JPH0590692A - Semiconductor laser device - Google Patents

Semiconductor laser device

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Publication number
JPH0590692A
JPH0590692A JP27842391A JP27842391A JPH0590692A JP H0590692 A JPH0590692 A JP H0590692A JP 27842391 A JP27842391 A JP 27842391A JP 27842391 A JP27842391 A JP 27842391A JP H0590692 A JPH0590692 A JP H0590692A
Authority
JP
Japan
Prior art keywords
frequency
semiconductor laser
output
section
laser output
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
Application number
JP27842391A
Other languages
Japanese (ja)
Other versions
JP2864814B2 (en
Inventor
Naoki Ishihara
直樹 石原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP3278423A priority Critical patent/JP2864814B2/en
Publication of JPH0590692A publication Critical patent/JPH0590692A/en
Application granted granted Critical
Publication of JP2864814B2 publication Critical patent/JP2864814B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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  • Semiconductor Lasers (AREA)

Abstract

PURPOSE:To obtain a semiconductor laser device capable of obtaining a stable frequency output not modulated in the output frequency of a laser. CONSTITUTION:Two of semiconductor laser output sections 1, 2 are installed, and a frequency fluctuation detecting section 20 detecting the fluctuation of the output frequency of one semiconductor laser output section and a frequency correcting section 21 correcting the fluctuation of the output frequency of one semiconductor laser output section on the basis of a frequency fluctuation signal detected by the frequency fluctuation detecting section 20 are juxtaposed to one semiconductor laser output section. The other semiconductor laser output section is jointly provided with a differential frequency detecting section 30 detecting the difference of the output frequency of the other semiconductor laser output section and one semiconductor laser output section and a frequency stabilizing controlling section 31 stably controlling an output from the other semiconductor laser output section to specified output frequency including differential zero on the basis of an output from the differential frequency-dividing detecting section 30.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、半導体レーザ装置に関
し、特にレーザ周波数の安定化を考慮した半導体レーザ
装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device in which stabilization of a laser frequency is taken into consideration.

【0002】[0002]

【従来の技術】従来の半導体レーザ装置は、発光スペク
トル周波数が回路電流及び温度により大きく変動すると
いう欠点をもっている。このため、従来の半導体レーザ
装置にあっては、周辺温度の安定化及び回路電流を安定
化する事により、発光スペクトル周波数の安定化を図る
という手法が採られてていた。
2. Description of the Related Art A conventional semiconductor laser device has a drawback that the emission spectrum frequency greatly varies depending on the circuit current and temperature. Therefore, in the conventional semiconductor laser device, a method has been adopted in which the emission spectrum frequency is stabilized by stabilizing the ambient temperature and the circuit current.

【0003】[0003]

【発明が解決しようとする課題】上述した従来の技術で
は、前述した如く半導体レーザ装置の発光スペクトルの
経時変化に伴うドリフトを除去する事は本質的に困難で
あり、従って、長期にわたり発光スペクトル周波数の安
定したレーザ光を得る事は困難であるという欠点があっ
た。
In the above-mentioned conventional technique, it is essentially difficult to eliminate the drift due to the change with time of the emission spectrum of the semiconductor laser device as described above. Therefore, the emission spectrum frequency is long-term. However, it is difficult to obtain a stable laser beam.

【0004】[0004]

【発明の目的】本発明は、かかる従来例の有する不都合
を改善し、とくに、レーザの出力周波数に変調のかから
ない安定した周波数出力を得ることのできる半導体レー
ザ装置を提供することを、その目的とする。
SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor laser device capable of improving the disadvantages of the conventional example and, in particular, providing a stable frequency output without modulation of the laser output frequency. To do.

