SURFACE-EMISSION LASER DIODE AND SURFACE-EMISSION LASER ARRAY, OPTICAL INTERCONNECTION SYSTEM, OPTICAL COMMUNICATION SYSTEM, ELECTROPHOTOGRAPHIC SYSTEM, AND OPTICAL DISK SYSTEM

• US 20090268769A1
• Filed: 04/24/2009
• Published: 10/29/2009
• Est. Priority Date: 11/27/2003
• Status: Active Grant

• Current Assignee: Naoto Jikutani
• Original Assignee: Naoto Jikutani
• Inventors: Jikutani, Naoto
• Granted Patent: US 7,940,825 B2
• Time in Patent Office: Days
• US Class Current: 372/45.10
• CPC Class Codes: H01S 2301/166 Single transverse or lateral mode
• CPC Class Codes: H01S 5/0655 Single transverse or lateral mode emission
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18319 comprising a periodical structure in lateral directions
• CPC Class Codes: H01S 5/18333 only above the active layer
• CPC Class Codes: H01S 5/1835 Non-circular mesa
• CPC Class Codes: H01S 5/18355 having a defined polarisation
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/205 Antiguided structures
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A surface-emission laser diode includes an active layer, a pair of cavity spacer layers formed at both sides of the active layer, a current confinement structure defining a current injection region into the active layer, and a pair of distributed Bragg reflectors opposing with each other across a structure formed of the active layer and the cavity spacer layers, the current confinement structure being formed by a selective oxidation process of a semiconductor layer, the pair of distributed Bragg reflectors being formed of semiconductor materials, wherein there is provided a region containing an oxide of Al and having a relatively low refractive index as compared with a surrounding region in any of the semiconductor distributed Bragg reflector or the cavity spacer layer in correspondence to a part spatially overlapping with the current injection region in a laser cavity direction.

Claims

1-10. -10. (canceled)

11. A surface-emission laser diode, comprising:

an active layer;

a pair of cavity spacer layers formed at both sides of said active layer;

a current confinement structure defining a current injection region into said active layer; and

a pair of distributed Bragg reflectors opposing with each other across a structure formed of said active layer and said pair of cavity spacer layers,

said current confinement structure comprising a high resistance region formed by an ion implantation process,

said pair of distributed Bragg reflectors being formed of semiconductor materials,

wherein there is provided a region containing an oxide of Al and having a relatively low refractive index than a surrounding region in any of said semiconductor distributed Bragg reflector or said cavity spacer layer in correspondence to a part spatially overlapping with said current injection region in a laser cavity direction.

12. A surface-emission laser diode according to claim 11, wherein there is provided any of a GaAs layer or a GaInP mixed crystal layer adjacent with an AlGaAs mixed crystal layer constituting said region of relatively low refractive index with respect to said surrounding region not injected with said molecules containing oxygen and located on an identical plane of said part where said ion implantation of said molecules has been made.

13. A surface emission laser diode according to claim 11, wherein an AlGaAs mixed crystal layer, constituting said region of relatively low refractive index with respect to said surrounding region not made with ion implantation of molecules containing oxygen and located on an identical plane perpendicular to said laser cavity direction, is provided at a location corresponding to an anti-node of a standing wave of laser oscillation occurring in said cavity structure, said AlGaAs mixed crystal layer being doped to a higher concentration level as compared with other AlGaAs mixed crystal layers constituting said surface-emission laser diode.

14. A surface-emission laser diode according to claim 11, wherein said region of relatively low refractive index is provided in plural numbers.

15. A surface-emission laser diode according to claim 11, wherein said region of relatively low refractive index is provided inside an n-type distributed Bragg reflector constituting one of said pair of distributed Bragg reflectors.

16. A surface-emission laser diode according to claim 11, wherein there is further provided a region of relatively high refractive index around said region of relatively low refractive index provided in spatial overlapping with said laser cavity region in said laser cavity direction, and wherein there is further provided a cladding region of low refractive index with respect to said high refractive region such that said cladding region is located around said region of high refractive index.

17. A surface-emission laser diode according to claim 16, wherein there is provided an anisotropy in a width of said high refractive region surrounded by said cladding region.

18. A surface-emission laser diode according to claim 16, wherein said cladding region is provided in a pair in a direction perpendicular to said laser cavity direction across a laser cavity region.

19. A surface-emission laser diode according to claim 11, wherein said region of relatively low refractive index has an anisotropic shape.

20. A surface-emission laser diode according to claim 11, wherein said active layer comprises a group III-V compound semiconductor material, said group III element comprises at least one of Ga and In, and wherein said group V element comprises one or more of As, N, Sb and P.

21-41. -41. (canceled)

42. A surface-emission laser array comprising a plurality of surface-emission laser diodes, said plurality of surface-emission laser diodes being arranged to form an array,

each of said plurality of surface-emission laser diodes comprising:

an active layer;

a pair of cavity spacer layers formed at both sides of said active layer;

a current confinement structure defining a current injection region into said active layer; and

a pair of distributed Bragg reflectors opposing with each other across a structure formed of said active layer and said pair of cavity spacer layers,

said current confinement structure comprising a high resistance region formed by an ion implantation process,

said pair of distributed Bragg reflectors being formed of semiconductor materials,

wherein there is provided a region containing an oxide of Al and having a relatively low refractive index than a surrounding region in any of said semiconductor distributed Bragg reflector or said cavity spacer layer in correspondence to a part spatially overlapping with said current injection region in a laser cavity direction.

