JPH0324521A - Optical modulation circuit - Google Patents
Optical modulation circuitInfo
- Publication number
- JPH0324521A JPH0324521A JP15838389A JP15838389A JPH0324521A JP H0324521 A JPH0324521 A JP H0324521A JP 15838389 A JP15838389 A JP 15838389A JP 15838389 A JP15838389 A JP 15838389A JP H0324521 A JPH0324521 A JP H0324521A
- Authority
- JP
- Japan
- Prior art keywords
- output
- circuit
- input
- semiconductor laser
- light
- 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
- 230000003287 optical effect Effects 0.000 title claims abstract description 32
- 239000004065 semiconductor Substances 0.000 claims abstract description 20
- 239000013307 optical fiber Substances 0.000 claims abstract description 12
- 238000001514 detection method Methods 0.000 claims description 8
- 230000008878 coupling Effects 0.000 claims description 3
- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 abstract description 2
- 239000003990 capacitor Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/0121—Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
- G02F1/0123—Circuits for the control or stabilisation of the bias voltage, e.g. automatic bias control [ABC] feedback loops
Abstract
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光変調回路に係り、特に分岐干
渉型光変調器（以下、外部変調器と略称する）を用いた
光変調回路に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical modulation circuit in optical communication, and particularly relates to an optical modulation circuit using a branching interference type optical modulator (hereinafter referred to as an external modulator). It is something.
従来の外部変調器を用いた光変調回路の一例を第２図に
示し説明する。An example of a conventional optical modulation circuit using an external modulator is shown in FIG. 2 and will be described.
図において、２１ぱ半導体レーザ、２２はレンズ、２３
は外部変調器、２４はレンズ、２５は光ファイバ、２６
は外部変調器２３に交流結合で入力される主信号にバイ
アス電圧を与えるバイアス供給回路、２Ｔぱ主信号源で
、この主信号源２７はコンデンサ２８を介して外部変調
器２３に接続されている。２９は半導体レーザ２１に接
続されたバイアス供給回路である。In the figure, 21 is a semiconductor laser, 22 is a lens, and 23 is a semiconductor laser.
is an external modulator, 24 is a lens, 25 is an optical fiber, 26
is a bias supply circuit that applies a bias voltage to the main signal input to the external modulator 23 by AC coupling, and is a 2T main signal source, and this main signal source 27 is connected to the external modulator 23 via a capacitor 28. . 29 is a bias supply circuit connected to the semiconductor laser 21.
このように構成された光変調回路において、変調主信号
は交流結合され、ある一定のバイアス電圧が印加されて
いる。In the optical modulation circuit configured in this manner, the modulation main signal is AC-coupled, and a certain bias voltage is applied.
上述した従来の外部変調器を用いた光変調回路では、変
調主信号は交流結合となってＤシ、一定のバイアスが印
加されているため、入力変調主信号情報のマーク率が変
動し、その直流バイアスレベルが変わると外部変調器の
変調レベルが変動してし甘うという課題があった。１た
、外部変調器に入力される半導体レーザ出力光のパワー
は、半導体レーザの後方光をモニタすることによう出力
光を一定に制御している。この構成で半導体レーザから
ファイバ間の光学系軸ずれが生じた場合、光学系軸ずれ
情報は検出不可能でｓｂファイバに結合する光出力パワ
ーは低下してし！うという課題があった。In the optical modulation circuit using the conventional external modulator described above, the modulated main signal is AC coupled and a constant bias is applied, so the mark rate of the input modulated main signal information fluctuates and its There was a problem in that the modulation level of the external modulator fluctuated when the DC bias level changed. Furthermore, the power of the semiconductor laser output light input to the external modulator is controlled to be constant by monitoring the rear light of the semiconductor laser. In this configuration, if an optical system axis misalignment occurs between the semiconductor laser and the fiber, the optical system axis misalignment information cannot be detected, and the optical output power coupled to the sb fiber will decrease! There was an issue.
本発明の光変調回路は、入出力部にレンズを設け、主信
号源が交流結合されている外部変調器と、この外部変調
器に結合された光ファイバ分岐部と、この光ファイバ分
岐部から一方の光出力が入力されるフォトダイオードと
、このフォトダイオードの光電流のピーク値を検出する
ピーク値検出回路と、このピーク値検出回路の出力電圧
が入力されかつ上記外部変調器に交流結合で入力される
主信号にバイアス電圧を与える第１のバイアス供給回路
と、半導体レーザと、この半導体レーザに接続される第
２のバイアス供給回路と、この第２のバイアス供給回路
に接続されるＡＰＣ制御回路を備え、上記ＡＰＣ制御回
路には上記フォトダイオドでモニタされた光出力パワー
情報がフィードバックされる構成としたものである。The optical modulation circuit of the present invention includes a lens in the input/output section, an external modulator to which a main signal source is AC-coupled, an optical fiber branch coupled to the external modulator, and an optical fiber branch connected to the external modulator. A photodiode to which one optical output is input, a peak value detection circuit to detect the peak value of the photocurrent of this photodiode, and an output voltage of this peak value detection circuit to which the output voltage is input and AC coupled to the external modulator. A first bias supply circuit that applies a bias voltage to an input main signal, a semiconductor laser, a second bias supply circuit connected to the semiconductor laser, and an APC control connected to the second bias supply circuit. The optical output power information monitored by the photodiode is fed back to the APC control circuit.
