JPH0732290B2 - Semiconductor laser device - Google Patents
Semiconductor laser deviceInfo
- Publication number
- JPH0732290B2 JPH0732290B2 JP10214586A JP10214586A JPH0732290B2 JP H0732290 B2 JPH0732290 B2 JP H0732290B2 JP 10214586 A JP10214586 A JP 10214586A JP 10214586 A JP10214586 A JP 10214586A JP H0732290 B2 JPH0732290 B2 JP H0732290B2
- Authority
- JP
- Japan
- Prior art keywords
- face
- film
- semiconductor laser
- output
- reflectance
- 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 title claims description 23
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 9
- 239000013078 crystal Substances 0.000 claims description 7
- 238000000151 deposition Methods 0.000 claims description 2
- 230000003287 optical effect Effects 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000002310 reflectometry Methods 0.000 description 5
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 238000003776 cleavage reaction Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000010365 information processing Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000007017 scission Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease 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
- H01S5/02—Structural details or components not essential to laser action
- H01S5/028—Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、光通信や光ディスク、レーザプリンタ等の光
情報処理装置の光源として用いられる半導体レーザ装置
に関するものである。Description: TECHNICAL FIELD The present invention relates to a semiconductor laser device used as a light source of an optical information processing device such as optical communication, an optical disc, and a laser printer.
（従来の技術） 昨今の半導体レーザ装置は、小型軽量，高効率，低価格
等の優れた特性を有するため、光通信や光情報処理装置
の光源として非常に重要な位置を占めている。現在光デ
ィスクやレーザプリンタ等に用いられているGaAlAs系の
半導体レーザのレーザ共振器（以下共振器と省略する）
は、通常、半導体結晶の劈開面を利用して作製されてい
る。GaAsは、屈折率が約3.6であるために、劈開面を利
用した共振器の端面の反射率が約30％であり、He−Neレ
ーザ等の気体レーザに比べて反射率の値が低い。前記の
ように反射率の低いGaAlAs系の半導体レーザでも発振が
可能なのは、GaAs結晶の発振利得が非常に大きいためで
ある。半導体結晶の両端を劈開して作製された共振器の
両端面は反射率が同一であるため、レーザ光は前記両端
面から同一出力で出射されるが、通常は前記両端面の片
側の端面（以下前端面と省略する）から出力されるレー
ザ光を主目的用に使用し、他の端面（以下後端面と省略
する）から出射されるレーザ光は、光検出器で受光して
光出力のモニタとして使用されている場合がほとんどで
ある。すなわち、後端面からの出射光の出力は、前端面
からの出射光の出力よりも少なくモニタ可能の程度の出
力でよい。後端面からの出射光の出力を少なくするため
に前記後端面の反射率を高くすれば、レーザ発振のしき
い電流値が減少する。また、前端面からの出射光の出力
が増加して共振器の効率が高くなり、共振器のＱ値が大
きくなるので単一モード性が良好となって雑音が減少
し、半導体レーザ装置としての特性が良くなる。(Prior Art) Recent semiconductor laser devices have excellent characteristics such as small size, light weight, high efficiency, and low price, and therefore, occupy a very important position as a light source for optical communication and optical information processing devices. Laser cavity of GaAlAs semiconductor laser currently used in optical disks and laser printers (hereinafter abbreviated as cavity)
Is usually manufactured by utilizing the cleavage plane of a semiconductor crystal. Since GaAs has a refractive index of about 3.6, the reflectivity of the end face of the resonator utilizing the cleavage plane is about 30%, which is lower than that of a gas laser such as a He-Ne laser. As described above, the GaAlAs-based semiconductor laser having a low reflectance can also oscillate because the GaAs crystal has an extremely large oscillation gain. Since both end faces of a resonator produced by cleaving both ends of a semiconductor crystal have the same reflectance, laser light is emitted from the both end faces with the same output, but usually one end face of the both end faces ( The laser light output from the front end face will be used for the main purpose, and the laser light emitted from the other end face (hereinafter abbreviated as the rear end face) will be received by the photodetector and Mostly used as a monitor. That is, the output of the light emitted from the rear end face may be smaller than the output of the light emitted from the front end face and may be an output that can be monitored. If the reflectance of the rear end face is increased in order to reduce the output of the light emitted from the rear end face, the threshold current value of laser oscillation decreases. Further, the output of the light emitted from the front end face increases, the efficiency of the resonator increases, and the Q value of the resonator increases, so that the single mode property is improved and the noise is reduced. The characteristics are improved.
