US Patent 7826507 Semiconductor laser device including highly reflective coating film

A semiconductor light-emitting device includes a light generation unit generating light with an oscillation wavelength λ, a light outgoing facet from which light generated at the light generation unit emerges, a light reflecting facet at which light generated at the light generation unit is reflected, and a high reflection film at the light reflecting facet and made of a dielectric multilayered film of at least three layers. The high reflection film includes a first layer which is in contact with the light reflection facet, is constituted of Al2O3, and has a thickness smaller than λ/4n, wherein n is the refractive index of Al2O3, a second layer which is in contact with the first layer, and a third layer which is in contact with the second layer and has a refractive index different from the refractive index of the second layer.