本発明においては、変調光出力波形をモニタすることに
よう、そのピーク値が一定になるようにフィードバック
回路を構成し、入力主信号のマーク率変化に対する直流
成分の変化をバイアス供給回路を制御することによう補
償する。In the present invention, in order to monitor the modulated light output waveform, a feedback circuit is configured so that its peak value is constant, and a bias supply circuit is controlled to control changes in the DC component in response to changes in the mark rate of the input main signal. In particular, we will compensate you accordingly.
以下、図面に基づき本発明の実施例を詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
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。FIG. 1 is a block diagram showing an embodiment of an optical modulation circuit according to the present invention.
図において、１は半導体レーザ、３は入出力部にレンズ
２，４を設け主信号源１０が交流結合されている外部変
調器、５はこの外部変調器３に結合された光ファイバ分
岐部、６はこの光ファイバ分岐部５から一方の光出力が
入力されるフォトダイオード、ＴＦｉ．抵抗、８はフォ
トダイオード６の光電流のピーク値を検出するピーク値
検出回路、９はこのピーク値検出回路８の出力電圧が入
力されかつ外部変調器３に交流結合で入力される主信号
にバイアス電圧を与えるバイアス供給回路、１１ぱコン
デンサ、１２は半導体レーザ１に接続されるバイアス供
給回路、１３はこのバイアス供給回路１２に接続される
ＡＰＣ （ Ａｕｔｏｍａｔｉｃ ｐｏｗｅｒＣｏｎｔ
ｒｏｌ ）制御回路である。In the figure, 1 is a semiconductor laser, 3 is an external modulator provided with lenses 2 and 4 at the input/output part and AC-coupled with the main signal source 10, and 5 is an optical fiber branch coupled to this external modulator 3. 6 is a photodiode to which one optical output from the optical fiber branch 5 is input, TFi. A resistor 8 is a peak value detection circuit that detects the peak value of the photocurrent of the photodiode 6, and 9 is a main signal to which the output voltage of the peak value detection circuit 8 is input and which is input to the external modulator 3 by AC coupling. A bias supply circuit that provides a bias voltage, 11 a capacitor, 12 a bias supply circuit connected to the semiconductor laser 1, and 13 an APC (Automatic power controller) connected to this bias supply circuit 12.
rol ) control circuit.
そして、ＡＰＣ制御回路１３にはフォトダイオード６で
モニタされた光出力パワー情報がフィードバックされる
ように構或されている。The APC control circuit 13 is configured so that optical output power information monitored by the photodiode 6 is fed back.
つぎにこの第１図に示す実施例の動作を説明する。Next, the operation of the embodiment shown in FIG. 1 will be explained.
１ず、半導体レーザ１はバイアス供給回路１２によシ発
光し、その半導体レーザ出力光は外部変調器３に入力さ
れる。１た、主信号源１０からの信号はコンデンサ１１
を介して外部変調器３に入力され、その変調電圧によシ
光強度変調される。First, the semiconductor laser 1 emits light by the bias supply circuit 12, and the output light from the semiconductor laser is input to the external modulator 3. 1, the signal from the main signal source 10 is connected to the capacitor 11
The light is input to the external modulator 3 via the modulator 3, and the light intensity is modulated by the modulation voltage.
そして、この外部変調器３を比力された光信号はレンズ
４を介し、光ファイバ分岐部５に入力される。この光フ
ァイバ分岐部５の出力光の一方は伝送路に送出され、他
方はフォトダイオード６に入力される。ここで、このフ
ォトダイオード６は逆バイアスが印加されて釦ウ、抵抗
Ｉが接続されている。そして、このフォトダイオード６
に入力される光パルスに応じたパルス電圧が得られる。The optical signal applied to the external modulator 3 is input to the optical fiber branch 5 via the lens 4. One of the output lights from the optical fiber branch 5 is sent out to the transmission line, and the other is input to the photodiode 6. Here, a reverse bias is applied to this photodiode 6, and a button C and a resistor I are connected. And this photodiode 6
A pulse voltage is obtained according to the optical pulse input to the .
つぎに、このパルス電圧がピーク値検出回路８に入力さ
れ、その入力されたパルス電圧のピーク値に応じた直流
電圧を出力する。そして、この出力電圧をバイアス供給
回路９に入力し０Ｃ／ＤＣ変換し外部変調器３に印加す
る。筐た、上記パルス電圧はＡＰＣ制御回路１３に入力
されて、半導体レーザ１の出力パワーを一定に補償する
ようにバイアス供給回路１２によシ、半導体レーザ１の
バイアス電流を制御する。Next, this pulse voltage is input to the peak value detection circuit 8, which outputs a DC voltage according to the peak value of the input pulse voltage. Then, this output voltage is input to the bias supply circuit 9, converted to 0C/DC, and applied to the external modulator 3. Then, the pulse voltage is input to the APC control circuit 13, and the bias supply circuit 12 controls the bias current of the semiconductor laser 1 so as to compensate the output power of the semiconductor laser 1 at a constant level.
