DISTRIBUTED FEEDBACK SEMICONDUCTOR LASER

• US 20190081454A1
• Filed: 09/01/2016
• Published: 03/14/2019
• Est. Priority Date: 03/15/2016
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: SAITO, Shinji, KAKUNO, Tsutomu, YAMANE, Osamu, TSUMURA, Akira
• Granted Patent: US 10,714,897 B2
• Time in Patent Office: Days
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/1215 Multiplicity of periods
• CPC Class Codes: H01S 5/1237 Lateral grating, i.e. grating only adjacent ridge or mesa
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/187 using Bragg reflection
• CPC Class Codes: H01S 5/3401 having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers
• CPC Class Codes: H01S 5/3402 intersubband lasers, e.g. transitions within the conduction or valence bands

Abstract

A distributed feedback semiconductor laser of includes a semiconductor stacked body and a first electrode. The semiconductor stacked body includes a first layer, an active layer that is provided on the first layer and is configured to emit laser light by an intersubband optical transition, and a second layer that is provided on the active layer. The semiconductor stacked body has a first surface including a flat portion and a trench portion; the flat portion includes a front surface of the second layer; the trench portion reaches the first layer from the front surface; the flat portion includes a first region and a second region; the first region extends along a first straight line; the second region extends to be orthogonal to the first straight line; and the trench portion and the second region outside the first region form a diffraction grating having a prescribed pitch along the first straight line. The first electrode is provided in the first region.

Claims

1. A distributed feedback semiconductor laser, comprising:

a semiconductor stacked body including a first layer, an active layer, and a second layer, the active layer being provided on the first layer and being configured to emit laser light by an intersubband optical transition, the second layer being provided on the active layer; and

a first electrode,

the semiconductor stacked body having a first surface including a flat portion and a trench portion, the flat portion including a front surface of the second layer, the trench portion reaching the first layer from the front surface, the flat portion including a first region and a second region, the first region extending along a first straight line, the second region extending to be orthogonal to the first straight line, the trench portion and the second region outside the first region forming a diffraction grating having a prescribed pitch along the first straight line, and

the first electrode being provided in the first region.

2. The distributed feedback semiconductor laser according to claim 1, wherein the trench portions are provided laterally symmetrically with respect to a central axis of the first electrode.

3. The distributed feedback semiconductor laser according to claim 1, wherein a wavelength of the laser light is not less than 2 □

m and not more than 100 □

m.

4. The distributed feedback semiconductor laser according to claim 2, wherein a wavelength of the laser light is not less than 2 □

m and not more than 100 □

m.

5. The distributed feedback semiconductor laser according to claim 1, wherein the laser light is emitted from a side surface of the semiconductor stacked body orthogonal to the first straight line among the side surfaces of the semiconductor stacked body.

6. The distributed feedback semiconductor laser according to claim 1 wherein

a pitch along the first straight line in the second region in a central portion forms a second-order diffraction grating,

a pitch along the first straight line in the second region provided at end portions on two sides of the central portion forms a first-order diffraction grating,

an opening is provided in the first electrode in a region adjacent to the central portion, and

the laser light is emitted in a substantially perpendicular direction from the first region exposed at the opening.

7. The distributed feedback semiconductor laser according to claim 2, wherein the laser light is emitted from a side surface of the semiconductor stacked body orthogonal to the first straight line among the side surfaces of the semiconductor stacked body.

8. The distributed feedback semiconductor laser according to claim 3, wherein the laser light is emitted from a side surface of the semiconductor stacked body orthogonal to the first straight line among the side surfaces of the semiconductor stacked body.

9. The distributed feedback semiconductor laser according to claim 4, wherein the laser light is emitted from a side surface of the semiconductor stacked body orthogonal to the first straight line among the side surfaces of the semiconductor stacked body.

10. The distributed feedback semiconductor laser according to claim 2, wherein

a pitch along the first straight line in the second region in a central portion forms a second-order diffraction grating,

a pitch along the first straight line in the second region provided at end portions on two sides of the central portion forms a first-order diffraction grating,

an opening is provided in the first electrode in a region adjacent to the central portion, and

the laser light is emitted in a substantially perpendicular direction from the first region exposed at the opening.

11. The distributed feedback semiconductor laser according to claim 3, wherein

a pitch along the first straight line in the second region in a central portion forms a second-order diffraction grating,

a pitch along the first straight line in the second region provided at end portions on two sides of the central portion forms a first-order diffraction grating,

an opening is provided in the first electrode in a region adjacent to the central portion, and

the laser light is emitted in a substantially perpendicular direction from the first region exposed at the opening.

12. The distributed feedback semiconductor laser according to claim 4, wherein

a pitch along the first straight line in the second region in a central portion forms a second-order diffraction grating,

a pitch along the first straight line in the second region provided at end portions on two sides of the central portion forms a first-order diffraction grating,

an opening is provided in the first electrode in a region adjacent to the central portion, and

the laser light is emitted in a substantially perpendicular direction from the first region exposed at the opening.