Abstract: A multi-wavelength semiconductor laser device includes: first and second device sections monolithically formed on a substrate; and a rear end face film formed together on a rear end face of each of the first and second device sections. The first device section is a light-emitting device section having an oscillation wavelength of ?1. The second device section is a light-emitting device section having an oscillation wavelength of ?2 (?1<?2). The rear end face film includes a layer in which N sets (N?2) of layers each having the combination of a low refractive index layer having a refractive index of n1 and a high refractive index layer having a refractive index of n3 (n1<n3) as one set are laminated, and an intermediate refractive index layer having a refractive index of n2 (n1<n2<n3) in order from the rear end face side, and is constituted by a film different from an Si film.

Abstract: A multi-wavelength semiconductor laser device includes: first and second device sections monolithically formed on a substrate; and a rear end face film formed together on a rear end face of each of the first and second device sections. The first device section is a light-emitting device section having an oscillation wavelength of ?1. The second device section is a light-emitting device section having an oscillation wavelength of ?2 (?1<?2). The rear end face film includes a layer in which N sets (N?2) of layers each having the combination of a low refractive index layer having a refractive index of n1 and a high refractive index layer having a refractive index of n3 (n1<n3) as one set are laminated, and an intermediate refractive index layer having a refractive index of n2 (n1<n2<n3) in order from the rear end face side, and is constituted by a film different from an Si film.