JPS6344780A - Spectral line width alteration device of laser beam source - Google Patents
Spectral line width alteration device of laser beam sourceInfo
- Publication number
- JPS6344780A JPS6344780A JP18921486A JP18921486A JPS6344780A JP S6344780 A JPS6344780 A JP S6344780A JP 18921486 A JP18921486 A JP 18921486A JP 18921486 A JP18921486 A JP 18921486A JP S6344780 A JPS6344780 A JP S6344780A
- Authority
- JP
- Japan
- Prior art keywords
- line width
- laser beams
- spectral line
- pzt
- spectral
- 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
- 230000003595 spectral effect Effects 0.000 title claims abstract description 33
- 230000004075 alteration Effects 0.000 title abstract 2
- 230000003287 optical effect Effects 0.000 claims description 13
- 239000004065 semiconductor Substances 0.000 abstract description 15
- 238000003079 width control Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 9
- 238000004891 communication Methods 0.000 description 8
- 238000001514 detection method Methods 0.000 description 7
- 230000008878 coupling Effects 0.000 description 6
- 238000010168 coupling process Methods 0.000 description 6
- 238000005859 coupling reaction Methods 0.000 description 6
- 230000003111 delayed effect Effects 0.000 description 6
- 238000001228 spectrum Methods 0.000 description 5
- 239000013307 optical fiber Substances 0.000 description 4
- 230000001427 coherent effect Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/14—External cavity lasers
- H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/06837—Stabilising otherwise than by an applied electric field or current, e.g. by controlling the temperature
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/0687—Stabilising the frequency of the laser
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
〔概 要〕
レーザ光源の外部共振器のレーザ光路内にチューニング
プレートを設け、そのフィネスを変更することによりレ
ーザ光源から出力されるレーザ光のスペクトル線幅を制
御するようにした。[Detailed Description of the Invention] [Summary] A tuning plate is provided in the laser optical path of an external resonator of a laser light source, and by changing the finesse of the tuning plate, the spectral line width of the laser light output from the laser light source is controlled. I made it.
本発明はレーザ光源のスペクトル線幅変更装置に関し、
更に詳しく言えば、レーザ光のスペクトル線幅制御にチ
ューニングプレートのフィネスを係わりしめるようにし
たレーザ光源のスペクトル線幅変更装置に関する。The present invention relates to a spectral linewidth changing device for a laser light source,
More specifically, the present invention relates to a spectral linewidth changing device for a laser light source in which the finesse of a tuning plate is involved in controlling the spectral linewidth of a laser beam.
通信の分野においてはそこで取り扱う情報量の急激な増
大９通信速度の向上環に対処するべく、従来の電気通信
方式を補完乃至はこれに代わるものとして光通信方式の
開発が活発に行なわれている。この光通信方式では光源
を不可欠とするが、その光源の代表的なものとして半導
体レーザがある。この半導体レーザは誘導放出を利用す
るため、現在使用可能な半導体レーザでは、そのレーザ
光のスペクトルに不回避的な広がりが生ずる。一方、現
在開発中にあるコヒーレント通信方式、とりわけ時間的
コヒーレンスを利用した通信方式ではレーザ光のスペク
トル線幅が狭いほど、そこに含まれる他の成分による通
信情報への影響が現れにくくなり、その通信に好結果を
７すので、その狭スペクトル線幅化が要求されている。In the field of communications, in order to cope with the rapid increase in the amount of information handled9 and the increasing communication speed, optical communication systems are being actively developed as a complement to or an alternative to conventional telecommunications systems. . This optical communication system requires a light source, and a typical example of such a light source is a semiconductor laser. Since this semiconductor laser utilizes stimulated emission, currently available semiconductor lasers inevitably broaden the spectrum of their laser light. On the other hand, in coherent communication systems currently under development, especially communication systems that utilize temporal coherence, the narrower the spectral linewidth of laser light, the less likely it is that other components contained therein will affect communication information. Narrowing the spectral linewidth is required to achieve good results in communications.
