Red light laser

Abstract

A semiconductor material vertical cavity surface emitting laser for emitting narrow linewidth light comprising a compound semiconductor material substrate and pairs of semiconductor material layers in a first mirror structure on the substrate of a first conductivity type each differing from that other in at least one constituent concentration and each first mirror pair separated from that one remaining by a first mirror spacer layer with a graded constituent concentration. An active region on the first mirror structure has plural quantum well structures separated by at least one active region spacer layer and there is a second mirror structure on the active region similar to the first but of a second conductivity type. A pair of electrical interconnections is separated by said substrate, said first mirror structure, said active region and said second mirror structure.

1. A laser system having a semiconductor material vertical cavity surface emitting laser for emitting narrow linewidth light, said laser comprising:
 a compound semiconductor material substrate;  
 at least two first mirror pairs of semiconductor material layers in a first mirror structure on said substrate of a first conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a first mirror member spacer layer with a graded constituent concentration, and each first mirror pair separated from that  the one remaining by a first mirror pair spacer layer with a graded constituent concentration;  
 an active region on said first mirror structure with plural quantum well structures comprising alternating layers of GaInP and AlGaInP with said quantum well structures being separated from said first mirror structure by at least one active region spacer layer;  
 at least two second mirror pairs of semiconductor material layers in a second mirror structure on said active region of a second conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a second mirror member spacer layer with a graded constituent concentration, and each second mirror pair separated from that  the one remaining by a second mirror pair spacer layer with a graded constituent concentration;  
 a gain guide layer proton implant based structure having a relatively greater electrical resistivity than said second mirror structure where located at least in part therein so as to surround an aperture region of said second mirror structure across from said active region and to be positioned separated from said active region by at least said two second mirror pairs of semiconductor material layers but less than six such second mirror pairs in said second mirror structure, said aperture region having pairs of side portions thereof each intersected by an axis common thereto that is parallel to said substrate and perpendicular to one other such axis with each said side portions in each said pair separated from one another by 6 μm to 12 μm; and  
 a pair of electrical interconnections to said laser separated from one another by said substrate, said first mirror structure, said active region and said second mirror structure.  
 
     
     
       2. The laser system of  claim 1  wherein said quantum well structures layers of GaInP are under stress in one direction and said quantum well structures layers of AlGaInP are under stress in an opposite direction. 
     
     
       3. The laser system of  claim 2  wherein said active region is separated from said first mirror structure by a active region spacer layer having two AlGaInP sublayers therein with that sublayer farthest from said first mirror structure being graduated in aluminum and gallium concentrations over a selected thickness. 
     
     
       4. The laser system of  claim 1  wherein said first mirror member spacer layer and said first mirror pair spacer layer each have a thickness exceeding  15  of at least 10  nm. 
     
     
       5. The laser system of  claim 1  further comprising a spreading layer on said second mirror structure having a thickness equaling an odd number of quarter wavelengths of said narrow linewidth light that said laser can emit. 
     
     
       6. The laser system of  claim 1  wherein said two first mirror pairs of semiconductor material layers each have one said semiconductor layer pair member therein formed of AlAs and that remaining one of said semiconductor layer pair members formed therein of AlGaAs with said first mirror member spacer layer and an adjacent said first mirror pair spacer layer together having a thickness equaling a half wavelength of said narrow linewidth light that said laser can emit. 
     
     
       7. The laser system of  claim 6  wherein said semiconductor layer pair members of AlAs are each equal in optical thickness to said semiconductor layer pair members of AlGaAs. 
     
     
       8. The laser system of  claim 6  wherein said semiconductor layer pair members of AlAs are each optically thicker than said semiconductor layer pair members of AlGaAs. 
     
     
       9. The laser system of  claim 1  wherein said first and second mirror structures are of opposite conductivity types. 
     
     
       10. The laser system of  claim 1  wherein said first and second mirror structures are both of n-type conductivity and said active region further comprises a pn tunnel junction. 
     
     
       11. The laser system of  claim 1  wherein said active region further comprises a zinc doped layer of relatively large conductivity separated from any GaInP layers therein by at least 27  20 nm. 
     
     
       12. The laser system of  claim 1  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlGaInP and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlGaInP. 
     
     
       13. The laser system of  claim 1  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlAs and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlAs. 
     
     
       14. The laser system of  claim 1  further comprising an isolation enclosing shell region in said laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure. 
     
     
       15. The laser system of  claim 1  wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure has an aperture opening therein across from said aperture region. 
     
     
       16. The laser system of  claim 15  further comprising a transparent mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount. 
     
     
       17. The laser system of  claim 15  further comprising an electrically conductive mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount, and wherein further said substrate has a metal contact made thereto with an aperture opening therein across said first mirror structure and said active region from said aperture region. 
     
