JPS6028422B2 - Optical receiving system control method - Google Patents
Optical receiving system control methodInfo
- Publication number
- JPS6028422B2 JPS6028422B2 JP52004927A JP492777A JPS6028422B2 JP S6028422 B2 JPS6028422 B2 JP S6028422B2 JP 52004927 A JP52004927 A JP 52004927A JP 492777 A JP492777 A JP 492777A JP S6028422 B2 JPS6028422 B2 JP S6028422B2
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- gain
- apd
- receiving system
- optical receiving
- 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
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
- H04B10/693—Arrangements for optimizing the preamplifier in the receiver
- H04B10/6931—Automatic gain control of the preamplifier
-
- 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)
- Light Receiving Elements (AREA)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】
(1ー 発明の利用分野
本発明は、APDを受光器とする光通信用光受信増幅器
に関し、特に受信S/Nを常に最大にする最適制御方式
に関する。DETAILED DESCRIPTION OF THE INVENTION (1) Field of Application of the Invention The present invention relates to an optical receiving amplifier for optical communication using an APD as a light receiver, and particularly relates to an optimal control method that always maximizes the reception S/N.
■ 従来技術
AuraそanchePhotoDiode(APD)
を受光器とする光受信系では光電変換S/Nを最大にす
るAPD増倍利得が存在する。■ Conventional technology Aura soanche Photo Diode (APD)
In an optical receiving system using a light receiver as a light receiver, there is an APD multiplication gain that maximizes the photoelectric conversion S/N.
これは光電変換S/Nを規定した時最適増倍利得で光受
信電力を最小にできることを示す。ところで、光受信電
力は光源や伝送路の経時損失変動や製造偏差、また伝送
距離の長短によって大幅に変化する。This shows that when the photoelectric conversion S/N is defined, the optical reception power can be minimized with the optimal multiplication gain. Incidentally, the optical reception power varies significantly depending on changes in loss over time of the light source and transmission path, manufacturing deviations, and the length of the transmission distance.
この大きな光受信電力の変動が存在する場合でも常に受
信系の最適化を確保することが望まれる。特に、アナグ
ロ伝送の場合には高いS/Nが必要であるため、この最
適制御は欠かせない技術である。しかるに、現在、この
最適制御解を与える方式並びに装置の報告はまだなされ
ていない。(3’ 発明の目的
本発明の目的は、APDを受光器とする光受信系に於い
て高いS/Nを得る為の最適制御方式を提供するにある
。It is desirable to always ensure optimization of the receiving system even in the presence of such large fluctuations in optical reception power. In particular, in the case of analog transmission, a high S/N ratio is required, so this optimal control is an indispensable technique. However, at present, there have been no reports on a method or device that provides this optimal control solution. (3' Purpose of the Invention The purpose of the present invention is to provide an optimal control method for obtaining a high S/N in an optical receiving system using an APD as a light receiver.
{4} 発明の総括説明
本発明は上記目的を達成するために、APD及びそれに
続く増幅器の利得を同時に制御するが、この場合増幅器
の関数形を最適状態を実現するためのAPD増倍利得と
光受信電力との間にある一定の関係を利用して決める。{4} General description of the invention In order to achieve the above object, the present invention simultaneously controls the gain of the APD and the subsequent amplifier, but in this case, the functional form of the amplifier is adjusted to the APD multiplication gain and the This is determined using a certain relationship with the optical reception power.
尚、増幅器の利得制御は増幅器の入力電圧、出力電圧の
どちらでもよいが、関数形が異なる。■ 実施例
以下、本発明を実施例を参照して詳細に説明する。Note that the gain control of the amplifier may be performed using either the input voltage or the output voltage of the amplifier, but the functional forms are different. (2) Examples Hereinafter, the present invention will be explained in detail with reference to examples.
APDを受光器とする光受信系のS/Nはで表わされる
。The S/N of an optical receiving system using an APD as a light receiver is expressed as.
