JPH03250680A - Frequency stabilized laser light source - Google Patents
Frequency stabilized laser light sourceInfo
- Publication number
- JPH03250680A JPH03250680A JP4740690A JP4740690A JPH03250680A JP H03250680 A JPH03250680 A JP H03250680A JP 4740690 A JP4740690 A JP 4740690A JP 4740690 A JP4740690 A JP 4740690A JP H03250680 A JPH03250680 A JP H03250680A
- Authority
- JP
- Japan
- Prior art keywords
- output
- semiconductor laser
- frequency
- oscillator
- oscillation frequency
- 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
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- 239000004065 semiconductor Substances 0.000 claims abstract description 61
- 230000010355 oscillation Effects 0.000 claims abstract description 37
- 238000001514 detection method Methods 0.000 claims abstract description 28
- 230000001360 synchronised effect Effects 0.000 claims abstract description 27
- 238000010521 absorption reaction Methods 0.000 claims abstract description 25
- 230000003287 optical effect Effects 0.000 claims abstract description 9
- 239000000126 substance Substances 0.000 claims abstract description 5
- 230000010287 polarization Effects 0.000 abstract description 6
- 230000006641 stabilisation Effects 0.000 abstract description 2
- 238000011105 stabilization Methods 0.000 abstract description 2
- 239000004020 conductor Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000003595 spectral effect Effects 0.000 description 4
- 101150118300 cos gene Proteins 0.000 description 3
- 230000035559 beat frequency Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 101100234408 Danio rerio kif7 gene Proteins 0.000 description 1
- 101100221620 Drosophila melanogaster cos gene Proteins 0.000 description 1
- 101150096607 Fosl2 gene Proteins 0.000 description 1
- 102100040678 Programmed cell death protein 1 Human genes 0.000 description 1
- 101710089372 Programmed cell death protein 1 Proteins 0.000 description 1
- 240000005499 Sasa Species 0.000 description 1
- 101100398237 Xenopus tropicalis kif11 gene Proteins 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000004847 absorption spectroscopy Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002861 ventricular Effects 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、半導体レーザを用いた周波数安定化レーザ光
源の安定性の改善に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to improving the stability of a frequency-stabilized laser light source using a semiconductor laser.
〈従来の技術〉
第7図は周波数安定化レーザ光源の第1の従来例を示す
ブロック図で、半導体レーザを直接変調して、その発振
周波数を原子および分子の吸収線の中心に制御するもの
を示している。半導体レーザ1の出力光はビームスプリ
ッタ2で2つの方向に分離し、一方の光は標準物質が封
入された吸収セル3に入射する。吸収セル3を透過した
光は光検出器4で検出されて電気信号に変換され、ロッ
クインアンプ等からなる同期検波口#15に入力する。<Prior art> Figure 7 is a block diagram showing a first conventional example of a frequency-stabilized laser light source, in which a semiconductor laser is directly modulated to control its oscillation frequency to the center of the absorption lines of atoms and molecules. It shows. The output light of the semiconductor laser 1 is separated into two directions by a beam splitter 2, and one of the lights enters an absorption cell 3 in which a standard substance is sealed. The light transmitted through the absorption cell 3 is detected by a photodetector 4, converted into an electrical signal, and input to a synchronous detection port #15 consisting of a lock-in amplifier or the like.
半導体レーザ1の発振周波数は発振器8の出力で電流変
調されており、同期検波回路5は発振器8の出力を参照
信号として同期検波を行う、P■制御回路6は同期検波
回路5の出力が一定となるように半導体レーザ1の電流
を制御する。PI制御回路69発振器8の発振出力およ
びバイアス電流源9の出力は加算回路7で加算されて半
導体レーザ1に入力される。この結果、半導体レーザ1
の発振周波数は吸収セル3の標準物質の原子または分子
の吸収線の中心に制御され、ビームスプリッタ2の他方
の出力光は原子または分子で決まる絶対値が高精度の周
波数となる。The oscillation frequency of the semiconductor laser 1 is current modulated by the output of the oscillator 8, and the synchronous detection circuit 5 performs synchronous detection using the output of the oscillator 8 as a reference signal. The current of the semiconductor laser 1 is controlled so that . The oscillation output of the PI control circuit 69 oscillator 8 and the output of the bias current source 9 are added by the adder circuit 7 and input to the semiconductor laser 1 . As a result, the semiconductor laser 1
The oscillation frequency of is controlled to the center of the absorption line of the atoms or molecules of the standard substance in the absorption cell 3, and the other output light of the beam splitter 2 has a frequency whose absolute value is determined by the atoms or molecules with high precision.
