JPH0734494B2 - Semiconductor laser device - Google Patents
Semiconductor laser deviceInfo
- Publication number
- JPH0734494B2 JPH0734494B2 JP3384887A JP3384887A JPH0734494B2 JP H0734494 B2 JPH0734494 B2 JP H0734494B2 JP 3384887 A JP3384887 A JP 3384887A JP 3384887 A JP3384887 A JP 3384887A JP H0734494 B2 JPH0734494 B2 JP H0734494B2
- Authority
- JP
- Japan
- Prior art keywords
- wavelength
- film
- reflectance
- semiconductor laser
- face
- 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 - Fee Related
Links
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、光通信や光情報処理装置に用いられる半導体
レーザ装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device used for optical communication and an optical information processing device.
従来の技術 近年半導体レーザは、光ディスク等の光情報処理装置の
光源として用いられている。光ディスクに情報を記録す
る場合や、書き換え可能な光ディスクでは、記録された
情報を消去する時、半導体レーザの光出力は、30mWから
40mWという高出力が要求される。2. Description of the Related Art In recent years, semiconductor lasers have been used as a light source for optical information processing devices such as optical disks. When recording information on an optical disc or when erasing recorded information on a rewritable optical disc, the optical output of the semiconductor laser is from 30 mW.
High output of 40mW is required.
半導体レーザを高出力動作させる時に問題になるのは信
頼性である。即ち過大な光密度のため、共振器端面が徐
々に損傷を受け、寿命が短くなるのである。この問題
は、レーザ光を主として外部に取り出す方の端面（前端
面）の反射率を下げて、端面における光密度を下げ、反
対の端面（後端面）の反射率を高くすることによって解
決された。（電子通信学会技術研究報告ED84−94,1984
年）。Reliability is a problem when operating a semiconductor laser at high output. That is, due to the excessive light density, the end faces of the resonator are gradually damaged and the life is shortened. This problem was solved by lowering the reflectance of the end face (front end face) that mainly takes out the laser light to lower the light density at the end face and increasing the reflectance of the opposite end face (rear end face). . (Technical report of IEICE ED84-94, 1984)
Year).
反射率を下げるには、レーザ光の波長の0.25波長の厚さ
（以後、0.25波長と記す）である誘電体膜を端面に被着
する。通常誘電体としてアルミナ（Al2O3）が用いられ
る。GaAsに被着した場合、反射率は約２％になる。一方
反射率を高くするには、アルミナとSiを交互に４層、膜
厚をそれぞれ0.25波長としたコーティングが用いられ
る。半導体レーザの後端面から出射されるレーザ光は、
通常ホトダイオードで受け、レーザ光出力のモニタとし
て用いられる。To reduce the reflectance, a dielectric film having a thickness of 0.25 wavelength of the laser light (hereinafter referred to as 0.25 wavelength) is applied to the end surface. Alumina (Al 2 O 3 ) is usually used as the dielectric. When deposited on GaAs, the reflectance is about 2%. On the other hand, in order to increase the reflectance, a coating is used in which four layers of alumina and Si are alternately formed and the thickness of each layer is 0.25 wavelength. The laser light emitted from the rear end surface of the semiconductor laser is
It is usually received by a photodiode and used as a monitor of laser light output.
第４図に、GaAsにアルミナとSiを交互に被着した時の反
射率の変化を示す。４層コーティングすることによっ
て、反射率は93％まで高めることができる。FIG. 4 shows the change in reflectance when alumina and Si are alternately deposited on GaAs. By coating four layers, the reflectance can be increased to 93%.