従来の共振器の後端面の反射率を高くする方法を、第５
図を参照して説明する。第５図は、従来の共振器のSi膜
の膜厚に対する後端面の反射率の理論値の関係図を示
す。第５図に示すように、共振器に膜厚0.25波長のAl2O
3膜を被着した場合、すなわち波長8000Åの共振器に屈
折率1.64のAl2O3を実際の膜厚1220Åで被着した場合
に、Siの膜厚の大きさにより後端面の反射率は異なり、
Siの膜厚を0.25波長、すなわち波長8000Åの場合は屈折
率3.3のSiの実際の膜厚を606Åとしたときに、前記後端
面の反射率は最大の約76％となる。しかも、Siの膜厚が
0.2波長から0.3波長まで変化しても前記後端面の反射率
の変化が少ないという利点がある。The conventional method for increasing the reflectance of the rear end surface of the resonator is described in
It will be described with reference to the drawings. FIG. 5 shows a relationship diagram of the theoretical value of the reflectance of the rear end face with respect to the film thickness of the Si film of the conventional resonator. As shown in FIG. 5, the resonator has a film thickness of 0.25 wavelength of Al 2 O.
When three films are deposited, that is, when Al 2 O 3 with a refractive index of 1.64 is deposited on a resonator with a wavelength of 8000 Å with an actual film thickness of 1220 Å, the reflectance of the rear end face depends on the size of Si film. Different,
When the Si film thickness is 0.25 wavelength, that is, when the actual film thickness of Si having a refractive index of 3.3 is 606 Å when the wavelength is 8000 Å, the reflectance of the rear end face becomes about 76% at the maximum. Moreover, the Si film thickness
Even if the wavelength changes from 0.2 to 0.3, there is an advantage that the reflectance of the rear end face hardly changes.
（発明が解決しようとする問題点） 前記従来の半導体レーザ装置では、コンパクトディスク
等に用いられている最大光出力5mW程度の半導体レーザ
装置においては、後端面からの出射光の出力が前端面か
らの出射光の出力の0.23倍では、十分なモニタ出力を得
ることができないという問題がある。後端面からの出射
光の出力を大きくするためには反射率を60％程度に下げ
ればよいが、そのためには第５図に示すようにSiの膜厚
を0.12波長に薄くする必要があり、Siの膜厚を0.12波長
にするとSiの膜厚の微妙変化に対する反射率の変化が大
きいため、Siの膜厚を精度良く製作しなければならない
ので、実用的に好ましくないという問題点がある。(Problems to be Solved by the Invention) In the conventional semiconductor laser device, in a semiconductor laser device having a maximum optical output of about 5 mW used for a compact disc or the like, the output of the light emitted from the rear end face is from the front end face. There is a problem that a sufficient monitor output cannot be obtained when the output of the output light is 0.23 times. In order to increase the output of the light emitted from the rear end face, the reflectance should be reduced to about 60%, but for that purpose, it is necessary to reduce the Si film thickness to 0.12 wavelength as shown in FIG. When the Si film thickness is set to 0.12 wavelength, the reflectance changes greatly with respect to the subtle changes in the Si film thickness. Therefore, the Si film thickness must be accurately manufactured, which is not preferable in practice.
（問題点を解決するための手段） 前記問題点を解決するために本発明は、共振器の後端面
に膜厚0.10波長のAl2O3コート膜と膜厚0.32波長のSiコ
ート膜を被着するか、または膜厚0.40波長のAl2O3コー
ト膜と膜厚0.18の波長のSiコート膜を被着した共振器に
よる半導体レーザ装置を提供するものである。(Means for Solving the Problems) In order to solve the above problems, the present invention provides an Al 2 O 3 coat film having a film thickness of 0.10 and a Si coat film having a film thickness of 0.32 on the rear end face of a resonator. The present invention provides a semiconductor laser device including a resonator, which is either deposited or coated with an Al 2 O 3 coating film having a wavelength of 0.40 and a Si coating film having a wavelength of 0.18.
（作用） 前記構成によれば、Siコート膜の膜厚が0.04波長程度、
すなわち約97Å変化しても反射率がほとんど変化しな
い、共振器後端面の反射率60％程度の特性の優れた半導
体レーザ装置を再現性良く得ることができる。(Operation) According to the above configuration, the thickness of the Si coat film is about 0.04 wavelength,
That is, it is possible to obtain with good reproducibility a semiconductor laser device having excellent characteristics in which the reflectance of the rear facet of the resonator is about 60%, in which the reflectance hardly changes even if it changes by about 97Å.
