Semiconductor laser device

• US 6,735,231 B2
• Filed: 11/09/2001
• Issued: 05/11/2004
• Est. Priority Date: 11/10/2000
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ito, Shigetoshi, Ono, Tomoki
• Primary Examiner(s): Ip, Paul
• Assistant Examiner(s): Nguyen, Dung T
• Application Number:
  US10/037,999
• Publication Number:
  US 20020181527A1
• Time in Patent Office: 914 Days
• Field of Search: 372/45, 372/44, 372/46, 372/50, 372/20
• US Class Current: 372/45.013
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 5/0658 Self-pulsating
• CPC Class Codes: H01S 5/3214 comprising materials from other groups of the Periodic Table than the materials of the active layer, e.g. ZnSe claddings and GaAs active layer
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A semiconductor laser device includes an active layer and a layer greater in bandgap energy than the active layer and having a stacked-layer structure mainly of gallium-nitride-based semiconductor for lasing. This device includes a gallium-nitride-based semiconductor layer substantially equal in bandgap to the active layer and containing at least one element selected from the group consisting of As, P and Sb for saturable absorption at a location apart from the active layer and inside the layer greater in bandgap energy than the active layer.

Claims

1. A semiconductor laser device having a semiconductor stacked-layer structure including a plurality of gallium-nitride-based semiconductor layers, said semiconductor stacked-layer structure comprising:

an active layer sandwiched by layers of large bandgap energy larger than the bandgap energy of said active layer; and

a saturable absorption layer of a gallium-nitride-based semiconductor containing at least one element selected from the group consisting of As, P and Sb, and provided at a location apart from said active layer and inside or in contact with one of said layers of large bandgap energy,

said layer greater in bandgap energy than said active layer being one of a clad layer and an optical guide layer.

2. The semiconductor laser device of claim 1, wherein said saturable absorption layer forms a quantum well structure.

3. The semiconductor laser device of claim 1, wherein said saturable absorption layer causes self-pulsation attributed to saturable absorption effect.

4. The semiconductor laser device of claim 1, wherein said saturable absorption layer is formed of gallium-nitride-based semiconductor represented by an expression Al_xIn_yGa₁₋

x−

yN<sub>1−

p−

q−

r</sub>As_pP_qSb_r, where 0≦

x, 0≦

y, x+y<

1,0≦

p, 0≦

q, 0≦

r, and 0.001≦

p+q+r≦

0.5.

5. The semiconductor laser device of claim 4, wherein in said expression, q+r=0 and 0.005≦

p.

6. The semiconductor laser device of claim 5, wherein in said expression, q+r=0 and 0.006≦

q.

7. The semiconductor laser device of claim 1, further comprising an AlGaN layer covering said saturable absorption layer.

8. The semiconductor laser device of claim 1, wherein said stacked-layer structure is formed on a GaN substrate.

9. The semiconductor laser device of claim 1, wherein said saturable absorption layer is lower in crystalinity than said layer greater in bandgap energy than said active layer.

10. A semiconductor laser device having a semiconductor stacked-layer structure including a plurality of gallium-nitride-based semiconductor layers, said semiconductor stacked-layer structure comprising:

an active layer sandwiched by layers of large bandgap energy larger than the bandgap energy of said active layer; and

a layer of a gallium-nitride-based semiconductor containing at least one element selected from the group consisting of As, P and Sb, having a peak wavelength of photoluminescence within ±

20 nm compared with the photoluminescence of said active layer, and provided at a location apart from said active layer and inside or in contact with one of said layers of large bandgap energy,

said layer greater in bandgap energy than said active layer is one of a clad layer and an optical guide layer.

11. The semiconductor laser device of claim 10, wherein said saturable absorption layer forms a quantum well structure.

12. The semiconductor laser device of claim 10, wherein said saturable absorption layer causes self-pulsation attributed to saturable absorption effect.

13. The semiconductor laser device of claim 10, wherein said saturable absorption layer is formed of gallium-nitride-based semiconductor represented by an expression Al_xIn_yGa₁₋

x−

yN<sub>1−

p−

q−

r</sub>As_pP_qSb_r, where 0≦

x, 0≦

y, x+y<

1, 0≦

p, 0≦

q, 0≦

r, and 0.001≦

p+q+r≦

0.5.

14. The semiconductor laser device of claim 13, wherein in said expression, q+r=0 and 0.005≦

p.

15. The semiconductor laser device of claim 13, wherein in said expression, q+r=0 and 0.006≦

q.

16. The semiconductor laser device of claim 13, further comprising an AlGaN layer covering said saturable absorption layer.

17. The semiconductor laser device of claim 13, wherein said stacked-layer structure is formed on a GaN substrate.

18. The semiconductor laser device of claim 13, wherein said saturable absorption layer is lower in crystalinity than said layer greater in bandgap energy than said active layer.