Vertical cavity surface emitting laser (VCSEL) using buried Bragg reflectors and method for producing same

• US 6,376,269 B1
• Filed: 02/02/1999
• Issued: 04/23/2002
• Est. Priority Date: 02/02/1999
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Chen, Yong, Wang, Shin-Yuan
• Primary Examiner(s): Pham, Long
• Application Number:
  US09/243,184
• Time in Patent Office: 1,176 Days
• Field of Search: 438/22, 438/29, 438/45, 438/46, 438/47, 372/50, 372/43, 372/44, 372/45, 372/98, 372/99
• US Class Current: 438/29
• CPC Class Codes: H01S 2301/163 Single longitudinal mode
• CPC Class Codes: H01S 2301/166 Single transverse or lateral mode
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/18305 with emission through the substrate, i.e. bottom emission
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/1833 with more than one structure
• CPC Class Codes: H01S 5/18341 Intra-cavity contacts
• CPC Class Codes: H01S 5/18369 based on dielectric materials
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/2216 nitrides
• CPC Class Codes: H01S 5/222 having a refractive index lower than that of the cladding layers or outer guiding layers
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A current confinement region located proximate to a pair of Bragg reflectors in a semiconductor laser and an epitaxial lateral overgrowth layer grown through an aperture in the current confinement region allows a desirable current flow in the laser. The placement of the current confinement region having an aperture formed therein allows the desired current flow through an active layer of the laser. This current flow allows the laser to achieve a single spatial mode output. Furthermore, the ability to place a pair of Bragg reflectors in close proximity to each other achieves a short optical cavity resulting in a single longitudinal mode output. Together, the single spatial mode and single longitudinal mode result in a desired single frequency output. The single frequency output is particularly useful for high speed, high rate optical and telecommunications.

Claims

1. A method for forming a semiconductor laser, comprising the steps of:

forming a substrate;

forming in said substrate a first reflector having a first reflectivity;

forming a substrate assembly by enclosing said first reflector in said substrate;

forming a current confinement region located on a surface of said substrate assembly;

growing an epitaxial lateral overgrowth layer over said current confinement region; and

forming a second reflector over said substrate assembly.

2. The method of claim 1, wherein said current confinement region forms an aperture proximate to said first reflector.

3. The method of claim 1, wherein said current confinement region comprises a dielectric layer.

4. The method of claim 1, wherein said current confinement region comprises a high bandgap semiconductor material.

5. The method of claim 1, wherein said substrate comprises indium phosphide.

6. The method of claim 1, wherein said substrate comprises gallium nitride.

7. The method of claim 1, wherein said current confinement region is formed by ion implantation.

8. The method of claim 7, wherein said ion implantation comprises ions selected from the group consisting of hydrogen, oxygen, helium and iron.

9. A method for forming an indium phosphide (InP), long wavelength semiconductor laser, comprising the steps of:

forming a substrate;

forming in said substrate a first reflector having a first reflectivity;

forming a substrate assembly by enclosing said first reflector in said substrate;

forming a second reflector having a second reflectivity;

forming a current confinement region in proximity to said first reflector, said current confinement region having an aperture defined therein and configured to direct a current flow within said laser, thus allowing an optical cavity formed between and including said first reflector and said second reflector to generate a desired lasing mode output; and

growing an epitaxial lateral overgrowth layer through said aperture in said current confinement region.

10. The method of claim 9, wherein said current confinement region is formed within said substrate assembly.

11. The method of claim 9, wherein said current confinement region is formed by depositing a dielectric layer.

12. The method of claim 9, wherein said current confinement region is formed by depositing a high bandgap semiconductor material.

13. The method of claim 9, wherein said current confinement region is formed by ion implantation.

14. The method of claim 13, wherein said ion implantation comprises ions selected from the group consisting of hydrogen, oxygen, helium and iron.