従来におけるレーザ光のスペクトル線幅制御手段は第６
図に示すものが知られている。Conventional means for controlling the spectral line width of laser light is the sixth
The one shown in the figure is known.
レーザダイオード５０から出力されたレーザ光はＧＲＴ
Ｎ５２．ビームスブリツタ５４．フアラデーアイソレー
タ５６を経て方向性結合器５８で２つの光ファイバ型リ
ング共振器６０．６２へ分けられる。The laser light output from the laser diode 50 is a GRT
N52. Beam blitter 54. It passes through a Faraday isolator 56 and is divided into two optical fiber type ring resonators 60 and 62 by a directional coupler 58.
光フアイバ型リング共振器６０は方向性結合器６４、位
相変調器６６及び発振器６８から成るものであって、入
力されて来たレーザ光のスペクトル線幅に対し予め決め
られたスペクトル線幅を中心にして尖鋭特性を呈するよ
うに調整構成されているものである。The optical fiber ring resonator 60 is composed of a directional coupler 64, a phase modulator 66, and an oscillator 68, and is centered at a predetermined spectral linewidth with respect to the spectral linewidth of the input laser beam. It is configured to be adjusted so that it exhibits sharp characteristics.
従って、入力レーザ光のスペクトル線幅が光フアイバ型
リング共振器６０に設定されているスペクトル線幅から
外れた度合に応じて決まる光出力が光検出器７０にて検
出される。その検出信号が反転増幅器７２、ピーク値保
持回路７４．差動増幅器７６、積分器７８、そしてハ、
ファ増幅器８０を介して、半導体レーザ５０の外部共振
器を構成するミラー８２の位置を変えるべくＰＺＴ板８
４に印加される如きフィードバック制御系により、レー
ザ光のスペクトル線幅制御を行なうようにし７ている。Therefore, the photodetector 70 detects a light output determined according to the degree to which the spectral linewidth of the input laser beam deviates from the spectral linewidth set in the optical fiber ring resonator 60. The detection signal is sent to the inverting amplifier 72, the peak value holding circuit 74. differential amplifier 76, integrator 78, and c.
Through the amplifier 80, the PZT plate 8 is used to change the position of the mirror 82 that constitutes the external resonator of the semiconductor laser 50.
The spectral line width of the laser beam is controlled by a feedback control system such as that applied to the laser beam 7.
この従来手段は、上述のところから明らかな如く、レー
ザ光のスペクトル線幅の制御に光フアイバ型リング共振
器６０のピーク値を用いるため、半導体レーザの光出力
変動、振動等による光学系のずれに起因する光出力変動
によってスペクトル線幅の制御にその影響が現れ易い構
成となっている。又、その線幅制御の容易性に欠ける。As is clear from the above, this conventional means uses the peak value of the optical fiber ring resonator 60 to control the spectral linewidth of the laser beam. The configuration is such that the control of the spectral linewidth is likely to be affected by fluctuations in the optical output caused by this. Furthermore, it is difficult to easily control the line width.
本発明は、斯かる問題点に鑑みて創作されたもので、新
たな自然法則を利用した線幅変更手段を有するレーザ光
源のスペクトル線幅変更装置を提供することを目的とす
る。The present invention was created in view of such problems, and an object of the present invention is to provide a spectral linewidth changing device for a laser light source that has a linewidth changing means that utilizes a new law of nature.
Ｃ問題点を解決するための手段〕
第１図は本発明の原理構成図を示す。本発明は、第１図
に示す如く、レーザ光源４の外部共振器１（７）Ｌ／−
ザ光路内にチューニングプレート２を設け、そのフィネ
スをフィネス変更手段３により変えて出力レーザ光のス
ペクトル線幅の調整乃至制御を行なうように構成したも
のである。Means for Solving Problem C] FIG. 1 shows a diagram of the principle configuration of the present invention. As shown in FIG. 1, the present invention provides an external resonator 1 (7) L/-
A tuning plate 2 is provided in the optical path, and the finesse of the tuning plate 2 is changed by a finesse changing means 3 to adjust or control the spectral line width of the output laser beam.
