LASER DIODES INCLUDING SUBSTRATES HAVING SEMIPOLAR SURFACE PLANE ORIENTATIONS AND NONPOLAR CLEAVED FACETS

1 . A laser diode comprising a substrate comprising (Al,In)GaN, an n-side cladding layer comprising (Al,In)GaN having an n-type conductivity, an n-side waveguide layer comprising (Al,In)GaN having an n-type conductivity, an active region, a p-side waveguide layer comprising (Al,In)GaN having a p-type conductivity, a p-side cladding layer comprising (Al,In)GaN having a p-type conductivity, and a laser cavity formed by cleaved facets, wherein:

the active region is interposed between the n-side cladding layer and the p-side cladding layer and extends substantially parallel to the n-side cladding layer and the p-side cladding layer;

the p-side waveguide layer is interposed between the active region and the p-side cladding layer;

the n-side waveguide layer is interposed between the active region and the n-side cladding layer;

the n-side cladding layer is interposed between the n-side waveguide layer and the substrate;

the active region comprises one or more InGaN quantum wells producing electrically-pumped stimulated emission of photons, wherein the emission of photons is guided along an axis of propagation by the n-side waveguide layer and the p-side waveguide layer, and the propagation along the axis of propagation is promoted by the n-side cladding layer and the p-side cladding layer;

the substrate comprises a crystal structure having a surface plane orientation within about 10 degrees of a 20 2 3 or a 20 23 crystallographic plane orientation; and

the laser cavity is formed by cleaved facets that have an orientation corresponding to a nonpolar plane of the crystal structure of the substrate.

2 . The laser diode of claim 1 , wherein the substrate has a surface plane orientation of about 20 2 3.

3 . The laser diode of claim 1 , wherein the substrate has a surface plane orientation of about 20 23

4 . The laser diode of claim 1 , wherein the cleaved facets have an orientation corresponding to the 11 2 0 plane of the crystal structure of the substrate.

5 . The laser diode of claim 1 , wherein the axis of propagation extends in a direction within about 10 degrees of the <11 2 0> direction with respect to the crystal structure of the substrate.

6 . The laser diode of claim 1 having an emission wavelength from about 470 nm to about 550 nm.

7 . The laser diode of claim 1 , wherein each InGaN quantum well is interposed between two (Al,In)GaN quantum well barriers.

8 . The laser diode of claim 1 , wherein each InGaN quantum well has a thickness from 1 nm to 10 nm.

9 . The laser diode of claim 7 , wherein each (Al,In)GaN quantum well barrier has a thickness from 1 nm to 30 nm.

10 . The laser diode of claim 1 , wherein the substrate is GaN with about a 20 2 3 surface plane orientation.

11 . The laser diode of claim 1 , wherein the substrate is GaN with about a 20 23 surface plane orientation.

12 . The laser diode of claim 1 , further comprising a ridge waveguide to optically guide the emitted photons.

13 . The laser diode of claim 1 , wherein the n-side cladding layer comprises AlInGaN having an n-type conductivity.

14 . The laser diode of claim 1 , wherein at least one of the n-side waveguide layer and the p-side waveguide layer comprises InGaN.

15 . The laser diode of claim 1 , wherein at least one of the n-side waveguide layer and the p-side cladding layer are partially or fully relaxed via formation of misfit dislocations positioned at least 20 nm from the InGaN quantum wells of the active region.

16 . A method of fabricating a laser diode comprising:

growing an epitaxial structure comprising a substrate comprising (Al,In)GaN, an n-side cladding layer comprising (Al,In)GaN having an n-type conductivity, an n-side waveguide layer comprising (Al,In)GaN having an n-type conductivity, an active region, a p-side waveguide layer comprising (Al,In)GaN having a p-type conductivity, and a p-side cladding layer comprising (Al,In)GaN having a p-type conductivity wherein:

the active region is interposed between the n-side cladding layer and the p-side cladding layer and extends substantially parallel to the n-side cladding layer and the p-side cladding layer;

the p-side waveguide layer is interposed between the active region and the p-side cladding layer;

the n-side waveguide layer is interposed between the active region and the n-side cladding layer;

the n-side cladding layer is interposed between the n-side waveguide layer and the substrate;

the active region comprises one or more InGaN quantum wells producing electrically-pumped stimulated emission of photons, wherein the emission of photons is guided along an axis of propagation by the n-side waveguide layer and the p-side waveguide layer, and the propagation along the axis of propagation is promoted by the n-side cladding layer and the p-side cladding layer; and

the substrate comprises a crystal structure having a surface plane orientation within about 10 degrees of a 20 2 3 or a 20 23 crystallographic plane orientation; and

cleaving the epitaxial structure to form facets that form a laser cavity, wherein the facets have an orientation corresponding to a nonpolar plane of the crystal structure of the substrate.

17 . The method of claim 16 , wherein the substrate has a surface plane orientation of about 20 2 3.

18 . The method of claim 16 , wherein the substrate has a surface plane orientation of about 20 23 .

19 . The method of claim 16 , wherein the axis of propagation extends in a direction within about 10 degrees of the <11 2 0> direction with respect to the crystal structure of the substrate and the cleaved facets have an orientation corresponding to the 11 2 0 plane of the crystal structure of the substrate.

20 . The method of claim 19 , further comprising forming a misfit dislocation in at least one of the n-side waveguide layer and the p-side cladding layer, wherein the misfit dislocation is formed at least 20 nm from an InGaN quantum well of the active region.