【0005】[0005]

【課題を解決するための手段】本発明では、半導体レー
ザ出力部が二体設けられている。この内、一方の半導体
レーザ出力部には、当該一方の半導体レーザ出力部の出
力周波数の変動を検出する周波数変動検出部と,この周
波数変動検出部で検出された周波数変動信号に基づいて
一方の半導体レーザ出力部の出力周波数の変動を補正す
る周波数補正部とが併設されている。また、他方の半導
体レーザ出力部には、当該他方の半導体レーザ出力部と
一方の半導体レーザ出力部の出力周波数の差を検出する
差分周波数検出部と,この差分周波数検出部の出力に基
づいて他方の半導体レーザ出力部の出力を差分ゼロを含
む所定の出力周波数に安定制御する周波数安定制御部と
併設する、という構成を採っている。これによって前述
した目的を達成しようとするものである。
In the present invention, two semiconductor laser output sections are provided. Among these, one semiconductor laser output unit has a frequency fluctuation detection unit that detects fluctuations in the output frequency of the one semiconductor laser output unit, and one of the semiconductor laser output units is based on the frequency fluctuation signal detected by the frequency fluctuation detection unit. A frequency correction unit that corrects fluctuations in the output frequency of the semiconductor laser output unit is also provided. Further, the other semiconductor laser output section has a difference frequency detection section for detecting a difference in output frequency between the other semiconductor laser output section and the one semiconductor laser output section, and the other based on the output of the difference frequency detection section. Of the semiconductor laser output section is provided together with a frequency stabilization control section that stably controls the output of the semiconductor laser output section to a predetermined output frequency including zero difference. This aims to achieve the above-mentioned object.

【0006】[0006]

【発明の実施例】以下、本発明の一実施例を図1に基づ
いて説明する。この図1に示す実施例は、半導体レーザ
出力部を二体備えている。一方の半導体レーザ出力部1
には、当該一方の半導体レーザ出力部1の出力周波数の
変動を検出する周波数変動検出部20と,この周波数変
動検出部20で検出される周波数変動信号に基づいて一
方の半導体レーザ出力部1の出力周波数の変動を補正す
る周波数補正部21とが併設されている。また、他方の
半導体レーザ出力部2には、当該他方の半導体レーザ出
力部2と一方の半導体レーザ出力部1の出力周波数の差
を検出する差分周波数検出部30と,この差分周波数検
出部30の出力に基づいて他方の半導体レーザ出力部2
の出力を差分ゼロを含む所定の出力周波数に安定制御す
る周波数安定制御部31とが併設されている。そして、
周波数安定制御部31と差分周波数検出部30との間に
は、位相検波器15を装備すると共に、この位相検波器
15の入力段に電圧制御発振器14が装備されている。
DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The embodiment shown in FIG. 1 includes two semiconductor laser output sections. One semiconductor laser output unit 1
Includes a frequency fluctuation detection unit 20 that detects fluctuations in the output frequency of the one semiconductor laser output unit 1 and one semiconductor laser output unit 1 based on the frequency fluctuation signal detected by the frequency fluctuation detection unit 20. A frequency correction unit 21 that corrects fluctuations in the output frequency is also provided. Further, the other semiconductor laser output unit 2 includes a differential frequency detection unit 30 that detects a difference between the output frequencies of the other semiconductor laser output unit 2 and the one semiconductor laser output unit 1, and the difference frequency detection unit 30. The other semiconductor laser output unit 2 based on the output
A frequency stability control unit 31 for stably controlling the output of 1 to a predetermined output frequency including zero difference is also provided. And
A phase detector 15 is provided between the frequency stability control unit 31 and the difference frequency detection unit 30, and a voltage controlled oscillator 14 is provided at the input stage of the phase detector 15.