（実施例） 本発明の半導体レーザ装置を、第１図ないし第４図を参
照して説明する。第１図は本発明の半導体レーザ装置の
共振器の斜視図、第２図は本発明の第１図の実施例にお
けるSi膜の膜厚に対する後端面の反射率の理論値の関係
図、第３図は本発明の第２の実施例におけるSi膜の膜厚
に対する後端面の反射率の理論値の関係図、第４図は光
出力とモニタ電流の関係を示す。(Example) A semiconductor laser device of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of a resonator of a semiconductor laser device of the present invention, and FIG. 2 is a relational diagram of the theoretical value of the reflectance of the rear end face with respect to the thickness of the Si film in the embodiment of FIG. 1 of the present invention. FIG. 3 shows the relationship between the theoretical value of the reflectance of the rear end surface and the film thickness of the Si film in the second embodiment of the present invention, and FIG. 4 shows the relationship between the optical output and the monitor current.
第１図において、半導体レーザ結晶１の前端面２には膜
厚0.5波長のAl2O3コート膜３が被着され、後端面４には
Al2O3コート膜３′とSiコート膜５が被着されている。
前端面２の反射率は、劈開しただけの半導体レーザ結晶
１の反射率と変わらず約30％である。後端面４の反射率
は、次に説明する膜厚の本発明のコード膜３′,5で約60
％となっている。この結果、後端面から出射するレーザ
光６′の出力は、前端面２から出射するレーザ光６の出
力の0.43倍となるが、フォトダイオード等で光電変換し
てモニタ出力を得るために用いるだけなので、この程度
の出力で十分である。In FIG. 1, a front end face 2 of a semiconductor laser crystal 1 is coated with an Al 2 O 3 coat film 3 having a film thickness of 0.5 wavelength, and a rear end face 4 thereof is covered.
An Al 2 O 3 coat film 3 ′ and a Si coat film 5 are deposited.
The reflectance of the front end face 2 is about 30%, which is the same as that of the semiconductor laser crystal 1 just cleaved. The reflectance of the rear end surface 4 is about 60 for the code films 3 ', 5 of the present invention having the film thickness described below.
%. As a result, the output of the laser light 6 ′ emitted from the rear end face becomes 0.43 times the output of the laser light 6 emitted from the front end face 2, but it is used only to obtain the monitor output by photoelectric conversion with a photodiode or the like. Therefore, this level of output is sufficient.
本発明の第１の実施例は、後端面４に膜厚0.10波長のAl
2O3コート膜３′を被着した上に0.28ないし0.36波長のS
iコート膜を被着した場合であり、この場合第２図に示
すように、Siコート膜５の膜厚が0.28ないし0.36波長の
間で反射率が余り変化せず略々60％の反射率を得られる
ことが分かる。In the first embodiment of the present invention, the rear end face 4 has a thickness of 0.10 wavelength of Al.
2 O 3 coating film 3 ′ is applied and S of 0.28 to 0.36 wavelength is applied.
This is the case where the i-coat film is deposited. In this case, as shown in FIG. 2, the reflectivity does not change much when the film thickness of the Si-coat film 5 is between 0.28 and 0.36 wavelengths, and the reflectivity is about 60%. You can get
本発明の第２の実施例は、後端面４に膜厚0.40波長のAl
2O3コート膜３′を被着した上に0.14ないし0.22波長のS
iコート膜を被着した場合であり、この場合第３図に示
すように、Siコート膜の膜厚が0.14ないし0.22波長の間
で反射率が余り変化せず略々60％の反射率を得られるこ
とが分かる。In the second embodiment of the present invention, the rear end surface 4 is made of Al having a thickness of 0.40 wavelength.
2 O 3 coat film 3 ′ is applied and S of 0.14 to 0.22 wavelength is applied.
This is the case where the i-coat film is deposited. In this case, as shown in FIG. 3, the reflectivity does not change so much when the film thickness of the Si-coat film is between 0.14 and 0.22 wavelengths, and the reflectivity is about 60%. You can see that you get.
第４図において、、曲線Ａは本発明の構成で波長率を60
％とした半導体レーザ装置、曲線Ｂは従来のAl2O3とSi
をそれぞれ0.25波長ずつ被着して反射率を76％とした半
導体レーザ装置の前方光出力に対するモニタ電流の特性
を示す。本発明の半導体レーザ装置によれば、光出力1m
W当たり95μＡのモニタ出力が得られるので自動光出力
制御（APC）等に使用するのに十分なモニタ出力値を得
ることができる。In FIG. 4, a curve A shows the wavelength ratio of 60 in the constitution of the present invention.
