Quantum cascade semiconductor laser

Patent metadata

Field	Value
Publication number	US-9774168-B2
Application number	US-201615088490-A
Country	US
Kind code	B2
Filing date	Apr 1, 2016
Priority date	Apr 3, 2015
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A quantum cascade semiconductor laser includes a substrate with a main surface including a waveguide area and a distributed Bragg reflection area that are arranged in a direction of a first axis; a laser region provided on the waveguide area, the laser region including a mesa waveguide having first and second side surfaces, and first and second burying regions provided on the first and second side surfaces, respectively; a distributed Bragg reflection region provided on the distributed Bragg reflection area, the distributed Bragg reflection region including a semiconductor wall having first bulk semiconductor regions and first laminate regions that are alternately arrayed in a direction of a second axis intersecting the first axis; and an upper electrode provided on the laser region. Each first bulk semiconductor region includes a bulk semiconductor layer. Each first laminate region includes a stacked semiconductor layer having a plurality of semiconductor layers.

First claim

What is claimed is:

1. A quantum cascade semiconductor laser comprising:
a substrate with a main surface including a waveguide area and a distributed Bragg reflection area that are arranged in a direction of a first axis;
a laser region provided on the waveguide area of the substrate, the laser region including a mesa waveguide having a first side surface and a second side surface, a first burying region provided on the first side surface and the main surface of the substrate, and a second burying region provided on the second side surface and the main surface of the substrate, the first and second side surfaces of the mesa waveguide extending in the direction of the first axis;
a distributed Bragg reflection region provided on the distributed Bragg reflection area of the substrate, the distributed Bragg reflection region including a semiconductor wall extending in a direction of a normal axis perpendicular to the main surface of the substrate, the semiconductor wall including a plurality of first bulk semiconductor regions and a plurality of first laminate regions that are alternately arrayed in a direction of a second axis intersecting the first axis and the normal axis; and
an upper electrode provided on the laser region, the upper electrode being in contact with a top surface of the mesa waveguide,
wherein each of the first bulk semiconductor regions includes a bulk semiconductor layer, and
each of the first laminate regions includes a stacked semiconductor layer having a plurality of semiconductor layers.

2. The quantum cascade semiconductor laser according to claim 1 ,
wherein the mesa waveguide includes a core layer and an upper cladding layer disposed on the core layer, and
the stacked semiconductor layer of the first laminate regions includes the core layer and the upper cladding layer.

3. The quantum cascade semiconductor laser according to claim 1 ,
wherein each of the first and second burying regions includes a plurality of second bulk semiconductor regions and a plurality of second laminate regions that are alternately arrayed in the direction of the second axis, and
each of the second laminate regions includes the stacked semiconductor layer of the first laminate regions.

4. The quantum cascade semiconductor laser according to claim 3 ,
wherein each of the first and second burying regions includes a first burying portion and a second burying portion that are arranged along the direction of the second axis in order from a waveguide axis toward a side surface of the quantum cascade semiconductor laser,
the first burying portion includes the second laminate regions and the second bulk semiconductor regions that are alternately arrayed in the direction of the second axis, and
the second burying portion does not include the second laminate regions and includes the second bulk semiconductor regions extending in the direction of the second axis.

5. The quantum cascade semiconductor laser according to claim 3 ,
wherein the second bulk semiconductor regions include an undoped or semi-insulating semiconductor.

6. The quantum cascade semiconductor laser according to claim 1 , further comprising a semiconductor capping layer provided on the first bulk semiconductor regions in the semiconductor wall,
wherein the semiconductor capping layer is in contact with the first bulk semiconductor regions of the semiconductor wall, and
the semiconductor capping layer is made of the same material as that of the first bulk semiconductor regions.

7. The quantum cascade semiconductor laser according to claim 1 ,
wherein the semiconductor wall includes a first portion and a second portion that are arranged along a direction of the second axis in order from a waveguide axis toward a side surface of the quantum cascade semiconductor laser,
the first portion includes the first laminate regions and the first bulk semiconductor regions that are alternately arrayed in the direction of the second axis, and
the second portion does not include the first laminate regions and includes the first bulk semiconductor regions.

8. The quantum cascade semiconductor laser according to claim 1 , further comprising an insulating film made of a dielectric material, the insulating film being provided between the upper electrode and the first burying region and between the upper electrode and the second burying region.

9. The quantum cascade semiconductor laser according to claim 1 , further comprising a semiconductor capping layer made of an undoped semiconductor or a semi-insulating semiconductor, the semiconductor capping layer being provided between the upper electrode and the first burying region and between the upper electrode and the second burying region.

10. The quantum cascade semiconductor laser according to claim 1 , further comprising a first reinforcing section connecting a first of the semiconductor walls and a second of the semiconductor walls with each other.

11. The quantum cascade semiconductor laser according to claim 10 ,
wherein the first and
the second of the semiconductor walls includes a portion that is connected to the reinforcing section, and
the reinforcing section and the portions of the first and the second of the semiconductor walls connected to the reinforcing section are made of the same material.

12. The quantum cascade semiconductor laser according to claim 1 , further comprising a reinforcing section connecting each of the first and second burying regions to the semiconductor wall.

13. The quantum cascade semiconductor laser according to claim 12 ,
wherein the semiconductor wall includes a connecting section that is connected to the reinforcing section, and
the reinforcing section and the connecting section of the semiconductor wall are made of the same material.

14. The quantum cascade semiconductor laser according to claim 12 ,
wherein the first burying region includes a portion that is connected to the reinforcing section,
the second burying region includes a portion that is connected to the reinforcing section, and
the reinforcing section and the portions of the first and the second burying regions that are connected to the reinforcing section are made of the same material.

15. The quantum cascade semiconductor laser according to claim 1 ,
wherein the semiconductor wall has a length shorter than a width of the substrate in the direction of the second axis.

Assignees

• Sumitomo Electric Industries

Inventors

• Hashimoto Jun-Ichi

Classifications

• H01S3/0675

  Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers · CPC title

• H01S5/125

  Distributed Bragg reflector [DBR] lasers · CPC title

• H01S5/2224

  semi-insulating semiconductors · CPC title

• H01S5/02461

  Structure or details of the laser chip to manipulate the heat flow, e.g. passive layers in the chip with a low heat conductivity · CPC title

• H01S5/3402 Primary

  intersubband lasers, e.g. transitions within the conduction or valence bands · CPC title