JPH07120834B2 - Semiconductor laser array device - Google Patents
Semiconductor laser array deviceInfo
- Publication number
- JPH07120834B2 JPH07120834B2 JP61311400A JP31140086A JPH07120834B2 JP H07120834 B2 JPH07120834 B2 JP H07120834B2 JP 61311400 A JP61311400 A JP 61311400A JP 31140086 A JP31140086 A JP 31140086A JP H07120834 B2 JPH07120834 B2 JP H07120834B2
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- array device
- laser array
- light
- stripe
- 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
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
- H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
- H01S5/4025—Array arrangements, e.g. constituted by discrete laser diodes or laser bar
- H01S5/4031—Edge-emitting structures
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- 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等の光源に用いられる
半導体レーザアレイ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 array device used as a light source for optical communication, an optical information processing device and the like.
従来の技術 半導体レーザは、空間的コヒーレンスに優れた光源で、
そのレーザ光の波長（〜0.8μｍ）程度のスポット径に
まで集光できるので、超高密度の光ディスクメモリや、
高品位のレーザビームプリンタなどに用いられている。
近年、メモリへの記録やプリンタの高速化のため、レー
ザ光出力の高出力への要求が益々強くなってきた。半導
体レーザを高出力駆動する時の問題点は、光導波路内で
のレーザビームの安定性もあるが、レーザ光の共振器端
面でのスポット径が小さく（約10μｍ×0.4μｍ）、光
密度が非常に高くなることである。端面での光密度が２
×106W/cm2以上になると、一般にレーザを構成する半導
体結晶が溶融し、素子が破壊されるに至る。上記のスポ
ット径を考えると、この時の光出力は80mwとなる。この
程度の光出力が１個の導波路からなる半導体レーザの光
出力の限界である。そこで、第５図に示すように、導波
路を平行に複数本並置し、導波路間を光学的に結合さ
せ、各導波路（以下ストライプと呼ぶ）の発振状態（位
相）に相関を持たせたマルチストライプのレーザアレイ
が作られた。Conventional technology A semiconductor laser is a light source with excellent spatial coherence.
Since it can be focused to a spot diameter of about the laser light wavelength (up to 0.8 μm), it can be used for ultra-high density optical disk memory,
It is used in high-quality laser beam printers.
In recent years, there has been an increasing demand for higher laser light output in order to record in a memory and speed up a printer. A problem when driving a semiconductor laser at high output is the stability of the laser beam in the optical waveguide, but the spot diameter of the laser beam at the cavity end face is small (about 10 μm × 0.4 μm), and the light density is It will be very high. The light density at the end face is 2
If it exceeds × 10 6 W / cm 2 , the semiconductor crystal that constitutes the laser generally melts and the device is destroyed. Considering the above spot diameter, the optical output at this time is 80 mw. This level of light output is the limit of the light output of the semiconductor laser including one waveguide. Therefore, as shown in FIG. 5, a plurality of waveguides are juxtaposed in parallel and the waveguides are optically coupled to each other so that the oscillation states (phases) of the respective waveguides (hereinafter referred to as stripes) have a correlation. A multi-stripe laser array was created.
発明が解決しようとする問題点 レーザアレイの放射パターン（遠視野像:FFP）は、各ス
トライプ内での光の位相によって敏感に変化する。Problems to be Solved by the Invention The radiation pattern (far field image: FFP) of the laser array is sensitively changed depending on the phase of light in each stripe.
第６図（ａ）に各ストライプ内の電界が同位相の場合
の、導波路内の光分布及びFFPを示す。この場合、FFPは
単峰性で幅の狭い（＜５゜）ビームとなる。しかし隣り
合うストライプの間で光強度が０とならないため、発振
しきい値が高い。第６図（ｂ）に示す場合は、各ストラ
イプで電界の位相がπずれており、この場合は、ストラ
イプ間で光強度が０となるため、光損失が少なくなって
しきい値が（ａ）の場合よりも低くなる。従って第５図
に示すレーザアレイは（ｂ）の反対称モード（out phas
e）で発振する。ところがこの場合FFPは双峰性となり、
単一スポットに絞り込むことができない。FIG. 6 (a) shows the optical distribution and FFP in the waveguide when the electric fields in each stripe have the same phase. In this case, the FFP is a monomodal, narrow beam (<5 °). However, since the light intensity does not become 0 between adjacent stripes, the oscillation threshold is high. In the case shown in FIG. 6 (b), the phase of the electric field is deviated by π in each stripe. In this case, the light intensity becomes 0 between the stripes, so that the optical loss decreases and the threshold value becomes (a ) Is lower than the case. Therefore, the laser array shown in FIG. 5 has the antisymmetric mode (out phas) of (b).
