JPH0265192A - Manufacture of distributed feedback semiconductor laser - Google Patents
Manufacture of distributed feedback semiconductor laserInfo
- Publication number
- JPH0265192A JPH0265192A JP63217129A JP21712988A JPH0265192A JP H0265192 A JPH0265192 A JP H0265192A JP 63217129 A JP63217129 A JP 63217129A JP 21712988 A JP21712988 A JP 21712988A JP H0265192 A JPH0265192 A JP H0265192A
- Authority
- JP
- Japan
- Prior art keywords
- distributed feedback
- semiconductor laser
- layer
- feedback semiconductor
- forming
- 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
- 239000004065 semiconductor Substances 0.000 title claims abstract description 29
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 230000003287 optical effect Effects 0.000 claims abstract description 13
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 230000012010 growth Effects 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 abstract description 10
- 230000010355 oscillation Effects 0.000 abstract description 9
- 239000013078 crystal Substances 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 6
- 238000005253 cladding Methods 0.000 description 4
- 101100269850 Caenorhabditis elegans mask-1 gene Proteins 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000002902 bimodal 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
- H01S5/12—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
-
- 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
- H01S5/12—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
- H01S5/124—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers incorporating phase shifts
- H01S5/1243—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers incorporating phase shifts by other means than a jump in the grating period, e.g. bent waveguides
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】
〔産業上の利用分野〕
この発明は、分布帰還型半導体レーザの製造方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a distributed feedback semiconductor laser.
第2図は、従来の分布帰還型半導体レーザの製造工程の
一部を示す断面斜視図である。図において、(1)は半
導体基板であり、あらかじめ表面に回折格子が形成しで
ある。(2)は光導波路層、(3)は活性層、(4]は
半導体基板と導電型の異なるクラッド層である。FIG. 2 is a cross-sectional perspective view showing a part of the manufacturing process of a conventional distributed feedback semiconductor laser. In the figure, (1) is a semiconductor substrate on which a diffraction grating has been formed in advance. (2) is an optical waveguide layer, (3) is an active layer, and (4) is a cladding layer having a conductivity type different from that of the semiconductor substrate.
上記各半導体層を形成した後、光の導波方向にメサスト
ライプの形成を行うが、この時、レーザ素子の中央部の
みストライプ幅を拡げて形成する。After forming each of the semiconductor layers described above, mesa stripes are formed in the light waveguide direction, but at this time, the stripe width is expanded only in the center of the laser element.
上記工程を経た後、埋め込み層の形成、及び電極形成を
行うことによりレーザ素子を形成する(図示せず)。After passing through the above steps, a laser element is formed by forming a buried layer and forming electrodes (not shown).
次にこのDFB−LD (DisLribul、ad
Fe6dback−Laaer piode) の特
性について説明する。Next, this DFB-LD (DisLribul, ad
The characteristics of Fe6dback-Laaer piode) will be explained.
一般にDFB−LDは、通常、光導波路に回折格子が形
成されており、これを反射器としてレーザ発振するため
、発振波長の選択性が、素子端面を共振器とするFP
(¥abry Perrot)−LDに比べ良いものに
なっている。In general, a DFB-LD has a diffraction grating formed in the optical waveguide, and uses this as a reflector to oscillate the laser, so the selectivity of the oscillation wavelength is better than that of an FP that uses the element end face as a resonator.
(¥abry Perrot) - Better than LD.
しかし、DFB−LDにおいて、単に回折格子を形成し
ただけでは、回折格子のピッチで決定されるブラッグ波
長で発振せずに、ブラッグ波長を中心として等距離の波
長の所に同じしきい利得を持つ発振モードが2つ存在す
るため、2モ一ド発振してしまう。そこで、発振モード
を1つにするために、以下のような製造方法が考えられ
ている。However, in a DFB-LD, simply forming a diffraction grating does not oscillate at the Bragg wavelength determined by the pitch of the diffraction grating, and instead has the same threshold gain at wavelengths equidistant from the Bragg wavelength. Since there are two oscillation modes, bimodal oscillation occurs. Therefore, in order to reduce the number of oscillation modes to one, the following manufacturing method has been considered.
(1)回折格子を形成する際に、光導波路の途中で回折
格子の位相をずらす方法(λ/45ift法)(2)先
導波路の途中で光導波路の屈折率を変化させることによ
り1人/d 5ift法と同様な効果を持たせた方法。(1) When forming a diffraction grating, the phase of the diffraction grating is shifted in the middle of the optical waveguide (λ/45ift method) (2) The refractive index of the optical waveguide is changed in the middle of the leading waveguide. d A method that has the same effect as the 5ift method.