以上説明したように本発明は、変調光出力波形をモニタ
することによシ、そのピーク値が一定になるようにフィ
ードバック回路を構成し、入力主信号のマーク率変化に
対する直流成分の変化をバイアス供給回路を制御するこ
とによう補償し、安定した光パルスを出力することがで
きる効果がある。筐た、それと同時に半導体レーザから
光ファイバ分岐１での光学系の軸ずれ等の出力光パワー
の低下を補償することが可能になるという効果がある。As explained above, the present invention configures a feedback circuit so that the peak value is constant by monitoring the modulated light output waveform, and biases the change in the DC component with respect to the mark rate change of the input main signal. Controlling the supply circuit has the effect of compensating and outputting stable optical pulses. At the same time, there is an effect that it becomes possible to compensate for a decrease in the output optical power due to an axis shift of the optical system at the optical fiber branch 1 from the semiconductor laser.
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、第２図は従来の光変調回路の一例を示すブロッ
ク図である。
１●・・・半導体レーザ、２・・・・レンズ、３・・・
・分岐干渉型光変調器、４・・・・レンズ、５●●・●
光ファイバ分岐部、６・・●●フォトダイオード、８・
・・・ピーク値検出回路、９・・・・バイアス供給回路
、１０・・・号源、１２・・・・バイアス供給回路、１
・・ＡＰＣ制御回路。FIG. 1 is a block diagram showing an embodiment of an optical modulation circuit according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional optical modulation circuit. 1●... Semiconductor laser, 2... Lens, 3...
・Branching interference type optical modulator, 4...lens, 5●●・●
Optical fiber branch, 6...●●photodiode, 8.
... Peak value detection circuit, 9 ... Bias supply circuit, 10 ... Signal source, 12 ... Bias supply circuit, 1
...APC control circuit.
Claims (1)
分岐干渉型光変調器と、この分岐干渉型光変調器に結合
された光ファイバ分岐部と、この光ファイバ分岐部から
一方の光出力が入力されるフォトダイオードと、このフ
ォトダイオードの光電流のピーク値を検出するピーク値
検出回路と、このピーク値検出回路の出力電圧が入力さ
れかつ前記分岐干渉型光変調器に交流結合で入力される
主信号にバイアス電圧を与える第１のバイアス供給回路
と、半導体レーザと、この半導体レーザに接続される第
２のバイアス供給回路と、この第２のバイアス供給回路
に接続されるＡＰＣ制御回路を備え、前記ＡＰＣ制御回
路には前記フォトダイオードでモニタされた光出力パワ
ー情報がフィードバックされる構成となつていることを
特徴とする光変調回路。A branching interference type optical modulator with a lens in the input/output section and AC coupling of the main signal source, an optical fiber branching part coupled to this branching interference type optical modulator, and one light from this optical fiber branching part. A photodiode to which the output is input, a peak value detection circuit to detect the peak value of the photocurrent of this photodiode, and an output voltage of the peak value detection circuit to which the output voltage is input and AC coupled to the branching interference type optical modulator. A first bias supply circuit that applies a bias voltage to an input main signal, a semiconductor laser, a second bias supply circuit connected to the semiconductor laser, and an APC control connected to the second bias supply circuit. 1. An optical modulation circuit comprising: a circuit, wherein optical output power information monitored by the photodiode is fed back to the APC control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1158383A JP2518403B2 (en) | 1989-06-22 | 1989-06-22 | Light modulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1158383A JP2518403B2 (en) | 1989-06-22 | 1989-06-22 | Light modulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0324521A true JPH0324521A (en) | 1991-02-01 |
| JP2518403B2 JP2518403B2 (en) | 1996-07-24 |
Family
ID=15670518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1158383A Expired - Lifetime JP2518403B2 (en) | 1989-06-22 | 1989-06-22 | Light modulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2518403B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006126796A (en) * | 2004-09-28 | 2006-05-18 | Aisin Seiki Co Ltd | Method of driving mach-zehnder light modulator, and light modulating device |
| JP2008231791A (en) * | 2007-03-20 | 2008-10-02 | Matsushita Electric Works Ltd | Rotary cover structure for chute of water collector |
| JP2009079389A (en) * | 2007-09-25 | 2009-04-16 | Panasonic Electric Works Co Ltd | Rainwater intake device |
-
1989
- 1989-06-22 JP JP1158383A patent/JP2518403B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006126796A (en) * | 2004-09-28 | 2006-05-18 | Aisin Seiki Co Ltd | Method of driving mach-zehnder light modulator, and light modulating device |
| JP2008231791A (en) * | 2007-03-20 | 2008-10-02 | Matsushita Electric Works Ltd | Rotary cover structure for chute of water collector |
| JP2009079389A (en) * | 2007-09-25 | 2009-04-16 | Panasonic Electric Works Co Ltd | Rainwater intake device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2518403B2 (en) | 1996-07-24 |
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