JPH0235831A - Light receiving/amplifying circuit - Google Patents
Light receiving/amplifying circuitInfo
- Publication number
- JPH0235831A JPH0235831A JP63184498A JP18449888A JPH0235831A JP H0235831 A JPH0235831 A JP H0235831A JP 63184498 A JP63184498 A JP 63184498A JP 18449888 A JP18449888 A JP 18449888A JP H0235831 A JPH0235831 A JP H0235831A
- Authority
- JP
- Japan
- Prior art keywords
- output
- signal
- variable gain
- gain amplifier
- photoelectric conversion
- 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
- 230000003287 optical effect Effects 0.000 claims description 38
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 238000001514 detection method Methods 0.000 claims description 15
- 239000000284 extract Substances 0.000 claims description 3
- 230000003321 amplification Effects 0.000 claims description 2
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 2
- 101150098161 APD1 gene Proteins 0.000 abstract 1
- 238000001228 spectrum Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Amplifiers (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は光伝送系において光信号を電気信号に変換する
光電変換素子を受光素子として用いる光受信増幅回路に
関し、特にメイ／のディジタル信号に低周波成分の副信
号を光の強度変ｖ４（ＰＡＭ）をすることにより転送す
る副信号重畳方式における光受信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 receiving and amplifying circuit that uses a photoelectric conversion element as a light receiving element for converting an optical signal into an electrical signal in an optical transmission system. The present invention relates to an optical receiving circuit in a sub-signal superimposition method in which a sub-signal having a low frequency component is transferred by changing the intensity of light v4 (PAM).
従来、この種の回路は、光電変換素子としてアバランシ
ェフォトダイオード（以下、ＡＰＤ）を用い、このＡＰ
Ｄの出力を可変利得調整する可変利得増幅器と、その利
得を制御する自動利得制御回路と、ＡＰＤを制御するた
めのＤ Ｃ／Ｄ Ｃコンバータを備え、光入力レベルが
小さい場合にはＡＰＤの増倍率Ｍを・変化させ、光入力
レベルの高い場合は可変利得増幅器の利得を変化させる
ことにより、光出力電力を一定にしようとするものであ
る。ここで、光入力レベルが小さい場合にはＡＰＤの増
倍率Ｍが大きくなシ、この時、ＡＰＤが発生する量子雑
音も大きくなシ、第３図に示すようなスペクトラムとな
る。Conventionally, this type of circuit uses an avalanche photodiode (hereinafter referred to as APD) as a photoelectric conversion element.
It is equipped with a variable gain amplifier that adjusts the gain of the D output, an automatic gain control circuit that controls the gain, and a DC/DC converter that controls the APD. The objective is to keep the optical output power constant by changing the magnification M and, when the optical input level is high, by changing the gain of the variable gain amplifier. Here, when the optical input level is small, the multiplication factor M of the APD is large, and at this time, the quantum noise generated by the APD is also large, resulting in a spectrum as shown in FIG.
ただし、第３図においては、メインデータ（ビットレイ
） ：ｆ（１）に低周波の副信号を振幅変調していして
いる九め、低周波帯域にその成分が存在する。しかして
、この周波数成分を低域ろ波器にて抽出すれば、副信号
の有無を副信号検出回路で検出することが可能である。However, in FIG. 3, main data (bit ray):f(1) is amplitude-modulated with a low-frequency sub-signal, and its component exists in the low-frequency band. If this frequency component is extracted using a low-pass filter, it is possible to detect the presence or absence of a sub-signal using a sub-signal detection circuit.
このとき、光入力信号が断となった場合、その電気出力
は第４図に示すようなスペクトラムとなり、ＡＰＤの増
倍率Ｍが最小受光レベル時に対し１０倍以上大きくなる
ことＫよυ、ＡＰＤから発する量子雑音も大きくな９、
前記低減ろ波器の出力に現われる雑音は、通常時の副信
号のレベルとの差が少なくなる。At this time, if the optical input signal is cut off, the electrical output will have a spectrum as shown in Figure 4, and the multiplication factor M of the APD will be more than 10 times larger than that at the minimum light reception level. The quantum noise emitted is also large9.