It oscillates in e). However, in this case, FFP becomes bimodal,
You cannot narrow down to a single spot.
本発明は、上記欠点に鑑み、FFPが単峰性である半導体
レーザアレイ装置を提供するものである。In view of the above drawbacks, the present invention provides a semiconductor laser array device in which the FFP has a single peak.
問題点を解決するための手段 上記問題点を解決するために、本発明の半導体レーザア
レイ装置は、２分の１波長（位相差がπ）の厚さの位相
板を、一つおきのストライプにのみ付けて構成されてい
る。Means for Solving the Problems In order to solve the above problems, the semiconductor laser array device of the present invention uses a phase plate having a thickness of a half wavelength (a phase difference of π) in every other stripe. It is configured only with.
作用 この構成によって、隣り合うストライプからの出射光の
位相のずれが位相板によって補正されて、全てのストラ
イプからの光の位相が揃う。Operation With this configuration, the phase shift of the emitted light from the adjacent stripes is corrected by the phase plate, and the phases of the light from all the stripes are aligned.
FFPは、導波路内の電界分布をフーリエ変換したものに
相当するから、各ストライプからの出射光の位相が一致
していれば、FFPは単峰性の広がり角の狭いのビームと
なる。The FFP corresponds to a Fourier transform of the electric field distribution in the waveguide. Therefore, if the phases of the emitted light from the stripes match, the FFP becomes a beam with a single-peaked narrow divergence angle.
実 施 例 第１図に本発明の一実施例による半導体レーザアレイ装
置を示す。半導体レーザ結晶８の構造は、第５図に示す
従来例と同一である。即ち、Ｐ型GaAs基板１上に、電流
狭窄層（ｎ−GaAs）２を介して、３本のストライプ溝７
より活性層（GaAlAs）４に電流が注入され、レーザ発振
が起こる。各ストライプ上のレーザ光は、横方向に結合
し、全体として同一の波長で発振する。ストライプの間
ではｎ−GaAs層２にレーザ光が吸収されるため、第６図
（ｂ）に示す反対称モードで発振する。つまり、中央の
ストライプの電界に対し、その両側の電界は位相がπだ
けずれる。そこで、端面に近接して位相補正板９を置
く。そして、中央のストライプに対応する部分の板厚
（d2）を、その両側の部分での板厚（d1）よりも２分の
１波長の光学的厚さ（実際の厚さに屈折率を掛けたも
の）だけ薄くする。このようにすると中央のストライプ
からの光より、その両側からの光の位相が補正板を通過
後πずれるので、補正板通過後は、位相のそろった３ビ
ームとなる。EXAMPLE FIG. 1 shows a semiconductor laser array device according to an example of the present invention. The structure of the semiconductor laser crystal 8 is the same as that of the conventional example shown in FIG. That is, three stripe grooves 7 are formed on the P-type GaAs substrate 1 with the current confinement layer (n-GaAs) 2 interposed therebetween.
A current is further injected into the active layer (GaAlAs) 4 to cause laser oscillation. The laser light on each stripe is laterally coupled and oscillates at the same wavelength as a whole. Since the laser light is absorbed by the n-GaAs layer 2 between the stripes, oscillation occurs in the antisymmetric mode shown in FIG. 6 (b). That is, the electric field on both sides of the electric field of the central stripe is out of phase by π. Therefore, the phase correction plate 9 is placed close to the end face. Then, the plate thickness (d 2 ) of the portion corresponding to the central stripe is set to an optical thickness (wavelength of the actual thickness that is half the wavelength of the plate thickness on both sides thereof (d 1 )). Multiply by)) to make it thinner. In this way, the phases of the light from both sides of the light from the central stripe deviate by π after passing through the correction plate, so that after passing through the correction plate, there are three beams with uniform phases.
第２図は第１図に示す半導体アレイ装置の上面図であ
る。半導体レーザ結晶８の片方の端面に、位相補正板９
があり、その板厚が、中央のストライプに対応する部分
のみ２分の１光学的厚さ分薄く構成されている。これに
より位相板透過後の電界分布は図示したとおり位相がそ
ろうので、FFPは図示するように狭い出射角の単峰性ビ
ームとなる。位相補正板としてはSiO2を用いるとよい。
本実施例では、d1＝300μm,d1−d2＝0.269μｍ（SiO2の
屈折率を1.45として、レーザ光波長0.78μｍで２分の１
波長に相当）とした。補正板はホトリソグラフィーを用
い、SiO2板をフッ酸でエッチングして作製した。位相補
正板は、レーザ端面より50μｍ離して設置した。FIG. 2 is a top view of the semiconductor array device shown in FIG. On one end face of the semiconductor laser crystal 8, the phase correction plate 9
The plate thickness is thinned by half the optical thickness only in the portion corresponding to the central stripe. As a result, the electric field distributions after passing through the phase plate have the same phases as shown in the figure, so that the FFP becomes a unimodal beam with a narrow emission angle as shown in the figure. It is preferable to use SiO 2 as the phase correction plate.
