Semiconductor laser apparatus

A semiconductor laser device comprising:

• two mirrors disposed to face each other in order to form a cavity;
• and
• an active layer disposed between the two mirrors, wherein at least one of the two mirrors is a multilayer mirror including at least one first nitride semiconductor layer containing Ga and at least one second nitride semiconductor layer containing Al, which are alternately laminated to each other,
• the second nitride semiconductor layer has a refractive index lower than that of the first nitride semiconductor layer, and,
• when the second nitride semiconductor layer is equally divided with respect to an optical film thickness into two portions, an In concentration of a first portion close to the active layer is lower than that of a second portion apart from the active layer.

A semiconductor laser device comprising:

• two mirrors disposed to face each other in order to form a cavity;
• and
• an active layer disposed between the two mirrors,
• wherein at least one of the two mirrors is a multilayer mirror including at least one first nitride semiconductor layer containing Ga and at least one second nitride semiconductor layer containing Al, which are alternately laminated to each other,
• wherein the first nitride semiconductor layer includes:
• a first region containing In and having a refractive index higher than that of the second nitride semiconductor layer;
• and
• a second region having a refractive index higher than that of the second nitride semiconductor layer and having an In concentration lower than that of the first region, and
• wherein the first region is disposed at a position closer to the active layer than a position at which the second region is disposed.

A semiconductor laser device comprising:

• two mirrors disposed to face each other in order to form a resonator;
• and
• an active layer disposed between the two mirrors, wherein
• at least one of the two mirrors is a multilayer mirror including at least one first nitride semiconductor layer containing Ga and at least one second nitride semiconductor layer containing Al, which are alternately laminated to each other,
• the first nitride semiconductor layer has a refractive index higher than that of the second nitride semiconductor layer, and,
• when the first nitride semiconductor layer is equally divided with respect to an optical film thickness into two portions, an In concentration of a first portion close to the active layer is higher than that of a second portion apart from the active layer.