JPS62159490A - Method for selection of semiconductor laser - Google Patents
Method for selection of semiconductor laserInfo
- Publication number
- JPS62159490A JPS62159490A JP239286A JP239286A JPS62159490A JP S62159490 A JPS62159490 A JP S62159490A JP 239286 A JP239286 A JP 239286A JP 239286 A JP239286 A JP 239286A JP S62159490 A JPS62159490 A JP S62159490A
- Authority
- JP
- Japan
- Prior art keywords
- laser
- dfb laser
- ratio
- cleaved
- elements
- 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
Landscapes
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は分布帰還型半導体レーザの選別方法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for selecting distributed feedback semiconductor lasers.
レーザ共振器中に回折格子を備えた分布帰還型半導体レ
ーザ（Ｄｉｓｔｒｉｂｕｔｅｄ Ｆｅ＠ｄ Ｂａｃｋ
Ｌａ５ｅｒ以下ＤＦＢレーザと略す）は、単一軸モード
発振を有する光源であるため、近年、急速に開発が進め
られ長距離大容量光通信用光源、光計測器用光源として
実用化されつつある。しかし、１枚のウェハからＤＦＢ
レーザを切り出すと、そのすべてが必ずしも単一軸モー
ド発振するわけではなく、発振軸モードが複数本存在し
たり、発蛋軸モードが単一であっても、出力レベルによ
シ発振軸モードの変化を起こしたりすることがある。（
以下この現象をキンクと称す）。１枚のウェハから、キ
ンクの現われる素子数を減らす対策として片側の光出射
面を無反射コーティング（反射率約１０％）する方法が
ある。しかし、この構造を採υ入れても完全にキンクの
起こる素子をなくすことはできない。Distributed feedback semiconductor laser (Distributed Fe@d Back) equipped with a diffraction grating in the laser cavity
Since the La5er (hereinafter abbreviated as DFB laser) is a light source having single-axis mode oscillation, its development has progressed rapidly in recent years, and it is being put into practical use as a light source for long-distance, large-capacity optical communications and a light source for optical measuring instruments. However, DFB from one wafer
When a laser is cut out, not all of it oscillates in a single axis mode, and even if there are multiple oscillation axis modes or a single oscillation axis mode, the oscillation axis mode changes depending on the output level. It may cause (
(Hereinafter, this phenomenon will be referred to as kink). As a measure to reduce the number of elements in which kinks appear from one wafer, there is a method of coating one side of the light emitting surface with an anti-reflection coating (reflectance of about 10%). However, even if this structure is adopted, elements that cause kink cannot be completely eliminated.
ＤＦＢレーザは、安定に単−葡モード動作することが必
須条件であるため、そのような素子を選別することが重
要になってくる。従来、単一軸モード動作の素子を選別
する方法として、その発振スペクトルを見たシ、入力電
流対微分光出力特性を見たりする方法があったが、これ
らの方法は直流入力電流のもとで動作させることが多く
、そのためにＤＦＢレーザを１つ１つヒートシンクに取
り付けなければいけない等の工程を含んでいた。Since stable single-mode operation is an essential condition for a DFB laser, it is important to select such a device. Conventionally, there have been methods to select devices operating in single-axis mode by looking at their oscillation spectra or by looking at differential optical output characteristics versus input current, but these methods only work under DC input current. The DFB lasers were often operated, and this included steps such as having to attach each DFB laser to a heat sink one by one.
本発明では単一軸モード半導体レーザにおいて、キンク
の少ない安定な単一軸モード動作を有する素子を選別す
る方法を提供することにある。An object of the present invention is to provide a method for selecting a device having stable single-axis mode operation with few kinks in a single-axis mode semiconductor laser.
本発明は、両端へき開型ＤＦＢレーザ、及び片面無反射
コーティング型ＤＦＢレーザの両党出射面の外部微分量
子効率の比を測定し、その比よりキンクの出にくい素子
を選別するものである。The present invention measures the ratio of external differential quantum efficiencies of both emission surfaces of a double-end cleavage type DFB laser and a single-sided anti-reflection coating type DFB laser, and selects an element that is less likely to cause kinks based on the ratio.
第１図に示すような片面ｌＯで無反射コーティング、片
面３２４へき開面の非対称ＤＦ’Ｂレーザの、両光出射
面の光出力比と、副モードとのしきい値利得差の小さい
素子の分布を計算すると、第２図のようＫなる。ＤＦＢ
レーザの前後光出力比は、レーザ共振器内の回折格子が
、その端面でどの位置で切れているかによって決まる。As shown in Figure 1, the optical output ratio of both light emitting surfaces of an asymmetric DF'B laser with 1O and anti-reflection coating on one side and 324 cleavage planes on one side, and the distribution of elements with small threshold gain differences with the secondary mode. When calculated, it becomes K as shown in Figure 2. DFB
The front-to-back optical output ratio of the laser is determined by where the diffraction grating in the laser resonator is cut at its end face.