しかしながら、上記のような装置では、出力光が周波数
変調されているため、瞬時周波数の安定性がなく、干渉
計測等の応用には不適当となり、応用範囲が狭くなると
いう欠点を有する。However, in the above-mentioned apparatus, since the output light is frequency-modulated, the instantaneous frequency is not stable, making it unsuitable for applications such as interferometric measurements, and has the drawback of narrowing the range of applications.
このような欠点を解決するために、半導体レーザ出力光
を音響光学変調器で外部変調し原子および分子の吸収線
に制御することにより、無変調出力を得るように構成し
たものがある。In order to solve these drawbacks, there is a structure in which a non-modulated output is obtained by externally modulating the output light of a semiconductor laser using an acousto-optic modulator and controlling it to atomic and molecular absorption lines.
〈発明が解決しようとする課題〉
しかしながら、そのような装置の場合には、音響光学変
調器が不安定なため、安定度が不十分であるという問題
がある。<Problems to be Solved by the Invention> However, in the case of such a device, there is a problem that the stability is insufficient because the acousto-optic modulator is unstable.
本発明はこのような課題を解決するためになされたもの
で、発振周波数が高安定に制御された周波数安定化レー
ザ光源を簡単な構成で実現することを目的とする。The present invention has been made to solve these problems, and an object of the present invention is to realize a frequency-stabilized laser light source whose oscillation frequency is highly stably controlled with a simple configuration.
く課題を解決するための手段〉
本発明に係る周波数安定化レーザ光源は第1の半導体レ
ーザと、この第1の半導体レーザの出力光を入力して特
定の周波数で吸収する物質を封入した吸収セルと、この
吸収セルを透過した光を検出する第1の光検出器と、前
記第1の半導体レーザの電流に変調を加える第1の発振
器と、この第1の発振器の出力またはその奇数倍周波数
の信号を参照信号として前記第1の光検出器の出力を入
力する第1の同期検波回路と、この第1の同期検波回路
の出力に基づいて前記第1の半導体レーザの発振周波数
を前記吸収セルの吸収線に制御する第1の制御回路と、
第2の半導体レーザと、前記第1.第2の半導体レーザ
の出力光を合波する光学手段と、この光学手段から出力
される出力光のビート信号を検出する第2の光検出器と
、第2の発振器と、この第2の発振器の出力と前記第2
の光検出器の出力を混合するミキサと、前記第1の発振
器の出力またはその奇数倍周波数の信号を参照信号とし
て前記ミキサの出力を同期検波する第2の同期検波回路
と、この第2の同期検波回路の出力に基づいて前記第1
の半導体レーザの発振周波数との差が前記第2の発振器
の発振周波数と等しくなるように前記第2の半導体レー
ザの発振周波数を制御する第2の制御回路とを備え、第
2の半導体レーザの出力が無変調となるように構成した
ことを特徴とする。Means for Solving the Problems> The frequency stabilized laser light source according to the present invention includes a first semiconductor laser and an absorber encapsulating a substance that inputs the output light of the first semiconductor laser and absorbs it at a specific frequency. a first photodetector for detecting light transmitted through the absorption cell; a first oscillator for modulating the current of the first semiconductor laser; and an output of the first oscillator or an odd multiple thereof. a first synchronous detection circuit that inputs the output of the first photodetector using a frequency signal as a reference signal; a first control circuit that controls the absorption line of the absorption cell;
a second semiconductor laser; an optical means for multiplexing the output light of the second semiconductor laser; a second photodetector for detecting the beat signal of the output light output from the optical means; a second oscillator; and the output of the second
a second synchronous detection circuit that synchronously detects the output of the mixer using the output of the first oscillator or a signal of an odd multiple frequency thereof as a reference signal; Based on the output of the synchronous detection circuit, the first
a second control circuit that controls the oscillation frequency of the second semiconductor laser such that the difference between the oscillation frequency of the second semiconductor laser and the oscillation frequency of the second semiconductor laser is equal to the oscillation frequency of the second oscillator; It is characterized by being configured so that the output is unmodulated.
さらに第3の発振器と、第2の発振器の出力を前記第3
の発振器の出力で周波数変調または位相変調する変調回
路とを備え、変調回路の出力と第2の光検出器の出力を
ミキサで混合し、第3の発振器の出力またはその奇数倍
周波数の信号を第2の同期検波回路の参照信号としても
よい。Furthermore, a third oscillator and an output of the second oscillator are connected to the third oscillator.