本発明によれば、レーザ光源の出力レーザ光のスペクト
ル線幅をチューニングプレート２のフィネスを変えるこ
とにより調整乃至制御することができる。According to the present invention, the spectral linewidth of the output laser light from the laser light source can be adjusted or controlled by changing the finesse of the tuning plate 2.
第２図は本発明の一実施例を示す。この図において、５
は半導体レーザダイオードで、これはレーザ駆動電源６
にて駆動される。７．８はコリメートレンズである。２
はチューニングプレートで、これは、例えばＰＺＴ９に
よりピボット１０の回りに回転し得るように構成されて
いる。１１はグレーティングで、これは半導体レーザダ
イオード５からのレーザ光を波長選択的に半導体レーザ
ダイオード５へ帰還させるものである。FIG. 2 shows an embodiment of the invention. In this figure, 5
is a semiconductor laser diode, which is a laser drive power supply 6
It is driven by. 7.8 is a collimating lens. 2
is a tuning plate, which is configured to be rotatable around a pivot 10 by, for example, PZT9. Reference numeral 11 denotes a grating, which returns the laser light from the semiconductor laser diode 5 to the semiconductor laser diode 5 in a wavelength-selective manner.
これら半導体レーザダイオード５とグレーティング１１
との間に外部共振器が形成されるが、その分解能ΔｖＥ
ｃは
で与えられる。但し、上式において、Ｋ、は半導体レー
ザダイオード５の端面で構成されるファブリ・ペロー共
振器の分解能の裾の広がり倍率、Ｋ２はチューニングプ
レート２のフィネスの裾の広がり倍率、ＦＳＲ３Ｌは半
導体レーザダイオード５の自由空間波長、Ｑｔｃは外部
共振器のフィネス、Ｑ、Ｕはチューニングプレート２の
フィネス、そしてＱ、Ｌは半導体レーザダイオード５の
フィネスである。These semiconductor laser diodes 5 and grating 11
An external resonator is formed between the
c is given by. However, in the above equation, K is the magnification of the resolution tail of the Fabry-Perot cavity formed by the end face of the semiconductor laser diode 5, K2 is the finesse tail broadening magnification of the tuning plate 2, and FSR3L is the semiconductor laser diode. 5, Qtc is the finesse of the external cavity, Q, U are the finesse of the tuning plate 2, and Q, L are the finesse of the semiconductor laser diode 5.
上式はレーザ光のスペクトル線幅がチューニングプレー
ト５のフィネスに反比例していることを示している。従
って、チューニングプレート５のフィネスを変えること
によって、レーザ光のスペクトル線幅を変えることが可
能になる。The above equation shows that the spectral linewidth of the laser beam is inversely proportional to the finesse of the tuning plate 5. Therefore, by changing the finesse of the tuning plate 5, it is possible to change the spectral line width of the laser beam.
そのフィネス制御手段は、第２図では、光カプラー１３
．遅延自己ホモダイン式ビート信号発生装互１４．線幅
検出装置１５そして線幅検出装置１５からＰＺＴ電圧を
受けるＰＺＴ９から成るフィードバック系にて構成され
るが、この系によれば半導体レーザダイオード５の出力
レーザ光が光カプラ−１３で分岐され、その分岐レーザ
光を受光する遅延自己ホモダイン式ビート信号発生装置
１４で発生されたビート信号から出力レーザ光のスペク
トル振幅が線幅検出装置１５で、検出され、その検出結
果に応したＰＺＴ電圧がＰＺＴ９へ帰還されるから、上
述した出力レーザ光のスペクトル線幅制御を為している
ことになる。The finesse control means is the optical coupler 13 in FIG.
．． Delayed self-homodyne beat signal generator 14. It is composed of a feedback system consisting of a line width detection device 15 and a PZT 9 that receives a PZT voltage from the line width detection device 15. According to this system, the output laser light of the semiconductor laser diode 5 is split by an optical coupler 13, The spectral amplitude of the output laser beam is detected by the line width detector 15 from the beat signal generated by the delayed self-homodyne beat signal generator 14 that receives the branched laser beam, and the PZT voltage corresponding to the detection result is detected by the PZT 9. Since the spectral line width of the output laser beam described above is controlled.
