Semiconductor laser device and method for fabricating the same

1. A double wavelength laser device comprising:

a first light emitting device for emitting laser light of a first wavelength, the first light emitting device including a first first-conductive-type cladding layer, a first active layer having a first window region in part thereof located in the vicinity of a light emitting edge surface and a first second-conductive-type cladding layer stacked in this order on a substrate; and

a second light emitting device for emitting laser light of a second wavelength, the second light emitting device including a second first-conductive-type cladding layer, a second active layer having a second window region in part thereof located in the vicinity of a light emitting edge surface and a second second-conductive-type cladding layer stacked in this order on the substrate,

wherein the first active layer is a layer containing AlGaAs,

wherein the second active layer is a layer containing AlGaInP,

wherein each of the first second-conductive-type cladding layer and the second second-conductive-type cladding layer is a layer containing AlGaInP, and

wherein a lattice mismatch value of the first second-conductive-type cladding layer is less than 0 and also less than a lattice mismatch value of the second second-conductive-type cladding layer.

2. The double wavelength laser device of claim 1 , wherein the lattice mismatch value of the first second-conductive-type cladding layer to the substrate is −3.0×10 −3 or more and less than −5.0×10 −4 ,

the lattice mismatch value of the second second-conductive-type cladding layer to the substrate is −5.0×10 −4 or more and 2.0×10 −3 or less.

3. The double wavelength laser device of claim 1 , wherein each of the impurity contained in the first window region and the impurity contained in the second window region contains Zn.

4. The double wavelength laser device of claim 1 , wherein the first second-conductive-type cladding layer contains a chemical compound expressed by a general formula of (Al x Ga 1-x )yIn 1-y P where 0≦x≦1 and 0≦y≦1,

wherein the second second-conductive-type cladding layer contains a chemical compound expressed by a general formula of (Al t Ga 1-t ) u In 1-u P where 0≦t≦1 and 0≦u≦1, and

wherein x and t satisfy the relationship of x<t.

5. The double wavelength laser device of claim 1 , wherein a first second-conductive type impurity contained in the first second-conductive-type cladding layer is a different element from the impurity contained in the first window region,

wherein a diffusion rate of the first second-conductive-type impurity in the first second-conductive-type cladding layer is smaller than a diffusion rate of the impurity contained in the first window region in the first second-conductive-type cladding layer.

6. The double wavelength laser device of claim 5 , wherein the first second-conductive-type impurity contains Mg.

7. The double wavelength laser device of claim 5 , wherein each of a concentration of the first second-conductive-type impurity contained in the first second-conductive-type cladding layer and a concentration of a second second-conductive-type impurity contained in the second second-conductive-type cladding layer is 6×10 17 cm −3 or more and 1.6×10 18 cm −3 or less.

8. The double wavelength laser device of claim 1 , wherein at least one of the first active layer and the second active layer has a quantum well structure.