JPS61212127A - Apd bias control circuit - Google Patents
Apd bias control circuitInfo
- Publication number
- JPS61212127A JPS61212127A JP60051874A JP5187485A JPS61212127A JP S61212127 A JPS61212127 A JP S61212127A JP 60051874 A JP60051874 A JP 60051874A JP 5187485 A JP5187485 A JP 5187485A JP S61212127 A JPS61212127 A JP S61212127A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- apd
- output
- amplifier
- bias voltage
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/691—Arrangements for optimizing the photodetector in the receiver
- H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
〔概要〕
アバランシェ・フォトダイオード（以下ＡＰＤと云う）
に安定な高圧バイアスを供給し、而も常にＡＰＤの規定
内で而も電流増倍率の高い動作をさせ得る様にバイアス
を制御する。[Detailed description of the invention] [Summary] Avalanche photodiode (hereinafter referred to as APD)
A stable high-voltage bias is supplied to the APD, and the bias is controlled so as to always operate within the APD specifications and with a high current multiplication factor.
本発明は光通信方式に於ける光−電気変換部に於いてＡ
ＰＤの最大バイアス電圧を制御する回路に関するもので
ある。The present invention provides A
This invention relates to a circuit that controls the maximum bias voltage of a PD.
従来のＡＰＤに供給するバイアス電圧は電流増倍率を高
くする為ＡＰＤの規定の上限に近い所で動作させるので
温度特性等によりＡＰＤを破壊する恐れがある。Since the bias voltage supplied to a conventional APD is operated close to the specified upper limit of the APD in order to increase the current multiplication factor, there is a risk that the APD may be destroyed due to temperature characteristics or the like.
従って従来から此の改善が強く望まれていた。Therefore, this improvement has long been strongly desired.
周知の如く光通信方式に於いて、受光素子としてはＡＰ
Ｄが通している。ＡＰＤは高バイアス電圧を必要とする
と云う欠点があるが、電流増倍作用により受光系のＳ／
Ｎを向上させることが出来ると云う利点がある。As is well known, in optical communication systems, AP is used as a light receiving element.
D is passing. APD has the disadvantage of requiring a high bias voltage, but due to the current multiplication effect, the S/
There is an advantage that N can be improved.
第２図はＡＰＤのバイアス電圧と、電流増倍率ａ及び暗
電流すの関係を説明する図である。FIG. 2 is a diagram illustrating the relationship between the bias voltage of the APD, the current multiplication factor a, and the dark current S.
図示する様にバイアス電圧が増加すると、電流増倍率ａ
が増加するが、同時に暗電流すも又増加する。尚暗電流
とはＡＰＤに光入力がない時に出力される電流のことで
、雑音となる。As shown in the figure, when the bias voltage increases, the current multiplication factor a
However, at the same time, the dark current also increases. Note that the dark current is a current that is output when there is no optical input to the APD, and it becomes noise.
従ってＡＰＤにバイアス電圧を印加する場合、バイアス
電圧を大きくして電流増倍率ａが大きい状態で使用する
のが普通である。Therefore, when applying a bias voltage to the APD, it is common to increase the bias voltage and use it in a state where the current multiplication factor a is large.
然しＡＰＤに印加するバイアス電圧には上限があり、此
の上限を越すとＡＰＤの破壊を招く恐れがある。However, there is an upper limit to the bias voltage applied to the APD, and exceeding this upper limit may lead to destruction of the APD.
此の上限はブレークダウン電圧■、と云われ、ブレーク
ダウン電圧１日は暗電流が１００μＡになる電圧で規定
されている。This upper limit is called the breakdown voltage (2), and the breakdown voltage (1 day) is defined as the voltage at which the dark current becomes 100 μA.
此の様にブレークダウン電圧■８に可なり近い最大バイ
アス電圧Ｖ、に固定して使用するので、種々の問題が発
生する。Since the breakdown voltage (1) is fixed at the maximum bias voltage V, which is quite close to 8, various problems occur.
即ち、ＡＰＤの温度変化によりＡＰＤのブレークダウン
電圧■８が変化する。例えば温度が高くなると暗電流す
は点線で示す特性Ｃに変化（右に移動）する。従ってブ
レークダウン電圧Ｖ、は右に移動して■８° となる。That is, the breakdown voltage (18) of the APD changes due to a change in the temperature of the APD. For example, when the temperature rises, the dark current changes to characteristic C (moves to the right) as shown by the dotted line. Therefore, the breakdown voltage V, moves to the right and becomes 8°.