ここでMはAPD増倍利得、Rは光電変換系数、P,は
光受信電力、eは電子電荷、xはAPDの余剰雑音因子
、kTは熱ェネルギ、Bは受信帯城、F‘ま増幅器の熱
雑音電力、Reqは等価熱雑音抵抗である。‘1}式よ
りS/Nを最大にする最適増倍利得Moptは次式で与
えられる。MoptニAP,‐刃Px
・・・……■但しA:(ヨ藷特;)汁X ……イ
31
Moptは{2}式からわかる様に光受信電力が大きく
なれば小さくなり、余剰雑音因子の値によりその変化割
合が増減する。Here, M is the APD multiplication gain, R is the photoelectric conversion system, P is the optical reception power, e is the electronic charge, x is the excess noise factor of the APD, kT is the thermal energy, B is the reception band strength, and F' is the amplifier. The thermal noise power of , Req is the equivalent thermal noise resistance. '1} From the equation, the optimum multiplication gain Mopt that maximizes the S/N is given by the following equation. Mopt Ni AP, -Blade Px
......■ However, A: (Yoimo special;) Soup increases or decreases.
この時のS/Nと光受信電力との関係はS/N広P12
十x ………【4Iとなる。第1図は
、増惜利得を最適化した場合のS/Nと光受信電力との
関係を示したもので、S/Nのピーク値は光受信電力の
増加とともに増大し、ピーク点は光受信電力の大きい方
に移動する。これにより、光受信電力が変化しても高い
S/Nを維持する為には増惜利得の最適化が必要である
ことがわかる。第2図に本発明の実施例を示す。The relationship between S/N and optical reception power at this time is S/N Hiro P12
10x......[4I] Figure 1 shows the relationship between S/N and optical reception power when the gain is optimized. The peak value of S/N increases as the optical reception power increases, and the peak point is Move to the side with higher received power. This shows that it is necessary to optimize the spare gain in order to maintain a high S/N even if the optical reception power changes. FIG. 2 shows an embodiment of the present invention.
同図で1は光入力端子、2はAPDを含むフロントエン
ド回路、3は増幅器、4は出力端子、5はAPDバイア
ス電圧制御回路である。この系の動作を略述すると端子
1より入力された光信号はAPDにより光電変換並びに
内部増幅された後増幅器3にて増幅され、端子4に出力
される。光受信電力が変化するとこの端子電圧も変化す
るが、変化の一部を制御回路5にて増幅し、APDのバ
イアス電圧及び増幅器の利得を制御することにより、変
化を抑圧させる。例えば光受信電力が増加した場合、聡
子4の電圧は増加するが、この増加分は、制御回路5を
介し、APD増倍利得及び増幅器利得を減じる様に働く
ので打ち消され、そのため、端子4の電圧の変化は極め
て小さいものとすることができる。さて、第2図の系で
、光受信電力が変化した時の増惜利得の変動は出力電圧
vo,APDバイアス電圧の制御電圧va、増惜利得M
及び増幅器利得Gの制御関数を夫々v。In the figure, 1 is an optical input terminal, 2 is a front end circuit including an APD, 3 is an amplifier, 4 is an output terminal, and 5 is an APD bias voltage control circuit. To briefly explain the operation of this system, an optical signal inputted from a terminal 1 is photoelectrically converted and internally amplified by an APD, then amplified by an amplifier 3, and outputted to a terminal 4. When the optical reception power changes, this terminal voltage also changes, but a part of the change is amplified by the control circuit 5, and the change is suppressed by controlling the bias voltage of the APD and the gain of the amplifier. For example, when the optical reception power increases, the voltage at Satoko 4 increases, but this increase is canceled out through the control circuit 5 to reduce the APD multiplication gain and amplifier gain. The change in voltage can be extremely small. Now, in the system shown in Figure 2, the fluctuation of the gain gain when the optical reception power changes is the output voltage vo, the control voltage va of the APD bias voltage, and the gain gain M
and the control function of the amplifier gain G, respectively, v.
ニV。(P,,G,M),vaニva(v。)}M=M
(va),G=G(v。).・・.・・.・・【5}
で定義すれば
で表わされる。dV. (P,,G,M),vaniva(v.)}M=M
(va), G=G(v.).・・・.・・・. ...[5} If it is defined, it can be expressed as.
これより、aG/avo→dG/dvoと置き換えて整
理すれば増幅器利得の制御関数を求めることができる。
即ち次に、■式で表わされる最適制御の条件を満たす様
に増幅器利得の関数形を決める。From this, the amplifier gain control function can be found by replacing aG/avo→dG/dvo.
That is, next, the functional form of the amplifier gain is determined so as to satisfy the optimum control condition expressed by equation (2).
