SEMICONDUCTOR LASER DEVICE HAVING A LOW REFLECTION FILM OF STABLE REFLECTANCE

摘要

A semiconductor laser device comprises a GaN substrate having a refractive index of 3.5 or below, a semiconductor layer laminated on the substrate, and a pair of facets forming a resonator and in face-to-face-relation to each other in a direction perpendicular to the direction of the laminated layer. One of the facets of the resonator includes a low reflection film, of a first dielectric film, a second dielectric film, a third dielectric film, and a fourth dielectric film. When the refractive indexes of these films are taken as n₁, n₂, n₃, and n₄, n₁=n₃ and n₂=n₄. The following relationship between the first dielectric film and the third dielectric film, and between the second dielectric film and the fourth dielectric film is established, nd+n'd'=plambda/4, where p is an integer, and lambda is oscillation wavelength of a laser beam generated by the semiconductor laser device.