Diffused channel semiconductor light sources

• US 9,705,283 B1
• Filed: 05/20/2015
• Issued: 07/11/2017
• Est. Priority Date: 05/20/2014
• Status: Active Grant

• Current Assignee: Sdphotonics, LLC, University of Central Florida Research Foundation Inc. (State University System of Florida)
• Original Assignee: Sdphotonics, LLC, University of Central Florida Research Foundation Inc. (State University System of Florida)
• Inventors: Deppe, Dennis G., Zhao, Guowei
• Primary Examiner(s): Carter, Michael
• Application Number:
  US14/717,692
• Time in Patent Office: 783 Days
• 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 5/042 Electrical excitation ; Circuits therefor monolithically integrated laser drive components H01S5/0261
• 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 5/187 using Bragg reflection
• CPC Class Codes: H01S 5/2059 by means of particular conductivity zones, e.g. obtained by particle bombardment or diffusion
• 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
• CPC Class Codes: H01S 5/423 having a vertical cavity
• CPC Class Codes: H04B 10/503 Laser transmitters

Abstract

A semiconductor vertical resonant cavity light source includes an upper mirror and a lower mirror that define a vertical resonant cavity. A first active region is within the vertical resonant cavity for light generation between the upper mirror and lower mirror. The vertical resonant cavity includes an inner mode confinement region and an outer current blocking region. A depleted heterojunction current blocking region (DHCBR) is within the outer current blocking region of at least one of the upper mirror, lower mirror, and first active region. A conducting channel within the inner mode confinement region is framed by the DHCBR. The DHCBR forces current flow into the conducting channel during operation of the light source. A cavity length within the inner mode confinement region equals or exceeds the cavity length formed in the DHCBR.

Claims

1. A semiconductor vertical resonant cavity light source (vertical light source), comprising:

an upper mirror and a lower mirror that define a vertical resonant cavity;

an active region within said vertical resonant cavity for light generation between said upper mirror and said lower mirror;

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

a conducting channel within said inner mode confinement region that is framed by said current blocking region, wherein said current blocking region forces current flow into said conducting channel during operation of said vertical light source, and

at least one cavity spacer layer between said current blocking region and said active region;

wherein said conducting channel includes impurity doping that increases its electrical conductivity, and wherein said conducting channel extends into said cavity spacer layer, and

wherein said impurity doping of said conducting channel is at least one of different from and greater than an impurity doping in said cavity spacer layer between said current blocking region and said active region.

2. The vertical light source of claim 1, wherein said impurity doping of said conducting channel comprises a selective p-type diffusion.

3. The vertical light source of claim 2, wherein said cavity spacer layer comprises an upper cavity spacer doping layer.

4. The vertical light source of claim 1, wherein said upper mirror comprises a p-type distributed Bragg reflector (DBR) and said lower mirror comprises an n-type DBR.

5. The vertical light source of claim 1, further comprising a depleted heterojunction current blocking region (DHCBR) within said current blocking region of at least one of said upper mirror, said lower mirror, and said first active region;

wherein said conducting channel is framed by said DHCBR, and

wherein said DHCBR also forces said current flow into said conducting channel during operation of said vertical light source.

6. A semiconductor vertical resonant cavity light source (vertical light source), comprising:

an upper mirror and a lower mirror that define a vertical resonant cavity;

an active region within said vertical resonant cavity for light generation between said upper mirror and said lower mirror;

said vertical resonant cavity including 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 active region, and

a conducting channel that includes impurity doping that increases its electrical conductivity within said inner mode confinement region that is framed by said DHCBR, wherein said DHCBR forces current flow into said conducting channel during operation of said vertical light source,

one or more upper cavity spacer doping layers placed between said DHCBR and said active region.

7. The vertical light source of claim 6, wherein said impurity doping comprises a selective p-type diffusion.

8. The vertical light source of claim 6, wherein said conducting channel comprises said selective p-type diffusion that extends into said cavity spacer doping layer.

9. The vertical light source of claim 6, wherein said upper mirror comprises a p-type distributed Bragg reflector (DBR) and said lower mirror comprises an n-type DBR.

10. The vertical light source of claim 9, wherein at least one period of said p-type DBR or said n-type DBR includes a mesa in said conducting channel that is 5 Å

to 300 Å

in height.

11. The vertical light source of claim 6, 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 1×

10¹⁷ cm<sup>−

3</sup>.

12. The vertical light source of claim 6, 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>.

13. A laser transmitter, comprising:

a housing having at least one semiconductor vertical resonant cavity light source (vertical light source) and electrical circuitry coupled to control said vertical light source therein for transmitting encoded laser data;

wherein said housing includes electronic circuitry for detecting a firing of blank or live ammunition;

wherein said housing includes at least one optical lens for transmitting a beam of said encoded laser data into free space;

wherein said vertical light source comprises;

an upper mirror and a lower mirror that define a vertical resonant cavity;

a first active region within said vertical resonant cavity for light generation between said upper mirror and said lower mirror;

said vertical resonant cavity including 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 is framed by said DHCBR, wherein said DHCBR forces current flow into said conducting channel during operation of said vertical light source.

14. The laser transmitter of claim 13, wherein said laser transmitter includes electronic circuitry for transmitting a wake-up pulse to a receiver and electronic circuitry for transmitting said encoded laser data to said receiver, wherein a transmission of said wake-up pulse occurs prior to a transmission of said encoded laser data.

15. The laser transmitter of claim 13, wherein said vertical light source comprises at least one vertical-cavity surface-emitting laser (VCSEL).

16. The laser transmitter of claim 15, wherein said at least one VCSEL comprises a VCSEL array including a plurality of said VCSELs.

17. The laser transmitter of claim 15, wherein said VCSEL further comprises one or more upper cavity spacer doping layers placed between said DHCBR and said first active region.

18. A tactical engagement system including:

a laser transmitter, comprising;

a first housing having at least one semiconductor vertical resonant cavity light source (vertical light source) and electrical circuitry coupled to control said vertical light source therein for transmitting encoded laser data;

wherein said housing includes electronic circuitry for detecting a firing of blank or live ammunition;

wherein said housing includes at least one optical lens for transmitting a beam of said encoded laser data into free space;

wherein said vertical light source comprises;

an upper mirror and a lower mirror that define a vertical resonant cavity;

a first active region within said vertical resonant cavity for light generation between said upper mirror and said lower mirror;

said vertical resonant cavity including 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 is framed by said DHCBR, wherein said DHCBR forces current flow into said conducting channel during operation of said vertical light source, and

a receiver in a second housing including at least one photodetector for generating electrical signals responsive to said encoded laser data and electrical circuitry coupled to an output of said photodetector for processing said electrical signals.