High power, fundamental transverse mode operation in double heterostructure lasers

Claim 2

In a semiconductor injection laser, a semiconductor body comprising: first and second wide bandgap semiconductor regions of opposite conductivity types, a first narrow bandgap active region of thickness d1 intermediate to and contiguous with said first and second wide bandgap regions, there being refractive index steps Delta 11 and Delta 12, respectively, at first interfaces between said first active region and said first and second wide bandgap regions, a second narrow bandgap active region of thickness d2 intermediate said first active region, the bandgap of said second active region being smaller than the bandgap of said first active region, there being refractive index steps Delta 21 and Delta 22, respectively, at second interfaces between said second active region and said first active region, a p-n junction located within said second active region, carriers injected under forward bias across said junction being confined to said second active region where they undergo radiative recombination to generate stimulated coherent radiation, and characterized in that: said second active region is centrally disposed within said first active region in order to discriminate against oddordered transverse modes, said second interfaces confine injected carriers to said second active region and permit said radiation to penetrate substantially beyond said second active region into adjacent portions of said first active region, d1 is greater than about 1 Mu m in order to reduce the optical power density in said active regions; and Delta 11, Delta 12 and d1 satisfy approximately the relationships Delta 11d12 0.1 Mu m2 Delta 12d12 in order to permit higher order transverse modes of said radiation to penetrate beyond said first interfaces into relatively higher absorption loss regions adjacent thereto.

Claim 3

The semiconductor body of claim 1 wherein said first and second wide bandgap regions comprise respectively AlxGa1 xAs and AlzGa1 zAs, said first active region comprises AlyGa1 yAs, y < x and y < z, and said second active region comprises AlpGa1 pAs where O < or = p < y.

Claim 4

The semiconductor body of claim 2 wherein x about z, (x-y) about (z-q).

Claim 5

The semiconductor body of claim 1 for operation at room temperature and above in combination with a heat sink thermally coupled to said body to extract heat from the region of said p-n junction.

Claim 6

In a semiconductor injection laser, a semiconductor body including first and second heteroboundaries defining a first active region of thickness d1 therebetween for confining recombination radiation, there being refractive index steps Delta 11 and Delta 12, respectively, at said first and second heteroboundaries, third and fourth heteroboundaries disposed between said first and second heteroboundaries, thereby defining a second active region of thickness d2 for confining carriers, the bandgap of said second active region being smaller than that of said first active region and there being refractive index steps Delta 21 and Delta 22, respectively, at said third and fourth heteroboundaries, a p-n junction located between said third and fourth heteroboundaries, and characterized in that: said second active region is centrally disposed within said first active region in order to discriminate against odd-ordered transverse modes; said third and fourth heteroboundaries confine injected carriers to said second active region and permit said radiation to penetrate substantially beyond said second active region into adjacent portions of said first active region; d1 is greater than about 1 Mu m in order to reduce the optical power density in said active regions; and Delta 11, Delta 12 and d1 satisfy approximately the relationships Delta 11d12 0.1 12m2 Delta 12d12 in order to permit higher order transverse modes of said radiation to penetrate beyond said first and second heteroboundaries into relatively higher absorption loss regions adjacent thereto.

Claim 7

In a semiconductor injection laser, a semiconductor body including first and second heteroboundaries defining a first active region of thickness d1 therebetween for confining recombination radiation, there being refractive index steps Delta 11 and Delta 12, respectively, at said first and second heteroboundaries, third and fourth heteroboundaries disposed between said first and second heteroboundaries, thereby defining a second active region of thickness d2 for confining carriers, the bandgap of said second active region being smaller than that of said first active region and there being refractive index steps Delta 21 and Delta 22, respectively, at said third and fourth heteroboundaries, a p-n junction located between said third and fourth heteroboundaries, and characterized in that: said second active region is centrally disposed within said first active region in order to discriminate against odd-ordered transverse modes; said third and fourth heteroboundaries confine injected carriers to said second active region and permit said radiation to penetrate substantially beyond said second active region into adjacent portions of said first active region; d1 is greater than about 1 Mu m in order to reduce the optical power density in said active regions; and Delta 11, Delta 12 and d1 satisfy approximately the relationships Delta 11d12 0.1 12m2 Delta 12d12 in order to permit higher order transverse modes of said radiation to penetrate beyond said first and second heteroboundaries into relatively higher absorption loss regions adjacent thereto.

Claim 8

The semiconductor body of claim 5 wherein the said first region comprises AlxGa1 xAs, x < 0 and said second region comprises AlyGa1 yAs, 0 < or = y < or = x.

