1. Technical Field
The present disclosure relates to a semiconductor laser device.
2. Description of the Related Art
Nowadays, nitride-based semiconductor laser devices can oscillate in ultraviolet to green ranges, and are used not only in light sources for optical discs but also in a variety of applications. Particularly, semiconductor laser devices which have the laser emission wavelength of blue or green, 430 nm or more, are expected to be applied to light sources for displays such as projectors and televisions.
There has been proposed a nitride-based semiconductor laser device including: an n-type clad layer; a n-side light guide layer containing an InGaN region; an active layer; a p-side light guide layer containing an InGaN region; and a p-type clad layer. The nitride-based semiconductor laser device includes barrier layers between the outermost well layer and the n-side and p-side light guide layers. The barrier layers have a band gap larger than the band gap of the InGaN region of each of the n-side and p-side light guide layers (e.g. Japanese Patent Application No. 2009-200437 A).
For a nitride-based semiconductor laser device which oscillate laser light having a long laser emission wavelength, various structures have been proposed, but there is still room for improvement in these structures.