% Semiconductor laser device, curve B is the conventional Al 2 O 3 and Si
The characteristics of the monitor current with respect to the forward light output of a semiconductor laser device having a reflectance of 76% by depositing 0.25 wavelengths for each of these are shown. According to the semiconductor laser device of the present invention, the optical output is 1 m.
Since a monitor output of 95 μA per W can be obtained, a monitor output value sufficient for use in automatic light output control (APC) or the like can be obtained.
（発明の効果） 本発明の端面コート膜の構成によれば、優れた特性の半
導体レーザ装置を量産することができて、大きな実用的
効果を得ることができる。(Effects of the Invention) According to the constitution of the end face coating film of the present invention, semiconductor laser devices having excellent characteristics can be mass-produced, and great practical effects can be obtained.
第１図は本発明の半導体レーザ装置の共振器の斜視図、
第２図は本発明の第１の実施例におけるSi膜の膜厚に対
する後端面の反射率の理論値の関係図、第３図は本発明
の第２の実施例におけるSi膜の膜厚に対する後端面の反
射率の理論値の関係図、第４図は光出力とモニタ電流の
関係図、第５図は従来の共振器のSi膜の膜厚に対する後
端面の反射率の理論値の関係図を示す。 １…半導体レーザ結晶、２…前端面、3,3′…Al2O3コー
ト膜、４…後端面、５…Siコート層、6,6′…レーザ
光。FIG. 1 is a perspective view of a resonator of a semiconductor laser device of the present invention,
FIG. 2 is a diagram showing the relationship between the theoretical value of the reflectance of the rear end face and the film thickness of the Si film in the first embodiment of the present invention, and FIG. 3 is the film thickness of the Si film in the second embodiment of the present invention. Fig. 4 is a relationship diagram of the theoretical value of the reflectance of the rear facet, Fig. 4 is a relationship diagram of the optical output and monitor current, and Fig. 5 is a relationship of the theoretical value of the reflectance of the rear facet with respect to the thickness of the Si film of the conventional resonator. The figure is shown. 1 ... Semiconductor laser crystal, 2 ... Front end face, 3,3 '... Al 2 O 3 coating film, 4 ... Rear end face, 5 ... Si coating layer, 6, 6' ... Laser light.
Claims (1)
も一方にAl2O3膜とSi膜を被着させるとともに、前記Al2
O3膜の膜厚が0.10波長で、前記Si膜の膜厚が0.28波長な
いし0.36波長であるか、または前記Al2O3膜の膜厚が0.4
0波長で、前記Si膜の膜厚が0.14波長ないし0.22波長で
あることを特徴とする半導体レーザ装置。1. A an Al 2 O 3 film and the Si film on at least one of the resonator end face of the semiconductor laser crystal with depositing said Al 2
The film thickness of the O 3 film is 0.10 wavelength, the film thickness of the Si film is 0.28 wavelength to 0.36 wavelength, or the film thickness of the Al 2 O 3 film is 0.4
A semiconductor laser device, wherein the Si film has a thickness of 0.14 to 0.22 wavelengths at 0 wavelength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10214586A JPH0732290B2 (en) | 1986-05-06 | 1986-05-06 | Semiconductor laser device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10214586A JPH0732290B2 (en) | 1986-05-06 | 1986-05-06 | Semiconductor laser device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62260381A JPS62260381A (en) | 1987-11-12 |
| JPH0732290B2 true JPH0732290B2 (en) | 1995-04-10 |
Family
ID=14319582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10214586A Expired - Lifetime JPH0732290B2 (en) | 1986-05-06 | 1986-05-06 | Semiconductor laser device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0732290B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5031186A (en) * | 1989-03-15 | 1991-07-09 | Matsushita Electric Industrial Co., Ltd. | Semiconductor laser device |
| FR2694457B1 (en) * | 1992-07-31 | 1994-09-30 | Chebbi Brahim | Semiconductor laser for detecting light radiation, method for obtaining a photosensitive detector, and application of such a laser to detect light radiation. |
| JP4286683B2 (en) | 2004-02-27 | 2009-07-01 | ローム株式会社 | Semiconductor laser |
-
1986
- 1986-05-06 JP JP10214586A patent/JPH0732290B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62260381A (en) | 1987-11-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |