Edge-emitting semiconductor laser

Patent metadata

Field	Value
Publication number	US-10063033-B2
Application number	US-201615375198-A
Country	US
Kind code	B2
Filing date	Dec 12, 2016
Priority date	May 31, 2016
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

An edge-emitting semiconductor laser includes: a semiconductor substrate; a first cladding layer having a first refractive index and formed on the semiconductor substrate; an active layer formed on the first cladding layer and having a second refractive index higher than the first refractive index; a Bragg reflector formed on the active layer and in which low-refractive-index layers and high-refractive-index layers each having a thickness larger than λ/4n are alternately laid one on another where λ is an lasing wavelength and n is a refractive index of a medium; a light absorption layer formed on the Bragg reflector and having bandgap energy lower than that of the active layer; and a second cladding layer formed on the light absorption layer and having a third refractive index lower than the second refractive index.

First claim

The invention claimed is:

1. An edge-emitting semiconductor laser comprising:
a semiconductor substrate;
a first cladding layer having a first refractive index and formed on the semiconductor substrate;
an active layer formed on the first cladding layer and having a second refractive index higher than the first refractive index;
a Bragg reflector formed on the active layer and including low-refractive-index layers and high-refractive-index layers, each of the low-refractive-index layers and each of the high-refractive-index layers having a thickness larger than λ/4n, and the low-refractive-index layers and the high-refractive-index layers are alternately laid one on another, where λ is a lasing wavelength and n is a refractive index of a medium;
a light absorption layer formed on the Bragg reflector and having bandgap energy lower than that of the active layer; and
a second cladding layer formed on the light absorption layer and having a third refractive index lower than the second refractive index.

2. The edge-emitting semiconductor laser according to claim 1 , wherein the Bragg reflector includes an AlGaInAs layer if doped to be p-type and includes an InGaAsP layer if doped to be n-type.

3. The edge-emitting semiconductor laser according to claim 1 , wherein a doping concentration in the Bragg reflector becomes lower with reduction in distance to the active layer and become higher with increase in distance from the active layer.

4. The edge-emitting semiconductor laser according to claim 1 , wherein the active layer includes a multiple quantum well layer.

5. The edge-emitting semiconductor laser according to claim 1 , wherein the active layer includes quantum dots.

6. An edge-emitting semiconductor laser comprising:
a semiconductor substrate;
a first cladding layer having a first refractive index and formed on the semiconductor substrate;
a light absorption layer formed on the first cladding layer;
a Bragg reflector formed on the light absorption layer and including low-refractive-index layers and high-refractive-index layers, each of the low-refractive-index layers and each of the high-refractive-index layers having a thickness larger than λ/4n, and the low-refractive-index layers and the high-refractive-index layers are alternately laid one on another, where λ is a lasing wavelength and n is a refractive index of a medium;
an active layer formed on the Bragg reflector and having a second refractive index higher than the first refractive index and bandgap energy higher than that of the light absorption layer; and
a second cladding layer formed on the active layer and having a third refractive index lower than the second refractive index.

7. The edge-emitting semiconductor laser according to claim 6 , wherein the Bragg reflector includes an AlGaInAs layer if doped to be p-type and includes an InGaAsP layer if doped to be n-type.

8. The edge-emitting semiconductor laser according to claim 6 , wherein a doping concentration in the Bragg reflector becomes lower with reduction in distance to the active layer and become higher with increase in distance from the active layer.

9. The edge-emitting semiconductor laser according to claim 6 , wherein the active layer includes a multiple quantum well layer.

10. The edge-emitting semiconductor laser according to claim 6 , wherein the active layer includes quantum dots.

11. An edge-emitting semiconductor laser comprising:
a semiconductor substrate;
a first cladding layer having a first refractive index and formed on the semiconductor substrate;
a first light absorption layer formed on the first cladding layer;
a first Bragg reflector formed on the first light absorption layer and including low-refractive-index layers and high-refractive-index layers, each of the low-refractive-index layers and each of the high-refractive-index layers having a thickness larger than λ/4n, and the low-refractive-index layers and the high-refractive-index layers are alternately laid one on another, where λ is a lasing wavelength and n is a refractive index of a medium;
an active layer formed on the first Bragg reflector and having a second refractive index higher than the first refractive index and bandgap energy higher than that of the first light absorption layer; and
a second Bragg reflector formed on the active layer and including low-refractive-index layers and high-refractive-index layers, each of the low-refractive-index layers and each of the high-refractive-index layers having a thickness larger than λ/4n, and the low-refractive-index layers and the high-refractive-index layers are alternately laid one on another;
a second light absorption layer formed on the second Bragg reflector and having bandgap energy lower than that of the active layer; and
a second cladding layer formed on the second light absorption layer and having a third refractive index lower than the second refractive index.

12. The edge-emitting semiconductor laser according to claim 11 , wherein each of the first and second Bragg reflectors includes an AlGaInAs layer if doped to be p-type and includes an InGaAsP layer if doped to be n-type.

13. The edge-emitting semiconductor laser according to claim 11 , wherein doping concentrations in the first and second Bragg reflectors become lower with reduction in distance to the active layer and become higher with increase in distance from the active layer.

14. The edge-emitting semiconductor laser according to claim 11 , wherein the active layer includes a multiple quantum well layer.

15. The edge-emitting semiconductor laser according to claim 11 , wherein the active layer includes quantum dots.

Assignees

• Mitsubishi Electric Corp

Inventors

• Fuchida Ayumi
• Okunuki Yuichiro

Classifications

• H01S2301/166

  Single transverse or lateral mode · CPC title

• H01S5/3213

  asymmetric clading layers · CPC title

• H01S5/305

  characterised by the doping materials used in the laser structure · CPC title

• H01S5/2027

  Reflecting region or layer, parallel to the active layer, e.g. to modify propagation of the mode in the laser or to influence transverse modes · CPC title

• H01S5/2022 Primary

  Absorbing region or layer parallel to the active layer, e.g. to influence transverse modes · CPC title