この計算では、端面における回折格子の位相を１６通ｐ
Ｋ分けて、両端面で計１６Ｘ１６＝２５６通シの場合で
計算したものである。In this calculation, the phase of the diffraction grating at the end face is determined by 16 p
This is calculated based on the case where the wire is divided into K, and there are a total of 16 x 16 = 256 threads on both end faces.
第２図の結果よシ、片面ＡＲコート型ＤＦＢレーザでは
元画後出力比が０．３から０．８の間の素子はキンクの
出る確率が少ないことがわかる。また、光の前後出力比
がこの付近の値をもつ素子は、第３図に示すように、副
モードとのしきい値利得差が大きい。副モードとのしき
い値利得差の大きい素子は、安定な単一軸モード動作を
意味し、温度が変動した場合の単一軸モード性や、変調
時の副モード抑圧比が良好であることを意味する。The results shown in FIG. 2 show that in single-sided AR-coated DFB lasers, the probability of kink occurring is low in elements with an output ratio after original image of between 0.3 and 0.8. Furthermore, as shown in FIG. 3, an element having a light front-to-back output ratio around this value has a large threshold gain difference with the sub-mode. A device with a large threshold gain difference from the secondary mode means stable single-axis mode operation, good single-axis mode property when the temperature fluctuates, and good secondary mode suppression ratio during modulation. do.
端面をコーティングしていない場合の両光出射面の光出
力比と、副モードとのしきい値利得差の小さい素子の分
布を計算すると第４図のようになる。両端へき開面の場
合は、光出力前後比が０．６〜１．３の素子がキンクが
少なく、単一軸モード性が良いことがわかる。FIG. 4 shows the distribution of the light output ratio of both light output surfaces when the end surfaces are not coated and the distribution of the element having a small threshold gain difference with the submode. In the case of cleaved planes at both ends, it can be seen that elements with optical output front-to-back ratios of 0.6 to 1.3 have fewer kinks and good single-axis mode properties.
片面をＳ１Ｎ膜で１０優に反射率を抑えた非対称ＤＦＢ
レーザの光の前後出力比と、キンク発生率の分布の実験
結果を第５図に示す。光の前後出力比が０．７付近を中
心にキンクの少ない素子が集中している。計算結果では
光の前後出力比が０．５付近で一番キンクが少なくなっ
ているが、これは実際の素子の端面反射率が正確には１
０％とはなっていないためであるつ
次に、ＤＦ’Ｂレーザの光の前後出力比の測定例を第６
図に示す。光の前後出力比を測定するには、ＤＦＢレー
ザはパルス駆動づ十分である。パルス駆動で評価できる
ため、ＤＦＢレーザをヒートシンクに融着して熱を放散
させてやる必要がなく、ＤＦＢレーザを治具にはさみ込
むだけで測定することができる。Asymmetrical DFB with S1N film on one side to reduce reflectance by over 10%
FIG. 5 shows the experimental results of the front-to-back output ratio of laser light and the distribution of kink occurrence rate. Elements with few kinks are concentrated around a light front-to-back output ratio of around 0.7. According to the calculation results, the kink is the least when the front-back output ratio of the light is around 0.5, but this is because the actual end face reflectance of the element is exactly 1.
This is because it is not 0%.Next, we will show an example of measuring the front and rear output ratio of the DF'B laser light in the sixth section.
As shown in the figure. Pulsed driving of a DFB laser is sufficient to measure the front-to-back power ratio of light. Since evaluation can be performed by pulse drive, there is no need to fuse the DFB laser to a heat sink to dissipate heat, and measurement can be performed simply by inserting the DFB laser into a jig.
