Semiconductor laser device with a protective film on the facets

摘要

A semiconductor laser device with a protective film on the facets, wherein said protective film is made of a multi-layered dielectric film composed of alternate layers consisting of at least two kinds of dielectric film, one of which is a first dielectric film of low refractive index and the other of which is a dielectric film of high refractive index, said multi-layered dielectric film which covers at least one of the facets therewith being a light-permeable film with a reflectivity of 30% or less.