出力電圧、制御電圧はv。The output voltage and control voltage are v.
=GMP,RReq ・・・・・・・・・
【8’va=Gdvo (Gd:帰還系利得).・・.
・・・・・■
で表わされる。=GMP, RReq ・・・・・・・・・
[8'va=Gdvo (Gd: feedback system gain).・・・.
...Represented by ■.
また、増倍利得を次式で近似する。但し、Vは電源電圧
、VBはAPD降伏電圧、nは定数である。Also, the multiplication gain is approximated by the following equation. However, V is the power supply voltage, VB is the APD breakdown voltage, and n is a constant.
{2){8)【9}式より、(7}式に必要な微分項を
求め、代入し、整理すると増幅器利得の関数形は崇(学
,傷・主X
1 2十x ..,......(11)
V。{2) {8) From the formula [9}, find the differential term necessary for the formula (7), substitute it, and rearrange it to get the functional form of the amplifier gain. .....(11)
V.
‐市G市となるから、これより で与えられる。-Since it will be City G City, from now on is given by
従って、この様に関数形を定義することにより光受信電
力が変化してもS/Nを常に最大にする最適制御を行な
うことが可能となる。第3図は本発明の他の実施例であ
るが、増幅器利得の制御を増幅器入力により行なう方式
でありこの方式の最適制御解も第2図の方式と同様にし
て求められる。Therefore, by defining the functional form in this way, it is possible to perform optimal control that always maximizes the S/N even if the optical reception power changes. FIG. 3 shows another embodiment of the present invention, in which the amplifier gain is controlled by the amplifier input, and the optimum control solution for this method can be found in the same manner as the method shown in FIG.
即ち、この方式の増幅器利得の関数形は但しvは増幅器
入力電圧、Cは定数
で定義すればよい。That is, the functional form of the amplifier gain of this system may be defined by where v is the amplifier input voltage and C is a constant.
通常、増幅器の利得は制御信号に線形で制御され、リー
ド構成上も容易である。Usually, the gain of the amplifier is controlled linearly with the control signal, and the lead configuration is easy.
従って、第2図、第3図の方式を具体化するには関数制
御回路により、制御関数を作りその信号にて増幅器利得
を制御する方が得策である。第4図、第5図に本発明の
他の実施例の一例を示す。第4図は第2図を変形したも
ので関数制御回路51は(12)式より定数部52及び
可変部53とそれらの出力を加算する部分54地算出ヵ
を(−学〉敷る部55より構成できる。Therefore, in order to embody the methods shown in FIGS. 2 and 3, it is better to create a control function using a function control circuit and use the signal to control the amplifier gain. FIG. 4 and FIG. 5 show an example of another embodiment of the present invention. FIG. 4 is a modification of FIG. 2, in which the function control circuit 51 includes a constant section 52, a variable section 53, a section 54 that adds the outputs of the constant section 52, a section 55 that adds up the outputs, and a section 55 that adds the ground calculation (- logic). It can be configured more easily.
また、第5図は第3図を変形したものであるが(13)
式より同様にして関数制御回路61は入力に反比例する
部62と−善美案により変化する部63及びそれらの出
力を加算する部分とにより構成できる。‘6}まとめ
以上、本発明はAPDの増倍利得及び増幅器の利得を同
時にするが、この時増幅器利得の制御関数を増惜利得と
光受信電力との関係(2’式を満たすように決めてやる
ことにより高いS/Nを確保しようとするところに特徴
がある。Also, Figure 5 is a modified version of Figure 3 (13)
According to the formula, the function control circuit 61 can be similarly constructed by a section 62 that is inversely proportional to the input, a section 63 that varies depending on the best and the best, and a section that adds their outputs. '6} Summary As described above, in the present invention, the multiplication gain of the APD and the gain of the amplifier are set simultaneously, but at this time, the control function of the amplifier gain is determined so as to satisfy the relationship between the multiplication gain and the optical reception power (Equation 2'). The feature is that it attempts to secure a high S/N by doing so.
従って、本発明によれば光受信電力が変化してもS/N
が常に最大となる様な最適化がなされるため、ァナグロ
伝送の場合に特に有効な手段となり、安定な画像などの
高品質伝送が可能である。Therefore, according to the present invention, even if the optical reception power changes, the S/N
Since optimization is performed so that the value is always maximized, this method is particularly effective in the case of analog digital transmission, and enables stable high-quality transmission of images and the like.