発明が解決しようとする問題点 ところが、４層コートによって反射率を93％まで高くし
た場合、前端面の反射率が２％なら、後端面から出射さ
れる光は前端面の100分の１程度になり、光出力のモニ
タが困難になる。従って後端面の反射率を85％程度にす
れば、後端面が95％の時の倍以上の光出力が得られる。
第４図よりわかる様に、４層目のSiの膜厚を0.11波長に
すれば、反射率は85％になる。しかしSiの膜厚の変化に
対して反射率の変化が大きいので、Siの膜厚のばらつき
がモニタ出力のばらつきに大きく影響を与える。従って
Siの膜厚が少々ばらついても反射率に大きな変化を与え
ない様な、膜厚条件が望まれる。The problem to be solved by the invention However, if the reflectance of the front end face is 2% when the reflectance is increased to 93% by the four-layer coating, the light emitted from the rear end face is about 1/100 of the front end face. Therefore, it becomes difficult to monitor the optical output. Therefore, if the reflectance of the rear end face is set to about 85%, a light output more than double that when the rear end face is 95% can be obtained.
As can be seen from FIG. 4, the reflectance becomes 85% when the film thickness of the fourth layer of Si is 0.11 wavelength. However, since the change in the reflectance is large with respect to the change in the film thickness of Si, the variation in the film thickness of Si has a great influence on the variation in the monitor output. Therefore
A film thickness condition is desired so that even if the Si film thickness varies a little, the reflectivity does not change significantly.
問題点を解決するための手段 本発明の半導体レーザ装置は、後端面に第一層のアルミ
ナ膜と第二層のシリコン膜のみ0.25波長膜厚で、第三層
のアルミナは0.05波長から0.10波長膜厚で、第四層のシ
リコン膜は、0.30波長から0.45波長膜厚となっている４
層からなる端面コートをそなえて構成されている。Means for Solving the Problems The semiconductor laser device of the present invention has a 0.25 wavelength film only for the alumina film of the first layer and the silicon film of the second layer on the rear end face, and the alumina of the third layer has a wavelength of 0.05 to 0.10 wavelength. In terms of film thickness, the thickness of the fourth silicon film is from 0.30 wavelength to 0.45 wavelength.
It is constructed with an end face coat consisting of layers.
作用 この場合の反射率を第２図に示す。第三層のアルミナ膜
が0.05波長膜厚のとき、第四層のシリコン膜が0.35から
0.45波長膜厚で反射率は79から81％が得られ、第三層の
アルミナ膜が0.10波長膜厚のときは、第四層のシリコン
膜が0.30から0.40波長膜厚で反射率が86から88％とな
る。Function The reflectance in this case is shown in FIG. When the third layer alumina film has a thickness of 0.05 wavelength, the fourth layer silicon film has a thickness of 0.35
A reflectance of 79 to 81% is obtained at a thickness of 0.45 wavelength, and when the alumina film of the third layer has a thickness of 0.10 wavelength, the reflectance of the silicon film of the fourth layer is 0.30 to 86 at a wavelength of 0.40 wavelength. 88%.
実施例 第１図に本発明の半導体レーザの構造図、そして第２図
に、アルミナ及びシリコンの膜厚に対する反射率を示
す。第三層のアルミナが0.05波長膜厚のときも0.10波長
膜厚のときも、第四層のシリコンの膜厚が0.10波長の範
囲でばらついても、反射率の変化はたかだか２％であ
り、反射率の制御性は非常に良い。EXAMPLE FIG. 1 shows the structure of the semiconductor laser of the present invention, and FIG. 2 shows the reflectance with respect to the film thickness of alumina and silicon. Whether the thickness of the third layer of alumina is 0.05 wavelength or 0.10 wavelength, or the thickness of the fourth layer of silicon varies within the range of 0.10 wavelength, the change in reflectance is at most 2%, The controllability of reflectance is very good.
