Method for producing semiconductor laser, semiconductor laser, optical pickup, and optical disk drive

An optical pickup device including a semiconductor laser having an edge window structure as a light source, the semiconductor laser comprising:

• a nitride-based III-V compound semiconductor substrate including a first region formed of a single crystal and having a first average dislocation density and a second region having a second average dislocation density higher than the first average dislocation density and disposed along a side parallel to a resonator length direction;
• a mask of an insulating film disposed on the nitride-based III-V compound semiconductor substrate at least at a position corresponding to the edge window structure;
• and
• a nitride-based III-V compound semiconductor layer including an active layer and grown in a region not covered by the mask on the nitride-based III-V compound semiconductor substrate,
• wherein,
• the mask has a first end and a second end in the resonator length direction,
• the first end of the mask is positioned at a resonator-edge forming position and a first portion of the mask extends from the first end over a given distance in the resonator length direction, the first portion having a first width that is constant starting at the first end and continuing over the given distance in the resonator length direction, and
• a second portion of the mask has a second width that decreases linearly, in the resonator length direction, from the first width to a zero width at the second end.

An optical disk drive including a semiconductor laser having an edge window structure as a light source, the semiconductor laser comprising:

• a nitride-based III-V compound semiconductor substrate including a first region formed of a single crystal and having a first average dislocation density and a second region having a second average dislocation density higher than the first average dislocation density and disposed along a side parallel to a resonator length direction;
• a mask of an insulating film disposed on the nitride-based III-V compound semiconductor substrate at least at a position corresponding to the edge window structure;
• and
• a nitride-based III-V compound semiconductor layer including an active layer and grown in a region not covered by the mask on the nitride-based III-V compound semiconductor substrate,
• wherein,
• the mask has a first end and a second end in the resonator length direction,
• the first end of the mask is positioned at a resonator-edge forming position and a first portion of the mask extends from the first end over a given distance in the resonator length direction, the first portion having a first width that is constant starting at the first end and continuing over the given distance in the resonator length direction, and
• a second portion of the mask has a second width that decreases linearly, in the resonator length direction, from the first width to a zero width at the second end.