Patent ID: 7577173

Claim:
A semiconductor laser device comprising: a GaN substrate; a semiconductor layer laminated on said GaN substrate; a resonator having front and rear facets which are in face-to-face relation to each other in a direction perpendicular to said semiconductor layer laminated on said GaN substrate; and a reflection film on said front facet of said semiconductor laser device from which laser light generated within said semiconductor laser is emitted, wherein said reflection film has a reflectance within a range of 5-17% at an oscillation wavelength λ of the laser light generated within said semiconductor laser device, includes an even number of alternating first and second dielectric films of respective different materials, laminated from said front facet of said semiconductor laser device, includes a total number of said first and second dielectric films not less than four, each of said first dielectric films has a refractive index and thickness of, respectively, n and d, each of said second dielectric films has a refractive index and thickness of, respectively, n′ and d′, and (nd+n′d′) is within a range of pλ/4±10%, wherein p is an integer, and the dielectric constant n of said first dielectric film is larger than the dielectric constant n′ of said second dielectric film.