分布帰遠型半導体レーザ共振器内の回折格子の位相が端
面において、どの位置で切れているかによって特性がま
ちまちであるため、単一軸モード性の良い素子を選別す
るには、従来レーザのスペクトル測定に頼っていた。レ
ーザのスペクトル測定には、熟練者をもってしても１回
５分から１０分かかり、１枚のウェハから５００素子近
くとれる素子を１つ１つスペクトル測定すると大変な手
間になる。これを光の前後比０．３〜０．８のものを先
に選別すれば、単一軸モードをもつ素子は８割以上あり
、工程の大幅な短縮化が実現できる。また、温度変動時
や、変調時においても、単一軸モードを維持する素子を
高い確率で選別することができる。Characteristics vary depending on where the phase of the diffraction grating in a distributed return type semiconductor laser resonator is cut off at the end face, so in order to select a device with good single-axis mode property, it is necessary to measure the spectrum of a conventional laser. was relying on It takes 5 to 10 minutes each time even for an experienced person to measure a laser spectrum, and measuring the spectrum of each of the nearly 500 elements that can be obtained from a single wafer is extremely time-consuming. If we first select those with a light front-to-front ratio of 0.3 to 0.8, more than 80% of the elements will have a single-axis mode, and the process can be significantly shortened. Further, even during temperature fluctuations or modulation, elements that maintain a single-axis mode can be selected with high probability.
第１図は、ＤＦＢレーザの例で、片面無反射コーティン
グ（Ｒ〜ｘｏ９６）した素子を示す図。
第２図は、片面無反射コーティング、片面へき開面型Ｄ
ＦＢレーザの前後光出力比とキンクの起こシやすさを計
算した結果を示す図である。第３図は、片面無反射コー
ティング、片面へき開面型ＤＦＢレーザで、光の前後出
力比が０．４から０．５における副モードとのしきい値
利得差の分布を計算した結果を示す図である。
第４図は、両端面へき開型ＤＦＢレーザにおける光の前
後出力比とキンクの起こりやすさの分布を計算した例を
示す図である。
第５図は、片面１０ｇ６ＡＲコート型ＤＦＢレーザの光
の前後出力比と、キンク発生率の分布の実験結果を示す
図である。
第６図は、光の前後出力比測定系の構成図である。FIG. 1 is an example of a DFB laser, which shows an element with anti-reflection coating on one side (R~xo96). Figure 2 shows one-sided non-reflective coating, one-sided cleavage type D.
FIG. 3 is a diagram showing the results of calculating the front and rear optical output ratio of an FB laser and the susceptibility to kink. Figure 3 is a diagram showing the results of calculating the distribution of the threshold gain difference with the secondary mode when the front-rear output ratio of light is 0.4 to 0.5 in a single-sided non-reflective coating and single-sided cleavage plane DFB laser. It is. FIG. 4 is a diagram showing an example of calculating the front-rear output ratio of light and the distribution of the likelihood of kink in a double-end facet cleavage type DFB laser. FIG. 5 is a diagram showing the experimental results of the light front and rear output ratios of a single-sided 10 g6 AR coated DFB laser and the distribution of the kink occurrence rate. FIG. 6 is a configuration diagram of a light front and rear output ratio measurement system.
Claims (1)
導体レーザの２つの光出射端面の光出力比が （イ）片面ＡＲコート、片面へき開型分布帰還型半導体
レーザではへき開側光出力／ＡＲコート側光出力＝０．
３〜０．８ （ロ）両端へき開型分布帰還半導体レーザでは両端面光
出力比＝０．６〜１．３ をもつ素子を良品として選別することを特徴とする選別
方法。[Claims] In a distributed feedback semiconductor laser with a diffraction grating in the laser resonator, the optical output ratio of the two light emitting end faces is (a) one side AR coated and one side cleaved. Side light output/AR coat side light output = 0.
3 to 0.8 (b) In a double-end cleaved distributed feedback semiconductor laser, a selection method characterized in that elements having a double-end facet optical output ratio of 0.6 to 1.3 are selected as good products.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP239286A JPS62159490A (en) | 1986-01-08 | 1986-01-08 | Method for selection of semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP239286A JPS62159490A (en) | 1986-01-08 | 1986-01-08 | Method for selection of semiconductor laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62159490A true JPS62159490A (en) | 1987-07-15 |
Family
ID=11527962
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP239286A Pending JPS62159490A (en) | 1986-01-08 | 1986-01-08 | Method for selection of semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62159490A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1143582A1 (en) * | 1999-09-29 | 2001-10-10 | The Furukawa Electric Co., Ltd. | Gain-coupled distributed feedback semiconductor laser |
-
1986
- 1986-01-08 JP JP239286A patent/JPS62159490A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1143582A1 (en) * | 1999-09-29 | 2001-10-10 | The Furukawa Electric Co., Ltd. | Gain-coupled distributed feedback semiconductor laser |
| EP1143582A4 (en) * | 1999-09-29 | 2002-04-10 | Furukawa Electric Co Ltd | Gain-coupled distributed feedback semiconductor laser |
| US6493369B2 (en) | 1999-09-29 | 2002-12-10 | The Furukawa Electrical Co., Ltd. | Gain-coupling distributed feedback type semiconductor laser device |
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