Optical semiconductor device and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-2016164259-A1
Application number	US-201615010820-A
Country	US
Kind code	A1
Filing date	Jan 29, 2016
Priority date	Aug 2, 2013
Publication date	Jun 9, 2016
Grant date	—

Abstract

A semiconductor laser in a ridge waveguide structure includes: a semiconductor substrate; a lower cladding layer which is formed on the semiconductor substrate; an active layer and a semiconductor layer which are in parallel on the lower cladding layer and are connected with each other; a first upper cladding layer locally aligned above the active layer; a second upper cladding layer locally aligned above the semiconductor layer; and a third upper cladding layer locally aligned above the active layer to confine light which is guided in the active layer, wherein the semiconductor layer has a band gap which is larger than that of the active layer. According to this constitution, an optical semiconductor device with high reliability in which the ridge waveguide structure whose manufacturing is relatively easy is applied, and current diffusion and electrical crosstalk between lasers in the ridge waveguide structure are suppressed is enabled.

First claim

What is claimed is:

1 . An optical semiconductor device, comprising:
a semiconductor substrate; a lower cladding layer which is formed on the semiconductor substrate; an active layer and a semiconductor layer which are in parallel on the lower cladding layer and are connected with each other; a first upper cladding layer locally aligned above the active layer; a second upper cladding layer locally aligned above the semiconductor layer; and a third upper cladding layer formed above the active layer to confine light which is guided in the active layer, wherein the semiconductor layer has a band gap which is larger than that of the active layer.

2 . The optical semiconductor device according to claim 1 ,
wherein at a cross section which is perpendicular to an optical waveguide direction, a connection part between the active layer and the semiconductor layer which are in parallel on the lower cladding layer and are connected with each other positions below a groove which defines the third upper cladding layer.

3 . The optical semiconductor device according to claim 2 ,
wherein an etch stop layer is formed between the first upper cladding layer and the third upper cladding layer.

4 . The optical semiconductor device according to claim 1 ,
wherein the semiconductor layer is an i-type semiconductor or a semi-insulating semiconductor.

5 . A manufacturing method of an optical semiconductor device, comprising:
forming a lower cladding layer on a semiconductor substrate; forming an active layer and a semiconductor layer which are in parallel on the lower cladding layer and are connected with each other; and forming an upper cladding layer which is aligned above the active layer and confines light which is guided in the active layer, wherein the semiconductor layer has a band gap which is larger than that of the active layer.

6 . The manufacturing method of the optical semiconductor device according to claim 5 ,
wherein the forming the upper cladding layer includes: forming a first upper cladding layer locally aligned above the active layer, a second upper cladding layer locally aligned above the semiconductor layer and a third upper cladding layer formed above the active layer to confine light which is guided in the active layer, wherein at a cross section which is perpendicular to an optical waveguide direction, a connection part between the active layer and the semiconductor layer which are in parallel on the lower cladding layer and are connected with each other positions below a groove which defines the third upper cladding layer.

7 . The manufacturing method of the optical semiconductor device according to claim 6 ,
wherein an etch stop layer is formed between the first upper cladding layer and the third upper cladding layer, and the third upper cladding layers are formed to be only above the first upper cladding layers by using the etch stop layer.

8 . The manufacturing method of the optical semiconductor device according to claim 5 ,
wherein the semiconductor layer is an i-type semiconductor or a semi-insulating semiconductor.

Assignees

• Fujitsu Ltd

Inventors

• Uetake Ayahito
• Matsuda Manabu

Classifications

• H01S5/3013

  AIIIBV compounds · CPC title

• H01S5/227

  Buried mesa structure {; Striped active layer} · CPC title

• H01S5/2205 Primary

  comprising special burying or current confinement layers · CPC title

• H01S5/34306

  emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers · CPC title

• H01S5/209

  special etch stop layers · CPC title