Semiconductor laser device, semiconductor laser module, and laser light source system for welding

Patent metadata

Field	Value
Publication number	US-10971897-B2
Application number	US-201816234344-A
Country	US
Kind code	B2
Filing date	Dec 27, 2018
Priority date	Jun 30, 2016
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A semiconductor laser device includes: a first conductivity side semiconductor layer, an active layer; and a second conductivity side semiconductor layer. The second conductivity side semiconductor layer includes a first semiconductor layer and a second semiconductor layer, the first semiconductor layer being closer to the active layer than the second semiconductor layer is. The second semiconductor layer defines a width of a current injection region for injecting current into an optical waveguide. The current injection region includes a width varying region in which a width varies. S1>S2, where S1 denotes a width of the width varying region on a front end face side, and S2 denotes a width of the width varying region on a rear end face side.

First claim

What is claimed is:

1. A semiconductor laser device which produces multi-transverse mode oscillation, the semiconductor laser device comprising:
a stacked structure in which a first conductivity side semiconductor layer, an active layer, and a second conductivity side semiconductor layer are stacked in stated order, wherein:
the stacked structure includes:
a front end face from which laser light emitted by the semiconductor laser device exits;
a rear end face opposite, in a lengthwise direction, to the front end face;
an optical waveguide for which the front end face and the rear end face are used as reflection mirrors of a resonator; and
a current injection region for injecting current into the optical waveguide,

the second conductivity side semiconductor layer includes a first semiconductor layer and a second semiconductor layer, the first semiconductor layer being closer to the active layer than the second semiconductor layer is,
the second semiconductor layer defines a width of the current injection region,
the current injection region includes a first end portion on a front end face side closer to the front end face and a second end portion on a rear end face side closer to the rear end face in the lengthwise direction, the first end portion of the current injection region is spaced apart from the front end face, and the second end portion of the current injection region is spaced apart from the rear end face,

the current injection region includes a width varying region in which a width varies,
S 1 >S 2 , where S denotes a width of the width varying region on a front end face side closer to the front end face, and S 2 denotes a width of the width varying region on a rear end face side closer to the rear end face,
the first conductivity side semiconductor layer includes a first light guiding layer,
the laser light emitted by the semiconductor laser device has a highest intensity in the first light guiding layer,
the second conductivity side semiconductor layer includes a second light guiding layer between the active layer and the first semiconductor layer,
the first semiconductor layer is a second conductivity side cladding layer,
the second semiconductor layer is a current blocking layer,
the second light guiding layer includes a first optical waveguide layer that is undoped, and a p-type second optical waveguide layer, the first optical waveguide layer being closer to the active layer than the p-type second optical waveguide layer is, and
the first optical waveguide layer has an Al concentration lower than an Al concentration of the p-type second optical wave guide layer.

2. The semiconductor laser device according to claim 1 , wherein
the stacked structure has a window-mirror structure on each of the front end face side and the rear end face side.

3. The semiconductor laser device according to claim 1 , wherein
a thickness of the first semiconductor layer in a region under the current injection region is same as a thickness of the first semiconductor layer in a region under the second semiconductor layer.

4. The semiconductor laser device according to claim 1 , wherein
0°<θ≤0.5°, where θ denotes an angle between the lengthwise direction of the resonator and a straight line which connects a widthwise end of the width varying region on the front end face side and a widthwise end of the width varying region on the rear end face side.

5. The semiconductor laser device according to claim 4 , wherein
0.238≤S 2 /S 1 ≤0.476, where S 1 denotes the width of the width varying region on the front end face side, and S 2 denotes the width of the width varying region on the rear end face side.

6. The semiconductor laser device according to claim 1 , wherein
the width varying region has a tapered shape defined by straight lines which connect widthwise ends on the front end face side to widthwise ends on the rear end face side.

7. The semiconductor laser device according to claim 1 , wherein
the second semiconductor layer has an opening corresponding to the current injection region.

8. The semiconductor laser device according to claim 7 , wherein
the stacked structure includes a second conductivity side contact layer stacked on the second semiconductor layer, and
the second conductivity side contact layer fills the opening.

9. The semiconductor laser device according to claim 1 , wherein
the active layer has a single quantum well structure.

10. The semiconductor laser device according to claim 1 , wherein
the first conductivity side semiconductor layer includes a first conductivity side cladding layer,
the first conductivity side cladding layer and the second conductivity side cladding layer have a composition represented by Al x Ga 1-x As, where 0<x<1,
at least one of the first conductivity side cladding layer and the second conductivity side cladding layer includes a stacked film which includes two or more layers having different Al ratios, and
among the two or more layers in the stacked film, a layer having a lower Al concentration is more distant from the active layer.

11. The semiconductor laser device according to claim 1 , wherein
the first light guiding layer has a composition represented by Al x Ga 1-x As, where 0<x<1,
the first light guiding layer includes a stacked film which includes two or more layers having different Al ratios, and
among the two or more layers in the stacked film, a layer having a lower Al concentration is closer to the active layer.

12. The semiconductor laser device according to claim 1 , wherein
the first conductivity side semiconductor layer includes a first conductivity side cladding layer, and
the first conductivity side cladding layer, the second conductivity side cladding layer, and the active layer are each made of an Al x Ga 1-x-y In y N based material, where 0≤x≤1 and 0≤y≤1.

13. The semiconductor laser device according to claim 1 , further comprising:
a plurality of stacked structures each of which is the stacked structure, wherein
the plurality of stacked structures are stacked with one or more tunnel junctions therebetween.

14. The semiconductor laser device according to claim 1 , wherein
the width of the width varying region on the front end face side is a width of the current injection region on the front end face side, and
the width of the width varying region on the rear end face side is a width of the current injection region on the rear end face side.

15. The semiconductor laser device according to claim 1 , wherein
the current injection region further includes a constant width region in which a width is constant.

16. The semiconductor laser device according to claim 15 , wherein
the constant width region is closer to the front end face than the width varying region is.

17. A semiconductor laser module, comprising:
the semiconductor laser device according to claim 1 .

18. A laser light source system for welding, comprising:
the semiconductor laser device according to claim 1 .

19. The semiconductor laser device according to claim 1 , wherein the first end portion of the current injection region is spaced apart from the front end face by a first part of the second semiconductor layer, and the second end portion of the current injection region is spaced apart from the rear end face by a second part of the second semiconductor layer.

Assignees

• Panasonic Ip Man Co Ltd
• Panasonic Semiconductor Solutions Co Ltd

Inventors

• Ikedo Norio
• Nakatani Tougo
• Okaguchi takahiro
• Yokoyama Takeshi
• Yabushita Tomohito
• Takayama Toru

Classifications

• B23K26/21 Primary

  by welding · CPC title

• H01S5/1014

  Tapered waveguide, e.g. spotsize converter (H01S5/1064 takes precedence) · CPC title

• H01S5/1003

  Waveguide having a modified shape along the axis, e.g. branched, curved, tapered, voids · CPC title

• H01S5/2031

  characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities · CPC title

• H01S5/1064

  varying width along the optical axis · CPC title