A modulation circuit that performs frequency modulation or phase modulation with the output of the third oscillator, and a mixer mixes the output of the modulation circuit and the output of the second photodetector, and outputs the output of the third oscillator or a signal of an odd multiple thereof. It may also be used as a reference signal for the second synchronous detection circuit.
く作用〉
第1の半導体レーザは電流変調で高安定となり、第2の
半導体レーザの発振周波数が第1の半導体レーザの発振
の中心周波数から第2の発振器の発振周波数だけずれた
ところに制御されるので、周波数が無変調かつ高安定と
なる。Effect> The first semiconductor laser becomes highly stable through current modulation, and the oscillation frequency of the second semiconductor laser is controlled to be shifted from the center frequency of oscillation of the first semiconductor laser by the oscillation frequency of the second oscillator. Therefore, the frequency is unmodulated and highly stable.
〈実施例〉 以下本発明を図面を用いて詳しく説明する。<Example> The present invention will be explained in detail below using the drawings.
第1図は本発明に係る周波数左室化レーザ光源の第1の
実施例を示す構成ブロック図である4第6図と同じ部分
は同一の記号を付して説明を省略する。】0は第2の半
導体レーザ、11は半導体レーザ10の出力光を2方向
に分離スるビームスプリッタ、12はビームスプリッタ
11を透過した光とビームスプリッタ2を透過した光を
合波する光学手段を構成する偏光ビームス1リツタ、1
3は2つの光が干渉するように偏波面を合せる偏光ビー
ムスプリッタ、14は偏光ビームスグリツタから出射さ
れた光を入射[7てビーhfS号を検出する第2の光検
出器、1+5はマイクロ波発振器行う第2の発振器、1
6は発振器15の出力と光検出器14の出力を混合(ミ
キシング)するマイクロ波ミキサ、17はミキサ16の
出力を入力17、発振器8の出力を参照信号とするロッ
クインアンプ等からなる第2の同期検波回路、】8は同
期検波回路17の出力を入力して対応する制御出力を第
2の半導体L−ザ10に加える第2のP1制御回路であ
る。FIG. 1 is a block diagram illustrating a first embodiment of a frequency left ventricular laser light source according to the present invention. 4 The same parts as in FIG. 6 are given the same symbols and their explanation will be omitted. 0 is a second semiconductor laser, 11 is a beam splitter that separates the output light of the semiconductor laser 10 into two directions, and 12 is an optical means that combines the light that has passed through the beam splitter 11 and the light that has passed through the beam splitter 2. Polarized beams constituting 1 liter, 1
3 is a polarizing beam splitter that aligns the plane of polarization so that the two lights interfere; 14 is a second photodetector that receives the light emitted from the polarizing beam splitter; 7 is a second photodetector that detects the beam hfS; The second oscillator, which performs a wave oscillator, 1
6 is a microwave mixer that mixes the output of the oscillator 15 and the output of the photodetector 14; 17 is a second lock-in amplifier that receives the output of the mixer 16 as an input 17 and uses the output of the oscillator 8 as a reference signal; 8 is a second P1 control circuit which inputs the output of the synchronous detection circuit 17 and applies a corresponding control output to the second semiconductor L-zer 10.
」−記の構成の装置の動作を次に説明する。従来例の説
明て′述べたように、標準′lIJ質の吸収線に制御さ
れた半導体L−ザ1の出力光はビームスプリッタ2を介
して出射され、ビームスプリッタ11を介して出射され
る#″導体シーサ10の出力光ど偏光ビームスグリツタ
12で合波される。偏光ビムスプリッタ12から出射さ
れた光は偏光ビムスプリッタ13て偏波面か合わされた
後、光検出器14でと−1−信号が検出される。;*v
x6でこのビーl−借号を発振器15の出力と混合した
後、同期検波回路17において発振器8の出力を参照信
号として同期検波を行う、F)■制御回路18は同期検
波出力がOとなるように半導体し →r10の発振周波
数を制御し、その結果半導体レーザ10の発振周波数は
半導体レーザ1の中心周波数から発振器15の発振周波
数だυずれた値どなり、ビームスプリッタ11を介して
その一部が出力される。The operation of the apparatus having the configuration described above will be explained below. As described in the description of the conventional example, the output light of the semiconductor laser 1 controlled to have a standard IJ quality absorption line is emitted via the beam splitter 2, and is emitted via the beam splitter 11. ``The output light of the conductor sheaser 10 is combined by the polarization beam splitter 12.The light emitted from the polarization beam splitter 12 has its polarization plane combined by the polarization beam splitter 13, and then the light is combined by the photodetector 14. A signal is detected.;*v
After mixing this B-L-sign with the output of the oscillator 15 at x6, synchronous detection is performed in the synchronous detection circuit 17 using the output of the oscillator 8 as a reference signal. F) ■ The control circuit 18 has a synchronous detection output of O. As a result, the oscillation frequency of the semiconductor laser 10 is shifted from the center frequency of the semiconductor laser 1 to the oscillation frequency of the oscillator 15. is output.