Claim 9

A semiconductor injection laser comprising a multilayered semiconductor body including the following contiguous epitaxial layers in the order recited: a first n-type wide bandgap layer, a second layer having a bandgap smaller than said first layer, a third layer having a bandgap smaller than said second layer, a fourth layer having a bandgap larger than said third layer, a fifth p-type layer having a bandgap larger than said fourth layer, said first and second layers and said fourth and fifth layers forming, respectively, first and second heteroboundaries at the interfaces therebetween, said interfaces being separated by a distance d1 and there being refractive index steps Delta 11 and Delta 12, respectively, at said first and second heteroboundaries, said second and third layers and said third and fourth layers forming, respectively, third and fourth heteroboundaries at the interfaces therebetween, said latter interfaces being separated by a distance d2 and there being refractive index steps Delta 21 and Delta 22, respectively, at said third and fourth heteroboundaries, a p-n junction located between said third and fourth heteroboundaries, means for forward biasing said junction and for applying thereto current in excess of the lasing threshold to generate stimulated coherent recombination radiation, means forming an optical cavity resonator for sustaining the radiation, means for providing egress of said radiation from said resonator, carriers injected across said junction under the influence of said forward biasing means being confined substantially to a second active region between said third and fourth heteroboundaries, and radiation generated by recombination of said injected carriers being confined substantially to a first active region between said first and second heteroboundaries, and characterized in that: said third and fourth heteroboundaries define said second active region centrally disposed between said first and second heteroboundaries in order to discriminate against odd-ordered transverse modes; sad third and fourth heteroboundaries confine injected carriers to said second active region and permit said radiation to penetrate substantially beyond said second active region into adjacent portions of said first active region; and d1, Delta 11 and Delta 12 satisfy approximately the relationships Delta 11d12 0.1 Mu m2 and Delta 12d12 0.1 Mu m2 in order to permit higher order transverse modes of said radiation to penetrate beyond said first and second heteroboundaries into relatively higher absorption loss regions adjacent thereto.

Claim 10

A semiconductor injection laser comprising a multilayered semiconductor body including the following contiguous epitaxial layers in the order recited: a first n-type wide bandgap layer, a second layer having a bandgap smaller than said first layer, a third layer having a bandgap smaller than said second layer, a fourth layer having a bandgap larger than said third layer, a fifth p-type layer having a bandgap larger than said fourth layer, said first and second layers and said fourth and fifth layers forming, respectively, first and second heteroboundaries at the interfaces therebetween, said interfaces being separated by a distance d1 and there being refractive index steps Delta 11 and Delta 12, respectively, at said first and second heteroboundaries, said second and third layers and said third and fourth layers forming, respectively, third and fourth heteroboundaries at the interfaces therebetween, said latter interfaces being separated by a distance d2 and there being refractive index steps Delta 21 and Delta 22, respectively, at said third and fourth heteroboundaries, a p-n junction located between said third and fourth heteroboundaries, means for forward biasing said junction and for applying thereto current in excess of the lasing threshold to generate stimulated coherent recombination radiation, means forming an optical cavity resonator for sustaining the radiation, means for providing egress of said radiation from said resonator, carriers injected across said junction under the influence of said forward biasing means being confined substantially to a second active region between said third and fourth heteroboundaries, and radiation generated by recombination of said injected carriers being confined substantially to a first active region between said first and second heteroboundaries, and characterized in that: said third and fourth heteroboundaries define said second active region centrally disposed between said first and second heteroboundaries in order to discriminate against odd-ordered transverse modes; sad third and fourth heteroboundaries confine injected carriers to said second active region and permit said radiation to penetrate substantially beyond said second active region into adjacent portions of said first active region; and d1, Delta 11 and Delta 12 satisfy approximately the relationships Delta 11d12 0.1 Mu m2 and Delta 12d12 0.1 Mu m2 in order to permit higher order transverse modes of said radiation to penetrate beyond said first and second heteroboundaries into relatively higher absorption loss regions adjacent thereto.

Claim 11

The laser of claim 7 for operation at room temperature and above in combination with a heat sink thermally coupled to said fifth layer to extract heat generated in said junction.

Claim 12

The laser of claim 8 including at least one stripe metallic electrical contact to said fifth layer.

Claim 13

The laser of claim 7 wherein the bandgaps of said first and fifth layers are equal and the bandgaps of said second and fourth layers are equal.

Claim 14

The laser of claim 7 wherein said first layer comprises AlxGa1 xAs, x < 0 said second layer comprises AlyGa1 yAs, 0 < y < x said third layer comprises AlpGa1 pAs, 0 < or = p < y said fourth layer comprises AlqGa1 qAs, 0 < q, p < q, and said layer comprises AlzGa1 zAs, 0 < z, g < z.

Claim 15

The laser of claim 11 wherein y about 8 < x about z.