変調器,14……低周波アナログ補助信
号駆動回路,21,22,23……トランジスタ,24……半導体レ
ーザ,25……抵抗,26,27……直流電圧源,28……コイル,2
9,30……主信号入力端子,31……補助信号入力端子。FIG. 1 is a block diagram showing one embodiment of an optical modulation circuit according to the present invention. FIG. 2 is a diagram showing a conventional optical modulation circuit, and FIGS. 3 (a) to 3 (c) are diagrams showing an output of a semiconductor laser, an analog auxiliary signal, and an output of a branch interference type optical modulator, respectively. 11 ... Digital main signal drive circuit, 12 ... Semiconductor laser, 13
... Branch interference type optical modulator, 14 ... Low frequency analog auxiliary signal drive circuit, 21,22,23 ... Transistor, 24 ... Semiconductor laser, 25 ... Resistance, 26,27 ... DC voltage source, 28 …… coil, 2
9,30 ... Main signal input terminal, 31 ... Auxiliary signal input terminal.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｈ０４Ｂ 10/04 10/06 10/142 (58)調査した分野(Int.Cl.6，ＤＢ名) H04B 10/00 - 10/28 H01S 3/096 H01S 3/103 G02F 1/035 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 identification code FI H04B 10/04 10/06 10/142 (58) Fields investigated (Int.Cl. 6 , DB name) H04B 10/00-10 / 28 H01S 3/096 H01S 3/103 G02F 1/035
Claims (1)
れ前記半導体レーザを前記デジタル主信号に基づいて駆
動するデジタル主信号駆動回路と，前記半導体レーザの
出射光を強度変調する分岐干渉型光変調器と，低周波ア
ナログ主信号がアナログ補助信号として与えられ前記分
岐干渉型光変調器を前記アナログ補助信号に応じて駆動
するアナログ信号駆動回路とを有することを特徴とする
光変調回路。1. A semiconductor laser, a digital main signal driving circuit to which a digital main signal is input and driving the semiconductor laser based on the digital main signal, and a branch interference type optical modulation for intensity-modulating the light emitted from the semiconductor laser. And an analog signal drive circuit to which the low frequency analog main signal is given as an analog auxiliary signal and drives the branch interference optical modulator according to the analog auxiliary signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1182529A JP2990698B2 (en) | 1989-07-17 | 1989-07-17 | Light modulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1182529A JP2990698B2 (en) | 1989-07-17 | 1989-07-17 | Light modulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0348535A JPH0348535A (en) | 1991-03-01 |
| JP2990698B2 true JP2990698B2 (en) | 1999-12-13 |
Family
ID=16119902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1182529A Expired - Lifetime JP2990698B2 (en) | 1989-07-17 | 1989-07-17 | Light modulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2990698B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090310641A1 (en) * | 2006-09-07 | 2009-12-17 | Matsushita Electric Industrial Co., Ltd. | Laser light source, planar light source, and liquid crystal display device |
| KR20130071799A (en) | 2011-12-21 | 2013-07-01 | 한국전자통신연구원 | Signal transmitting/receiving apparatus and method for controlling polarization |
-
1989
- 1989-07-17 JP JP1182529A patent/JP2990698B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0348535A (en) | 1991-03-01 |
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