第1図はAPDを受光器とする光受信系の最適状態に於
ける光受信電力をSノNとの相関を示す図、第2図、第
3図、第4図、第5図は本発明の実施例を示すブロック
接続図である。
多「図
多Z図
多 ・Z 図
多ム図
多メ図Figure 1 is a diagram showing the correlation between optical reception power and S/N in the optimal state of an optical receiving system using an APD as a receiver, and Figures 2, 3, 4, and 5 are 1 is a block connection diagram showing an embodiment of the invention. FIG. Multi-Z drawing multi-Z drawing multi-Z drawing multi-Z drawing multi-Z drawing
Claims (1)
回路出力を入力とする利得可変の増幅器と該増幅器出力
を入力とする固定増幅器及び関数制御回路とから構成さ
れる光受信系において前記固定増幅器出力により前記A
PDの増倍利得を制御し、かつ同時に前記関数制御回路
出力により前記増幅器の利得GをGα=K_1v_0β
+K_2 (但し、v_0:増幅器出力、α,β,K_1,K_
2:定数)なる形で制御し、前記増幅器出力を一定にす
ることを特徴とする光受信系の制御方式。[Scope of Claims] 1. An optical receiving system consisting of a Front End circuit that uses an APD as a light receiver, a variable gain amplifier that uses the output of the circuit as an input, a fixed amplifier that uses the output of the amplifier as an input, and a function control circuit. The fixed amplifier output causes the A
The multiplication gain of the PD is controlled, and at the same time, the gain G of the amplifier is set to Gα=K_1v_0β by the output of the function control circuit.
+K_2 (However, v_0: amplifier output, α, β, K_1, K_
2: A control method for an optical receiving system, characterized in that the output of the amplifier is controlled to be constant.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP52004927A JPS6028422B2 (en) | 1977-01-21 | 1977-01-21 | Optical receiving system control method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP52004927A JPS6028422B2 (en) | 1977-01-21 | 1977-01-21 | Optical receiving system control method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5390802A JPS5390802A (en) | 1978-08-10 |
JPS6028422B2 true JPS6028422B2 (en) | 1985-07-04 |
Family
ID=11597222
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP52004927A Expired JPS6028422B2 (en) | 1977-01-21 | 1977-01-21 | Optical receiving system control method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6028422B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5911215B2 (en) * | 1980-06-25 | 1984-03-14 | 富士通株式会社 | optical receiver circuit |
JPS5757049A (en) * | 1980-09-22 | 1982-04-06 | Fujitsu Ltd | Light agc system |
-
1977
- 1977-01-21 JP JP52004927A patent/JPS6028422B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS5390802A (en) | 1978-08-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3418654B2 (en) | Preamplifier | |
JPH10200342A (en) | Bias voltage supply circuit | |
JP2006261866A (en) | Preamplifier | |
JP2003168933A (en) | Photoreceiving circuit | |
JPS6028422B2 (en) | Optical receiving system control method | |
JP4083551B2 (en) | Preamplifier | |
JP3415986B2 (en) | Optical receiver amplifier | |
JP4613495B2 (en) | Preamplifier | |
JPS6057726B2 (en) | Gain control method for optical signal receiver | |
JP2003258580A (en) | Optical reception circuit | |
JP2842404B2 (en) | Avalanche photodiode bias circuit | |
JPS6079839A (en) | Optical reception circuit | |
JPH04183124A (en) | Apd light receiving circuit | |
JPS60111540A (en) | Temperature compensating circuit of apd | |
JP2606163B2 (en) | Automatic gain circuit of optical receiver | |
JPH02278906A (en) | Optical reception circuit | |
JP2536412B2 (en) | Optical AGC circuit | |
JPH03286605A (en) | Optical receiver circuit | |
JP3039875B2 (en) | Optical receiver | |
JPH0644196Y2 (en) | Optical receiver | |
JPH0575355A (en) | Bias circuit for avalanche photodiode | |
JPS62185419A (en) | Optical reception circuit | |
JPS596020Y2 (en) | Photoelectric conversion circuit | |
JPS5925533B2 (en) | Optical communication receiver | |
SU1164863A1 (en) | Low-frequency amplifier |