【0007】これを更に詳述すると、本実施例では、2
つの1.5 μm半導体レーザ1,2と両レーザを温度制御
する温度制御器18と、1.5 〔μm〕の光を吸収するア
セチレンセル6と、このアセチレンセル6を温度制御す
る温度制御器8と、アセチレンセル6をシールドする磁
気シールドケース7と、アセチレンセル6通過後の光を
検出する光検出器9と、変調信号を発生させる発振器1
0と、光検出器9の出力を位相検波する位相検波器11
と、位相検波器出力を1.5 μm半導体レーザへ帰還させ
る周波数制御器12と、2つのレーザ光を合成あるいは
分岐する3個あるいはそれ以上のハーフミラー3,4,
5と、光信号を電気信号に変換する変換器13と、オフ
セット周波数を発生させる電圧制御発振器14と、交換
器出力と前述の発振器出力の位相を比較する位相検波器
15と、この位相検波器15の出力の高周波成分を除去
する低域通過フィルタ16と、この低域通過フィルタ出
力を1.5 μm半導体レーザへ帰還する周波数制御器17
とを有している。
This will be described in more detail. In this embodiment, 2
Two 1.5 μm semiconductor lasers 1 and 2, a temperature controller 18 for controlling the temperature of both lasers, an acetylene cell 6 for absorbing 1.5 [μm] of light, a temperature controller 8 for controlling the temperature of the acetylene cell 6, and an acetylene A magnetic shield case 7 that shields the cell 6, a photodetector 9 that detects light after passing through the acetylene cell 6, and an oscillator 1 that generates a modulation signal.
0 and a phase detector 11 for phase-detecting the output of the photodetector 9
And a frequency controller 12 for returning the output of the phase detector to the semiconductor laser of 1.5 μm, and three or more half mirrors 3, 4 for synthesizing or splitting two laser beams.
5, a converter 13 for converting an optical signal into an electric signal, a voltage controlled oscillator 14 for generating an offset frequency, a phase detector 15 for comparing the phases of the exchange output and the above-mentioned oscillator output, and this phase detector. A low-pass filter 16 for removing high-frequency components of the output of 15, and a frequency controller 17 for feeding back the output of the low-pass filter to a 1.5 μm semiconductor laser.
And have.

【0008】次に、上記実施例の動作について説明す
る。1.5 μm半導体レーザ1及び1.5μm半導体レーザ
2は温度制御器(1)18により温度制御されており、
短時間における発光スペクトルをまず安定化させる。
Next, the operation of the above embodiment will be described. The temperature of the 1.5 μm semiconductor laser 1 and the 1.5 μm semiconductor laser 2 is controlled by the temperature controller (1) 18,
First, the emission spectrum in a short time is stabilized.

【0009】半導体レーザ1の出力はハーフミラー4に
て二分割され、片方はハーフミラー5に供給される一
方、他方はアセチレンセル6に供給される。アセチレン
セル6は1.5 μm帯特有のスペクトルに対して急峻な吸
収特性を有しており、温度制御器8及び磁気シールドケ
ース7により温度・磁気を一定にすると、吸収の中心周
波数は極めて安定な周波数となる。半導体レーザ(1)
1に発振器10よりの信号で予め位相変調を加えた状態
でアセチレンセル6に入射する光の周波数がアセチレン
原子固有の周波数を基準にして正又は負にずれると、光
検出器9の出力の交流信号は位相が180 °ずれる。これ
を位相検波器11にて位相誤差信号を得た後、増幅器等
より構成される周波数制御器12を通じて半導体レーザ
1の電流に負帰還をかけると、半導体レーザ1の光周波
数をアセチレン原子の吸収線の中心に制御する事ができ
る。このようにして、半導体レーザ1の周波数がまず安
定化される。
The output of the semiconductor laser 1 is divided into two by a half mirror 4, one of which is supplied to a half mirror 5 and the other of which is supplied to an acetylene cell 6. The acetylene cell 6 has a steep absorption characteristic for the spectrum peculiar to the 1.5 μm band, and if the temperature and magnetism are made constant by the temperature controller 8 and the magnetic shield case 7, the absorption center frequency is a very stable frequency. Becomes Semiconductor laser (1)
When the frequency of the light incident on the acetylene cell 6 in the state where the signal from the oscillator 10 is phase-modulated in advance to 1 is deviated to the positive or negative with respect to the frequency specific to the acetylene atom, the output of the photodetector 9 is exchanged The signals are 180 degrees out of phase. After the phase error signal is obtained by the phase detector 11, the current of the semiconductor laser 1 is negatively fed back through the frequency controller 12 composed of an amplifier or the like, and the optical frequency of the semiconductor laser 1 is absorbed by the acetylene atom. You can control the center of the line. In this way, the frequency of the semiconductor laser 1 is first stabilized.