第３図は遅延自己ホモダイン式ビート信号発生装Ｚを示
し、これは２個の四端子方向性結合器２０．２２及び光
遅延線２４から成り、第１の四端子方向性結合器２０の
一方の方向性結合端子対の入力端子に入力半導体レーザ
光が入力されると、その第１の四端子方向性結合器２０
の一方の方向性結合端子対の出力端子から出力されたレ
ーザ光は第２の四端子方向性結合器２２内の、ダミー終
端されている方向性結合端子対以外のもう１つの方向性
結合端子対を介して光遅延線２４に入力され、この光遅
延線２４において第１の四端子方向性結合器２０におけ
る光スペクトル間の相関性を除き得るだけ遅延された後
、第１の西端子方向性結合器２０の他方の方向性結合端
子対の入力端子に入力され、そしてその出力端子に光学
的に結合された光検出器２６の出力が増幅器２８で増幅
されることによりスペクトル線幅成分についてのビート
信号が得られる。FIG. 3 shows a delayed self-homodyne beat signal generator Z, which consists of two four-terminal directional couplers 20, 22 and an optical delay line 24, one of the first four-terminal directional couplers 20. When the input semiconductor laser light is input to the input terminal of the directional coupling terminal pair, the first four-terminal directional coupler 20
The laser beam output from the output terminal of one of the directional coupling terminal pairs is transmitted to another directional coupling terminal other than the dummy-terminated directional coupling terminal pair in the second four-terminal directional coupler 22. The signal is input to the optical delay line 24 via the optical delay line 24, and is delayed in the optical delay line 24 as much as possible to remove the correlation between the optical spectra in the first four-terminal directional coupler 20. The output of the photodetector 26, which is input to the input terminal of the other directional coupling terminal pair of the directional coupler 20 and optically coupled to its output terminal, is amplified by the amplifier 28 to obtain information about the spectral linewidth component. beat signal is obtained.
又、第２の四端子方向性結合器２２の他方の方向性結合
端子対のダミー終端側とは反対側の端子から大力レーザ
光成分が出力される。Further, a high-power laser beam component is output from the terminal on the opposite side to the dummy termination side of the other directional coupling terminal pair of the second four-terminal directional coupler 22.
第４図は線幅検出値２１５の構成例を示す。第４図装置
はスペクトルアナライザ３０．半値検出器３２．基準電
圧発生器３４及びＰＺＴ駆動用比較器３６から成り、ビ
ート信号のスペクトル分布をスペクトルアナライザ３０
で分析し、その分布の半値幅を半値検出器３２で検出し
てその値と基準値とをＰＺＴ駆動用比較器３６で比較し
て上述ＰＺＴ９へ印加すべきＰＺＴ電圧電圧線幅検出値
を発生するものである。FIG. 4 shows a configuration example of the line width detection value 215. The device shown in FIG. 4 is a spectrum analyzer 30. Half value detector 32. It consists of a reference voltage generator 34 and a PZT driving comparator 36, and the spectral distribution of the beat signal is measured by a spectrum analyzer 30.
The half value width of the distribution is detected by the half value detector 32, and this value is compared with the reference value by the PZT driving comparator 36 to generate the PZT voltage voltage line width detection value to be applied to the above-mentioned PZT9. It is something to do.
第５図は上述フィネス制御手段をオープンループとした
他の実施例を示さんとするものであり、その構成要素中
第２図実施例の構成要素と同一の構成要素には同一の参
照番号を付してその説明を省略する。４０はＰ Ｚ Ｔ
？！！Ｉ御装置である。この実施例はＰＺＴｆｉ＋制
御装置４０にてＰＺＴ９を制御して出力レーザ光のスペ
クトル線幅を可変にしようとするものである。FIG. 5 shows another embodiment in which the finesse control means described above is an open loop, and the same reference numerals are given to the same components as those in the embodiment of FIG. 2. The explanation will be omitted. 40 is PZT
? ! ! It is an I-controlled device. In this embodiment, the PZTfi+control device 40 controls the PZT9 to make the spectral line width of the output laser beam variable.