The difference between the noise appearing in the output of the filter attenuation and the level of the sub-signal during normal operation is reduced.
このように、上述した従来の光受信回路においては、光
入力断時ＡＰＤＯ増倍率Ｍが大きくなるため、ＡＰＤか
らの量子雑音が増倍率Ｍにほぼ比例して増加する。この
ため、雑音レベルが通常の副信号レベルとほとんど差が
なくなシ、副信号検出回路での検出が困難となってくる
。そのため、温度変動により雑音レベル、副信号レベル
が変動した、９、ＡＰＤのばらつきによりその雑音レベ
ルが変動したシするため、副信号検出回路に温度補償回
路をもうけたシ、あるいはＡＰＤのばらつきを補償する
ための調整回路等が必要となシ、その検出はきわめて複
雑な回路になるという問題があった。In this way, in the conventional optical receiving circuit described above, the APDO multiplication factor M increases when the optical input is interrupted, so the quantum noise from the APD increases almost in proportion to the multiplication factor M. For this reason, the noise level has almost no difference from the normal sub-signal level, making detection by the sub-signal detection circuit difficult. Therefore, the noise level and sub-signal level fluctuate due to temperature fluctuations, and the noise level fluctuates due to APD variations. Therefore, a temperature compensation circuit is provided in the sub-signal detection circuit, or the APD variations are compensated for. There is a problem in that an adjustment circuit or the like is required for the detection, and the detection requires an extremely complicated circuit.
このような問題点を解決するため、本発明の光受信増幅
回路は、光信号を電気信号に変換しかつバイアス電圧の
制御により増倍率が変わる光電変換素子と、該光電変換
素子の出力を自動的に可変利得調整する可変利得増幅器
と、該可変利得増幅器の出力を検出しておる基準電圧と
比較し、その可変利得増幅器の利得を制御する自動利得
制御回路と、前記光電変換素子を制御する高圧の制御回
路を含み、光入力断時に前記可変利得増幅器の出力より
抽出するクロック断検出回路の制御により前記高圧制御
回路から前記光電変換素子に与える電圧を光入力断直前
の制御電圧になるように前記自動利得制御回路と高圧制
御回路の間にアナログ記憶器を備え、前記光電変換素子
の増倍度を一定に制御するようにしたものである。In order to solve these problems, the optical receiver amplification circuit of the present invention includes a photoelectric conversion element that converts an optical signal into an electrical signal and whose multiplication factor changes by controlling a bias voltage, and a photoelectric conversion element that automatically converts the output of the photoelectric conversion element. a variable gain amplifier that adjusts the gain of the variable gain amplifier, an automatic gain control circuit that compares the output of the variable gain amplifier with a detected reference voltage and controls the gain of the variable gain amplifier, and controls the photoelectric conversion element. The voltage applied from the high voltage control circuit to the photoelectric conversion element is controlled to be the control voltage immediately before the optical input is interrupted by controlling a clock interruption detection circuit that includes a high voltage control circuit and extracts from the output of the variable gain amplifier when the optical input is interrupted. An analog memory is provided between the automatic gain control circuit and the high voltage control circuit, and the multiplication factor of the photoelectric conversion element is controlled to be constant.
したがって、本発明においては、光入力断の時でも副信
号とＡＰＤなどの光電変換素子から発生する雑音とのレ
ベル差を十分にとることが可能になる。Therefore, in the present invention, even when optical input is cut off, it is possible to maintain a sufficient level difference between the sub signal and the noise generated from a photoelectric conversion element such as an APD.