この動作を数式を用いて説明すると次のようになる。半
導体レーザ1の電界振幅E1はE =e 5inf
2rf1t −(Δf/fII)1
cos2rf L+F (t)) −(
1)111
で表される。ただしflは半導体レーザーの発振の中心
周波数、ψ1 は)は半導体レーサーの位相ノイズ、f
は発振器8の発振周波数、Δでは最大周波数偏移であ
る。また半導体レーザー0の電界振幅E2は
E =e s i n (2yrf2t+si’2
(t) ’t2
・・・ (2)
で表される。ただしψ2 (t)は半導体レーザ2の位
相ノイズである。光検出器14に誘起される光電流1.
。は、
1 (X:(E +E2)
PD 1
2e e cos (2π(f −f2 )tl
2 1
+ψ(1,)−ψ2は)−(Δf/f□)c。This operation can be explained using a mathematical formula as follows. The electric field amplitude E1 of the semiconductor laser 1 is E = e 5inf
2rf1t −(Δf/fII)1 cos2rf L+F (t)) −(
1) Represented by 111. However, fl is the center frequency of the oscillation of the semiconductor laser, ψ1 is the phase noise of the semiconductor laser, f
is the oscillation frequency of the oscillator 8, and Δ is the maximum frequency deviation. Further, the electric field amplitude E2 of the semiconductor laser 0 is E = e sin (2yrf2t+si'2
(t) 't2... (2) Represented by: However, ψ2 (t) is the phase noise of the semiconductor laser 2. Photocurrent induced in photodetector 14 1.
. is 1 (X: (E + E2) PD 1 2e e cos (2π(f - f2) tl
2 1 +ψ(1,)-ψ2 is)-(Δf/f□)c.
S2πft + +I DC・= (3)となる。ここ
で
91’(t)=P (t) −95,、ct>とし、
直流分I。0はAC結合することで除去すると、
I =K cos (2π(f、 −f2)t、→
−ψPD 1
(t) −(Δ f/f )cos2 π
f □ 土、 )・・・ (4)
となる。マイクロ波発振器15の出力■8をV −=
e s i、 n、 2 x f 3t
−(5)3
とすると、ミー8ガ16の出力■HIxはV =K
[5in(2π(f −f −f3)旧×
2 1 2
t5」ψ(t)−(Δf 、’ f ) c o s
2πf□t)−I s i n (2r (fl−f
2+f3 ) t+so (t)(Af/f )co
s2πf、t、)]・・ (6)
となる。ここでf”fl”f2 f3の成分のみを考え
ると、
Vux−= K2 S ]、 n ! 2 yr f
t (Δf′fII)cos2πf t+p (t
)i =・(7)躇
となる。半導体レーザのスペクトル線幅は冒−レンツ分
布をし、スペクトル線の半値幅をΔf1とすると、(7
)式はローレンツ分布を持ったとl−信号が周波数f□
、最大周波数制移Δfで正弦波的に変化していると考え
られる(第2図)。したがって(7)式はローレンツ分
布の一般式を用いて次のように書換えることができる。S2πft + +I DC·= (3). Here, 91'(t)=P (t) -95,, ct>,
DC component I. If 0 is removed by AC coupling, I = K cos (2π(f, -f2)t, →
−ψPD 1 (t) −(Δ f/f )cos2 π
f □ Sat, )... (4) becomes. The output ■8 of the microwave oscillator 15 is V - =
e s i, n, 2 x f 3t
- (5) 3, the output ■HIx of Me8ga16 is V = K
[5in(2π(f −f −f3) old×
2 1 2 t5''ψ(t)−(Δf,'f)cos
2πf□t)-I sin (2r (fl-f
2+f3) t+so (t)(Af/f)co
s2πf, t, )]... (6) Now, considering only the components of f"fl"f2 f3, Vux-=K2 S], n! 2 yr f
t (Δf′fII)cos2πf t+p (t
) i =・(7). The spectral linewidth of a semiconductor laser has an F-Lentz distribution, and if the half-width of the spectral line is Δf1, then (7
) has a Lorentz distribution, and the l-signal has a frequency f□
, it is thought to vary sinusoidally with a maximum frequency shift Δf (Fig. 2). Therefore, equation (7) can be rewritten as follows using the general equation of Lorentz distribution.