     
       18. The laser system of  claim 1  wherein said laser is a first laser and wherein that one of said pair of electrical interconnections made to said first laser that is closer to said second mirror structure thereof has an aperture opening therein across from said aperture region therein, and further comprising a second semiconductor material vertical cavity surface emitting laser on said substrate adjacent to said first laser that is similar to said first laser except for that one of said pair of electrical interconnections made to said second laser that is closer to said second mirror structure thereof is without an aperture opening therein. 
     
     
       19. The laser system of  claim 18  further comprising an isolation enclosing shell region in said first laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure of said first laser and located in part between said first laser and said second laser. 
     
     
       20. The laser of  claim 1  wherein said gain guide layer structure is a first gain guide layer structure and said aperture region of said second mirror structure is a first aperture region, and further comprising a second gain guide layer structure formed of an oxide material to have a relatively greater electrical resistivity than said second mirror structure where located at least in part therein and on a side of said first gain guide layer structure opposite that side thereof closer to said active region so as to surround a second aperture region of said second mirror structure across from said first aperture region. 
     
     
       21. The laser of  claim 20  wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure has an aperture opening therein across from said second aperture region. 
     
     
       22. The laser of  claim 1  wherein a surface of said first mirror structure parallel to said substrate extends past said active region and has made thereto one said pair of electrical interconnections made to said laser, and wherein a surface of said second mirror structure parallel to said substrate is across from said gain guide layer structure without being across from said aperture region and has made thereto that remaining one said pair of electrical interconnections made to said laser. 
     
     
       23. The laser system of  claim 1  wherein said substrate has a thickness less than 100 μm and further comprising said substrate being bonded to a base having a large thermal conductivity. 
     
     
       24. The laser system of  claim 23  wherein said base is electrically conductive and serves as one of said pair of electrical interconnections made to said laser. 
     
     
       25. A semiconductor material vertical cavity surface emitting laser for emitting narrow linewidth light, said laser comprising:
 a compound semiconductor material substrate;  
 at least two first mirror pairs of semiconductor material layers in a first mirror structure on said substrate of a first conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a first mirror member spacer layer with a graded constituent concentration, and each first mirror pair separated from that  the one remaining by a first mirror pair spacer layer with a graded constituent concentration;  
 an active region on said first mirror structure with plural quantum well structures comprising alternating layers of GaInP and AlGaInP with said quantum well structures being separated from said first mirror structure by at least one active region spacer layer, said active region further comprising a zinc doped layer of relatively large conductivity separated from any GaInP layers therein by at least 27  20 nm;  
 at least two second mirror pairs of semiconductor material layers in a second mirror structure on said active region of a second conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a second mirror member spacer layer with a graded constituent concentration, and each second mirror pair separated from that  the one remaining by a second mirror pair spacer layer with a graded constituent concentration;  
 a gain guide layer structure formed of an oxide material to have a relatively greater electrical resistivity than said second mirror structure where located at least in part therein so as to surround an aperture region of said second mirror structure across from said active region and to be positioned separated from said active region; and  
 a pair of electrical interconnections to said laser separated from one another by said substrate, said first mirror structure, said active region and said second mirror structure.  
 
     
     
       26. The laser system of  claim 25  wherein said quantum well structures layers of GaInP are under stress in one direction and said quantum well structures layers of AlGaInP are under stress in an opposite direction. 
     
     
       27. The laser system of  claim 26  wherein said active region is separated from said first mirror structure by a active region spacer layer having two AlGaInP sublayers therein with that sublayer farthest from said first mirror structure being graduated in aluminum and gallium concentrations over a selected thickness. 
     
     
       28. The laser system of  claim 25  wherein said first mirror member spacer layer and said first mirror pair spacer layer each have a thickness exceeding  15  of at least 10  nm. 
     
     
       29. The laser system of  claim 25  further comprising a spreading layer on said second mirror structure having a thickness equaling an odd number of quarter wavelengths of said narrow linewidth light that said laser can emit. 
     
     
       30. The laser system of  claim 25  wherein said first and second mirror structures are of opposite conductivity types. 
     
     
       31. The laser system of  claim 25  wherein said first and second mirror structures are both of n-type conductivity and said active region further comprises a pn tunnel junction. 
     
     
       32. The laser system of  claim 25  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlGaInP and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlGaInP. 
     
     
       33. The laser system of  claim 25  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlAs and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlAs. 
     
     
       34. The laser system of  claim 25  further comprising an isolation enclosing shell region in said laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure. 
     
     
       35. The laser system of  claim 25  wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure has an aperture opening therein across from said aperture region. 
     
     
       36. The laser system of  claim 35  further comprising a transparent mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount. 
     
     
       37. The laser system of  claim 35  further comprising an electrically conductive mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount, and wherein further said substrate has a metal contact made thereto with an aperture opening therein across said first mirror structure and said active region from said aperture region. 
     
