JPH0545891B2 - - Google Patents
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- Publication number
- JPH0545891B2 JPH0545891B2 JP17910787A JP17910787A JPH0545891B2 JP H0545891 B2 JPH0545891 B2 JP H0545891B2 JP 17910787 A JP17910787 A JP 17910787A JP 17910787 A JP17910787 A JP 17910787A JP H0545891 B2 JPH0545891 B2 JP H0545891B2
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- frequency
- signal light
- light
- signal
- 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
- 239000004065 semiconductor Substances 0.000 claims description 45
- 238000001514 detection method Methods 0.000 claims description 12
- 238000000034 method Methods 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000295 emission spectrum Methods 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
Landscapes
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、所定の周波数で発光する半導体レ
ーザに外部信号光を入射し、半導体レーザ内で発
生する両者の差の周波数の電気信号を利用して、
信号光の周波数及び強度を検出するようにした半
導体レーザを用いた信号光検出装置に関する。[Detailed Description of the Invention] [Industrial Application Field] This invention involves inputting external signal light into a semiconductor laser that emits light at a predetermined frequency, and utilizing an electrical signal generated within the semiconductor laser at a frequency that is the difference between the two. do,
The present invention relates to a signal light detection device using a semiconductor laser that detects the frequency and intensity of signal light.
従来、信号光を検出する手段としては、半導体
や光電子増倍管等の光検出器を用いて、光信号の
強度等の情報を電気信号に変換して信号を抽出す
る直接検出方式、あるいは半導体か光電子増倍管
等の光検出器で、信号光と参照光の周波数の異な
る２種類の光を受けて、その差の周波数から信号
光の情報を検出するヘテロダイン方式等が用いら
れていた。
Conventionally, methods for detecting signal light include a direct detection method in which the signal is extracted by converting information such as the intensity of the optical signal into an electrical signal using a photodetector such as a semiconductor or a photomultiplier tube, or a method using a semiconductor A photodetector such as a photomultiplier tube receives two types of light having different frequencies, a signal light and a reference light, and a heterodyne method is used, in which information about the signal light is detected from the difference in frequency.
上記のような従来の信号光検出手段において、
直接検出方式を用いた場合には、信号光の強度情
報の検出しか得られないという問題点がある。ま
た、従来のヘテロダイン検出方式を用いた場合に
は、信号光の強度及び発振周波数の検出が可能で
あるが、参照光用光源と光検出器とが別個に必要
であるという問題点がある。
In the conventional signal light detection means as described above,
When a direct detection method is used, there is a problem in that only intensity information of the signal light can be detected. Furthermore, when the conventional heterodyne detection method is used, it is possible to detect the intensity and oscillation frequency of the signal light, but there is a problem in that a reference light source and a photodetector are separately required.
本発明は、従来の信号光検出方式の上記問題点
を解消するためになされたもので、参照光用光源
と光検出器とを兼ねさせ、別個の参照光用光源を
必要としない簡単な構成で、外部信号光の強度並
びに周波数を容易に検出することができるように
した半導体レーザを用いた信号光検出装置を提供
することを目的とするものである。 The present invention has been made in order to solve the above-mentioned problems of the conventional signal light detection method, and has a simple configuration that serves as a reference light source and a photodetector, eliminating the need for a separate reference light source. It is an object of the present invention to provide a signal light detection device using a semiconductor laser that can easily detect the intensity and frequency of external signal light.
