Surface-emission laser diode and surface-emission laser array, optical interconnection system, optical communication system, electrophotographic system, and optical disk system

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.

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.

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.

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.

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.

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.