     
       38. The laser system of  claim 25  wherein said laser is a first laser and wherein that one of said pair of electrical interconnections made to said first laser that is closer to said second mirror structure thereof has an aperture opening therein across from said aperture region therein, and further comprising a second semiconductor material vertical cavity surface emitting laser on said substrate adjacent to said first laser that is similar to said first laser except for that one of said pair of electrical interconnections made to said second laser that is closer to said second mirror structure thereof is without an aperture opening therein. 
     
     
       39. The laser system of  claim 38  further comprising an isolation enclosing shell region in said first laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure of said first laser and located in part between said first laser and said second laser. 
     
     
       40. The laser of  claim 25  wherein a surface of said first mirror structure parallel to said substrate extends past said active region and has made thereto one said pair of electrical interconnections made to said laser, and wherein a surface of said second mirror structure parallel to said substrate is across from said gain guide layer structure without being across from said aperture region and has made thereto that remaining one said pair of electrical interconnections made to said laser. 
     
     
       41. The laser system of  claim 25  wherein said substrate has a thickness less than 100 μm and further comprising said substrate being bonded to a base having a large thermal conductivity. 
     
     
       42. The laser system of  claim 41  wherein said base is electrically conductive and serves as one of said pair of electrical interconnections made to said laser. 
     
     
       43. A semiconductor material vertical cavity surface emitting laser for emitting narrow linewidth light, said laser comprising:
 a compound semiconductor material substrate;  
 at least two first mirror pairs of semiconductor material layers in a first mirror structure on said substrate of a first conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a first mirror member spacer layer with a graded constituent concentration, and each first mirror pair separated from that  the one remaining by a first mirror pair spacer layer with a graded constituent concentration, said first mirror member spacer layer and said first mirror pair spacer layer each having a thickness exceeding  15  of at least 10  nm;  
 an active region on said first mirror structure with plural quantum well structures comprising alternating layers of GaInP and AlGaInP with said quantum well structures separated from said first mirror structure by at least one active region spacer layer;  
 at least two second mirror pairs of semiconductor material layers in a second mirror structure on said active region of a second conductivity type with each pair member differing from that  the other in at least one constituent concentration and separated from one another by a second mirror member spacer layer with a graded constituent concentration, and each second mirror pair separated from that  the one remaining by a second mirror pair spacer layer with a graded constituent concentration, said second mirror member spacer layer and said second mirror pair spacer layer each having a thickness exceeding  15  of at least 10  nm;  
 a gain guide layer structure formed of an oxide material to have a relatively greater electrical resistivity than said second mirror structure where located at least in part therein so as to surround an aperture region of said second mirror structure across from said active region and to be positioned separated from said active region; and  
 a pair of electrical interconnections to said laser separated from one another by said substrate, said first mirror structure, said active region and said second mirror structure.  
 
     
     
       44. The laser system of  claim 43  wherein said quantum well structures layers of GaInP are under stress in one direction and said quantum well structures layers of AlGaInP are under stress in an opposite direction. 
     
     
       45. The laser system of  claim 44  wherein said active region is separated from said first mirror structure by a active region spacer layer having two AlGaInP sub layers therein with that sublayer farthest from said first mirror structure being graduated in aluminum and gallium concentrations over a selected thickness. 
     
     
       46. The laser system of  claim 43  further comprising a spreading layer on said second mirror structure having a thickness equaling an odd number of quarter wavelengths of said narrow linewidth light that said laser can emit. 
     
     
       47. The laser system of  claim 43  wherein said first and second mirror structures are of opposite conductivity types. 
     
     
       48. The laser system of  claim 43  wherein said first and second mirror structures are both of n-type conductivity and said active region further comprises a pn tunnel junction. 
     
     
       49. The laser system of  claim 43  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlGaInP and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlGaInP. 
     
     
       50. The laser system of  claim 43  wherein said active region spacer layer is a first active region spacer layer of n-type conductivity AlAs and further comprising said quantum well structures of said active region being separated from said second mirror structure by a second active region spacer layer of p-type conductivity AlAs. 
     
     
       51. The laser system of  claim 43  further comprising an isolation enclosing shell region in said laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure. 
     
     
       52. The laser system of  claim 43  wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure has an aperture opening therein across from said aperture region. 
     
     
       53. The laser system of  claim 52  further comprising a transparent mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount. 
     
     
       54. The laser system of  claim 52  further comprising an electrically conductive mount and wherein that one of said pair of electrical interconnections made to said laser that is closer to said second mirror structure is electrically interconnected to said mount, and wherein further said substrate has a metal contact made thereto with an aperture opening therein across said first mirror structure and said active region from said aperture region. 
     