【0010】次に、1.5 μm半導体レーザ2の出力はハ
ーフミラー3にて二分割され、片方はレーザの最終出力
となる一方、他方はハーフミラー5に加えられ、ハーフ
ミラー4からの光と合成されて変換器13に加えられ
る。変換器13は半導体レーザ1と半導体レーザ2の周
波数の差を電気信号として出力し、位相検波器15に供
給する。位相検波器15には一方から電圧制御発振器1
4の出力が供給されており、位相検波器15の出力を低
域通過フィルタ16を介して周波数制御器17に加え、
半導体レーザ2に帰還してやると、半導体レーザ2の周
波数と半導体レーザ1の周波数の差は電圧制御発振器の
周波数となる。つまりアセチレンセル6の吸収周波数を
R ,半導体レーザ1の周波数をf1 ,半導体レーザ2
の周波数をf2 ,VCOの周波数をfV とすると、f1
=fR であるから、「f2 =f1 +fV 」又は「f2
1−fV 」に安定化される。また、位相検波器15の
出力は低域通過フィルタ16を介している為、半導体レ
ーザ1に加えられている位相変調は半導体レーザ2には
加えられず、電圧制御発振器14に加える制御電圧を変
えることにより、半導体レーザ2の周波数をある帯域の
内で任意に設定することができる。
Next, the output of the 1.5 μm semiconductor laser 2 is divided into two by the half mirror 3, one of which is the final output of the laser, while the other is added to the half mirror 5 and combined with the light from the half mirror 4. And added to the converter 13. The converter 13 outputs the difference in frequency between the semiconductor laser 1 and the semiconductor laser 2 as an electric signal and supplies it to the phase detector 15. The phase detector 15 is connected to the voltage controlled oscillator 1 from one side.
4 is supplied, the output of the phase detector 15 is added to the frequency controller 17 via the low pass filter 16,
When it is fed back to the semiconductor laser 2, the difference between the frequency of the semiconductor laser 2 and the frequency of the semiconductor laser 1 becomes the frequency of the voltage controlled oscillator. That is, the absorption frequency of the acetylene cell 6 is f R , the frequency of the semiconductor laser 1 is f 1 , and the semiconductor laser 2 is
F 2 and the VCO frequency are f V , f 1
= F R , “f 2 = f 1 + f V ” or “f 2 =
f 1 −f V ”. Further, since the output of the phase detector 15 is passed through the low pass filter 16, the phase modulation applied to the semiconductor laser 1 is not applied to the semiconductor laser 2 and the control voltage applied to the voltage controlled oscillator 14 is changed. As a result, the frequency of the semiconductor laser 2 can be arbitrarily set within a certain band.

【0011】[0011]

【発明の効果】以上説明したように、本発明によると、
1.5 μm半導体レーザの周波数をアセチレンの吸収線に
より安定化し、第2の1.5 μm半導体レーザとの周波数
差が一定のオフセット周波数となるような系を構成する
ことにより、1.5〔μm〕帯のレーザ周波数に変調の加
わらない優れた短期安定度と長期安定度を持たせる事が
でき、又、オフセット周波数を変化させた場合には、レ
ーザ周波数をある帯域内の任意の周波数に設定すること
ができる。この為、従来の半導体レーザでは得られなか
った独立し、かつ周波数を可変できる高安定な長波長帯
光源としての半導体レーザ装置を提供することができ
る。
As described above, according to the present invention,
By stabilizing the frequency of the 1.5 μm semiconductor laser by the absorption line of acetylene and constructing a system where the frequency difference from the second 1.5 μm semiconductor laser is a constant offset frequency, the laser frequency in the 1.5 μm band is increased. It is possible to provide excellent short-term stability and long-term stability without the addition of modulation, and when the offset frequency is changed, the laser frequency can be set to an arbitrary frequency within a certain band. Therefore, it is possible to provide a semiconductor laser device as a highly stable long-wavelength band light source, which is independent from the conventional semiconductor laser and which can vary the frequency.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例を示す全体的構成図である。FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