以下、本発明を図面に示す実施例に基づいて詳細に説明
する。Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
第１図は本発明による光受信増幅回路の一実施例を示す
プｐツク図である。同図において、１は光入力信号ＩＮ
を受光する受光素子としてのＡＰＤ１２はそのＡＰＤｌ
の出力の電気信号を増幅する前置増幅器、３は外部制御
回路にて利得を自動的に可変する可変利得増幅器、４は
この可変利得増幅器３の出力のピーク値を検出するピー
ク値検出器、５はこのピーク値検出器４のピーク信号検
出出力と基準電圧とを比較しその差電圧を増幅してその
出力により前記可変利得増幅器３の利得を制御する自動
利得制御回路であり、これは直流増幅器からなる。６は
この利得制御回路５の出力を保持するアナログ記憶器で
あシ、この記憶器６は、例えば電界効果トランジスタ（
ＦＥＴ）とコンデンサとの組合わせＫよる回路から構成
されている。また、ＴはＡＰＤＩに高圧のバイアス電圧
を加えてその増倍率Ｍを制御する高圧制御回路としての
Ｄ Ｃ／Ｄ Ｃコンバータでアシ、自動利得制御回路５
の出力をアナログ記憶器６を介してＤＣ／ＤＣコンバー
タＴに入力することにより、このコンバータＴによりＡ
ＰＤ１の逆バイアス電圧として必要な１００Ｖ程度の電
圧へ変換してＡＰＤｌの増倍率Ｍを変化させ電気出力信
号ＯＵＴが一定になるように制御されるものとなってい
る。そして、光入力信号ＩＮが断となった時、可変利得
増幅器３の出力により抽出するクロック断検出回路１０
の制御により、ＤＣ／ＤＣコンバータＴからＡＰＤＩに
与える電圧がその光入力断直前の制御電圧になるように
なされている。FIG. 1 is a diagram showing an embodiment of an optical receiving and amplifying circuit according to the present invention. In the same figure, 1 is the optical input signal IN
The APD 12 as a light receiving element that receives the APDl
3 is a variable gain amplifier whose gain is automatically varied by an external control circuit; 4 is a peak value detector that detects the peak value of the output of the variable gain amplifier 3; Reference numeral 5 denotes an automatic gain control circuit that compares the peak signal detection output of the peak value detector 4 with a reference voltage, amplifies the difference voltage, and controls the gain of the variable gain amplifier 3 using the output. Consists of an amplifier. Reference numeral 6 denotes an analog memory that holds the output of this gain control circuit 5, and this memory 6 is, for example, a field effect transistor (
The circuit consists of a combination K of a FET) and a capacitor. In addition, T is a DC/DC converter serving as a high voltage control circuit that applies a high bias voltage to APDI and controls its multiplication factor M, and an automatic gain control circuit 5.
By inputting the output of A to the DC/DC converter T via the analog storage 6, this converter T
The voltage is converted into a voltage of about 100V required as the reverse bias voltage of PD1, and the multiplication factor M of APDl is changed to control the electric output signal OUT to be constant. Then, when the optical input signal IN is disconnected, a clock disconnection detection circuit 10 extracts the output from the variable gain amplifier 3.
Through this control, the voltage applied from the DC/DC converter T to the APDI becomes the control voltage immediately before the optical input is cut off.
さらに、可変利得増幅器３の出力のうち低周波の副信号
を低域ろ波器８を通して副信号検出回路９にて検出する
ものとなっている。なお、第１図中、１１は光入力端子
、１２は電気出力端子である。Furthermore, a low-frequency sub-signal out of the output of the variable gain amplifier 3 is passed through a low-pass filter 8 and detected by a sub-signal detection circuit 9. In FIG. 1, 11 is an optical input terminal, and 12 is an electrical output terminal.
上記実施例構成の光受信増幅回路において、光入力信号
ＩＮが供給される通常時は、利得制御回路５の出力に基
づき可変利得増幅器３の利得を制御することにより、従
来と同様に光出力電力を一定に保つように動作を行なう
。一方、光入力信号ＩＮが断となった時、電力出力信号
ＯＵＴには、ＡＰＤｌ 、前置増幅器２．可変利得増幅
器３か醪生ずる雑音のみが出力する。この時、メインデ
ータのクロックを検出しているクロック断検出回路１０
の出力は、アナログ記憶器６に与えることにより、Ｄ
Ｃ７０Ｃコンバータ１の出力には光入力が断となる直前
の電圧がＡＰＤｌへ与えるよう制御し、ＡＰＤｌの増倍
率Ｍをあらかじめ定められた増倍率の範囲以上になら々
いよう制御する。このため、光入力信号断のとき、電気
出力信号ＯＵＴの雑音レベルは、第２図に示すように最
小受光レベル時の雑音レベルに対し数ｄＢＬかアップせ
ず、低域ろ波器８を通して得られる副信号は、副信号検
出回路９にて容易にその有無を識別することが可能とな
る。In the optical receiving amplifier circuit having the configuration of the above embodiment, when the optical input signal IN is normally supplied, the gain of the variable gain amplifier 3 is controlled based on the output of the gain control circuit 5, so that the optical output power can be maintained as in the conventional case. The operation is performed so as to keep the value constant. On the other hand, when the optical input signal IN is cut off, the power output signal OUT includes APDl, preamplifier 2. Only the noise generated by the variable gain amplifier 3 is output. At this time, the clock disconnection detection circuit 10 detecting the main data clock
The output of D is given to the analog storage 6.
