Laser device, method of manufacturing the same, laser device array, light source and light module

Patent metadata

Field	Value
Publication number	US-9300114-B2
Application number	US-201213435061-A
Country	US
Kind code	B2
Filing date	Mar 30, 2012
Priority date	Mar 31, 2011
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

Provided is a laser device comprising a substrate, an active layer, and a current confinement layer. The current confinement layer includes an oxide layer that is formed extending from a edge of the current confinement layer in a parallel plane parallel to a surface of the substrate, toward a center of the current confinement layer along the parallel plane, and that does not have an inflection point between the edge and a tip portion formed closer to the center or has a plurality of inflection points formed between the edge and the tip portion.

First claim

What is claimed is:

1. A laser device configured to output laser light, the laser device comprising:
a substrate; and
a mesa post on the substrate, the mesa post comprising:
an active layer formed above the substrate; and
a current confinement layer configured to confine current flowing through the active layer, wherein

the current confinement layer includes
a first layer,
a second layer,
a third layer, and
an oxide layer that is formed in the first, second and third layers,

in a thickness direction of the substrate, the first layer is arranged below the second layer and above the third layer,
Al contents of the second layer and the third layer are smaller than an Al content of the first layer,
the Al content of the first layer is a maximum Al content of the current confinement layer,
thicknesses of the second layer and the third layer in the thickness direction of the substrate are greater than a thickness of the first layer in the thickness direction of the substrate,
the oxide layer extends from a side surface of the mesa post to a tip portion,
between the side surface of the mesa post and the tip portion,
the entire thickness of the first layer is occupied by the oxide layer,
the entire thickness of the second layer is not occupied by the oxide layer, and
the entire thickness of the third layer is not occupied by the oxide layer,

at least one of
(a) in the second layer, the oxide layer has a triangular shape with sides formed by the side surface of the mesa post and a bottom surface of the second layer, respectively, and
(b) in the third layer, the oxide layer has a triangular shape with sides formed by the side surface of the mesa post and an upper surface of the third layer, respectively, and

at least one of
(i) in the thickness direction of the substrate, a maximum thickness of the oxide layer in the second layer is greater than the thickness of the first layer, and
(ii) in the thickness direction of the substrate, a maximum thickness of the oxide layer in the third layer is greater than the thickness of the first layer.

2. The laser device according to claim 1 , further comprising:
a lower reflective layer and an upper reflective layer, wherein
the active layer is formed, in the thickness direction of the substrate, between the lower reflective layer and the upper reflective layer.

3. The laser device according to claim 1 , wherein, in the thickness direction of the substrate, the oxide layer has a thickness that increases at a constant rate from the tip portion toward the side surface of the mesa post.

4. The laser device according to claim 1 , wherein the oxide layer is symmetrical with respect to a parallel plane parallel to a surface of the substrate and passing through the tip portion.

5. The laser device according to claim 1 , wherein the oxide layer is asymmetrical with respect to a parallel plane parallel to a surface of the substrate and passing through the tip portion.

6. The laser device according to claim 5 , wherein a maximum thickness of a portion of the oxide layer above the parallel plane is greater than a maximum thickness of a portion of the oxide layer below the parallel plane.

7. The laser device according to claim 5 , wherein a bottom surface of the oxide layer is contained in the parallel plane.

8. The laser device according to claim 1 , wherein
the first layer contains Al x Ga 1−x As (0<x<1),
the second layer contains Al y Ga 1−y As (0<y<1, x>y), and
the tip portion of the oxide layer is formed in the first layer.

9. The laser device according to claim 8 , wherein the second layer includes a digital alloy.

10. The laser device according to claim 1 , wherein
the first layer contains Al x Ga 1−x As (0<x<1),
the second layer contains Al y Ga 1−y As (0<y<1, x>y),
the third layer contains Al z Ga 1−z As (0<z<1, x>z), and
the tip portion of the oxide layer is formed in the first layer.

11. The laser device according to claim 10 , wherein
the current confinement layer further includes:
a fourth layer containing Al a Ga 1−a As (0<a<1, y<a<x) and formed between the first layer and the second layer; and
a fifth layer containing Al b Ga 1−b As (0<b<1, y<b<a) and formed between the fourth layer and the second layer,

the oxide layer is also formed in the fourth layer and the fifth layer, and
an upper surface of the oxide layer has inflection points respectively at
an interface between the fourth layer and the fifth layer, and
an interface between the fifth layer and the second layer.

12. A laser device array, comprising:
a base material; and
a plurality of the laser devices according to claim 1 , wherein
the plurality of the laser devices are arranged on the base material in a one-dimensional or two-dimensional array.

13. A light source, comprising:
the laser device according to claim 1 ; and
a control circuit configured to control a voltage applied to the laser device.

14. A light module, comprising:
the laser device according to claim 1 ;
an optical waveguide configured to propagate the laser light; and
an optical coupling section that optically couples the laser device and the optical waveguide.

15. The laser device according to claim 1 , wherein
in the second layer, the triangular shape of the oxide layer has perpendicular sides formed by the side surface of the mesa post and the bottom surface of the second layer, respectively, and
in the third layer, the triangular shape of the oxide layer has perpendicular sides formed by the side surface of the mesa post and the upper surface of the third layer, respectively.

16. A method of manufacturing a laser device,
the laser device comprising a substrate and a mesa post on the substrate, the mesa post comprising:
an active layer formed above the substrate; and
a current confinement layer configured to confine current flowing through the active layer, wherein

the current confinement layer includes
a first layer,
a second layer,
a third layer, and
an oxide layer that is formed in the first, second and third layers,

in a thickness direction of the substrate, the first layer is arranged below the second layer and above the third layer,
Al contents of the second layer and the third layer are smaller than an Al content of the first layer,
the Al content of the first layer is a maximum Al content of the current confinement layer,
thicknesses of the second layer and the third layer in the thickness direction of the substrate are greater than a thickness of the first layer in the thickness direction of the substrate,
the oxide layer extends from a side surface of the mesa post to a tip portion,
between the side surface of the mesa post and the tip portion,
the entire thickness of the first layer is occupied by the oxide layer,
the entire thickness of the second layer is not occupied by the oxide layer, and
the entire thickness of the third layer is not occupied by the oxide layer,

at least one of
(a) in the second layer, the oxide layer has a triangular shape with sides formed by the side surface of the mesa post and a bottom surface of the second layer, respectively, and
(b) in the third layer, the oxide layer has a triangular shape with sides formed by the side surface of the mesa post and an upper surface of the third layer, respectively, and

at least one of
(i) in the thickness direction of the substrate, a maximum thickness of the oxide layer in the second layer is greater than the thickness of the first layer, and
(ii) in the thickness direction of the substrate, a maximum thickness of the oxide layer in

Assignees

• Shimizu Hitoshi
• Suzuki Toshihito
• Kawakita Yasumasa
• Takaki Keishi
• Furukawa Electric Co Ltd

Inventors

• Shimizu Hitoshi
• Suzuki Toshihito
• Kawakita Yasumasa
• Takaki Keishi

Classifications

• H01S2301/176

  Specific passivation layers on surfaces other than the emission facet · CPC title

• H01S5/0021

  Degradation or life time measurements · CPC title

• H01S5/18358

  containing spacer layers to adjust the phase of the light wave in the cavity · CPC title

• H01S5/18311 Primary

  using selective oxidation · CPC title

• H01S5/18333

  only above the active layer · CPC title