上記問題点を解決するため、本発明は、所定の
印加電流により所定の周波数で発光する半導体レ
ーザと、該半導体レーザを励起するための低域通
過フイルタを有する電源と、前記半導体レーザに
外部から該半導体レーザ光と異なる周波数で発光
している信号光を入射することにより、前記半導
体レーザ内で発生する、外部信号光と半導体レー
ザ光の２つの光の周波数の差の周波数をもつ電気
信号を蓄え得る、前記半導体レーザと可変帯域フ
イルタと負荷とを含む共振器回路とを備え、前記
共振器回路の前記可変帯域フイルタの調整による
共振時に得られる前記差周波数の電気信号から信
号光の周波数を検出すると共に、共振時の差周波
数の電気信号に基づき負荷により得られる出力か
ら信号光の強度を検出するように構成するもので
ある。
In order to solve the above-mentioned problems, the present invention provides a semiconductor laser that emits light at a predetermined frequency using a predetermined applied current, a power supply having a low-pass filter for exciting the semiconductor laser, and an external source for the semiconductor laser. By inputting a signal light emitted at a frequency different from that of the semiconductor laser light, an electric signal having a frequency that is the difference between the frequencies of two lights, the external signal light and the semiconductor laser light, generated within the semiconductor laser is generated. a resonator circuit including the semiconductor laser, a variable band filter, and a load capable of storing data; At the same time, the intensity of the signal light is detected from the output obtained by the load based on the electric signal of the difference frequency at the time of resonance.
このように構成することにより、１個の半導体
レーザで参照光用光源と光検出器とを兼ねさせる
ことができ、発光スペクトルが既知の半導体レー
ザを用いることによつて信号光の強度及び周波数
を、参照光用光源を用いずに容易に検出すること
が可能となる。 With this configuration, one semiconductor laser can serve both as a reference light source and a photodetector, and by using a semiconductor laser with a known emission spectrum, the intensity and frequency of the signal light can be adjusted. , it becomes possible to easily detect the light without using a reference light source.
以下実施例について説明する。図は、本発明に
係る半導体レーザを用いた信号光検出装置の一実
施例を示すブロツク構成図である。図において、
１は発光スペクトルが既知の半導体レーザで、所
定の印加電流によつて所定の周波数の発光が得ら
れるようになつており、その発光部には外部より
信号光を図示しない光学系を介して入射できるよ
うになつている。例えば、（3.75×1014Hz＋2GH）
程度の信号光を検出する場合には、半導体レーザ
としては、1mA程度の印加電流により3.75×1014
Hz（8000Å）の周波数で発光するGaAs系の半導
体レーザが用いられる。そして該半導体レーザ１
には低域通過フイルタ２を介して該半導体レーザ
励起用の電源３が接続されている。なお上記半導
体レーザ励起用の電源３としては通常直流電源
（上記3.75×1014Hzの周波数で発光するGaAs系半
導体レーザを用いる場合は、２〜3Vの直流電源）
が用いられ、また上記低域通過フイルタ２は、前
記半導体レーザに所定の周波数で発光させる電流
を印加できると共に、信号光の入射により半導体
レーザ１内で発生した高周波電気信号の電源３へ
の侵入、並びに電源３側から半導体レーザを含む
接続回路への不要信号の侵入を阻止する特性をも
つものである。例えば、後述の可変帯域フイルタ
の帯域幅を１〜2GHzとした場合には、上記低域
通過フイルタ２の遮断周波数は1KHz程度とする。
４は可変帯域フイルタで負荷抵抗５と直列に接続
され、この直列回路が前記半導体レーザ１及び低
域フイルタ２と電源３の直列回路に、並列に接続
されている。なお、負荷抵抗としては、通常1Ω
程度のものが用いられる。６は外部の可視域等の
信号光光源で、７は該光源６からの信号光で、前
述のとおり、光学系を介して半導体レーザ１に入
射されるようになつている。
Examples will be described below. The figure is a block configuration diagram showing an embodiment of a signal light detection device using a semiconductor laser according to the present invention. In the figure,
Reference numeral 1 designates a semiconductor laser with a known emission spectrum, which is designed to emit light at a predetermined frequency by applying a predetermined current, and into which signal light is incident from the outside via an optical system (not shown). I'm starting to be able to do it. For example, (3.75×10 14 Hz + 2GH)
When detecting a signal light of about 3.75×10 14 with an applied current of about 1 mA,
A GaAs-based semiconductor laser that emits light at a frequency of Hz (8000 Å) is used. and the semiconductor laser 1
A power source 3 for excitation of the semiconductor laser is connected through a low-pass filter 2 to. Note that the power supply 3 for excitation of the semiconductor laser is a normal DC power supply (2 to 3V DC power supply when using the GaAs semiconductor laser that emits light at the frequency of 3.75×10 14 Hz).