The output of the C70C converter 1 is controlled so that the voltage immediately before the optical input is cut off is applied to the APDl, and the multiplication factor M of the APDl is controlled so as to stay within a predetermined range of multiplication factors. Therefore, when the optical input signal is cut off, the noise level of the electrical output signal OUT is only a few dBL higher than the noise level at the minimum received light level, as shown in FIG. The sub-signal detecting circuit 9 can easily identify the presence or absence of the sub-signal.
なお、光電変換素子としてはＡＰＤに限らず、それと同
等の機能をもつ素子を用いることもできる。Note that the photoelectric conversion element is not limited to the APD, and an element having the same function as the APD can also be used.
以上説明したように、本発明によれば、光入力断の時で
も副信号とＡＰＤなどの光電変換素子から発生する雑音
とのレベル差を十分とることができるため、副信号検出
回路のみが他のユニットで構成される場合でも光電変換
素子のばらつきによる雑音レベルの違いによる副信号検
出回路のスレッショルドの調整は不要となシ、ユニット
の組み合わせに関係なく完全な動作をすることができる
。As explained above, according to the present invention, even when optical input is interrupted, it is possible to maintain a sufficient level difference between the sub signal and the noise generated from a photoelectric conversion element such as an APD. Even when the system is configured with units, there is no need to adjust the threshold of the sub-signal detection circuit due to differences in noise levels due to variations in photoelectric conversion elements, and perfect operation can be achieved regardless of the combination of units.
これによ如、調整工数の簡素化を計り、捷た、部品点数
の少ない総合的に経済的なシステムを構成することが可
能となる。This makes it possible to simplify the adjustment man-hours and construct an overall economical system with a reduced number of parts.
ま九、光入力信号が復旧し断となる直前の光入力信号と
なった場合、ＡＰＤなどの光電変換素子の増倍率Ｍは光
入力信号が断となる直前の増倍率を保持していることに
より、前置増幅器及び可変利得増幅器には光入力断直前
の電気信号レベルが入力され、短時間に正常な電気信号
が出力可能となる等の効果がある。(9) When the optical input signal is restored and becomes the optical input signal just before the optical input signal was disconnected, the multiplication factor M of the photoelectric conversion element such as APD must maintain the multiplication factor just before the optical input signal was disconnected. As a result, the electrical signal level immediately before the optical input is cut off is input to the preamplifier and the variable gain amplifier, and a normal electrical signal can be outputted in a short time.
第１図は本発明の一実施例を示すブロック図、第２図は
上記実施例において得られる光入力断時の電気出力のス
ペクトラムを示す図、第３図は通常時における電気出力
のスペクトラムを示す図、第４図は従来回路におけ３光
入力断時の電気出力のスペクトラムを示す図である。
１・・・・受光素子（ＡＰＤ）、２・・・・前置増幅器
、３・・・自可変利得増幅器、４＃・・・ピーク値検出
器、５・・・・自動利得制御回路、６・・・・アナログ
記憶器、７拳・・−ＤＣ／ＤＣコンバータ、８・・・・
低域ろ波器、９会・・・副信号検出回路、１０・・・・
クロック断検出回路。FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the spectrum of the electrical output when the optical input is cut off, obtained in the above embodiment, and FIG. 3 is the spectrum of the electrical output during normal times. FIG. 4 is a diagram showing the spectrum of electrical output when three optical inputs are cut off in a conventional circuit. 1... Light receiving element (APD), 2... Preamplifier, 3... Automatically variable gain amplifier, 4#... Peak value detector, 5... Automatic gain control circuit, 6 ...Analog memory, 7 fists...-DC/DC converter, 8...