■NJX−”K/ [1+ + (f+Δfsfn2y
rf。■NJX-”K/ [1+ + (f+Δfsfn2y
rf.
1)/Δf1) ] ・・・(8)ただ
しKは比例定数である。(8ン式の5in2πflt成
分振幅Vt工は、
5in2πf t=−1
および
5in2 π f t=1
2 2 2−2fΔf)−
Δf −に/(Δf +f1
±Δf2+2fΔf)
2222
+Δf ) −4f Δで )
・・・ (9)同期検波回路17の出力はこのvflに
比例し、例えば半導体レーザ1,10のスペクトル線幅
Δf1を30MH2,fi大周波数偏移Δfを30MH
2とし、fを−500〜500MHz!で掃引したとき
の同期検波出力vfIlは第3図のようになる。1)/Δf1)] (8) where K is a proportionality constant. (The 5in2πflt component amplitude Vt of the 8-in formula is 5in2πft=-1 and 5in2πft=1 2 2 2-2fΔf) -
Δf - / (Δf + f1 ±Δf2 + 2fΔf) 2222 +Δf ) -4f Δ)
(9) The output of the synchronous detection circuit 17 is proportional to this vfl. For example, if the spectral line width Δf1 of the semiconductor lasers 1 and 10 is 30MH2, and the fi large frequency deviation Δf is 30MH2.
2, and f is -500 to 500MHz! The synchronous detection output vfIl when swept is as shown in FIG.
第3図の同期検波出力の0クロスポイントaに半導体レ
ーザ10の発振周波数を制御すれば、t=r1−f2−
f3=O・ (10)すなわち
f1f2=f3 ・・・(11)となるので、
ビート周波数は発振器15のマイクロ波周波数と一致す
る。すなわち第4図に示すように、半導体レーザ1の発
振の中心周波数f1は吸収線周波数に高確度、周波数高
安定状態で制御されており、マイクロ波周波数f3も安
定なので、半導体レーザ10の発振周波数で2も高安定
度となる。If the oscillation frequency of the semiconductor laser 10 is controlled to the 0 cross point a of the synchronous detection output in FIG. 3, then t=r1-f2-
f3=O・(10) That is, f1f2=f3...(11), so
The beat frequency matches the microwave frequency of the oscillator 15. That is, as shown in FIG. 4, the center frequency f1 of the oscillation of the semiconductor laser 1 is controlled to the absorption line frequency with high accuracy and in a highly stable frequency state, and the microwave frequency f3 is also stable, so the oscillation frequency of the semiconductor laser 10 is 2 also has high stability.
このような構成の周波数安定化レーザ光源によれば、第
1の半導体レーザの発振周波数を電流変調で吸収線周波
数に制御し、マイクロ波でオフセットをかけて第2の半
導体レーザの発振周波数を制御することにより、無変調
、周波数高安定度の光出力を得ることができる。According to the frequency-stabilized laser light source having such a configuration, the oscillation frequency of the first semiconductor laser is controlled to the absorption line frequency by current modulation, and the oscillation frequency of the second semiconductor laser is controlled by offset using microwaves. By doing so, it is possible to obtain a non-modulated optical output with high frequency stability.
またマイクロ波の周波数を変えることで、光出力周波数
を高安定・高確度で掃引することかできる0例えば20
0’rHzに対して1〜2GH2掃引することができる
。In addition, by changing the microwave frequency, the optical output frequency can be swept with high stability and accuracy.
A 1-2 GH2 sweep is possible for 0'rHz.
電流変調で吸収線に制御しているので、音響光学変調器
における光路変化等が起きないため、周波数安定度が優
れている。Since the absorption line is controlled by current modulation, no optical path changes occur in the acousto-optic modulator, resulting in excellent frequency stability.
なお上記の実施例において、同期検波の参照周波数はf
lを用いて1次微分信号の0クロスポイン1〜に制御し
ていたが、3f、を参照周波数として3次微分信号の0
クロスポイントに制御することもできる。一般にf、の
奇数倍の参照周波数を用いて奇数次の微分信号の0クロ
スポイントに制御することができる。In the above embodiment, the reference frequency for coherent detection is f
l was used to control the 0 cross point of the first-order differential signal from 1 to 1, but using 3f as the reference frequency, the 0-cross point of the third-order differential signal
It can also be controlled at cross points. Generally, it is possible to control the zero cross point of the odd-order differential signal by using a reference frequency that is an odd multiple of f.
