Patent ID: 6370177
Filing Date: 2002-04-09
Classification: H01S,Y10S

Abstract:
A semiconductor laser comprising:a laser device having a first end facet emitting laser beam therefrom, and a second end surface, wherein the first end facet is opposed to the second end facet; and a multi-layered high reflectivity coating formed on the second facet, and including, a first low refractivity film formed on the second end facet of the semiconductor laser, made by an apparatus for forming a thin film without damaging the film, and having a coefficient of linear expansion is 30% more/less than that of a substrate of the semiconductor laser, a refractivity n1 less than 1.8, and an optical thickness thereof about &lgr;/4 while &lgr; is defined as a wavelength of the semiconductor laser, a first high refractivity film formed on the first low refractivity film, made by an apparatus for forming a thin film without damaging the film, and having a refractivity n2 more than 1.9, a negative imaginary part of the refractivity less than 0.05, and an optical thickness thereof about &lgr;/4, and a second low refractivity coating formed on the first high refractivity film, made by an apparatus for forming a thin film without damaging the film, and having a refractivity n3 less than 1.7 and less than n1, wherein the second low refractivity film is made by a material different from a material of the first low refractivity film.