この従来例は、上記(2)の方法に当たる。This conventional example corresponds to the method (2) above.
(参考文献; H,Kogelnik and CJ、
5hank、’Coupled mode theor
y of distributed feedback
lasers、’ J、Appl、Phys、vol
、43.pp 2327.1972 )〔発明が解決し
ようとする課題〕
従来の分布帰還型半導体レーザは1以上のように構成さ
れていたため、メサストライプの幅の広い部分に流れる
電流が発振に寄与しない無効電流となり、しきい値電流
の低減が困難という問題点があった。(References; H, Kogelnik and CJ,
5hank, 'Coupled mode theor
y of distributed feedback
lasers,' J, Appl, Phys, vol.
, 43. pp 2327.1972) [Problems to be Solved by the Invention] Conventional distributed feedback semiconductor lasers were configured as one or more, so the current flowing through the wide part of the mesa stripe became a reactive current that did not contribute to oscillation. However, there was a problem in that it was difficult to reduce the threshold current.
この発明は、上記のような問題点を解消するためになさ
れたものであり、単一波長発振できるとともに、しきい
値の低減が可能となる分布帰還型半導体レーザを得るこ
とを目的とする。The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a distributed feedback semiconductor laser that is capable of oscillating a single wavelength and of reducing the threshold value.
この発明に係る分布帰還型半導体レーザは、光CVD結
晶成長技術の選択成長性を用いることにより、活性層と
導波路層の厚みの比率を部分的に変化させたものである
。The distributed feedback semiconductor laser according to the present invention is one in which the ratio of the thicknesses of the active layer and the waveguide layer is partially changed by using the selective growth property of the optical CVD crystal growth technique.
この発明における分布帰還型半導体レーザは、活性層と
導波路層の厚みの比率を部分的に変化させることにより
、部分的に屈折率を変化させてλ/45hifL法と同
様な効果が得られ、低しきい値で単一波長発振する。In the distributed feedback semiconductor laser of the present invention, by partially changing the ratio of the thickness of the active layer and the waveguide layer, the refractive index is partially changed, and an effect similar to that of the λ/45hifL method can be obtained. Single wavelength oscillation with low threshold.
以下、この発明の一実施例を図について説明する。第1
図(a)〜(d)は、分布帰還型半導体レーザの製造工
程の一部を示した断面図である。第1図に於いて(1]
〜(4)は第2図の従来例に示したものと同等であるの
で説明を省略する。An embodiment of the present invention will be described below with reference to the drawings. 1st
Figures (a) to (d) are cross-sectional views showing a part of the manufacturing process of a distributed feedback semiconductor laser. In Figure 1 (1)
-(4) are the same as those shown in the conventional example of FIG. 2, so their explanation will be omitted.
t5+ 1.t 遮へいマスクl 、 +61は遮へい
マス’y 1 (511−明暗の逆転した遮へいマスク
2.+71は結晶成長の際の照射光である。t5+ 1. t shielding mask l, +61 is shielding mass 'y 1 (511-shielding mask 2 with reversed brightness and darkness. +71 is irradiation light during crystal growth.
ます、回折格子を形成した半導体基板(υ(第1図(a
))上に遮へいマスク1(5)を設置することにより半
導体基板(1)の一部に光を当てながら、光導波路1層
(2)を形成する(v、1図(b))。次に、遮へいマ
スク2(6)を用いて光をあてる部分と遮へいする部分
を反転させ、活性層(3)を形成する(第1図(C))
。First, the semiconductor substrate (υ) on which the diffraction grating is formed (Fig. 1 (a)
)) One layer of optical waveguide (2) is formed while exposing a part of the semiconductor substrate (1) to light by placing a shielding mask 1 (5) thereon (v, Figure 1 (b)). Next, the active layer (3) is formed by using the shielding mask 2 (6) to invert the light-irradiated part and the shielded part (Fig. 1 (C)).
.
その後、半導体基板(1)と導電型の異なるクラッド層
(4)を形成する(第1図(d))。Thereafter, a cladding layer (4) having a conductivity type different from that of the semiconductor substrate (1) is formed (FIG. 1(d)).