The low-pass filter 2 is capable of applying a current to the semiconductor laser to cause it to emit light at a predetermined frequency, and also prevents the high-frequency electrical signal generated within the semiconductor laser 1 from entering the power supply 3 due to the incidence of signal light. , and has the characteristic of preventing unnecessary signals from entering the connection circuit including the semiconductor laser from the power source 3 side. For example, when the bandwidth of the variable band filter described later is set to 1 to 2 GHz, the cutoff frequency of the low-pass filter 2 is set to about 1 KHz.
4 is a variable band filter connected in series with a load resistor 5, and this series circuit is connected in parallel with the series circuit of the semiconductor laser 1, low-pass filter 2, and power supply 3. Note that the load resistance is usually 1Ω.
A certain degree is used. Reference numeral 6 indicates a signal light source in the external visible range, and 7 indicates signal light from the light source 6, which is incident on the semiconductor laser 1 via the optical system, as described above.
次にこのように構成した信号光検出装置におい
て、更に具体化したものにおける未知の信号光の
周波数及び入力強度を検出する動作について説明
する。まず半導体レーザ１に遮断周波数1KHzの
低域通過フイルタ２を通して、2Vの直流電源３
から1mAの電流を供給し、該半導体レーザ１を
3.75×1014Hzの周波数で、0.5mWの出力（変換効
率50％）で連続発光させておく。この状態におい
て半導体レーザ１の発光部が、外部の光源６から
未知の信号光７の照射を受けたとする。そのとき
の信号光７の発光周波数をfsとし、半導体レーザ
１の発光周波数をfp（＝3.75×1014Hz）とした場
合、一般に半導体レーザ１においては、（fs＋fp）、
２（fs＋fp）、…、（fs−fp）、２（fs−fp）、…の周
波
数成分の電流が発生する。 Next, the operation of detecting the frequency and input intensity of unknown signal light in a more specific version of the signal light detection device configured as described above will be described. First, pass the semiconductor laser 1 through a low-pass filter 2 with a cutoff frequency of 1KHz, and then pass it through a 2V DC power supply 3.
A current of 1mA is supplied from the semiconductor laser 1.
Continuously emit light at a frequency of 3.75×10 14 Hz and an output of 0.5 mW (conversion efficiency 50%). Assume that the light emitting section of the semiconductor laser 1 is irradiated with unknown signal light 7 from the external light source 6 in this state. When the emission frequency of the signal light 7 at that time is f s and the emission frequency of the semiconductor laser 1 is f p (=3.75×10 14 Hz), generally in the semiconductor laser 1, (f s + f p ),
Currents with frequency components of 2(f s +f p ), . . . , (f s −f p ), 2(f s −f p ), . . . are generated.
この際、半導体レーザ１、可変帯域フイルタ
（帯域幅１〜2GHz）４及び負荷抵抗（1Ω）５を
含む回路構成部材からなる共振器回路において、
可変帯域フイルタ４の特性を調整して、（fs−fp）
の周波数成分の電流に対して共振器回路を形成す
る。これにより、（fs−fp）の周波数成分が他の周
波数成分よりエネルギー蓄積が大となり、負荷抵
抗５を介して他の周波数成分より信号対雑音比の
大きい（fs−fp）の周波数成分の出力Ｐ（fs−fp）
を得ることができる。 At this time, in a resonator circuit consisting of circuit components including a semiconductor laser 1, a variable band filter (bandwidth 1 to 2 GHz) 4, and a load resistor (1Ω) 5,
By adjusting the characteristics of the variable band filter 4, (f s − f p )
A resonator circuit is formed for a current with a frequency component of . As a result, the frequency component of (f s − f p ) has greater energy storage than other frequency components, and the frequency component of (f s − f p ), which has a higher signal-to-noise ratio than other frequency components, is transferred through the load resistor 5. Frequency component output P (f s − f p )
can be obtained.