以上述べたように本発明によれば、レーザ光のスペクト
ル線幅の調整乃至制御を外部共振器内に設けられたチュ
ーニングプレートのフィネスの変更により行なうことが
できる。従って、スペクトル線幅の制御が容易になる。As described above, according to the present invention, the spectral line width of laser light can be adjusted or controlled by changing the finesse of the tuning plate provided within the external resonator. Therefore, the spectral linewidth can be easily controlled.
第１図は本発明の原理構成図、
第２図は本発明の一実施例を示す図、
第３図は遅延自己ホモダイン式ビート信号発生装置の構
成例を示す図、
第４図は線幅検出装置の構成例を示す図、第５図は本発
明の他の実施例を示す図、第６図は従来のスペクトル線
幅制御構成図である。
第１図及び第２図において、
１は外部共振器、
２はチューニングプレート、
３はフィネス変更手段である。
本発明の原理構成図
第１図
本発明の一実施例
Ｉ［２図
線幅検出装置の構成例
第４図
遅延自己ホモダイン式ビート信号発生装置の構成例１１
１３ 図
本発明の他の実施例
第５図
従来のスペクトル線幅制御構成図
第 ６ 図Figure 1 is a diagram showing the principle configuration of the present invention. Figure 2 is a diagram showing an embodiment of the present invention. Figure 3 is a diagram showing an example of the configuration of a delayed self-homodyne beat signal generator. Figure 4 is a line width diagram. FIG. 5 is a diagram showing another embodiment of the present invention, and FIG. 6 is a diagram showing a conventional spectral linewidth control configuration. In FIGS. 1 and 2, 1 is an external resonator, 2 is a tuning plate, and 3 is a finesse changing means. Principle configuration diagram of the present invention Fig. 1 Embodiment I of the present invention Fig. 2 Configuration example of a line width detection device Fig. 4 Configuration example 11 of a delayed self-homodyne beat signal generation device
Figure 13 Another embodiment of the present invention Figure 5 Conventional spectrum linewidth control configuration diagram Figure 6
Claims (1)
部共振器（１）のレーザ光路内に設けられたチューニン
グプレート（２）と、 該チューニングプレート（２）のフィネスを変更するた
めのフィネス変更手段（３）とを設けたことを特徴とす
るレーザ光源のスペクトル線幅変更装置。[Claims] In a laser light source having an external resonator (1), a tuning plate (2) provided in the laser optical path of the external resonator (1), and changing the finesse of the tuning plate (2). A spectral linewidth changing device for a laser light source, characterized in that it is provided with a finesse changing means (3) for changing the finesse.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18921486A JPS6344780A (en) | 1986-08-12 | 1986-08-12 | Spectral line width alteration device of laser beam source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18921486A JPS6344780A (en) | 1986-08-12 | 1986-08-12 | Spectral line width alteration device of laser beam source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6344780A true JPS6344780A (en) | 1988-02-25 |
Family
ID=16237461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18921486A Pending JPS6344780A (en) | 1986-08-12 | 1986-08-12 | Spectral line width alteration device of laser beam source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6344780A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0952643A2 (en) * | 1998-04-23 | 1999-10-27 | Ando Electric Co., Ltd. | External cavity type wavelength-tunable light source |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62291082A (en) * | 1986-04-04 | 1987-12-17 | エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン | Tunable solid state laser and material of the same |
-
1986
- 1986-08-12 JP JP18921486A patent/JPS6344780A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62291082A (en) * | 1986-04-04 | 1987-12-17 | エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン | Tunable solid state laser and material of the same |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0952643A2 (en) * | 1998-04-23 | 1999-10-27 | Ando Electric Co., Ltd. | External cavity type wavelength-tunable light source |
| EP0952643A3 (en) * | 1998-04-23 | 2000-04-26 | Ando Electric Co., Ltd. | External cavity type wavelength-tunable light source |
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