In the present embodiment, d 1 = 300 μm, d 1 −d 2 = 0.269 μm (Since the refractive index of SiO 2 is 1.45, the laser light wavelength is 0.78 μm and is 1/2.
Equivalent to the wavelength). The correction plate was formed by using photolithography and etching the SiO 2 plate with hydrofluoric acid. The phase correction plate was placed 50 μm away from the laser end face.
第３図に、電流光出力特性を示す。素子が破壊するに至
る光出力は230mwと高く、単一ストライプレーザではけ
っして得られない値である。また第４図に遠視野像の強
度分布FFPを示す。ここで横軸は角度を示す。図示した
とおり、単峰性で、半値角が1.4゜と鋭いピークが得ら
れている。FIG. 3 shows current light output characteristics. The optical output up to the destruction of the device is as high as 230 mw, a value never obtained with a single-stripe laser. Figure 4 shows the intensity distribution FFP of the far-field pattern. Here, the horizontal axis represents the angle. As shown in the figure, it is unimodal and has a sharp peak with a half-value angle of 1.4 °.
発明の効果 本発明によれば、高出力でビームのコヒーレンスの良い
半導体レーザが得られ、その実用的効果は大なるものが
ある。EFFECTS OF THE INVENTION According to the present invention, a semiconductor laser with high output and good beam coherence can be obtained, and the practical effects thereof are great.
第１図は本発明の半導体レーザアレイ装置の構造図、第
２図はその作用を説明するための図、第３図は電流−光
出力特性図、第４図は遠視野像の強度分布図、第５図は
従来の半導体レーザアレイ装置の構造図、第６図は電界
分布とFFPの説明図である。 １……Ｐ型GaAs基板、２……ｎ型GaAs電流狭窄層、３…
…Ｐ型GaAlAsクラッド層、４……GaAlAs活性層、５……
ｎ型GaAlAsクラッド層、６……ｎ型GaAsコンタクト層、
７……ストライプ溝、８……半導体レーザ結晶、９……
位相補正板。FIG. 1 is a structural diagram of a semiconductor laser array device of the present invention, FIG. 2 is a diagram for explaining its operation, FIG. 3 is a current-light output characteristic diagram, and FIG. 4 is an intensity distribution diagram of a far field image. FIG. 5 is a structural diagram of a conventional semiconductor laser array device, and FIG. 6 is an explanatory diagram of electric field distribution and FFP. 1 ... P-type GaAs substrate, 2 ... n-type GaAs current confinement layer, 3 ...
… P-type GaAlAs cladding layer, 4 …… GaAlAs active layer, 5 ……
n-type GaAlAs cladding layer, 6 ... n-type GaAs contact layer,
7 ... Striped groove, 8 ... Semiconductor laser crystal, 9 ...
Phase correction plate.
Claims (1)
に結合されるとともに、共振器端面の少なくとも一方の
側において、各レーザ出射部に対応して、隣り合う出射
部に対するものより光学的距離が２分の１波長異なった
厚さの誘電体板が近接して設けられていることを特徴と
する半導体レーザアレイ装置。1. A plurality of optical waveguides are arranged in parallel and optically coupled to each other, and at least on one side of an end face of a resonator, corresponding to each laser emitting portion, the optical waveguide is arranged to be adjacent to each other. 1. A semiconductor laser array device, wherein dielectric plates having a thickness different by one half wavelength are provided in proximity to each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61311400A JPH07120834B2 (en) | 1986-12-25 | 1986-12-25 | Semiconductor laser array device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61311400A JPH07120834B2 (en) | 1986-12-25 | 1986-12-25 | Semiconductor laser array device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63164287A JPS63164287A (en) | 1988-07-07 |
| JPH07120834B2 true JPH07120834B2 (en) | 1995-12-20 |
Family
ID=18016740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61311400A Expired - Lifetime JPH07120834B2 (en) | 1986-12-25 | 1986-12-25 | Semiconductor laser array device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07120834B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19948353B4 (en) * | 1999-10-07 | 2012-08-30 | Universität Stuttgart Institut für Strahlwerkzeuge | A laser radiation source and method for generating a coherent total laser radiation field |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6393186A (en) * | 1986-10-08 | 1988-04-23 | Sharp Corp | Semiconductor laser array device |
-
1986
- 1986-12-25 JP JP61311400A patent/JPH07120834B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63164287A (en) | 1988-07-07 |
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