又温度が低くなると暗電流すは点線で示す特性ｄに変化
（左に移動）する。Furthermore, when the temperature decreases, the dark current changes to the characteristic d shown by the dotted line (moves to the left).
従って今固定バイアスで使用していると、例えば温度が
高くなるとブレークダウン電圧Ｖ、高（なるが、反面電
流増倍率ａは低くなる。Therefore, if it is currently used with a fixed bias, for example, as the temperature rises, the breakdown voltage V will increase (but on the other hand, the current multiplication factor a will decrease).
逆に温度が高くなると電流増倍率ａは高（なるが、反面
ブレークダウン電圧■、低くなり、ＡＰＤの破壊を招く
恐れがある。On the other hand, as the temperature rises, the current multiplication factor (a) becomes high (but on the other hand, the breakdown voltage (2) decreases, which may lead to destruction of the APD.
又ＡＰＤに流す電流にリミッタを設ける方法もあるが、
此の方法では歪特性が悪くなると云う欠点がある。There is also a method of installing a limiter on the current flowing to the APD,
This method has the disadvantage that distortion characteristics deteriorate.
本発明の目的は上記従来方式の欠点を除去し、ＡＰＤの
最大バイアス電圧をフィードバック回路により制御して
ＡＰＤ素子の温度特性のバラツキに依る影響を無くすこ
とである。An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional system and to control the maximum bias voltage of the APD by a feedback circuit to eliminate the influence of variations in the temperature characteristics of the APD element.
第１図に示す様にＡＰＤＩの出力に接続される前置増幅
器２の出力端で帯域外の雑音を帯域濾波器４により抽出
し、此の雑音レベルを検波器５で直流電圧に直し、此の
直流電圧が成る基準値以上となった時ＡＰＤ １のバイ
アス電圧を加減することにより常に高い電流増倍率の動
作点で安定的に動作させることにより達成される。As shown in Fig. 1, at the output end of the preamplifier 2 connected to the output of the APDI, out-of-band noise is extracted by a bandpass filter 4, this noise level is converted to a DC voltage by a detector 5, and then this noise level is converted to DC voltage by a detector 5. This is achieved by adjusting the bias voltage of APD 1 when the DC voltage of APD 1 exceeds a reference value, thereby stably operating at an operating point with a constant high current multiplication factor.
本発明に依るとＡＰＤＩの出力に接続される前置増幅器
２の出力端に於ける帯域外の雑音レベルを監視し、成る
基準値を越えた時ＡＰＤＩのバイアス電圧を制御するこ
とによりＡＰＤｌを常に高い電流増倍率の動作点で而も
安定に動作させ得ると云う効果が生まれる。According to the present invention, the out-of-band noise level at the output terminal of the preamplifier 2 connected to the output of the APDI is monitored, and when the out-of-band noise level exceeds a reference value, the bias voltage of the APDI is controlled to keep the APDl constant. The effect is that stable operation can be achieved even at an operating point with a high current multiplication factor.
第１図は本発明に依るＡＰＤバイアス制御回路の一実施
例を示す図である。FIG. 1 is a diagram showing one embodiment of an APD bias control circuit according to the present invention.
図中、１はＡＰＤ、２は前置増幅器、３は増幅器、４は
帯域濾波器、５は検波器、６は比較器である。In the figure, 1 is an APD, 2 is a preamplifier, 3 is an amplifier, 4 is a bandpass filter, 5 is a detector, and 6 is a comparator.
以下図に従って本発明の詳細な説明する。The present invention will be described in detail below with reference to the drawings.
ＡＰＤＩは光信号を受けて電気信号に変換し、変換され
た電気信号は前置増幅器２で増幅され、更に増幅器３で
増幅されて出力される。The APDI receives an optical signal and converts it into an electrical signal, and the converted electrical signal is amplified by a preamplifier 2, further amplified by an amplifier 3, and output.
本発明では前置増幅器２の出力に帯域濾波器４を接続し
て電気信号の中から使用帯域外の周波数成分を抽出する
。In the present invention, a bandpass filter 4 is connected to the output of the preamplifier 2 to extract frequency components outside the used band from the electrical signal.
抽出された使用帯域外の周波数成分は検波器５により直
流電圧に変換される。The extracted frequency components outside the used band are converted into DC voltage by the detector 5.
此の直流電圧Ｖを比較器６に入力して規定電圧値■。と
比較する。Input this DC voltage V to the comparator 6 to obtain the specified voltage value ■. Compare with.