またV 出力のfi f2+f3の信号を用IX
いても同様に制御することができる。この場合にはf
f2 f3の信号を用いる場合より出力光の周波数
が2f3だけ高くなる。Furthermore, the same control can be achieved even if the signal of fi f2+f3 of the V output is used. In this case f
The frequency of the output light is higher by 2f3 than when using f2 f3 signals.
またミキサー5を省略してf3=0とすれば、f 2
= f 1で安定化することができる。ただしこの場合
にf2の周波数掃引はできない。Also, if mixer 5 is omitted and f3=0, f 2
= f 1 can be stabilized. However, in this case, f2 frequency sweep is not possible.
第5図は本発明に係る周波数安定化レーザ光源の第2の
実施例を示す構成ブロック図である。第1図と同じ部分
は同一の記号を付して説明を省略する。19は変調用の
第3の発振器、20は発振器15のマイクロ波出力信号
を発振器19の出力で周波数変調する変調回路である。FIG. 5 is a block diagram showing a second embodiment of the frequency stabilized laser light source according to the present invention. The same parts as in FIG. 1 are given the same symbols and the explanation is omitted. 19 is a third oscillator for modulation, and 20 is a modulation circuit that frequency-modulates the microwave output signal of the oscillator 15 with the output of the oscillator 19.
ミキサ16は変調回路20の出力と光検出器14の出力
を混合し、同期検波回路17は発振器19の出力を参照
信号として同期検波を行う。その他の構成は第1図の場
合と同じである。The mixer 16 mixes the output of the modulation circuit 20 and the output of the photodetector 14, and the synchronous detection circuit 17 performs synchronous detection using the output of the oscillator 19 as a reference signal. The other configurations are the same as in the case of FIG.
発振器15から出力されるマイクロ波は変調回路20に
より変調周波数1□2で周波数変調されるので、ミキサ
16の出力と−1・信号はfra2で変調されている。Since the microwave output from the oscillator 15 is frequency-modulated by the modulation circuit 20 at a modulation frequency of 1□2, the output of the mixer 16 and the -1 signal are modulated at fra2.
同期検波回路17においてミキサ16の出力を’n2で
同期検波し、その出力がOになるように制御すれば、半
導体レーザ1,10間のビート周波数がマイクロ波中心
周波数と等しくなる。If the output of the mixer 16 is synchronously detected by 'n2 in the synchronous detection circuit 17 and controlled so that the output becomes O, the beat frequency between the semiconductor lasers 1 and 10 becomes equal to the microwave center frequency.
このような構成の周波数安定化レーザ光源によれば、二
重変調とすることにより、半導体レーザ1の発振周波数
を吸収線周波数に制御するための周波数偏移と、半導体
レ−リ゛10e。′f′尋体1.−ザ1の発振周波数1
1Jオフセツトを(、っ′て制御丈るメ1zめの周波数
偏移どが独立で、イれぞれに最適値を選ぶことができ(
1の゛て゛、安定度やS/Nが向1するにh Jj吸収
綜f鹸全輻と4′#体L7〜ザのスペクトル線幅か大き
く異なる場合に有効下゛ある。According to the frequency stabilized laser light source having such a configuration, the frequency shift for controlling the oscillation frequency of the semiconductor laser 1 to the absorption line frequency by double modulation and the semiconductor laser 10e. 'f' Hirontai 1. -The 1 oscillation frequency 1
Since the 1J offset (and the 1z frequency deviation are independent), the optimum value can be selected for each (
Point 1 is less effective when the stability and S/N are significantly different from each other in terms of the spectral linewidth of the total radiation of the hJj absorption beam and the 4'# body L7~.
また半導体1.−9−リ′10を!1″導体L−ヂ1の
発振周波数にオフセラ1−をもンて制御1′る制御系に
おいて、変調をフイ;i o波C3かげているのて゛、
1′導体レーサ]の発振周波数を吸収線周波数に制t&
Illツ゛z1制御系r、こ゛1暫をり−えることなく
、安定度を向lτる、ご゛とができる、
なお上記の実施例ζ゛は半導体t、−ザ】91oども1
次微分て゛制御するように棺[戊Iているが、参照周波
数C1,それぞれ3f 3f、、2を用いて3次1
1゛
微分のOりDスボイントに制御し、又もよい。一般にf
n’l fl2の奇数1きの参照周波数を用い′て奇数
次の微分信−号の0り冒ζポインl=に制御リ−ること
がでさ2)。Also semiconductor 1. -9-ri'10! In a control system in which the oscillation frequency of the 1" conductor L-1 is controlled by adding an off-celler 1-1, the modulation is suppressed;
1' conductor laser]'s oscillation frequency to the absorption line frequency.
