Optical semiconductor element, method of manufacturing optical semiconductor element and optical module

• US 20060222032A1
• Filed: 08/31/2005
• Published: 10/05/2006
• Est. Priority Date: 03/16/2005
• Status: Abandoned Application

• Current Assignee: Opnext Japan, Inc. (Oclaro (Canada), Inc.)
• Original Assignee: Opnext Japan, Inc. (Oclaro (Canada), Inc.)
• Inventors: Sakuma, Yasushi, Okamoto, Kaoru, Washino, Ryu, Motoda, Katsuya
• Application Number:
  US11/215,122
• Publication Number:
  US 20060222032A1
• Time in Patent Office: Days
• US Class Current: 372/50.100
• CPC Class Codes: H01S 5/12 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18
• CPC Class Codes: H01S 5/227 Buried mesa structure ; Striped active layer
• CPC Class Codes: H01S 5/30 Structure or shape of the active region; Materials used for the active region

Abstract

An InGaAsP thin film layer having the same index of refraction as a diffraction grating is inserted between a p-type InP clad layer and the diffraction grating composed of an InGaAsP layer. In this structure, the InGaAsP layer is present over an active layer, and the amount of thermal diffusion of dopant to the vicinity of the active layer does not depend on an aperture width or the presence or absence of the diffraction grating when the p-type InP clad layer is grown, thereby obtaining a stable optical output, a threshold current, and slope efficiency.

Claims

1. An optical semiconductor element, comprising:

a lower guide layer formed on an InP substrate,

an active layer,

an upper guide layer,

an etching stop layer of a diffraction grating layer,

a diffraction grating obtained by patterning said diffraction grating layer,

a p-type clad layer, and

a diffusion prevention layer between said diffraction grating and said p-type clad layer,

wherein said diffusion prevention layer preventing dopant of said p-type clad layer from thermally diffusing to said active layer.

3. The optical semiconductor element according to claim 1, wherein said active layer is made of InGaAsP or InGaAlAs.

5. The optical semiconductor element according to claim 1, wherein said diffraction grating layer is made of In_xGa₍₁₋

x)As_yP<sub>(1−

y)</sub> (0≦

x≦

1, 0≦

y≦

1).

2. An optical semiconductor element, comprising:

a lower guide layer formed on an InP substrate,

an active layer,

an upper guide layer,

an etching stop layer of a diffraction grating layer,

a diffraction grating obtained by patterning said diffraction grating layer,

a p-type clad layer, and

a thin film layer between said diffraction grating and said p-type clad layer,

wherein the thin film layer being almost identical in composition to said diffraction grating layer.

4. The optical semiconductor element according to claim 2, wherein said active layer is made of InGaAsP or InGaAlAs.

6. The optical semiconductor element according to claim 2, wherein said diffraction grating layer is made of In_xGa₍₁₋

x)As_yP<sub>(1−

y)</sub> (0≦

x≦

1, 0≦

y≦

1).

7. An optical semiconductor element, comprising:

an n-type InAlAs lower guide layer formed on an InP substrate,

an InGaAlAs active layer,

a p-type InAlAs upper guide layer,

an InP etching stop layer of an InGaAsP diffraction grating layer,

a diffraction grating obtained by patterning said diffraction grating layer,

an InGaAsP thin film layer, and

a p-type InP clad layer,

said p-type InP clad layer having a ridge waveguide etched to said InGaAsP thin film layer.

8. An optical module, comprising:

an optical semiconductor element having a lower guide layer formed on an InP substrate, an active layer, an upper guide layer, an etching stop layer of a diffraction grating layer, a diffraction grating obtained by patterning said diffraction grating layer, a p-type clad layer, and a diffusion prevention layer between said diffraction grating and said p-type clad layer,

an optical fiber for transmitting light from said optical semiconductor element, and

a housing for housing said optical semiconductor element and an end of said optical fiber,

wherein said diffusion prevention layer preventing dopant of said p-type clad layer from thermally diffusing to said active layer.

9. A method of manufacturing an optical semiconductor element, comprising:

growing a lower guide layer, an active layer, an upper guide layer, an InP etching stop layer, and a diffraction grating layer on an InP substrate,

working a diffraction grating on said diffraction grating layer of a formation part of a waveguide, and growing a diffusion prevention layer and a p-type InP clad layer on said diffraction grating, said diffusion prevention layer preventing dopant of said p-type InP clad layer from thermally diffusing to said active layer.

10. The method of manufacturing the optical semiconductor element according to claim 9, further comprising etching said p-type InP clad layer on both sides of said waveguide to said diffusion prevention layer.

11. A method of manufacturing an optical semiconductor element, comprising:

growing an InAlAs lower guide layer, an InGaAlAs active layer, an InAlAs upper guide layer, an InP etching stop layer, and a diffraction grating layer on an InP substrate,

working a diffraction grating on said diffraction grating layer of a formation part of a waveguide,

growing a diffusion prevention layer and said p-type InP clad layer on said diffraction grating, said diffusion prevention layer preventing dopant of said p-type InP clad layer from thermally diffusing to said active layer, and

etching said p-type InP clad layer on both sides of said waveguide to said diffusion prevention layer.