43-51. -51. (canceled)

52. An optical communication system that uses a surface-emission laser diode as a communication optical source,

said surface-emission laser diode comprising:

an active layer;

a pair of cavity spacer layers formed at both sides of said active layer;

a current confinement structure defining a current injection region into said active layer; and

a pair of distributed Bragg reflectors opposing with each other across a structure formed of said active layer and said pair of cavity spacer layers,

said current confinement structure comprising a high resistance region formed by an ion implantation process,

said pair of distributed Bragg reflectors being formed of semiconductor materials,

wherein there is provided a region containing an oxide of Al and having a relatively low refractive index than a surrounding region in any of said semiconductor distributed Bragg reflector or said cavity spacer layer in correspondence to a part spatially overlapping with said current injection region in a laser cavity direction.

53-68. -68. (canceled)

69. A surface-emission laser diode constructed on a substrate having a substrate surface, comprising:

an active layer parallel to said substrate surface;

a pair of cavity spacer layers provided so as to sandwich said active layer;

a pair of distributed Bragg reflectors provided across said active layer and said cavity spacer layers so as to sandwich said active layer and said cavity spacer layers therebetween;

a high resistance region defining a current injection region for injecting a current into said active layer,

laser oscillation being caused in a laser cavity region between said pair of distributed Bragg reflectors acting as cavity mirrors in a direction perpendicular to said substrate surface in correspondence to said current injection region,

a refractive index structure provided in a plane parallel to said substrate surface, said refractive index structure comprising;

a low refractive index core including said laser cavity region at a central part thereof; and

a periodic structure provided around said low refractive index core, said periodic structure comprising a low refractive region surrounding said low refractive index core and a high refractive index region surrounding said low refractive index region, said low refractive index region and said high refractive index region being repeated alternately in said plane parallel to said substrate,

wherein any of a width of said low refractive index core or a shape of said periodic structure is changed between a specific direction parallel to said substrate surface and other directions parallel to said substrate surface different from said specific direction.

70. A surface-emission laser diode according to claim 69, wherein said low refractive index core has a width different between two directions parallel to said substrate surface and crossing perpendicularly with each other.

71. A surface-emission layer diode according to any of claims 69, wherein a reflection wavelength band of said periodic structure is set, in one of said two directions crossing perpendicularly with each other, to be longer than a wavelength of a fundamental transverse mode in said same direction and projected upon said substrate surface.

72. A surface-emission laser diode according to claim 69, wherein said periodic structure is different between two directions parallel to said substrate surface and crossing perpendicularly with each other.

73. A surface-emission layer diode according to any of claims 72, wherein a reflection wavelength band of said periodic structure is set, in one of said two directions crossing perpendicularly with each other, to be longer than a wavelength of a fundamental transverse mode in said same direction and projected upon said substrate surface.

75-76. -76. (canceled)

77. A surface-emission laser array formed of a plurality of surface-emission laser diodes, each of said plurality of surface-emission laser diodes being constructed on a substrate having a substrate surface and comprising:

an active layer parallel to said substrate surface;

a pair of cavity spacer layers provided so as to sandwich said active layer;

a pair of distributed Bragg reflectors provided across said active layer and said cavity spacer layers so as to sandwich said active layer and said cavity spacer layers therebetween;

a high resistance region defining a current injection region for injecting a current into said active layer,

laser oscillation being caused in a laser cavity region between said pair of distributed Bragg reflectors acting as cavity mirrors in a direction perpendicular to said substrate surface in correspondence to said current injection region,

a refractive index structure provided in a plane parallel to said substrate surface, said refractive index structure comprising;

a low refractive index core including said laser cavity region at a central part thereof; and

a periodic structure provided around said low refractive index core, said periodic structure comprising a low refractive region surrounding said low refractive index core and a high refractive index region surrounding said low refractive index region, said low refractive index region and said high refractive index region being repeated alternately in said plane parallel to said substrate,

wherein any of a width of said low refractive index core or a shape of said periodic structure is changed between a specific direction parallel to said substrate surface and other directions parallel to said substrate surface different from said specific direction.

78-81. -81. (canceled)

82. An optical communication system that uses the surface-emission laser diode constructed on a substrate having a substrate surface, said surface-emission laser diode comprising:

an active layer parallel to said substrate surface;

a pair of cavity spacer layers provided so as to sandwich said active layer;

a pair of distributed Bragg reflectors provided across said active layer and said cavity spacer layers so as to sandwich said active layer and said cavity spacer layers therebetween;

a high resistance region defining a current injection region for injecting a current into said active layer,

laser oscillation being caused in a laser cavity region between said pair of distributed Bragg reflectors acting as cavity mirrors in a direction perpendicular to said substrate surface in correspondence to said current injection region,

a refractive index structure provided in a plane parallel to said substrate surface, said refractive index structure comprising;

a low refractive index core including said laser cavity region at a central part thereof; and

a periodic structure provided around said low refractive index core, said periodic structure comprising a low refractive region surrounding said low refractive index core and a high refractive index region surrounding said low refractive index region, said low refractive index region and said high refractive index region being repeated alternately in said plane parallel to said substrate,

wherein any of a width of said low refractive index core or a shape of said periodic structure is changed between a specific direction parallel to said substrate surface and other directions parallel to said substrate surface different from said specific direction.

83-90. -90. (canceled)