1,2 半導体レーザ出力部 14 電圧制御発振器 15 位相検波器 20 周波数変動検出部 21 周波数補正部 30 差分周波数検出部 31 周波数安定制御部 1, 2 semiconductor laser output unit 14 voltage controlled oscillator 15 phase detector 20 frequency fluctuation detection unit 21 frequency correction unit 30 differential frequency detection unit 31 frequency stability control unit

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 半導体レーザ出力部を二体設け、一方の
半導体レーザ出力部に、当該一方の半導体レーザ出力部
の出力周波数の変動を検出する周波数変動検出部と,こ
の周波数変動検出部で検出された周波数変動信号に基づ
いて前記一方の半導体レーザ出力部の出力周波数の変動
を補正する周波数補正部とを併設し、前記他方の半導体
レーザ出力部に、当該他方の半導体レーザ出力部と前記
一方の半導体レーザ出力部の出力周波数の差を検出する
差分周波数検出部と,この差分周波数検出部の出力に基
づいて前記他方の半導体レーザ出力部の出力を差分ゼロ
を含む所定の出力周波数に安定制御する周波数安定制御
部とを併設したこと特徴とした半導体レーザ装置。
1. A semiconductor laser output section is provided, and a semiconductor laser output section has a frequency fluctuation detection section for detecting fluctuations in the output frequency of the one semiconductor laser output section, and a frequency fluctuation detection section for detecting the frequency fluctuation detection section. A frequency correction unit that corrects the fluctuation of the output frequency of the one semiconductor laser output unit based on the frequency fluctuation signal is provided, and the other semiconductor laser output unit and the one of the other semiconductor laser output unit Differential frequency detecting section for detecting the difference in output frequency of the semiconductor laser output section, and stable control of the output of the other semiconductor laser output section to a predetermined output frequency including zero difference based on the output of the difference frequency detecting section. A semiconductor laser device characterized in that a frequency stability control unit is also provided.
【請求項2】 前記周波数安定制御部と差分周波数検出
部との間に、位相検波器を装備すると共に、この位相検
波器の入力段に電圧制御発振器を装備したことを特徴と
する請求項1記載の半導体レーザ装置。
2. A phase detector is provided between the frequency stability control unit and the differential frequency detection unit, and a voltage controlled oscillator is provided at an input stage of the phase detector. The described semiconductor laser device.
JP3278423A 1991-09-30 1991-09-30 Semiconductor laser device Expired - Lifetime JP2864814B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3278423A JP2864814B2 (en) 1991-09-30 1991-09-30 Semiconductor laser device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3278423A JP2864814B2 (en) 1991-09-30 1991-09-30 Semiconductor laser device

Publications (2)

Publication Number Publication Date
JPH0590692A true JPH0590692A (en) 1993-04-09
JP2864814B2 JP2864814B2 (en) 1999-03-08

Family

ID=17597138

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3278423A Expired - Lifetime JP2864814B2 (en) 1991-09-30 1991-09-30 Semiconductor laser device

Country Status (1)

Country Link
JP (1) JP2864814B2 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01291478A (en) * 1988-05-19 1989-11-24 Fujitsu Ltd Method and equipment for stabilization of oscillation frequency of semiconductor laser
JPH03250680A (en) * 1990-02-28 1991-11-08 Yokogawa Electric Corp Frequency stabilized laser light source

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01291478A (en) * 1988-05-19 1989-11-24 Fujitsu Ltd Method and equipment for stabilization of oscillation frequency of semiconductor laser
JPH03250680A (en) * 1990-02-28 1991-11-08 Yokogawa Electric Corp Frequency stabilized laser light source

Also Published As

Publication number Publication date
JP2864814B2 (en) 1999-03-08

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