US 9,871,348 B2Granted

Semiconductor laser device

AssigneeMitsubishi Electric Corporation

InventorKimio Shigihara

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Abstract

An active layer is provided on a side closer to the second conductivity type cladding layer than a center of the light guide layer in the light guide layer. A first conductivity type low-refractive-index layer is formed between the first conductivity type cladding layer and the light guide layer and has a refractive index which is lower than a refractive index of the first conductivity type cladding layer. A layer thickness d of the light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying 2 ⁢ π λ ⁢ n g 2 - n c 2 ⁢ d 2 ≧ π 2 . The active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a case in which the active layer is disposed at a center of the light guide layer while there is not the first conductivity type low-refractive-index layer.

Claims13

Dependent claims

A semiconductor laser device comprising:

a semiconductor substrate of a first conductivity type;
a first conductivity type cladding layer on the semiconductor substrate;
a light guide layer on the first conductivity type cladding layer;
a second conductivity type cladding layer on the light guide layer;
an active layer on a side closer to the second conductivity type cladding layer than a center of the light guide layer in the light guide layer;
and
a first conductivity type low-refractive-index layer formed between the first conductivity type cladding layer and the light guide layer and having a refractive index which is lower than a refractive index of the first conductivity type cladding layer,
wherein λ is an oscillating wavelength of the semiconductor laser device, nc is refractive indexes of the first conductivity type cladding layer and the second conductivity type cladding layer, ng is a refractive index of the light guide layer, a layer thickness d of the light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying
2
⁢
π
λ
⁢
n
g
2
-
n
c
2
⁢
d
2
≧
π
2
,
and
the active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a device in which the active layer is disposed at a center of the light guide layer while there is not the first conductivity type low-refractive-index layer, but which is otherwise the same as the semiconductor laser device.

26 more elements

A semiconductor laser device comprising:

a semiconductor substrate of a first conductivity type;
a first conductivity type cladding layer on the semiconductor substrate;
a light guide layer including a first light guide layer of the first conductivity type on the first conductivity type cladding layer and a second light guide layer of a second conductivity type on the first light guide layer, the second light guide layer comprising a first portion and a second portion;
an active layer in the second light guide layer, so that the first portion of the second light guide layer is below the active layer, and the second portion of the second light guide layer is above the active layer;
and
a second conductivity type cladding layer on the second light guide layer,
wherein a refractive index of the second light guide layer is higher than a refractive index of the first light guide layer,
a layer thickness of the second light guide layer is smaller than a layer thickness of the first light guide layer,
λ is an oscillating wavelength of the semiconductor laser device, nc is refractive indexes of the first conductivity type cladding layer and the second conductivity type cladding layer, ng is a refractive index of the first light guide layer, a sum d of a layer thickness of the first light guide layer and a layer thickness of the second light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying
2
⁢
π
λ
⁢
n
g
2
-
n
c
2
⁢
d
2
≧
π
2
,
and
the active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a case in which the refractive indexes of the first light guide layer and the second light guide layer are the same and the active layer is disposed at a center of the light guide layer.

27 more elements

A semiconductor laser device comprising:

a semiconductor substrate of a first conductivity type;
a first conductivity type cladding layer on the semiconductor substrate;
a light guide layer including a first light guide layer of the first conductivity type on the first conductivity type cladding layer and a second light guide layer of a second conductivity type on the first light guide layer, the second light guide layer comprising a first portion and a second portion;
an active layer in the second light guide layer, so that the first portion of the second light guide layer is below the active layer, and the second portion of the second light guide layer is above the active layer;
a second conductivity type cladding layer on the second light guide layer;
and
a first conductivity type low-refractive-index layer formed between the first conductivity type cladding layer and the light guide layer and having a refractive index which is lower than a refractive index of the first conductivity type cladding layer,
wherein a refractive index of the second light guide layer is higher than a refractive index of the first light guide layer,
a layer thickness of the second light guide layer is smaller than a layer thickness of the first light guide layer,
λ is an oscillating wavelength of the semiconductor laser device, nc is refractive indexes of the first conductivity type cladding layer and the second conductivity type cladding layer, ng is a refractive index of the first light guide layer, a sum d of a layer thickness of the first light guide layer and a layer thickness of the second light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying
2
⁢
π
λ
⁢
n
g
2
-
n
c
2
⁢
d
2
≧
π
2
,
and
the active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a case in which the refractive indexes of the first light guide layer and the second light guide layer are the same, refractive indexes of the first conductivity type cladding layer and the second conductivity type cladding layer are the same, the active layer is disposed at a center of the light guide layer while there is not the first conductivity type low-refractive-index layer.

28 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/160,249Filed 20 May 2016
Priority: JP 2015-20827122 Oct 2015
Published: US 2017/0117685 A127 Apr 2017
Granted: 16 Jan 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H01S 5/2031
Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers: characterized by special waveguide layers, e.g. asymmetric waveguide layers…
H01S 5/22
Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or…:…
H01S 5/3213
Characterised by special cladding layers, e.g. details on band-discontinuities: asymmetric clading layers
H01S 5/2004
Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or…:…