Low-pass filter, 9...Sub signal detection circuit, 10...
Clock disconnection detection circuit.
Claims (1)
り増倍率が変わる光電変換素子と、該光電変換素子の出
力を自動的に可変利得調整する可変利得増幅器と、該可
変利得増幅器の出力を検出してある基準電圧と比較し、
その可変利得増幅器の利得を制御する自動利得制御回路
と、前記光電変換素子を制御する高圧の制御回路を含み
、光入力断時に前記可変利得増幅器の出力より抽出する
クロック断検出回路の制御により前記高圧制御回路から
前記光電変換素子に与える電圧を光入力断直前の制御電
圧になるように前記自動利得制御回路と高圧制御回路の
間にアナログ記憶器を備え、前記光電変換素子の増倍度
を一定に制御するようにしたことを特徴とする光受信増
幅回路。A photoelectric conversion element that converts an optical signal into an electrical signal and whose multiplication factor changes by controlling a bias voltage, a variable gain amplifier that automatically adjusts the gain of the output of the photoelectric conversion element, and detects the output of the variable gain amplifier. Compare it with the reference voltage that has been set,
It includes an automatic gain control circuit that controls the gain of the variable gain amplifier, and a high-voltage control circuit that controls the photoelectric conversion element, and controls a clock interruption detection circuit that extracts the output from the variable gain amplifier when the optical input is interrupted. An analog memory device is provided between the automatic gain control circuit and the high voltage control circuit so that the voltage applied to the photoelectric conversion element from the high voltage control circuit becomes the control voltage immediately before the optical input is cut off, and the multiplication factor of the photoelectric conversion element is adjusted. An optical receiving amplification circuit characterized by constant control.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63184498A JPH0235831A (en) | 1988-07-26 | 1988-07-26 | Light receiving/amplifying circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63184498A JPH0235831A (en) | 1988-07-26 | 1988-07-26 | Light receiving/amplifying circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0235831A true JPH0235831A (en) | 1990-02-06 |
Family
ID=16154240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63184498A Pending JPH0235831A (en) | 1988-07-26 | 1988-07-26 | Light receiving/amplifying circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0235831A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04131057U (en) * | 1991-05-28 | 1992-12-01 | 日本電気株式会社 | optical receiver |
| JPH05122153A (en) * | 1991-10-25 | 1993-05-18 | Nec Corp | Photodetecting circuit |
| US7420990B2 (en) | 2004-01-28 | 2008-09-02 | Rambus Inc. | Adaptive-allocation of I/O bandwidth using a configurable interconnect topology |
| US7535958B2 (en) | 2004-06-14 | 2009-05-19 | Rambus, Inc. | Hybrid wired and wireless chip-to-chip communications |
| CN103091568A (en) * | 2013-01-21 | 2013-05-08 | 华中科技大学 | Avalanche photodiode excessive noise factor measuring system |
| CN107137074A (en) * | 2017-03-31 | 2017-09-08 | 浙江大学 | A kind of instrument amplifier for bioelectrical signals |
-
1988
- 1988-07-26 JP JP63184498A patent/JPH0235831A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04131057U (en) * | 1991-05-28 | 1992-12-01 | 日本電気株式会社 | optical receiver |
| JPH05122153A (en) * | 1991-10-25 | 1993-05-18 | Nec Corp | Photodetecting circuit |
| US7420990B2 (en) | 2004-01-28 | 2008-09-02 | Rambus Inc. | Adaptive-allocation of I/O bandwidth using a configurable interconnect topology |
| US7535958B2 (en) | 2004-06-14 | 2009-05-19 | Rambus, Inc. | Hybrid wired and wireless chip-to-chip communications |
| CN103091568A (en) * | 2013-01-21 | 2013-05-08 | 华中科技大学 | Avalanche photodiode excessive noise factor measuring system |
| CN107137074A (en) * | 2017-03-31 | 2017-09-08 | 浙江大学 | A kind of instrument amplifier for bioelectrical signals |
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