Semiconductor laser device

A semiconductor laser device, comprising:

• a first cladding layer including n-type AlGaN;
• a first light guide layer including GaN and provided on the first cladding layer;
• an active layer provided on the first light guide layer;
• an overflow blocking layer provided on the active layer;
• a second light guide layer including GaN and provided on the overflow blocking layer;
• a second cladding layer provided on the second light guide layer including a ridge portion extending like a stripe in axial direction of an optical cavity and a non-ridge portion located on both sides of the ridge portion;
• a contact layer including p+-type GaN and provided on the ridge portion;
• and
• an insulator layer provided on the both side faces of the ridge portion and the contact layer, and a upper face of the non-ridge portion,
• the active layer having a single or multiple quantum well structure including a well layer of InwGa1-wN (0.08≦w≦0.2) and a barrier layer of InbGa1-bN (0.01≦b≦0.05),
• the second cladding layer including AlyGa1-yN (0≦y≦0.1),
• the overflow blocking layer including AlzGa1-zN (y<z), and
• a thickness of D (μm) of the non-ridge portion and an axial length of L (μm) of the optical cavity satisfying formulas
• L≧750−400×(D/0.01)
• and
• 0<D≦0.01,
• wherein a full width at half maximum of a horizontal far field pattern of a beam emitted from the active layer has a width of not less than 9.2 degrees.

A semiconductor laser devices comprising:

• a substrate having a first electrode on a first surface of the substrate;
• a first cladding layer including n-type AlGaN and provided on a second surface of the substrate;
• a first light guide layer including GaN and provided on the first cladding layer;
• an active layer provided on the first light guide layer;
• an overflow blocking layer provided on the active layer;
• a second light guide layer including GaN and provided on the overflow blocking layer;
• a second cladding layer provided on the second light guide layer including a ridge portion extending like a stripe in axial direction of an optical cavity and a non-ridge portion located on both sides of the ridge portion;
• a contact layer including p+-type GaN provided on the ridge portion;
• an insulator layer provided on the both side faces of the ridge portion and the contact layer, and a upper face of the non-ridge portion;
• and
• a second electrode provided on the contact layer and the insulator,
• the active layer having a single or multiple quantum well structure including a well layer of InwGa1-wN (0.08≦w≦0.2) and a barrier layer of InbGa1-bN (0.01≦b≦0.05),
• the cladding layer including AlyGa1-yN (0≦y≦0.1),
• the overflow blocking layer including AlzGa1-zN (y<z), and
• a thickness of D (μm) of the non-ridge portion and an axial length of L (μm) of the optical cavity satisfying formulas
• L≧750−400×(D/0.01)
• and
• 0<D≦0.01,
• wherein a full width at half maximum of a horizontal far field pattern of a beam emitted from the active layer has a width of not less than 9.2 degrees.