上記結晶成長終了後(以下図示せず)メサストライプ形
成、埋め込み成長、電極形成を行う。After the above crystal growth is completed (not shown below), mesa stripe formation, buried growth, and electrode formation are performed.
次に動作について説明する。従来例で示したように、光
導波路層(2)の途中で屈折率を変化させることにより
、λ/45ift 法と同様な効果が得られる。すなわ
ち、ブラッグ波長のみで単一波長発振可能な分布帰還型
半導体レーザが得られる。Next, the operation will be explained. As shown in the conventional example, by changing the refractive index in the middle of the optical waveguide layer (2), the same effect as the λ/45ift method can be obtained. That is, a distributed feedback semiconductor laser capable of single-wavelength oscillation using only the Bragg wavelength can be obtained.
また、上記実施例では;半導体基板(11に回折格子を
形成した後、結晶成長を行なったが、半導体基板tll
上に活性層(31、光導波路層(2)を形成した後、回
折格子を形成し、クラッドB(4)を形成しても良い。In addition, in the above embodiment; crystal growth was performed after forming the diffraction grating on the semiconductor substrate (11).
After forming an active layer (31) and an optical waveguide layer (2) thereon, a diffraction grating may be formed, and then a cladding B (4) may be formed.
以上のように、この発明によれば、光CVD技術を用い
て光導波路を形成したので、低しきい値の分布帰還型半
導体レーザが得られる効果がある。As described above, according to the present invention, since the optical waveguide is formed using the optical CVD technique, a distributed feedback semiconductor laser with a low threshold value can be obtained.
第1図(al〜(d)はこの発明の一実施例による分布
帰還型半導体レーザの製造工程の一部を示す断面図、第
2図は従来の分布帰還型半導体レーザの製造工程の一部
を示した断面斜視図である。
図において、(υは半導体基板、(2)は光導波路層、
(3)は活性層%(4)はクラッド層、(5)は遮へい
マスク1 、 [61は遮へいマスク2、(7)は照射
光である。
なお、図中、同一符号は同一、又は相当部分を示す。FIGS. 1A to 1D are cross-sectional views showing part of the manufacturing process of a distributed feedback semiconductor laser according to an embodiment of the present invention, and FIG. 2 is a part of the manufacturing process of a conventional distributed feedback semiconductor laser. It is a cross-sectional perspective view showing (υ) a semiconductor substrate;
(3) is the active layer% (4) is the cladding layer, (5) is the shielding mask 1, [61 is the shielding mask 2, and (7) is the irradiation light. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.
Claims (1)
直となるようなストライプを持つマスクを用いて光を遮
へいし、光CVDにより第一の半導体層を形成した後、
上記マスクと明暗の反転したマスクを用いて、上記と同
様に光CVDを用いて第二の半導体層を形成し、全面に
わたり、上記半導体基板と導電型の異なる第三の半導体
層を形成した後、例えば、光の導波方向にメサストライ
プを形成し、埋め込み成長を行うことを特徴とする分布
帰還型半導体レーザの製造方法。After forming a first semiconductor layer by optical CVD on a semiconductor substrate on which a diffraction grating is formed, using a mask having stripes perpendicular to the light waveguide direction to block light,
After forming a second semiconductor layer using photo-CVD in the same manner as above using a mask whose brightness and darkness are reversed from the above mask, and forming a third semiconductor layer having a conductivity type different from that of the semiconductor substrate over the entire surface. , for example, a method of manufacturing a distributed feedback semiconductor laser characterized by forming mesa stripes in the light waveguide direction and performing buried growth.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63217129A JPH0265192A (en) | 1988-08-30 | 1988-08-30 | Manufacture of distributed feedback semiconductor laser |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63217129A JPH0265192A (en) | 1988-08-30 | 1988-08-30 | Manufacture of distributed feedback semiconductor laser |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0265192A true JPH0265192A (en) | 1990-03-05 |
Family
ID=16699308
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP63217129A Pending JPH0265192A (en) | 1988-08-30 | 1988-08-30 | Manufacture of distributed feedback semiconductor laser |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0265192A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0936496A (en) * | 1995-07-21 | 1997-02-07 | Nec Corp | Semiconductor light emitting element and fabrication thereof |
-
1988
- 1988-08-30 JP JP63217129A patent/JPH0265192A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0936496A (en) * | 1995-07-21 | 1997-02-07 | Nec Corp | Semiconductor light emitting element and fabrication thereof |
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