Semiconductor laser device

1. A semiconductor laser device made of a group III nitride semiconductor having a major growth surface defined by a nonpolar plane or a semipolar plane, comprising:

a cavity including an active layer containing In; and

distributed Bragg reflectors coating both cavity end faces of the cavity respectively, each of the reflectors having a central wavelength λ c of a reflectance spectrum satisfying the relation λ SP −10 nm≦λ c ≦λ SP +10 nm with respect to an emission peak wavelength λ SP of spontaneous emission in the active layer,

wherein the emission peak wavelength of the spontaneous emission is a peak wavelength of a current injection spectrum at a current density of not more than 0.1 kA/cm 2 .

2. The semiconductor laser device according to claim 1 , wherein the central wavelength λ c of the reflectance spectrum of each of the distribution Bragg reflectors satisfies the relation λ SP −5 nm≦λ c ≦λ SP +5 nm with respect to the emission peak wavelength λ SP of the spontaneous emission in the active layer.

3. The semiconductor laser device according to claim 1 , wherein the emission peak wavelength of the spontaneous emission is a peak wavelength of a current injection spectrum at a current density of not more than 500 μA/cm 2 .

4. The semiconductor laser device according to claim 1 , wherein the emission peak wavelength of the spontaneous emission is a photoluminescence peak wavelength in a case of weakly exciting the active layer at an excitation density of not more than 30 W/cm 2 .

5. The semiconductor laser device according to claim 1 , wherein the emission wavelength of the active layer is not less than 450 nm.

6. The semiconductor laser device according to claim 1 , wherein the active layer includes a quantum well layer having a thickness of not more than 100 Å.

7. The semiconductor laser device according to claim 1 , wherein the major growth surface is defined by an m-plane.

8. The semiconductor laser device according to claim 1 , wherein a cavity direction is a c-axis direction, and the cavity end faces are defined by c-planes formed by cleavage.

9. A semiconductor laser device made of a group III nitride semiconductor having a major growth surface defined by a nonpolar plane or a semipolar plane, comprising:

a cavity including an active layer containing In; and

distributed Bragg reflectors coating both cavity end faces of the cavity respectively, each of the reflectors having a central wavelength λ c of a reflectance spectrum satisfying the relation λ SP −10 nm≦λ c ≦λ sp +10 nm with respect to an emission peak wavelength λ SP of spontaneous emission in the active layer,

wherein the emission peak wavelength of the spontaneous emission is a peak wavelength of a current injection spectrum at a current density of not more than 500 μA/cm 2 .

10. The semiconductor laser device according to claim 9 , wherein the central wavelength μ c of the reflectance spectrum of each of the distribution Bragg reflectors satisfies the relation λ SP −5 nm≦λ c ≦λ SP +5 nm with respect to the emission peak wavelength λ SP of the spontaneous emission in the active layer.

11. The semiconductor laser device according to claim 9 , wherein the emission peak wavelength of the spontaneous emission is a photoluminescence peak wavelength in a case of weakly exciting the active layer at an excitation density of not more than 30 W/cm 2 .

12. The semiconductor laser device according to claim 9 , wherein the emission wavelength of the active layer is not less than 450 nm.

13. The semiconductor laser device according to claim 9 , wherein the active layer includes a quantum well layer having a thickness of not more than 100 Å.

14. The semiconductor laser device according to claim 9 , wherein the major growth surface is defined by an m-plane.

15. The semiconductor laser device according to claim 9 , wherein a cavity direction is a c-axis direction, and the cavity end faces are defined by c-planes formed by cleavage.

16. A semiconductor laser device made of a group III nitride semiconductor having a major growth surface defined by a nonpolar plane or a semipolar plane, comprising:

a cavity including an active layer containing In; and

distributed Bragg reflectors coating both cavity end faces of the cavity respectively, each of the reflectors having a central wavelength λ c of a reflectance spectrum satisfying the relation λ SP −10 nm≦λ c ≦λ SP +10 nm with respect to an emission peak wavelength λ SP of spontaneous emission in the active layer,

wherein the emission peak wavelength of the spontaneous emission is a photoluminescence peak wavelength in a case of weakly exciting the active layer at an excitation density of not more than 30 W/cm 2 .

17. The semiconductor laser device according to claim 16 , wherein the central wavelength λ c of the reflectance spectrum of each of the distribution Bragg reflectors satisfies the relation λ SP −5 nm≦λ c ≦λ SP +5 nm with respect to the emission peak wavelength λ SP of the spontaneous emission in the active layer.

18. The semiconductor laser device according to claim 16 , wherein the emission peak wavelength of the spontaneous emission is a peak wavelength of a current injection spectrum at a current density of not more than 0.1 kA/cm 2 .

19. The semiconductor laser device according to claim 16 , wherein the emission peak wavelength of the spontaneous emission is a peak wavelength of a current injection spectrum at a current density of not more than 500 μA/cm 2 .

20. The semiconductor laser device according to claim 16 , wherein the emission wavelength of the active layer is not less than 450 nm.

21. The semiconductor laser device according to claim 16 , wherein the active layer includes a quantum well layer having a thickness of not more than 100 Å.

22. The semiconductor laser device according to claim 16 , wherein the major growth surface is defined by an m-plane.

23. The semiconductor laser device according to claim 16 , wherein a cavity direction is a c-axis direction, and the cavity end faces are defined by c-planes formed by cleavage.