若し直流電圧■が規定電圧値ｖ０より大きい時はフィー
ドバックしてバイアス電圧を下げる。If the DC voltage (2) is larger than the specified voltage value v0, it is fed back and the bias voltage is lowered.
若し直流電圧■が規定電圧値Ｖ０より小さい時はバイア
ス電圧を変えない。If the DC voltage (■) is smaller than the specified voltage value V0, the bias voltage is not changed.
此の場合、ＡＰＤｌがブレークダウン電圧ＶＩの直前時
に発生する雑音量に対応する検波器５の入力直流電圧よ
り小さい値に規定電圧値■。を設定する。In this case, the specified voltage value (■) is set to a value smaller than the input DC voltage of the detector 5, which corresponds to the amount of noise generated just before the breakdown voltage VI. Set.
以上詳細に説明した様に本発明によれば、ＡＰＤの最大
バイアス電圧をフィードバック回路により制御してＡＰ
Ｄ素子の温度特性のバラツキに依る影響を無くすことが
出来ると云う大きい効果がある。As explained in detail above, according to the present invention, the maximum bias voltage of the APD is controlled by the feedback circuit, and the maximum bias voltage of the APD is controlled by the feedback circuit.
This has the great effect of eliminating the influence of variations in the temperature characteristics of the D elements.
第１図は本発明に依るＡＰＤバイアス制御回路の一実施
例を示す図である。
第２図はＡＰＤのバイアス電圧と、電流増倍率ａ及び暗
電流すの関係を説明する図である。
図中、１はＡＰＤ、２は前置増幅器、３は増幅器、４は
帯域濾波器、５は検波器、６は比較器である。FIG. 1 is a diagram showing one embodiment of an APD bias control circuit according to the present invention. FIG. 2 is a diagram illustrating the relationship between the bias voltage of the APD, the current multiplication factor a, and the dark current S. In the figure, 1 is an APD, 2 is a preamplifier, 3 is an amplifier, 4 is a bandpass filter, 5 is a detector, and 6 is a comparator.
Claims (1)
変換回路に於いて、 該アバランシェ・フォトダイオード１出力の電気信号を
増幅する前置増幅器２、 該前置増幅器２出力に接続される必要帯域外の雑音を抽
出する帯域濾波器４、 該帯域濾波器４出力を直流電圧に変換する検波器５、 該検波器５出力の直流電圧と基準電圧を比較する比較器
６、 及び該比較器６出力により前記アバランシェ・フォトダ
イオードのバイアスを制御する手段を有することを特徴
とするＡＰＤバイアス制御回路。[Claims] In an optical-to-electrical conversion circuit using an avalanche photodiode 1, a preamplifier 2 for amplifying an electrical signal output from the avalanche photodiode 1, connected to the output of the preamplifier 2; a bandpass filter 4 for extracting noise outside the required band; a detector 5 for converting the output of the bandpass filter 4 into a DC voltage; a comparator 6 for comparing the DC voltage output from the detector 5 with a reference voltage; An APD bias control circuit comprising means for controlling the bias of the avalanche photodiode using the output of a comparator 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60051874A JPS61212127A (en) | 1985-03-15 | 1985-03-15 | Apd bias control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60051874A JPS61212127A (en) | 1985-03-15 | 1985-03-15 | Apd bias control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61212127A true JPS61212127A (en) | 1986-09-20 |
Family
ID=12899027
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60051874A Pending JPS61212127A (en) | 1985-03-15 | 1985-03-15 | Apd bias control circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61212127A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1065809A1 (en) * | 1999-07-02 | 2001-01-03 | CSEM Centre Suisse d'Electronique et de Microtechnique SA | Adaptive array sensor and electrical circuit therefore |
| JP2015106784A (en) * | 2013-11-29 | 2015-06-08 | 住友電気工業株式会社 | Optical communication module, optical communication device and optical communication method |
-
1985
- 1985-03-15 JP JP60051874A patent/JPS61212127A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1065809A1 (en) * | 1999-07-02 | 2001-01-03 | CSEM Centre Suisse d'Electronique et de Microtechnique SA | Adaptive array sensor and electrical circuit therefore |
| US6469489B1 (en) | 1999-07-02 | 2002-10-22 | Csem Centre Suisse D'electronique Et De Microtechnique Sa | Adaptive array sensor and electrical circuit therefore |
| JP2015106784A (en) * | 2013-11-29 | 2015-06-08 | 住友電気工業株式会社 | Optical communication module, optical communication device and optical communication method |
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