そして、半導体レーザ１への信号光７の入力を
Ｐ（fs）、半導体レーザ自身の発光出力をＰ（fp）、
係数をＡとしたとき、一般的に負荷抵抗５からの
出力Ｐ（fs−fp）は、次式(1)で表すことができる。 Then, the input of the signal light 7 to the semiconductor laser 1 is P(f s ), the emission output of the semiconductor laser itself is P(f p ),
When the coefficient is A, the output P (f s −f p ) from the load resistor 5 can generally be expressed by the following equation (1).
Ｐ（fs−fp）＝Ａ・Ｐ（fs）・Ｐ（fp） …(1)
ここで、係数Ａを求めるため、上記のように、
周波数が3.75×1014Hzで、出力が0.5mWの半導体
レーザ１、遮断周波数1KHzの低域通過フイルタ
２、2Vの直流電源３、帯域幅１〜2GHzの可変帯
域フイルタ４、1Ωの負荷抵抗５を用いた信号光
検出装置に、予め既知の信号光（周波数：3.75×
1014Hz＋2GHz、入力：1μW）を入射させて、差
周波数（fs−fp＝2GHz）の出力Ｐ（fs−fp）を求め
たところ、0.1mWが得られた。これにより、係
数Ａを２×105／Ｗに設定した。 P(f s − f p )=A・P(f s )・P(f p )…(1) Here, in order to find the coefficient A, as above,
A semiconductor laser 1 with a frequency of 3.75×10 14 Hz and an output of 0.5 mW, a low-pass filter 2 with a cutoff frequency of 1 KHz, a 2 V DC power supply 3, a variable band filter 4 with a bandwidth of 1 to 2 GHz, a 1 Ω load resistor 5 A known signal light (frequency: 3.75×
10 14 Hz + 2 GHz, input: 1 μW) was incident, and the output P (f s − f p ) at the difference frequency (f s − f p =2 GHz) was determined, and 0.1 mW was obtained. As a result, the coefficient A was set to 2×10 5 /W.
次に、上記のように構成した信号光検出回路
に、上記のように未知の信号光を入射させ、可変
帯域フイルタ４を調整して、（fs−fp）の周波数成
分の電流に対して共振回路を形成させた時点にお
いて、負荷抵抗５を介して出力Ｐ（fs−fp）を測定
したところ、0.12mWの出力が得られた。これを
(1)式に代入することにより、未知の信号光の入力
Ｐ（fs）は1.2μWであることが検出された。また
可変帯域フイルタ４を調整して共振回路を形成さ
せた時点における可変帯域フイルタ４の調整値の
読みから、差周波数（fs−fp）は1.8GHzであるこ
とが測定され、これにより信号光の周波数fsは、
fs＝fp＋1.8GHz＝3.75×1014Hz＋1.8GHzであるこ
とが検出された。 Next, the unknown signal light is input as described above into the signal light detection circuit configured as above, and the variable band filter 4 is adjusted to detect the current of the frequency component of (f s − f p ). At the time when a resonant circuit was formed, the output P (f s −f p ) was measured through the load resistor 5, and an output of 0.12 mW was obtained. this
By substituting into equation (1), it was detected that the input P(f s ) of the unknown signal light was 1.2 μW. Also, from the reading of the adjustment value of the variable band filter 4 at the time when the variable band filter 4 was adjusted to form a resonant circuit, it was determined that the difference frequency (f s − f p ) was 1.8 GHz, which caused the signal The frequency of light f s is
It was detected that f s = f p +1.8 GHz = 3.75×10 14 Hz + 1.8 GHz.
なお上記実施例では、可変帯域フイルタの読み
から信号光の周波数の検出を行うようにしたもの
を示したが、共振器回路に結合させた周波数測定
器により検出するようにしてもよい。 In the above embodiment, the frequency of the signal light is detected from the reading of the variable band filter, but the frequency may be detected by a frequency measuring device coupled to the resonator circuit.
以上のように（fs−fp）の周波数成分に対して
低損失の共振回路を形成するように、可変帯域フ
イルタを調整することにより、この周波数成分の
エネルギーを蓄積することができ、微弱な入射信
号光に対しても高感度の光検出装置として機能さ
せることができる。 As described above, by adjusting the variable band filter so as to form a low-loss resonant circuit for the frequency component (f s − f p ), the energy of this frequency component can be stored, and the energy of this frequency component can be stored. It is possible to function as a highly sensitive photodetection device even for incident signal light.