It is possible to improve the stability of the control system without changing the control system for a while.
To control the third-order differential, we use the reference frequency C1, 3f, 3f, , 2 to
It is also possible to control the O or D point of the 1' differential. Generally f
It is possible to control the odd-order differential signal to the zero point l= by using the odd-numbered reference frequency of n'lfl2.
また変調回路20て゛位相変調をが0てもよい。Further, the modulation circuit 20 may have zero phase modulation.
2、i、、−、、、−、に、:、 iiこノ@ JR施
ml t=、 S イて、’−r’4 f)r= ly
−サ1 ノ出射光の一部を、jテング光、とり、て吸収
セル3C51人射I21、伯の 部を反対の方向から細
い光束て′グUブ光とし、で吸収)ニル3に入射I5て
飽和吸収(r’+ ”’jを得る#l!l和吸収法〈堀
5角田1北野、数崎。小川9飽和吸収分光を用いた゛r
導導体l/ササ周波数7、電化、信学1、k報OQ E
82−116 )を用い′i01ば、Jり安定な周波
数ジ定化1.−ザ尤源を実現づる、:Jかできる。2,i,,-,,,-,ni,:, iiKono @ JR sml t=, S ite,'-r'4 f) r= ly
- A part of the emitted light is taken as J-tengu light, and the part of the part is made into a thin beam from the opposite direction, and is absorbed by Nil-3. I5 to obtain saturated absorption (r'+ ``'j #l!l Sum absorption method〈Hori 5 Tsunoda 1 Kitano, Kazuzaki. Ogawa 9 Using saturated absorption spectroscopy ゛r
Conductor l/sasa frequency 7, electrification, telecommunications 1, k report OQ E
82-116), the stable frequency constant 1. - Realize the source: J can do it.
・S発明の効脣ト・
以1 、、f=べなように本発明によれば、介、1も(
周波数か高安定t、二制御さ7ン、な周波数安定化し
サ光afaを節部な積数て・実現する1丁とかできる。・Effects of S invention ・ According to the present invention, according to the present invention, , 1 also has (
Frequency is high stability, second control, high frequency stabilization.
It is possible to create a device that realizes a complex product of light afa.
4、)予−n FfJjの簡単な説明
第1図は本発明に係る周波数安定化し−17F光源の第
1の実施例を事″づ”棺成ブ冒ツク図 第2し1・−第
4し1は第1図装置の動作を示τ゛諜、明図、第55し
は本発明に係る周波数安定化し、・−ザ光源の第二2の
実施例を示1桐成ブC7ツク図、第6図は周べ数支定化
し−ザ光源の従来例を示′1楕成プロ・ツク図である。4.) Brief explanation of FfJj Figure 1 shows the first embodiment of the frequency stabilized -17F light source according to the present invention. Fig. 1 shows the operation of the device; Fig. 55 shows a second embodiment of the frequency-stabilized light source according to the present invention; Fig. 1 shows the operation of the device; FIG. 6 is an elliptical diagram showing a conventional example of a light source with a circumferential power.
1・・・第1の半導体レーザ、3・・・吸収セル、・ト
・・第1の光検出器、5・・・第1の同期検波回路、6
・・・miの制御回路、8・・・第1の発振器、1o・
・・第;1の¥′導体L・−ザ、12・・・光′Y:1
絞、1・1・・・第2の光検出器、15・・第2の発掘
・器、16・・・ミ人ザ、17・・・第2の同期検波回
路、18・・・第2の制御11:1回路、10・・・第
3の発振器、20・・・鴇′調1111路 fl・・
第1の半導体Y・−ザの発振周波数、f2・・・第2の
半導体レーザ“の発振周波数。DESCRIPTION OF SYMBOLS 1... First semiconductor laser, 3... Absorption cell,... First photodetector, 5... First synchronous detection circuit, 6
...mi control circuit, 8...first oscillator, 1o.
... No. 1 \' conductor L - the, 12... Light 'Y: 1
Aperture, 1.1...Second photodetector, 15...Second excavator/device, 16...Mijinza, 17...Second synchronous detection circuit, 18...Second Control of 11:1 circuit, 10...Third oscillator, 20...1111-way fl...
The oscillation frequency of the first semiconductor laser, f2...the oscillation frequency of the second semiconductor laser.
