Surface light emitting type semiconductor laser having a vertical cavity

• US 20030076864A1
• Filed: 10/22/2002
• Published: 04/24/2003
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Ichihara, Jun, Sai, Hironobu
• Granted Patent: US 6,856,635 B2
• Time in Patent Office: Days
• US Class Current: 372/43
• CPC Class Codes: H01S 5/02257 using windows, e.g. specially adapted for back-reflecting light to a detector inside the housing
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/0683 by monitoring the optical output parameters
• CPC Class Codes: H01S 5/18311 using selective oxidation

Abstract

A lower multilayer reflection film (2), a light emitting layer forming portion (6) and an upper multilayer reflection film (8) are sequentially formed on a substrate (1) to form a semiconductor laminated portion (9), and a current injection region A is formed at a part of the semiconductor laminated portion so as to emit light from the surface in the center thereof. And, according to the present invention, the current injection region A is formed so as to be deflected from a center of the substrate. As a result, there is provided a surface light emitting type semiconductor laser capable of monitoring a light emitting power correctly and controlling it automatically in order to achieve the constant light emitting power in a case where the surface light emitting type laser chip is used as a light source for a pickup or the like.

Claims

1. A surface light emitting type semiconductor laser having a vertical cavity comprising:

a substrate; and

a semiconductor laminated portion which has a lower multilayer reflection film, a light emitting layer forming portion and an upper multilayer reflection film formed sequentially on said substrate,

wherein a current injection region is formed at a part of said semiconductor laminated portion so as to emit a light from a surface in a center thereof and said current injection region is deflected from a center of said substrate.

2. A semiconductor laser according to claim 1, wherein said substrate is in the form of a square and said current injection region is formed so as to be deflected toward the corner of said square substrate.

3. A semiconductor laser according to claim 1, wherein an outlet of a laser beam provided on a surface of said upper multilayer reflection film almost in a center of said current injection region is formed so as to be away from a center of said substrate toward one side thereof by 20 μ

m or more.

4. A semiconductor laser according to claim 1, wherein an outlet of a laser beam provided on a surface of said upper multilayer reflection film almost in a center of said current injection region is formed so as to be away from a center of said substrate toward one side thereof by {fraction (1/9)} to ⅛

or more of a length of one side of said substrate.

5. A semiconductor laser according to claim 1, wherein said substrate is in the form of a square and an outlet of a laser beam provided on a surface of said upper multilayer reflection film almost in a center of said current injection region is formed at a position away from one end face of said substrate by 20 μ

m to 70 μ

m.

6. A semiconductor laser according to claim 1, wherein said light emitting layer forming portion has a structure in which an active layer is sandwiched by lower and upper spacer layers made of a semiconductor having a band gap larger than that of said active layer to confine a carrier in said active layer.

7. A semiconductor laser according to claim 6, wherein said active layer is of a quantum well structure.

8. A semiconductor laser according to claim 6, wherein said active layer and said spacer layers are formed of an AlGaAs based compound semiconductor.

9. A semiconductor laser according to claim 1, wherein said current injection region is formed by insulating a part of said light emitting layer forming portion in the periphery thereof by ion implantation.

10. A semiconductor laser according to claim 1, wherein said current injection region is formed by intervening a current blocking layer for preventing current injection except for said current injection region between said light emitting layer forming portion and said upper or lower multilayer reflection film.

11. A semiconductor laser according to claim 10, wherein said current blocking layer is made of AlAs and has an oxide region formed by oxidizing a part except for said current injection region from its outer periphery.

12. A semiconductor laser comprising:

a light receiving element provided on one surface of a stem;

a surface light emitting type laser chip mounted on a surface of said light receiving element;

a cap having a light transmission window formed of a transparent body in a center thereof and provided so as to cover said laser chip,

wherein a current injection region of said laser chip is deflected from a center of a substrate, and said light receiving element and said laser chip are provided such that an outlet of a laser beam of said chip is positioned just under a center of said light transmission window.