Composite semiconductor light source pumped by a spontaneous light emitter

• US 9,118,162 B2
• Filed: 05/20/2014
• Issued: 08/25/2015
• Est. Priority Date: 01/14/2011
• Status: Active Grant

• Current Assignee: University of Central Florida Research Foundation Inc. (State University System of Florida)
• Original Assignee: University of Central Florida Research Foundation Inc. (State University System of Florida)
• Inventors: Deppe, Dennis G.
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): CARTER, MICHAEL W
• Application Number:
  US14/282,547
• Publication Number:
  US 20140247853A1
• Time in Patent Office: 462 Days
• US Class Current: 1/1
• CPC Class Codes: H01S 5/026 Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers stabilisation of output H01S5/06
• CPC Class Codes: H01S 5/041 Optical pumping
• CPC Class Codes: H01S 5/183 having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• 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 5/18361 Structure of the reflectors, e.g. hybrid mirrors
• CPC Class Codes: H01S 5/18397 Plurality of active layers vertically stacked in a cavity for multi-wavelength emission
• CPC Class Codes: H01S 5/40 Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30 H01S5/50 takes precedence

Abstract

A composite light source includes a substrate having a top surface, and a first vertical light source formed in the substrate. The first light source includes least a lower mirror, a first active region above the lower mirror, wherein the first active region has a thickness sufficient when electrically pumped to emit predominantly a spontaneous vertical emission from the first active region towards the top surface having an angular range of at least (≧) 30°. A second light source is formed in the substrate above the first active region including a second active region. The spontaneous vertical emission is at a first wavelength λ₁ that optically drives said second active region to provide an emission at a second wavelength λ₂, wherein λ₂>λ₁.

Claims

1. A composite light source, comprising:

a substrate having a top surface;

a first vertical light source formed on said substrate, including;

at least a lower mirror;

a first active region above said lower mirror, said first active region having a thickness sufficient when electrically pumped to emit predominantly a spontaneous vertical emission from said first active region towards said top surface having an angular range of at least (≧

) 30°

;

a second light source formed on said substrate above said first active region including a second active region,

wherein said spontaneous vertical emission is at a first wavelength λ

₁ that optically drives said second active region to provide an emission at a second wavelength λ

₂, wherein λ

₂>

λ

₁,

further comprising a first electrode above said substrate and a second electrode on a bottom side of said lower mirror.

2. The composite light source of claim 1, further comprising an upper mirror on said substrate above said second light source so that said first vertical light source is within a vertical resonant cavity.

3. The composite light source of claim 2, wherein:

said vertical resonant cavity includes an inner mode confinement region and an outer current blocking region;

a depleted heterojunction current blocking region (DHCBR) within said outer current blocking region of at least one of said upper mirror, said lower mirror, and said first active region, and

a conducting channel within said inner mode confinement region that physically contacts and is framed by said DHCBR, wherein said DHCBR forces current flow into said conducting channel during operation of said composite light source.

4. The composite light source of claim 3, wherein a more lightly doped side of said DHCBR has a maximum p-type concentration of 1×

10¹⁷ cm<sup>−

3</sup>, and wherein said conducting channel has a minimum p-type concentration of at least 5×

10¹⁷ cm<sup>−

3</sup>.

5. The composite light source of claim 3, wherein said conducting channel comprises a selective p-type diffusion.

6. The composite light source of claim 3, wherein a more lightly doped side of said DHCBR has a maximum p-type concentration of 1×

10¹⁶ cm<sup>−

3</sup>, and wherein said conducting channel has a minimum p-type concentration of at least 5×

10¹⁷ cm<sup>−

3</sup>.

7. The composite light source of claim 2, wherein said upper mirror comprises a p-type distributed Bragg reflector (DBR) and said lower mirror comprises an n-type DBR.

8. The composite light source of claim 1, wherein said first vertical light source is a light emitting diode (LED).

9. The composite light source of claim 1, wherein said second light source comprises a lateral light source.

10. The composite light source of claim 1, wherein said first active region is between 1 μ

m and 5 μ

m thick.

11. The composite light source of claim 1, wherein said second active region has a doping level <

1×

10¹³ cm<sup>−

3</sup>.

12. The composite light source of claim 1, wherein said second active region is undoped.

13. The composite light source of claim 1, further comprising a first electrode above said first active region and a second electrode on a bottom side of said lower mirror.

14. The composite light source of claim 1, further comprising a first electrode including a center aperture at a top of said composite light source and a second electrode on a bottom side of said lower mirror.

15. The composite light source of claim 1, wherein said substrate comprises GaAs.

16. A composite light source, comprising:

a substrate having a top surface;

a first vertical light source formed on said substrate, including;

at least a lower mirror;

a first active region above said lower mirror, said first active region having a thickness sufficient when electrically pumped to emit predominantly a spontaneous vertical emission from said first active region towards said top surface having an angular range of at least (≧

) 30°

;

a second light source formed on said substrate above said first active region including a second active region,

wherein said spontaneous vertical emission is at a first wavelength λ

₁ that optically drives said second active region to provide an emission at a second wavelength λ

₂, wherein λ

₂>

λ

₁,

further comprising an upper mirror on said substrate above said second light source so that said first vertical light source is within a vertical resonant cavity, wherein;

said vertical resonant cavity includes an inner mode confinement region and an outer current blocking region;

a depleted heterojunction current blocking region (DHCBR) within said outer current blocking region of at least one of said upper mirror, said lower mirror, and said first active region, and

a conducting channel within said inner mode confinement region that physically contacts and is framed by said DHCBR, wherein said DHCBR forces current flow into said conducting channel during operation of said composite light source.

17. The composite light source of claim 16, wherein said conducting channel comprises a selective p-type diffusion.

18. The composite light source of claim 16, wherein said upper mirror comprises a p-type distributed Bragg reflector (DBR) and said lower mirror comprises an n-type DBR.

19. A composite light source, comprising:

a substrate having a top surface;

a first vertical light source formed on said substrate, including;

at least a lower mirror;

a first active region above said lower mirror, said first active region having a thickness sufficient when electrically pumped to emit predominantly a spontaneous vertical emission from said first active region towards said top surface having an angular range of at least (≧

) 30°

;

a second light source formed on said substrate above said first active region including a second active region,

wherein said spontaneous vertical emission is at a first wavelength λ

₁ that optically drives said second active region to provide an emission at a second wavelength λ

₂, wherein λ

₂>

λ

₁,

further comprising an upper mirror on said substrate above said second light source so that said first vertical light source is within a vertical resonant cavity,

wherein said upper mirror comprises a p-type distributed Bragg reflector (DBR) and said lower mirror comprises an n-type DBR.