端面へのアルミナとシリコンのコートは、スパッタ法で
行う。第３図（ａ），（ｂ）に、従来の端面コート法を
行った半導体レーザ装置の40mW出力時のモニタ電流の分
布（第３図ａ）と、本発明による端面コート法を行った
半導体レーザ装置の40mW出力時のモニタ電流の分布（第
３図ｂ）を示す。モニタ電流は平均して２倍以上得られ
ており、また、そのばらつきも大幅に改善されているこ
とがわかる。Alumina and silicon are coated on the end faces by a sputtering method. FIGS. 3 (a) and 3 (b) show the distribution of the monitor current at a 40 mW output of the semiconductor laser device which has been subjected to the conventional edge coating method (FIG. 3a), and the semiconductor which has been subjected to the edge coating method according to the present invention. The distribution of the monitor current when the laser device outputs 40 mW (Fig. 3b) is shown. It can be seen that the monitor current is more than doubled on average, and the variation is also greatly improved.
発明の効果 本発明による端面コート法を用いた半導体レーザ装置
は、耐面コートの膜厚の変化に対しても安定な反射率が
得られ、これによりばらつきが少なく実用的なレベルの
モニタ電流をもち、光ディスク等の応用に際して大なる
効果を有する。EFFECTS OF THE INVENTION The semiconductor laser device using the end face coating method according to the present invention can obtain a stable reflectance with respect to a change in the film thickness of the face-resistant coating, which allows a monitor current of a practical level with little variation. It has a great effect when applied to optical disks and the like.
第１図は本発明の半導体レーザ装置の構造図、第２図は
本発明の端面コート法による反射率を示す図、第３図は
モニタ電流の分布を従来の半導体レーザ装置と比較して
示す図、第４図は従来の端面コート法による反射率を示
す図である。 １……半導体レーザ結晶、２……アルミナ・コート膜、
３……シリコン・コート膜、４……ホト・ダイオード、
５……後方出射光、６……前方出射光。FIG. 1 is a structural diagram of a semiconductor laser device of the present invention, FIG. 2 is a diagram showing reflectance by the end face coating method of the present invention, and FIG. 3 is a monitor current distribution in comparison with a conventional semiconductor laser device. FIG. 4 and FIG. 4 are views showing the reflectance by the conventional end face coating method. 1 ... Semiconductor laser crystal, 2 ... Alumina coat film,
3 ... Silicon coat film, 4 ... Photo diode,
5: rearward emitted light, 6: frontward emitted light.
Claims (1)
い方から順に、アルミナ膜，シリコン膜，アルミナ膜，
シリコン膜からなる４層膜があり、その厚さがレーザ光
の波長による光学的距離で、結晶に一番近いアルミナ膜
が0.25波長、その次のシリコン膜も0.25波長、その上の
アルミナ膜は0.05波長から0.10波長で、最後の結晶から
一番離れたシリコン膜の膜厚は、0.30波長から0.45波長
であることを特徴とする半導体レーザ装置。1. An alumina film, a silicon film, an alumina film, and at least one resonator end face in this order from the one closer to the crystal.
There is a 4-layer film consisting of a silicon film, the thickness of which is the optical distance depending on the wavelength of the laser light, the alumina film closest to the crystal is 0.25 wavelength, the next silicon film is 0.25 wavelength, and the alumina film on it is A semiconductor laser device characterized in that the thickness of the silicon film farthest from the last crystal is 0.050 to 0.10 wavelength and 0.30 to 0.45 wavelength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3384887A JPH0734494B2 (en) | 1987-02-17 | 1987-02-17 | Semiconductor laser device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3384887A JPH0734494B2 (en) | 1987-02-17 | 1987-02-17 | Semiconductor laser device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63200589A JPS63200589A (en) | 1988-08-18 |
| JPH0734494B2 true JPH0734494B2 (en) | 1995-04-12 |
Family
ID=12397920
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3384887A Expired - Fee Related JPH0734494B2 (en) | 1987-02-17 | 1987-02-17 | Semiconductor laser device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0734494B2 (en) |
-
1987
- 1987-02-17 JP JP3384887A patent/JPH0734494B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63200589A (en) | 1988-08-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |