JPH01268180A - Semiconductor laser array device - Google Patents

Abstract

PURPOSE:To suppress heat generation, and obtain a device which can stably oscillate with a high output with a long life by forming the thickness of a part opposing the part between stripe regions of a first clad layer and a part opposing the outside of each stripe region of an outermost side near a laser light emitting end face thicker than that at the center. CONSTITUTION:Since a first clad layer 17 becomes thicker at the part between stripe regions 17a and the outer parts of the outermost regions 17a in the vicinity of the laser light emitting end face than a center except the vicinity of the laser light emitting end face, the quantity of a light passing the thick layer 17 is reduced, and the quantity of light absorbed in an N-type Al0.1Ga0.9As current narrowing layer 11 is decreased. As a result, the heat generation due to the light absorption of the layer 11 is suppressed, and a laser light can stably oscillates with high output over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to, for example, a semiconductor laser array device in which a plurality of active waveguides are formed in a stripe shape.

(Prior Art) A semiconductor laser array device in which a plurality of active waveguides are formed in a stripe shape can obtain higher output than a normal semiconductor laser device in which a single active waveguide is formed.
It has been actively researched and developed as a solid-state laser excitation light source such as a YAG laser, a light source for optical communications, or a light source for image printers.

The inventors of the present application have developed the VSIS (V-chan) shown in FIG.
neledSubstrate Inner 5tri
pe) type laser array device.

J9. Appl, Phys, Vol. 58. N
o, 7, p. 2783 (1985). This VSIS type laser array device.

For example, it is manufactured as follows. First, p-type Ga
After growing an n-type Alo, +Gao, qAs current confinement layer 61 on the As substrate 60 by liquid phase growth, a thin n-type GaAs layer 69 for preventing oxidation on one surface is similarly grown by liquid phase growth. Next, a plurality of (five in this example) grooves each having an inverted trapezoidal cross section and extending in the resonance direction are formed in parallel by chemical etching so that the bottom surface of each groove is located within the substrate 60. After that, inside each groove and the current confinement layer 61
A p-type lo, 33 Gao, btΔS first ground layer 63 is grown thereon so that its upper surface is flat. As a result, a first cladding layer 63 having a plurality of stripe regions 62 is formed. Io, 13Gao, b7As first cladding layer 63 to the flattened p-type
On top, p-type Alo, otGao, 938S active layer 6
4. N-type 8 10.33 Gao, 67AS second crat layer 65. An n-type GaAs cap layer 66 is sequentially grown. Then, a p-side electrode 67 is provided on the substrate 60 and an n-side electrode 68 is provided on the cap layer 66. Thereafter, an output end face is provided by the interfold method. As a result, as shown in FIG. 3, a semiconductor laser array device is obtained in which a plurality of stripe regions 62 extending in the resonance direction are formed.

In the semiconductor laser array device, since the stripe regions are sandwiched between the current confinement layers 61 over the entire region in the resonance direction, current is confined in each stripe region. As a result, a plurality of optical waveguides extending in the resonance direction are formed within the active layer 64. Each optical waveguide is a 2-loss waveguide type refractive index optical waveguide, and each leading waveguide 7 is optically coupled, so that stable array mode oscillation can be obtained.

(Problem to be solved by the invention) In such a conventional semiconductor laser array device.

Each stripe region provided to form an active waveguide is sandwiched between current confinement layers 61 over the entire resonance direction, and light is absorbed by the current confinement layers 61. I get a fever. Particularly during high light output operation, the amount of light absorbed by the current confinement layer 61 also increases, resulting in an increase in the amount of heat generated per unit. In the vicinity of the laser beam emitting end face, the optical power density is maximum, so the amount of heat generated is maximum, and the deterioration of the vicinity of the laser beam emitting end face is accelerated.

The present invention solves the above-mentioned conventional problems, and its purpose is to provide a long-life semiconductor laser array device that can suppress heat generation in the vicinity of the light emitting end face and stably oscillate up to high output. There is a particular thing.

(Means for Solving the Problems) A semiconductor laser array device of the present invention is provided above a semiconductor substrate through a semiconductor layer capable of absorbing light.

A first cladding layer, an active layer, and a second cladding layer are sequentially laminated, and the first cladding layer includes a plurality of current paths to form a plurality of guide waveguides extending in the resonance direction within the active layer. a semiconductor laser array device in which stripe regions are formed parallel to the resonance direction, the thickness of a portion of the first cladding layer that faces between each stripe region and a portion that faces the outside of each outermost stripe region; The laser beam is characterized in that a portion near at least one laser beam emitting end face is thicker than a central portion excluding the near portion, thereby achieving the above object.

(Example) The present invention will be described below with reference to Examples.

In the semiconductor laser array device of the present invention, for example, as shown in FIG.
go, 33Gao, 67AS A flat p-type old sandwiched between the first cladding layer 17 and the n-type AI0.33Gao, r+7AS second cladding layer 19. ,. 7Gao, q3
It has an AS active layer 18. The first one disposed on the substrate 10 side
In the cladding layer 17, a plurality of striped regions 17a, 17a, . They are provided so as to protrude toward the substrate 10 at intervals of . The bottom surface of each stripe region 17a is located within the substrate 10.

Each stripe region 17a of the first cladding layer 17 is.

In the central part excluding the vicinity of each laser beam emitting end face, an n-type A1°, 1 is laminated on the substrate 10 and is capable of absorbing light.
Gao, 9AS current confinement layer 11 and a thin n-type G for surface oxidation prevention that can also absorb light and is laminated on top of it.
It is sandwiched by an aAs surface protective layer 14. In the vicinity of each laser beam emitting end face, the layer thickness of the portion of the first cladding layer 17 facing between the respective stripe regions 17a.

The layer thickness of each of the outermost striped regions 17a and 17a is thicker than the central portion excluding the vicinity of each laser beam emitting end face. In the vicinity of each laser beam emitting end face, the thickness of the first layer 17 is one layer thinner in the outermost portion of the thicker portion of the first rad layer 17 facing the outside of the outermost striped region 17a. and the substrate 10, an n-type A1°,
An IGo, 9AS current confinement layer 11 and a thin n-type GaAs surface protection layer 14 for preventing surface oxidation are interposed.

As a result, each stripe region 17a has a relatively thin layer of AI. , 1Gao, 9AS are sandwiched only by the current confinement layer 11.

n-type Alo, 5iGao, stacked on the active layer 18
An n-type GaAs cap layer 20 is laminated on the 678S second cladding layer 19, and an n-side electrode 22 is provided on the n-type GaAs cap layer 20. On the other hand, a p-side electrode 21 is provided on the p-type GaAs substrate 10 .

A semiconductor laser array device having such a configuration is as follows.

It is manufactured as follows. Next, on the p-type GaAs substrate 10, for example, by liquid phase growth, n-type Alo, +Ga
o. A qAs current confinement layer 11 and an n-type GaAs surface protection layer 12 are sequentially grown. Next, n-type Alo, +Gao, gAs are formed on the surface of the n-type GaAs surface protection layer 12 by photolithography and chemical etching.
A plurality of groove portions whose bottom surfaces penetrate through the current confinement layer 11 and reach onto the substrate 10.

Form at appropriate intervals. After forming a plurality of grooves in this way, the area between the grooves in the vicinity of the laser beam emitting end face and a predetermined area outside each outermost groove are etched to form an n-type GaAs surface protective layer. 12 and Alo, +Gao.

The upper part of the As current confinement layer 11 is removed and the current confinement layer 1 is
1 to a predetermined thickness.

In this state, the liquid phase growth method was used again.

Inside each groove, Alo, +Gao, q8S current narrows to layer 1
1 or on the n-type GaAs surface protective layer 12, p-type Al
e, x3Gao, 6? AS first cladding layer 17,
Stack them so that their surfaces are flat. Next, the p-type Ale, 13Gao, 678S first cladding layer 17
On top, p-type Alo, o7G was grown using the same liquid phase growth method.
ao, 93AS active layer 1B, n-type Alo, :+
+Gao, 6? AS second cladding layer 19. n-type GaA
The s-cap layers 20 are grown one after another to each have a predetermined thickness.

Thereafter, a p-side electrode 21 is provided on the substrate 10.

A semiconductor laser array device according to the present invention can be obtained by disposing an n-side electrode on the n-type GaAs cap layer 20 and forming a laser beam emitting end face by a method.

The semiconductor laser array device of the present invention has n-type Alo, +Gao,
q ■ Current confinement layer 11 and n-type GaA layered above it
the first cladding layer 17 sandwiched between the s surface protective layer 14;
A current path is formed by confining the current in each stripe region 17a, and a current path is formed in each stripe region 17a.
Light is oscillated from each region in the p-type ^1o, o7Gao, and 93AS active layers 18 facing the . In this case, the thickness of the portion between each stripe region 17a of the first cladding layer 17 is the same as the thickness of the portion between each stripe region 17a of the first cladding layer 17 in the vicinity of the laser beam emitting end surface in the central portion excluding the portion near the laser beam emitting end surface that is optically oscillated. Since the thin first cladding layer 17 is thinner than the first cladding layer 17, light passing between each stripe region 17a of the thin first cladding layer 17 is reliably absorbed by the n-type AI0.1Gaa, 9As current confinement layer 11. As a result, l becomes p-type. ,. qGao
, 93AS An optical waveguide is formed within the active layer 18.

Light is stably confined within each optical waveguide,
Waves are stably guided in each optical waveguide in array mode.

The light guided within each optical waveguide is emitted from each laser beam emitting end face. At this time, in the vicinity of each laser beam emitting end surface, the first cladding layer 17 has a layer thickness that is smaller than that of the first cladding layer 17 in the portion between each stripe region 17a and the outer portion of each outermost stripe region 17a. Since the thickness of each layer is thicker than the thickness of each layer in the central part excluding the central part, the amount of light passing through the thickened first cladding layer 17 part is reduced, and the n-type A1°, lGa0.9^S current confinement layer 11 The amount of light absorbed is reduced. As a result, in the semiconductor laser array device of the present invention, heat generation due to light absorption in the current confinement layer 11 is suppressed, and laser light can be stably oscillated at high output over a long period of time.

FIG. 2 is an exploded perspective view showing another embodiment of the semiconductor laser array device of the present invention. In this semiconductor laser array device, each stripe region 17a of the p-type Alo, 5iGao, and It is sandwiched between current confinement layers 11''.In the central part excluding the vicinity of each laser beam emitting end face, the layer is made of p-type. An n-type GaAs current confinement layer 11'' laminated on the substrate 10, and n-type AIG, IGao,
Js anti-meltback layer 23 and n-type GaAs surface protection layer 14 laminated on the anti-meltback layer 23
It is sandwiched between.

In this semiconductor laser array device, the layer thickness of the portion of the first cladding layer 17 facing between each stripe region 17a and the portion facing the outside of each outermost stripe region is the same as in the above embodiment. The area near the output end face is
It is thicker than the central portion except for the portion near each laser beam emitting end face. The rest of the structure is the same as that of the embodiment shown in FIG. 5.

Such a semiconductor laser array device is manufactured in a secondary manner. First, an n-type GaAs layer is placed on a p-type GaAs plate 10.
Current confinement layer 11', to n-type 10. lGa0.9
^S Anti-meltback layer 23. and an n-type GaAs surface protection layer 14.

For example, they are grown sequentially by a liquid phase growth method. Next.

Surface protective layer 14. A plurality of grooves (five in this example) are formed parallel to the resonance direction at predetermined intervals, penetrating the anti-meltback layer 23 and the current confinement layer 11'' and reaching the substrate 10. The surface protective layer 14 and n-type Alo in a portion corresponding to the vicinity of the light emitting end face,
Gao, qΔS anti-meltback layer 23 is removed by etching.

In this state, p-type Alo, 13Gao, aJ
s first cladding layer 17 is applied between each groove, on the n-type GaAs current confinement layer 11'' in a portion corresponding to the portion near the laser beam emitting end surface, and on the surface protection layer 14 in the central portion excluding the portion near the laser beam emitting end surface. For example, the n-type GaAs current confinement layer 11'' is laminated using a liquid phase growth method so that its surface becomes flat.At this time, the n-type GaAs current confinement layer 11'' from which the anti-meltback layer 23 in the vicinity of the laser beam emitting end face has been removed is It is etched by the back and its thickness becomes thinner. As a result, p-type A1゜, 33Ga0.6□＾
In the S first cladding layer I7, the thickness of the portion between each stripe region 17a and the outer portion of each outermost stripe region corresponds to the portion near the laser beam emitting end face.
It is thicker than the central portion except for the portion near the laser beam emitting end face.

Then, the p-type Alo, 3zGao, 67AS first
p-type A10.07Gao, q3A on cladding layer I7
s active layer 18. n-type Alo, , 3yGao, 67A
S cladding layer 19. n-type GaAs cap layer 20.