     
       55. The laser system of  claim 43  wherein said laser is a first laser and wherein that one of said pair of electrical interconnections made to said first laser that is closer to said second mirror structure thereof has an aperture opening therein across from said aperture region therein, and further comprising a second semiconductor material vertical cavity surface emitting laser on said substrate adjacent to said first laser that is similar to said first laser except for that one of said pair of electrical interconnections made to said second laser that is closer to said second mirror structure thereof is without an aperture opening therein. 
     
     
       56. The laser system of  claim 55  further comprising an isolation enclosing shell region in said first laser extending along and surrounding an axis perpendicular to said substrate and surrounding but spaced apart from said aperture region of said second mirror structure in said gain guide layer structure of said first laser and located in part between said first laser and said second laser. 
     
     
       57. The laser of  claim 43  wherein a surface of said first mirror structure parallel to said substrate extends past said active region and has made thereto one said pair of electrical interconnections made to said laser, and wherein a surface of said second mirror structure parallel to said substrate is across from said gain guide layer structure without being across from said aperture region and has made thereto that remaining one said pair of electrical interconnections made to said laser. 
     
     
       58. The laser system of  claim 43  wherein said substrate has a thickness less than 100 μm and further comprising said substrate being bonded to a base having a large thermal conductivity. 
     
     
       59. The laser system of  claim 58  wherein said base is electrically conductive and serves as one of said pair of electrical interconnections made to said laser. 
     
     
       60. The laser system of  claim 13  wherein a high thermal conductivity layer is provided adjacent to at least one of said first and second active region spacer layers.  
     
     
       61. The laser system of  claim 25  wherein said two first mirror pairs of semiconductor material layers each have one said semiconductor layer pair member therein formed of AlAs and that remaining one of said semiconductor layer pair members formed therein of AlGaAs with said first mirror member spacer layer and an adjacent said first mirror pair spacer layer together having a thickness equaling a half wavelength of said narrow linewidth light that said laser can emit.  
     
     
       62. The laser system of  claim 61  wherein said semiconductor layer pair members of AlAs are each equal in optical thickness to said semiconductor layer pair members of AlGaAs.  
     
     
       63. The laser system of  claim 61  wherein said semiconductor layer pair members of AlAs are each optically thicker than said semiconductor layer pair members of AlGaAs.  
     
     
       64. The laser system of  claim 25  wherein said second mirror structure has at least six second mirror pairs of semiconductor material layers including, and structured like, said two second mirror pairs of semiconductor material layers, and said gain guide layer is positioned separated from said active region by said six second mirror pairs of semiconductor material layers.  
     
     
       65. The laser system of  claim 33  wherein sides of said first and second active region spacer layers positioned farthest from said quantum well structures are separated from one another by a distance equal to one wavelength of said narrow linewidth light that said laser can emit.  
     
     
       66. The laser system of  claim 33  wherein sides of said first and second active region spacer layers positioned farthest from said quantum well structures are separated from one another by a distance equal to an integer multiple of one- half of one wavelength of said narrow linewidth light that said laser can emit.    
     
     
       67. The laser system of  claim 33  wherein a high thermal conductivity layer is provided adjacent to at least one of said first and second active region spacer layers.  
     
     
       68. The laser system of  claim 43  wherein said two first mirror pairs of semiconductor material layers each have one said semiconductor layer pair member therein formed of AlAs and that remaining one of said semiconductor layer pair members formed therein of AlGaAs with said first mirror member spacer layer and an adjacent said first mirror pair spacer layer together having a thickness equaling a half wavelength of said narrow linewidth light that said laser can emit.  
     
     
       69. The laser system of  claim 68  wherein said semiconductor layer pair members of AlAs are each equal in optical thickness to said semiconductor layer pair members of AlGaAs.  
     
     
       70. The laser system of  claim 68  wherein said semiconductor layer pair members of AlAs are each optically thicker than said semiconductor layer pair members of AlGaAs.  
     
     
       71. The laser system of  claim 43  wherein said second mirror structure has at least six second mirror pairs of semiconductor material layers including, and structured like, said two second mirror pairs of semiconductor material layers, and said gain guide layer is positioned separated from said active region by said six second mirror pairs of semiconductor material layers.  
     
     
       72. The laser system of  claim 50  wherein sides of said first and second active region spacer layers positioned farthest from said quantum well structures are separated from one another by a distance equal to one wavelength of said narrow linewidth light that said laser can emit.  
     
     
       73. The laser system of  claim 50  wherein sides of said first and second active region spacer layers positioned farthest from said quantum well structures are separated from one another by a distance about equal to an integer multiple of one- half of one wavelength of said narrow linewidth light that said laser can emit.    
     
     
       74. The laser system of  claim 50  wherein a high thermal conductivity layer is provided adjacent to at least one of said first and second active region spacer layers.