Claims (2)
の出力光を入力して特定の周波数で吸収する物質を封入
した吸収セルと、この吸収セルを透過した光を検出する
第1の光検出器と、前記第1の半導体レーザの電流に変
調を加える第1の発振器と、この第1の発振器の出力ま
たはその奇数倍周波数の信号を参照信号として前記第1
の光検出器の出力を入力する第1の同期検波回路と、こ
の第1の同期検波回路の出力に基づいて前記第1の半導
体レーザの発振周波数を前記吸収セルの吸収線に制御す
る第1の制御回路と、第2の半導体レーザと、前記第1
、第2の半導体レーザの出力光を合波する光学手段と、
この光学手段から出力される出力光のビート信号を検出
する第2の光検出器と、第2の発振器と、この第2の発
振器の出力と前記第2の光検出器の出力を混合するミキ
サと、前記第1の発振器の出力またはその奇数倍周波数
の信号を参照信号として前記ミキサの出力を同期検波す
る第2の同期検波回路と、この第2の同期検波回路の出
力に基づいて前記第1の半導体レーザの発振周波数との
差が前記第2の発振器の発振周波数と等しくなるように
前記第2の半導体レーザの発振周波数を制御する第2の
制御回路とを備え、第2の半導体レーザの出力が無変調
となるように構成したことを特徴とする周波数安定化レ
ーザ光源。(1) A first semiconductor laser, an absorption cell filled with a substance that absorbs the output light of the first semiconductor laser at a specific frequency, and a first semiconductor laser that detects the light transmitted through the absorption cell. a photodetector; a first oscillator that modulates the current of the first semiconductor laser;
a first synchronous detection circuit inputting the output of the photodetector, and a first synchronous detection circuit controlling the oscillation frequency of the first semiconductor laser to the absorption line of the absorption cell based on the output of the first synchronous detection circuit. a control circuit, a second semiconductor laser, and the first control circuit.
, an optical means for multiplexing the output light of the second semiconductor laser;
a second photodetector that detects the beat signal of the output light output from the optical means; a second oscillator; and a mixer that mixes the output of the second oscillator and the output of the second photodetector. a second synchronous detection circuit that synchronously detects the output of the mixer using the output of the first oscillator or a signal of an odd multiple frequency thereof as a reference signal; a second control circuit that controls the oscillation frequency of the second semiconductor laser such that the difference between the oscillation frequency of the first semiconductor laser and the oscillation frequency of the second semiconductor laser is equal to the oscillation frequency of the second oscillator; A frequency-stabilized laser light source characterized by being configured such that the output is unmodulated.
の発振器の出力で周波数変調または位相変調する変調回
路とを備え、変調回路の出力と第2の光検出器の出力を
ミキサで混合し、第3の発振器の出力またはその奇数倍
周波数の信号を第2の同期検波回路の参照信号とする請
求項1記載の周波数安定化レーザ光源。(2) A third oscillator and the output of the second oscillator
A modulation circuit that performs frequency modulation or phase modulation with the output of the third oscillator, and a mixer mixes the output of the modulation circuit and the output of the second photodetector, and outputs the output of the third oscillator or a signal of an odd multiple thereof. 2. The frequency-stabilized laser light source according to claim 1, wherein the frequency-stabilized laser light source is used as a reference signal for the second synchronous detection circuit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4740690A JPH03250680A (en) | 1990-02-28 | 1990-02-28 | Frequency stabilized laser light source |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4740690A JPH03250680A (en) | 1990-02-28 | 1990-02-28 | Frequency stabilized laser light source |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH03250680A true JPH03250680A (en) | 1991-11-08 |
Family
ID=12774243
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4740690A Pending JPH03250680A (en) | 1990-02-28 | 1990-02-28 | Frequency stabilized laser light source |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH03250680A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0590692A (en) * | 1991-09-30 | 1993-04-09 | Nec Corp | Semiconductor laser device |
JPH0576068U (en) * | 1992-03-24 | 1993-10-15 | 横河電機株式会社 | Frequency stabilized light source |
KR100363238B1 (en) * | 1995-05-09 | 2003-02-05 | 삼성전자 주식회사 | Method and apparatus for generating second harmonic |
-
1990
- 1990-02-28 JP JP4740690A patent/JPH03250680A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0590692A (en) * | 1991-09-30 | 1993-04-09 | Nec Corp | Semiconductor laser device |
JPH0576068U (en) * | 1992-03-24 | 1993-10-15 | 横河電機株式会社 | Frequency stabilized light source |
KR100363238B1 (en) * | 1995-05-09 | 2003-02-05 | 삼성전자 주식회사 | Method and apparatus for generating second harmonic |
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