以上実施例に基づいて説明したように、本発明
によれば、所定の周波数で発光している半導体レ
ーザに外部の信号光を照射することによつて発生
する両者の差の周波数をもつ電気信号に対して、
低損失の共振回路を形成してエネルギーの蓄積を
行い、信号光の強度及び周波数の検出を行うよう
にしたので、入射の調整が煩雑で且つコスト高を
招く別個の参照光用の光源を必要とせず、簡単な
構成で微弱な信号光の強度並びに周波数の検出を
行うことができる。
As described above based on the embodiments, according to the present invention, an electric signal having a frequency that is the difference between the two, which is generated by irradiating an external signal light to a semiconductor laser emitting light at a predetermined frequency, For,
Since a low-loss resonant circuit is formed to store energy and detect the intensity and frequency of the signal light, a separate reference light source is required, which requires complicated input adjustment and increases costs. The intensity and frequency of weak signal light can be detected with a simple configuration.
図は、本発明に係る半導体レーザを用いた信号
光検出装置の一実施例を示すブロツク構成図であ
る。
図において、１は半導体レーザ、２は低域通過
フイルタ、３は電源、４は可変帯域フイルタ、５
は負荷抵抗、６は信号光光源、７は信号光を示
す。
The figure is a block diagram showing an embodiment of a signal light detection device using a semiconductor laser according to the present invention. In the figure, 1 is a semiconductor laser, 2 is a low-pass filter, 3 is a power supply, 4 is a variable band filter, 5
is a load resistance, 6 is a signal light source, and 7 is a signal light.
Claims (1)
る半導体レーザと、該半導体レーザを励起するた
めの低域通過フイルタを有する電源と、前記半導
体レーザに外部から該半導体レーザ光と異なる周
波数で発光している信号光を入射することによ
り、前記半導体レーザ内で発生する、外部信号光
と半導体レーザ光の２つの光の周波数の差の周波
数をもつ電気信号を蓄え得る、前記半導体レーザ
と可変帯域フイルタと負荷とを含む共振器回路と
を備え、前記共振器回路の前記可変帯域フイルタ
の調整による共振時に得られる前記差周波数の電
気信号から信号光の周波数を検出すると共に、共
振時の差周波数の電気信号に基づき負荷により得
られる出力から信号光の強度を検出するように構
成したことを特徴とする半導体レーザを用いた信
号光検出装置。1. A semiconductor laser that emits light at a predetermined frequency with a predetermined applied current; a power source having a low-pass filter for exciting the semiconductor laser; said semiconductor laser and a variable band filter capable of storing an electrical signal having a frequency that is the difference between the frequencies of two lights, an external signal light and a semiconductor laser light, generated in said semiconductor laser by inputting a signal light therein; a resonator circuit including a load, the frequency of the signal light is detected from the electrical signal of the difference frequency obtained at the time of resonance by adjustment of the variable band filter of the resonator circuit, and the electrical signal of the difference frequency at the time of resonance is detected. A signal light detection device using a semiconductor laser, characterized in that the intensity of the signal light is detected from the output obtained by a load based on the signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17910787A JPH01152320A (en) | 1987-07-20 | 1987-07-20 | Signal light detector using semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17910787A JPH01152320A (en) | 1987-07-20 | 1987-07-20 | Signal light detector using semiconductor laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01152320A JPH01152320A (en) | 1989-06-14 |
| JPH0545891B2 true JPH0545891B2 (en) | 1993-07-12 |
Family
ID=16060143
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17910787A Granted JPH01152320A (en) | 1987-07-20 | 1987-07-20 | Signal light detector using semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01152320A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3071524U (en) | 2000-03-06 | 2000-09-14 | 株式会社小林 | Nose pad |
-
1987
- 1987-07-20 JP JP17910787A patent/JPH01152320A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01152320A (en) | 1989-06-14 |
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