For example, they are laminated one by one by a liquid phase growth method. after that.

A p-side electrode 21 is provided on a p-type GaAs substrate 10, and an n-type G
After disposing the n-side electrode 22 on the aAs cap layer 20,
By forming the laser beam emitting end face using the multi-layer method.

The semiconductor laser array device of this example is obtained.

Also the semiconductor laser array device in this example.

Similar to the semiconductor laser array device in the above embodiment, the current confinement layer 11' suppresses heat generation due to light absorption in the vicinity of the laser light emitting end face, and stably oscillates laser light in array mode up to high output over a long period of time. It is possible.

The output characteristics of the semiconductor laser array device of the present invention shown in FIGS. 1 and 2 were compared with the output characteristics of a conventional semiconductor laser array device. In a conventional semiconductor laser array device, when a transmission film is provided on one side of the laser beam emitting end face and a total reflection film is provided on the other side (asymmetric coating), C0D (C
atastrophic Optical Damage
) The optical output was about 400 mW. In addition, when oscillating at an ambient temperature of 50'C and an optical output of 100n+W, 5
Its lifespan was about 1000 hours. In the semiconductor laser array device of the present invention, when two asymmetric coatings are applied, the COD optical output is about 600 mW.

In addition, under the condition of an ambient temperature of 50°C, the light output is reduced to 20°C.
When oscillated at 0 mW, it was possible to oscillate stably for over 1000 hours.

Note that the semiconductor laser array device of the present invention can also be applied to a case where all the semiconductor layers have polarities opposite to those of the above embodiments. Furthermore, in the above embodiments, a VSTS type semiconductor laser array device was described.

The present invention is not limited to such embodiments, but can be applied to a semiconductor laser array device in which a layer capable of absorbing light is provided on the semiconductor substrate side of the first cladding layer. Furthermore, in the above embodiment, the optical waveguide in the active layer has a constant width in the resonance direction,
Although the distance between each optical waveguide was constant, the width of the leading waveguide may be different in the resonance direction, and the distance between adjacent optical waveguides may be different in the resonance direction. Further, the present invention can also be applied to a semiconductor laser array device in which the active optical waveguide has a branch-coupled shape. Further, in the above embodiment, a GaAs-AlGaAs type semiconductor material is used as the semiconductor, but an InP-1nGaAsP type semiconductor material may also be used.

(Effects of the Invention) In the semiconductor laser array device of the present invention, the thickness of the portion between each stripe region and the outer portion of each outermost stripe region in the first cladding layer on the semiconductor substrate side is such that the laser beam In the vicinity of the output end face, it is thicker than in the central part excluding the vicinity, so in the central part,
Light absorption by the light absorption layer on the sides of the stripe region allows stable array mode oscillation up to high output. In the vicinity of the laser beam emitting end face, the amount of light absorbed by the light absorption layer on the sides of the stripe region can be suppressed, so that heat generation in that area is suppressed. As a result, the semiconductor laser array device of the present invention can stably oscillate laser in array mode at high output over a long period of time.

FIGS. 1 and 2 are exploded perspective views showing an example of a semiconductor laser array device of the present invention, respectively, and FIG. 3 is a perspective view showing an example of a conventional semiconductor laser array device.

10・p-type GaAs substrate, 11・n-type Alo, +Ga
o, Js current confinement layer, 11''...n-type GaAs current confinement layer, 14...n-type GaAs surface protection layer, 17-
p-type Alo, :+3Gao, 67AS first cladding layer, 17a...stripe region, 18...p-type A
le,. .

Gao, 938S active layer, 19/n-type Alo, 5s
GF1o, 6? AS second cladding layer, 20... n-type GaAs cap layer.

that's all

Claims (1)

[Claims] 1. A first cladding layer, an active layer, and a second cladding layer are sequentially laminated above a semiconductor substrate with a semiconductor layer capable of absorbing light interposed therebetween, and the first cladding layer is a semiconductor laser array device in which a plurality of stripe regions serving as current paths are formed in parallel to the resonance direction to form a plurality of optical waveguides extending in the resonance direction in the active layer, wherein the first cladding The thickness of the part of the layer facing between each stripe area and the part of the layer facing the outside of each outermost stripe area is such that the thickness of the area near at least one of the laser beam emitting end faces is greater than that of the center area excluding the vicinity area. A semiconductor laser array device characterized by being thick.